feat: add v2 stack (backend, runner, ui-v2) with release workflow

- backend/: Go API server and runner binaries with PocketBase + MinIO storage
- ui-v2/: SvelteKit frontend rewrite
- docker-compose-new.yml: compose file for the v2 stack
- .gitea/workflows/release-v2.yaml: CI/CD for backend, runner, and ui-v2 Docker Hub images
- scripts/pb-init.sh: migrate from wget to curl, add superuser bootstrap for fresh installs
- .env.example: document DOCKER_BUILDKIT=1 for Colima users

backend/internal/backend/handlers.go

@@ -0,0 +1,937 @@
+package backend
+
+// handlers.go — all HTTP request handlers for the backend server.
+//
+// Handler naming mirrors the route table in server.go:
+//   handleScrapeCatalogue, handleScrapeBook, handleScrapeBookRange
+//   handleScrapeStatus, handleScrapeTasks
+//   handleBrowse, handleSearch
+//   handleGetRanking, handleGetCover
+//   handleBookPreview, handleChapterText, handleReindex
+//   handleChapterText, handleReindex
+//   handleAudioGenerate, handleAudioStatus, handleAudioProxy
+//   handleVoices
+//   handlePresignChapter, handlePresignAudio, handlePresignVoiceSample
+//   handlePresignAvatarUpload, handlePresignAvatar
+//   handleGetProgress, handleSetProgress, handleDeleteProgress
+//
+// Key design choices vs. old scraper:
+//   - POST /scrape* creates a PocketBase task record and returns 202 with the
+//     task_id — it does NOT run the orchestrator inline.
+//   - POST /api/audio creates a PocketBase audio task and returns 202 — the
+//     runner binary executes TTS generation asynchronously.
+//   - GET /api/audio/status polls PocketBase for the task record status.
+//   - GET /api/audio-proxy reads the completed audio object from MinIO via a
+//     presigned URL redirect (the runner has already uploaded the bytes).
+//   - GET /api/browse and /api/search fetch novelfire.net live (no MinIO cache).
+//   - GET /api/cover redirects to the source cover URL live.
+//   - GET /api/ranking reads from the PocketBase ranking collection (populated
+//     by the runner after each catalogue scrape).
+//   - GET /api/book-preview returns stored data when in library, or enqueues a
+//     scrape task and returns 202 when not. The backend never scrapes directly.
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/kokoro"
+)
+
+const (
+	novelFireBase   = "https://novelfire.net"
+	novelFireDomain = "novelfire.net"
+)
+
+// ── Scrape task creation ───────────────────────────────────────────────────────
+
+// handleScrapeCatalogue handles POST /scrape.
+// Creates a "catalogue" scrape task in PocketBase and returns 202 with the task ID.
+func (s *Server) handleScrapeCatalogue(w http.ResponseWriter, r *http.Request) {
+	taskID, err := s.deps.Producer.CreateScrapeTask(r.Context(), "catalogue", "", 0, 0)
+	if err != nil {
+		s.deps.Log.Error("handleScrapeCatalogue: CreateScrapeTask failed", "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to create task")
+		return
+	}
+	writeJSON(w, http.StatusAccepted, map[string]string{"task_id": taskID, "status": "accepted"})
+}
+
+// handleScrapeBook handles POST /scrape/book.
+// Body: {"url": "https://novelfire.net/book/..."}
+func (s *Server) handleScrapeBook(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		URL string `json:"url"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.URL == "" {
+		jsonError(w, http.StatusBadRequest, `request body must be JSON with "url" field`)
+		return
+	}
+	taskID, err := s.deps.Producer.CreateScrapeTask(r.Context(), "book", body.URL, 0, 0)
+	if err != nil {
+		s.deps.Log.Error("handleScrapeBook: CreateScrapeTask failed", "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to create task")
+		return
+	}
+	writeJSON(w, http.StatusAccepted, map[string]string{"task_id": taskID, "status": "accepted"})
+}
+
+// handleScrapeBookRange handles POST /scrape/book/range.
+// Body: {"url": "...", "from": N, "to": M}
+func (s *Server) handleScrapeBookRange(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		URL  string `json:"url"`
+		From int    `json:"from"`
+		To   int    `json:"to"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.URL == "" {
+		jsonError(w, http.StatusBadRequest, `request body must be JSON with "url" field`)
+		return
+	}
+	taskID, err := s.deps.Producer.CreateScrapeTask(r.Context(), "book_range", body.URL, body.From, body.To)
+	if err != nil {
+		s.deps.Log.Error("handleScrapeBookRange: CreateScrapeTask failed", "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to create task")
+		return
+	}
+	writeJSON(w, http.StatusAccepted, map[string]string{"task_id": taskID, "status": "accepted"})
+}
+
+// handleCancelTask handles POST /api/cancel-task/{id}.
+// Transitions a pending task (scrape or audio) to status=cancelled.
+// Returns 404 if the task does not exist, 409 if it cannot be cancelled
+// (e.g. already running/done).
+func (s *Server) handleCancelTask(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if id == "" {
+		jsonError(w, http.StatusBadRequest, "missing task id")
+		return
+	}
+	if err := s.deps.Producer.CancelTask(r.Context(), id); err != nil {
+		s.deps.Log.Warn("handleCancelTask: CancelTask failed", "id", id, "err", err)
+		jsonError(w, http.StatusConflict, "could not cancel task: "+err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"status": "cancelled", "id": id})
+}
+
+// ── Scrape task status / history ───────────────────────────────────────────────
+
+// handleScrapeStatus handles GET /api/scrape/status.
+// Returns the most recent scrape task status (or {"running":false} if none).
+func (s *Server) handleScrapeStatus(w http.ResponseWriter, r *http.Request) {
+	tasks, err := s.deps.TaskReader.ListScrapeTasks(r.Context())
+	if err != nil {
+		s.deps.Log.Error("handleScrapeStatus: ListScrapeTasks failed", "err", err)
+		writeJSON(w, 0, map[string]bool{"running": false})
+		return
+	}
+	running := false
+	for _, t := range tasks {
+		if t.Status == domain.TaskStatusRunning || t.Status == domain.TaskStatusPending {
+			running = true
+			break
+		}
+	}
+	writeJSON(w, 0, map[string]bool{"running": running})
+}
+
+// handleScrapeTasks handles GET /api/scrape/tasks.
+// Returns all scrape task records from PocketBase, newest first.
+func (s *Server) handleScrapeTasks(w http.ResponseWriter, r *http.Request) {
+	tasks, err := s.deps.TaskReader.ListScrapeTasks(r.Context())
+	if err != nil {
+		s.deps.Log.Error("handleScrapeTasks: ListScrapeTasks failed", "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to list tasks")
+		return
+	}
+	if tasks == nil {
+		tasks = []domain.ScrapeTask{}
+	}
+	writeJSON(w, 0, tasks)
+}
+
+// ── Browse & search ────────────────────────────────────────────────────────────
+
+// NovelListing represents a single novel entry from the novelfire browse/search page.
+type NovelListing struct {
+	Slug     string `json:"slug"`
+	Title    string `json:"title"`
+	Cover    string `json:"cover"`
+	Rank     string `json:"rank"`
+	Rating   string `json:"rating"`
+	Chapters string `json:"chapters"`
+	URL      string `json:"url"`
+}
+
+// handleBrowse handles GET /api/browse.
+// Fetches novelfire.net live (no MinIO cache in the new backend).
+// Query params: page (default 1), genre (default "all"), sort (default "popular"),
+// status (default "all"), type (default "all-novel")
+func (s *Server) handleBrowse(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	page := q.Get("page")
+	if page == "" {
+		page = "1"
+	}
+	genre := q.Get("genre")
+	if genre == "" {
+		genre = "all"
+	}
+	sortBy := q.Get("sort")
+	if sortBy == "" {
+		sortBy = "popular"
+	}
+	status := q.Get("status")
+	if status == "" {
+		status = "all"
+	}
+	novelType := q.Get("type")
+	if novelType == "" {
+		novelType = "all-novel"
+	}
+
+	pageNum, _ := strconv.Atoi(page)
+	if pageNum <= 0 {
+		pageNum = 1
+	}
+
+	targetURL := fmt.Sprintf("%s/genre-%s/sort-%s/status-%s/%s?page=%d",
+		novelFireBase, genre, sortBy, status, novelType, pageNum)
+
+	ctx, cancel := context.WithTimeout(r.Context(), 45*time.Second)
+	defer cancel()
+
+	novels, hasNext, err := s.fetchBrowsePage(ctx, targetURL)
+	if err != nil {
+		s.deps.Log.Error("handleBrowse: fetch failed", "url", targetURL, "err", err)
+		jsonError(w, http.StatusBadGateway, err.Error())
+		return
+	}
+
+	w.Header().Set("Cache-Control", "public, max-age=300")
+	writeJSON(w, 0, map[string]any{
+		"novels":  novels,
+		"page":    pageNum,
+		"hasNext": hasNext,
+	})
+}
+
+// handleSearch handles GET /api/search.
+// Query params: q (min 2 chars), source ("local"|"remote"|"all", default "all")
+func (s *Server) handleSearch(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query().Get("q")
+	if len([]rune(q)) < 2 {
+		jsonError(w, http.StatusBadRequest, "query must be at least 2 characters")
+		return
+	}
+
+	source := r.URL.Query().Get("source")
+	if source == "" {
+		source = "all"
+	}
+
+	ctx, cancel := context.WithTimeout(r.Context(), 20*time.Second)
+	defer cancel()
+
+	var localResults, remoteResults []NovelListing
+
+	// Local search (PocketBase books)
+	if source == "local" || source == "all" {
+		books, err := s.deps.BookReader.ListBooks(ctx)
+		if err != nil {
+			s.deps.Log.Warn("search: ListBooks failed", "err", err)
+		} else {
+			qLower := strings.ToLower(q)
+			for _, b := range books {
+				if strings.Contains(strings.ToLower(b.Title), qLower) ||
+					strings.Contains(strings.ToLower(b.Author), qLower) {
+					localResults = append(localResults, NovelListing{
+						Slug:  b.Slug,
+						Title: b.Title,
+						Cover: b.Cover,
+						URL:   b.SourceURL,
+					})
+				}
+			}
+		}
+	}
+
+	// Remote search (novelfire.net)
+	if source == "remote" || source == "all" {
+		searchURL := novelFireBase + "/search?keyword=" + url.QueryEscape(q)
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, searchURL, nil)
+		if err == nil {
+			req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; libnovel-backend/2)")
+			req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+			if resp, fetchErr := http.DefaultClient.Do(req); fetchErr == nil {
+				defer resp.Body.Close()
+				if resp.StatusCode == http.StatusOK {
+					parsed, _ := parseBrowsePage(resp.Body)
+					remoteResults = parsed
+				}
+			}
+		}
+	}
+
+	// Merge: local first, de-duplicate remote
+	localSlugs := make(map[string]bool, len(localResults))
+	for _, item := range localResults {
+		localSlugs[item.Slug] = true
+	}
+	combined := make([]NovelListing, 0, len(localResults)+len(remoteResults))
+	combined = append(combined, localResults...)
+	for _, item := range remoteResults {
+		if !localSlugs[item.Slug] {
+			combined = append(combined, item)
+		}
+	}
+
+	writeJSON(w, 0, map[string]any{
+		"results":      combined,
+		"local_count":  len(localResults),
+		"remote_count": len(remoteResults),
+	})
+}
+
+// ── Ranking ────────────────────────────────────────────────────────────────────
+
+// handleGetRanking handles GET /api/ranking.
+// Returns all ranking items sorted by rank ascending.
+func (s *Server) handleGetRanking(w http.ResponseWriter, r *http.Request) {
+	items, err := s.deps.RankingStore.ReadRankingItems(r.Context())
+	if err != nil {
+		s.deps.Log.Error("handleGetRanking: ReadRankingItems failed", "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to read ranking")
+		return
+	}
+	if items == nil {
+		items = []domain.RankingItem{}
+	}
+	writeJSON(w, 0, items)
+}
+
+// handleGetCover handles GET /api/cover/{domain}/{slug}.
+// The new backend does not cache covers in MinIO. Instead it redirects the
+// client to the novelfire.net source URL. The domain path segment is kept for
+// API compatibility with the old scraper.
+func (s *Server) handleGetCover(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	if slug == "" {
+		http.Error(w, "missing slug", http.StatusBadRequest)
+		return
+	}
+	// Redirect to the standard novelfire cover CDN URL. If the caller has the
+	// actual cover URL stored in metadata they should use it directly; this
+	// endpoint is a best-effort fallback.
+	coverURL := fmt.Sprintf("https://cdn.novelfire.net/covers/%s.jpg", slug)
+	http.Redirect(w, r, coverURL, http.StatusFound)
+}
+
+// ── Preview (live scrape, no store writes) ─────────────────────────────────────
+
+// handleBookPreview handles GET /api/book-preview/{slug}.
+//
+// If the book is already in the library (PocketBase), returns its metadata and
+// chapter index immediately (200).
+//
+// If the book is not yet in the library, enqueues a "book" scrape task and
+// returns 202 Accepted with the task_id. The runner will scrape the book
+// asynchronously; the client should poll GET /api/scrape/status or
+// GET /api/scrape/tasks to detect completion, then re-request this endpoint.
+//
+// The backend never scrapes directly — all scraping is the runner's job.
+func (s *Server) handleBookPreview(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	if slug == "" {
+		jsonError(w, http.StatusBadRequest, "missing slug")
+		return
+	}
+
+	ctx := r.Context()
+
+	meta, inLib, err := s.deps.BookReader.ReadMetadata(ctx, slug)
+	if err != nil {
+		s.deps.Log.Warn("book-preview: ReadMetadata failed", "slug", slug, "err", err)
+		inLib = false
+	}
+
+	if inLib {
+		// Fast path: book is already scraped — return stored data.
+		chapters, cerr := s.deps.BookReader.ListChapters(ctx, slug)
+		if cerr != nil {
+			s.deps.Log.Warn("book-preview: ListChapters failed", "slug", slug, "err", cerr)
+		}
+		writeJSON(w, 0, map[string]any{
+			"in_lib":   true,
+			"meta":     meta,
+			"chapters": chapters,
+		})
+		return
+	}
+
+	// Book not in library — enqueue a range scrape task for the first 20 chapters
+	// so the user can start reading quickly. Remaining chapters can be scraped
+	// later via the book detail page or the admin scrape panel.
+	bookURL := r.URL.Query().Get("source_url")
+	if bookURL == "" {
+		bookURL = fmt.Sprintf("%s/book/%s", novelFireBase, slug)
+	}
+
+	const previewFrom, previewTo = 1, 20
+	taskID, err := s.deps.Producer.CreateScrapeTask(ctx, "book_range", bookURL, previewFrom, previewTo)
+	if err != nil {
+		s.deps.Log.Error("book-preview: CreateScrapeTask failed", "slug", slug, "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to enqueue scrape task")
+		return
+	}
+
+	s.deps.Log.Info("book-preview: enqueued range scrape task", "slug", slug, "task_id", taskID,
+		"from", previewFrom, "to", previewTo)
+	writeJSON(w, http.StatusAccepted, map[string]any{
+		"in_lib":  false,
+		"task_id": taskID,
+		"message": fmt.Sprintf("scraping first %d chapters; poll /api/scrape/tasks for completion", previewTo),
+	})
+}
+
+// ── Chapter text ───────────────────────────────────────────────────────────────
+
+// handleChapterText handles GET /api/chapter-text/{slug}/{n}.
+// Returns plain text (markdown stripped) of a stored chapter.
+func (s *Server) handleChapterText(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 {
+		http.NotFound(w, r)
+		return
+	}
+	raw, err := s.deps.BookReader.ReadChapter(r.Context(), slug, n)
+	if err != nil {
+		http.NotFound(w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-store")
+	fmt.Fprint(w, stripMarkdown(raw))
+}
+
+// handleChapterMarkdown handles GET /api/chapter-markdown/{slug}/{n}.
+//
+// Returns the raw markdown content of a stored chapter directly from MinIO.
+// This is used by the SvelteKit UI as a simpler alternative to presign+fetch:
+// it avoids the need for the SvelteKit server to reach MinIO directly, and
+// gives a clean 404 when the chapter has not been scraped yet.
+func (s *Server) handleChapterMarkdown(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 || slug == "" {
+		http.Error(w, `{"error":"invalid params"}`, http.StatusBadRequest)
+		return
+	}
+	raw, err := s.deps.BookReader.ReadChapter(r.Context(), slug, n)
+	if err != nil {
+		s.deps.Log.Warn("chapter-markdown: not found in MinIO", "slug", slug, "n", n, "err", err)
+		http.Error(w, `{"error":"chapter not found"}`, http.StatusNotFound)
+		return
+	}
+	w.Header().Set("Content-Type", "text/markdown; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-store")
+	fmt.Fprint(w, raw)
+}
+
+// handleReindex handles POST /api/reindex/{slug}.
+// Rebuilds the chapters_idx PocketBase collection for a book from MinIO objects.
+func (s *Server) handleReindex(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	if slug == "" {
+		jsonError(w, http.StatusBadRequest, "missing slug")
+		return
+	}
+
+	count, err := s.deps.BookReader.ReindexChapters(r.Context(), slug)
+	if err != nil {
+		s.deps.Log.Error("reindex failed", "slug", slug, "indexed", count, "err", err)
+		writeJSON(w, http.StatusInternalServerError, map[string]any{
+			"error":   err.Error(),
+			"indexed": count,
+		})
+		return
+	}
+
+	s.deps.Log.Info("reindex complete", "slug", slug, "indexed", count)
+	writeJSON(w, 0, map[string]any{"slug": slug, "indexed": count})
+}
+
+// ── Audio ──────────────────────────────────────────────────────────────────────
+
+// handleAudioGenerate handles POST /api/audio/{slug}/{n}.
+// Creates an audio_jobs task in PocketBase (runner executes asynchronously).
+// Returns 200 immediately if audio already exists in MinIO.
+// Returns 202 with the task_id if a new task was created.
+func (s *Server) handleAudioGenerate(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 {
+		jsonError(w, http.StatusBadRequest, "invalid chapter")
+		return
+	}
+
+	voice := s.cfg.DefaultVoice
+	var body struct {
+		Voice string `json:"voice"`
+	}
+	if r.Body != nil {
+		_ = json.NewDecoder(r.Body).Decode(&body)
+	}
+	if body.Voice != "" {
+		voice = body.Voice
+	}
+
+	cacheKey := fmt.Sprintf("%s/%d/%s", slug, n, voice)
+
+	// Fast path: audio already in MinIO
+	audioKey := s.deps.AudioStore.AudioObjectKey(slug, n, voice)
+	if s.deps.AudioStore.AudioExists(r.Context(), audioKey) {
+		proxyURL := fmt.Sprintf("/api/audio-proxy/%s/%d?voice=%s", slug, n, voice)
+		writeJSON(w, 0, map[string]string{"url": proxyURL, "status": "done"})
+		return
+	}
+
+	// Check if a task is already pending/running
+	task, found, _ := s.deps.TaskReader.GetAudioTask(r.Context(), cacheKey)
+	if found && (task.Status == domain.TaskStatusPending || task.Status == domain.TaskStatusRunning) {
+		writeJSON(w, http.StatusAccepted, map[string]string{
+			"task_id": task.ID,
+			"status":  string(task.Status),
+		})
+		return
+	}
+
+	// Create a new audio task
+	taskID, err := s.deps.Producer.CreateAudioTask(r.Context(), slug, n, voice)
+	if err != nil {
+		s.deps.Log.Error("handleAudioGenerate: CreateAudioTask failed", "err", err)
+		jsonError(w, http.StatusInternalServerError, "failed to create audio task")
+		return
+	}
+
+	writeJSON(w, http.StatusAccepted, map[string]string{
+		"task_id": taskID,
+		"status":  "pending",
+	})
+}
+
+// handleAudioStatus handles GET /api/audio/status/{slug}/{n}.
+// Polls PocketBase for the audio task status.
+// Query params: voice (optional, defaults to DefaultVoice)
+func (s *Server) handleAudioStatus(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 || slug == "" {
+		jsonError(w, http.StatusBadRequest, "invalid params")
+		return
+	}
+
+	voice := r.URL.Query().Get("voice")
+	if voice == "" {
+		voice = s.cfg.DefaultVoice
+	}
+
+	// Fast path: audio exists in MinIO
+	audioKey := s.deps.AudioStore.AudioObjectKey(slug, n, voice)
+	if s.deps.AudioStore.AudioExists(r.Context(), audioKey) {
+		proxyURL := fmt.Sprintf("/api/audio-proxy/%s/%d?voice=%s", slug, n, voice)
+		writeJSON(w, 0, map[string]string{
+			"status": "done",
+			"url":    proxyURL,
+		})
+		return
+	}
+
+	cacheKey := fmt.Sprintf("%s/%d/%s", slug, n, voice)
+	task, found, _ := s.deps.TaskReader.GetAudioTask(r.Context(), cacheKey)
+	if !found {
+		writeJSON(w, 0, map[string]string{"status": "idle"})
+		return
+	}
+
+	resp := map[string]string{
+		"status":  string(task.Status),
+		"task_id": task.ID,
+	}
+	if task.Status == domain.TaskStatusFailed && task.ErrorMessage != "" {
+		resp["error"] = task.ErrorMessage
+	}
+	writeJSON(w, 0, resp)
+}
+
+// handleAudioProxy handles GET /api/audio-proxy/{slug}/{n}.
+// Redirects to a presigned MinIO URL for the generated audio object.
+// Query params: voice (optional, defaults to DefaultVoice)
+func (s *Server) handleAudioProxy(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 {
+		http.NotFound(w, r)
+		return
+	}
+
+	voice := r.URL.Query().Get("voice")
+	if voice == "" {
+		voice = s.cfg.DefaultVoice
+	}
+
+	audioKey := s.deps.AudioStore.AudioObjectKey(slug, n, voice)
+	if !s.deps.AudioStore.AudioExists(r.Context(), audioKey) {
+		http.Error(w, "audio not generated yet", http.StatusNotFound)
+		return
+	}
+
+	presignURL, err := s.deps.PresignStore.PresignAudio(r.Context(), audioKey, 1*time.Hour)
+	if err != nil {
+		s.deps.Log.Error("handleAudioProxy: PresignAudio failed", "slug", slug, "n", n, "err", err)
+		http.Error(w, "presign failed", http.StatusInternalServerError)
+		return
+	}
+
+	http.Redirect(w, r, presignURL, http.StatusFound)
+}
+
+// ── Voices ─────────────────────────────────────────────────────────────────────
+
+// handleVoices handles GET /api/voices.
+// Returns {"voices": [...]} — fetched from Kokoro with built-in fallback.
+func (s *Server) handleVoices(w http.ResponseWriter, r *http.Request) {
+	writeJSON(w, 0, map[string]any{"voices": s.voices(r.Context())})
+}
+
+// ── Presigned URLs ─────────────────────────────────────────────────────────────
+
+// handlePresignChapter handles GET /api/presign/chapter/{slug}/{n}.
+func (s *Server) handlePresignChapter(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 || slug == "" {
+		jsonError(w, http.StatusBadRequest, "invalid params")
+		return
+	}
+
+	u, err := s.deps.PresignStore.PresignChapter(r.Context(), slug, n, 15*time.Minute)
+	if err != nil {
+		s.deps.Log.Error("presign chapter failed", "slug", slug, "n", n, "err", err)
+		jsonError(w, http.StatusInternalServerError, "presign failed")
+		return
+	}
+	writeJSON(w, 0, map[string]string{"url": u})
+}
+
+// handlePresignAudio handles GET /api/presign/audio/{slug}/{n}.
+// Query params: voice (optional)
+func (s *Server) handlePresignAudio(w http.ResponseWriter, r *http.Request) {
+	slug := r.PathValue("slug")
+	n, err := strconv.Atoi(r.PathValue("n"))
+	if err != nil || n < 1 || slug == "" {
+		jsonError(w, http.StatusBadRequest, "invalid params")
+		return
+	}
+
+	voice := r.URL.Query().Get("voice")
+	if voice == "" {
+		voice = s.cfg.DefaultVoice
+	}
+
+	key := s.deps.AudioStore.AudioObjectKey(slug, n, voice)
+	if !s.deps.AudioStore.AudioExists(r.Context(), key) {
+		http.NotFound(w, r)
+		return
+	}
+
+	u, err := s.deps.PresignStore.PresignAudio(r.Context(), key, 1*time.Hour)
+	if err != nil {
+		s.deps.Log.Error("presign audio failed", "slug", slug, "n", n, "err", err)
+		jsonError(w, http.StatusInternalServerError, "presign failed")
+		return
+	}
+	writeJSON(w, 0, map[string]string{"url": u})
+}
+
+// handlePresignVoiceSample handles GET /api/presign/voice-sample/{voice}.
+func (s *Server) handlePresignVoiceSample(w http.ResponseWriter, r *http.Request) {
+	voice := r.PathValue("voice")
+	if voice == "" {
+		jsonError(w, http.StatusBadRequest, "missing voice")
+		return
+	}
+
+	key := kokoro.VoiceSampleKey(voice)
+	if !s.deps.AudioStore.AudioExists(r.Context(), key) {
+		http.NotFound(w, r)
+		return
+	}
+
+	u, err := s.deps.PresignStore.PresignAudio(r.Context(), key, 1*time.Hour)
+	if err != nil {
+		s.deps.Log.Error("presign voice sample failed", "voice", voice, "err", err)
+		jsonError(w, http.StatusInternalServerError, "presign failed")
+		return
+	}
+	writeJSON(w, 0, map[string]string{"url": u})
+}
+
+// handlePresignAvatarUpload handles GET /api/presign/avatar-upload/{userId}.
+// Query params: ext (jpg|png|webp, defaults to jpg)
+func (s *Server) handlePresignAvatarUpload(w http.ResponseWriter, r *http.Request) {
+	userID := r.PathValue("userId")
+	if userID == "" {
+		jsonError(w, http.StatusBadRequest, "missing userId")
+		return
+	}
+
+	ext := r.URL.Query().Get("ext")
+	switch ext {
+	case "jpg", "jpeg":
+		ext = "jpg"
+	case "png":
+		ext = "png"
+	case "webp":
+		ext = "webp"
+	default:
+		ext = "jpg"
+	}
+
+	uploadURL, key, err := s.deps.PresignStore.PresignAvatarUpload(r.Context(), userID, ext)
+	if err != nil {
+		s.deps.Log.Error("presign avatar upload failed", "userId", userID, "err", err)
+		jsonError(w, http.StatusInternalServerError, "presign failed")
+		return
+	}
+	writeJSON(w, 0, map[string]string{"upload_url": uploadURL, "key": key})
+}
+
+// handlePresignAvatar handles GET /api/presign/avatar/{userId}.
+func (s *Server) handlePresignAvatar(w http.ResponseWriter, r *http.Request) {
+	userID := r.PathValue("userId")
+	if userID == "" {
+		jsonError(w, http.StatusBadRequest, "missing userId")
+		return
+	}
+
+	u, found, err := s.deps.PresignStore.PresignAvatarURL(r.Context(), userID)
+	if err != nil {
+		s.deps.Log.Error("presign avatar failed", "userId", userID, "err", err)
+		jsonError(w, http.StatusInternalServerError, "presign failed")
+		return
+	}
+	if !found {
+		http.NotFound(w, r)
+		return
+	}
+	writeJSON(w, 0, map[string]string{"url": u})
+}
+
+// ── Progress ───────────────────────────────────────────────────────────────────
+
+// handleGetProgress handles GET /api/progress.
+// Returns {"slug": chapterNum, "slug_ts": timestampMs, ...}
+func (s *Server) handleGetProgress(w http.ResponseWriter, r *http.Request) {
+	sid := ensureSession(w, r)
+	entries, err := s.deps.ProgressStore.AllProgress(r.Context(), sid)
+	if err != nil {
+		s.deps.Log.Error("AllProgress failed", "err", err)
+		entries = nil
+	}
+
+	progress := make(map[string]any, len(entries)*2)
+	for _, p := range entries {
+		progress[p.Slug] = p.Chapter
+		progress[p.Slug+"_ts"] = p.UpdatedAt.UnixMilli()
+	}
+	writeJSON(w, 0, progress)
+}
+
+// handleSetProgress handles POST /api/progress/{slug}.
+// Body: {"chapter": N}
+func (s *Server) handleSetProgress(w http.ResponseWriter, r *http.Request) {
+	sid := ensureSession(w, r)
+	slug := r.PathValue("slug")
+	if slug == "" {
+		jsonError(w, http.StatusBadRequest, "missing slug")
+		return
+	}
+
+	var body struct {
+		Chapter int `json:"chapter"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.Chapter < 1 {
+		jsonError(w, http.StatusBadRequest, "invalid body")
+		return
+	}
+
+	p := domain.ReadingProgress{
+		Slug:      slug,
+		Chapter:   body.Chapter,
+		UpdatedAt: time.Now(),
+	}
+	if err := s.deps.ProgressStore.SetProgress(r.Context(), sid, p); err != nil {
+		s.deps.Log.Error("SetProgress failed", "slug", slug, "err", err)
+		jsonError(w, http.StatusInternalServerError, "store error")
+		return
+	}
+	writeJSON(w, 0, map[string]string{})
+}
+
+// handleDeleteProgress handles DELETE /api/progress/{slug}.
+func (s *Server) handleDeleteProgress(w http.ResponseWriter, r *http.Request) {
+	sid := ensureSession(w, r)
+	slug := r.PathValue("slug")
+	if slug == "" {
+		jsonError(w, http.StatusBadRequest, "missing slug")
+		return
+	}
+
+	if err := s.deps.ProgressStore.DeleteProgress(r.Context(), sid, slug); err != nil {
+		s.deps.Log.Error("DeleteProgress failed", "slug", slug, "err", err)
+		// non-fatal
+	}
+	writeJSON(w, 0, map[string]string{})
+}
+
+// ── Browse page parsing helpers ────────────────────────────────────────────────
+
+// fetchBrowsePage fetches pageURL and parses NovelListings from the HTML.
+func (s *Server) fetchBrowsePage(ctx context.Context, pageURL string) ([]NovelListing, bool, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, pageURL, nil)
+	if err != nil {
+		return nil, false, fmt.Errorf("build request: %w", err)
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; libnovel-backend/2)")
+	req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+	req.Header.Set("Accept-Language", "en-US,en;q=0.9")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, false, fmt.Errorf("fetch %s: %w", pageURL, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		_, _ = io.Copy(io.Discard, resp.Body)
+		return nil, false, fmt.Errorf("upstream returned %d", resp.StatusCode)
+	}
+
+	novels, hasNext := parseBrowsePage(resp.Body)
+	return novels, hasNext, nil
+}
+
+// parseBrowsePage parses a novelfire HTML body and returns novel listings.
+// It uses a simple string-scanning approach to avoid importing golang.org/x/net/html
+// in this package (that dependency is only in internal/novelfire).
+func parseBrowsePage(r io.Reader) ([]NovelListing, bool) {
+	data, err := io.ReadAll(r)
+	if err != nil {
+		return nil, false
+	}
+	body := string(data)
+
+	var novels []NovelListing
+	hasNext := false
+
+	// Detect "next page" link
+	if strings.Contains(body, `rel="next"`) ||
+		strings.Contains(body, `aria-label="Next"`) ||
+		strings.Contains(body, `class="next"`) {
+		hasNext = true
+	}
+
+	// Extract novel slugs and titles using simple regex patterns.
+	// novelfire.net novel items: <li class="novel-item">...</li>
+	// Each contains an anchor like <a href="/book/{slug}">
+	slugRe := regexp.MustCompile(`href="/book/([^/"]+)"`)
+	titleRe := regexp.MustCompile(`class="novel-title[^"]*"[^>]*>([^<]+)<`)
+	coverRe := regexp.MustCompile(`data-src="(https?://[^"]+)"`)
+
+	slugMatches := slugRe.FindAllStringSubmatch(body, -1)
+	titleMatches := titleRe.FindAllStringSubmatch(body, -1)
+	coverMatches := coverRe.FindAllStringSubmatch(body, -1)
+
+	seen := make(map[string]bool)
+	for i, sm := range slugMatches {
+		slug := sm[1]
+		if seen[slug] {
+			continue
+		}
+		seen[slug] = true
+
+		novel := NovelListing{
+			Slug: slug,
+			URL:  novelFireBase + "/book/" + slug,
+		}
+		if i < len(titleMatches) {
+			novel.Title = strings.TrimSpace(titleMatches[i][1])
+		}
+		if i < len(coverMatches) {
+			novel.Cover = coverMatches[i][1]
+		}
+		if novel.Title != "" {
+			novels = append(novels, novel)
+		}
+	}
+
+	return novels, hasNext
+}
+
+// ── Markdown stripping ─────────────────────────────────────────────────────────
+
+// stripMarkdown removes common markdown syntax from src, returning plain text.
+func stripMarkdown(src string) string {
+	src = regexp.MustCompile(`(?m)^#{1,6}\s+`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`\*{1,3}|_{1,3}`).ReplaceAllString(src, "")
+	src = regexp.MustCompile("(?s)```.*?```").ReplaceAllString(src, "")
+	src = regexp.MustCompile("`[^`]*`").ReplaceAllString(src, "")
+	src = regexp.MustCompile(`\[([^\]]+)\]\([^)]+\)`).ReplaceAllString(src, "$1")
+	src = regexp.MustCompile(`!\[[^\]]*\]\([^)]+\)`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`(?m)^>\s?`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`(?m)^[-*_]{3,}\s*$`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`\n{3,}`).ReplaceAllString(src, "\n\n")
+	return strings.TrimSpace(src)
+}
+
+// ── Hardcoded Kokoro voice fallback ───────────────────────────────────────────
+
+// kokoroVoices is the built-in fallback list used when the Kokoro service is
+// unavailable. Matches the list in the old scraper helpers.go.
+var kokoroVoices = []string{
+	// American English
+	"af_alloy", "af_aoede", "af_bella", "af_heart", "af_jadzia",
+	"af_jessica", "af_kore", "af_nicole", "af_nova", "af_river",
+	"af_sarah", "af_sky",
+	"am_adam", "am_echo", "am_eric", "am_fenrir", "am_liam",
+	"am_michael", "am_onyx", "am_puck",
+	// British English
+	"bf_alice", "bf_emma", "bf_lily",
+	"bm_daniel", "bm_fable", "bm_george", "bm_lewis",
+	// Spanish
+	"ef_dora", "em_alex",
+	// French
+	"ff_siwis",
+	// Hindi
+	"hf_alpha", "hf_beta", "hm_omega", "hm_psi",
+	// Italian
+	"if_sara", "im_nicola",
+	// Japanese
+	"jf_alpha", "jf_gongitsune", "jf_nezumi", "jf_tebukuro", "jm_kumo",
+	// Portuguese
+	"pf_dora", "pm_alex",
+	// Chinese
+	"zf_xiaobei", "zf_xiaoni", "zf_xiaoxiao", "zf_xiaoyi",
+	"zm_yunjian", "zm_yunxi", "zm_yunxia", "zm_yunyang",
+}

backend/internal/backend/server.go

@@ -0,0 +1,285 @@
+// Package backend implements the HTTP API server for the LibNovel backend.
+//
+// The server exposes all endpoints consumed by the SvelteKit UI:
+//   - Book/chapter reads from PocketBase/MinIO via bookstore interfaces
+//   - Task creation (scrape + audio) via taskqueue.Producer — the runner binary
+//     picks up and executes those tasks asynchronously
+//   - Presigned MinIO URLs for media playback/upload
+//   - Session-scoped reading progress
+//   - Live novelfire.net browse/search (no scraper interface needed; direct HTTP)
+//   - Kokoro voice list
+//
+// The backend never scrapes directly. All scraping (metadata, chapter list,
+// chapter text, audio TTS) is delegated to the runner binary via PocketBase
+// task records. GET /api/book-preview enqueues a task when the book is absent.
+//
+// All external dependencies are injected as interfaces; concrete types live in
+// internal/storage and are wired by cmd/backend/main.go.
+package backend
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/libnovel/backend/internal/bookstore"
+	"github.com/libnovel/backend/internal/kokoro"
+	"github.com/libnovel/backend/internal/taskqueue"
+)
+
+// Dependencies holds all external services the backend server depends on.
+// Every field is an interface so test doubles can be injected freely.
+type Dependencies struct {
+	// BookReader reads book metadata and chapter text from PocketBase/MinIO.
+	BookReader bookstore.BookReader
+	// RankingStore reads ranking data from PocketBase.
+	RankingStore bookstore.RankingStore
+	// AudioStore checks audio object existence and computes MinIO keys.
+	AudioStore bookstore.AudioStore
+	// PresignStore generates short-lived MinIO URLs.
+	PresignStore bookstore.PresignStore
+	// ProgressStore reads/writes per-session reading progress.
+	ProgressStore bookstore.ProgressStore
+	// Producer creates scrape/audio tasks in PocketBase.
+	Producer taskqueue.Producer
+	// TaskReader reads scrape/audio task records from PocketBase.
+	TaskReader taskqueue.Reader
+	// Kokoro is the TTS client (used for voice list only in the backend;
+	// audio generation is done by the runner).
+	Kokoro kokoro.Client
+	// Log is the structured logger.
+	Log *slog.Logger
+}
+
+// Config holds HTTP server tuning parameters.
+type Config struct {
+	// Addr is the listen address, e.g. ":8080".
+	Addr string
+	// DefaultVoice is used when no voice is specified in audio requests.
+	DefaultVoice string
+	// Version and Commit are embedded in /health and /api/version responses.
+	Version string
+	Commit  string
+}
+
+// Server is the HTTP API server.
+type Server struct {
+	cfg  Config
+	deps Dependencies
+
+	// voiceMu guards cachedVoices. Populated lazily on first GET /api/voices.
+	voiceMu      sync.RWMutex
+	cachedVoices []string
+}
+
+// New creates a Server from cfg and deps.
+func New(cfg Config, deps Dependencies) *Server {
+	if cfg.DefaultVoice == "" {
+		cfg.DefaultVoice = "af_bella"
+	}
+	if deps.Log == nil {
+		deps.Log = slog.Default()
+	}
+	return &Server{cfg: cfg, deps: deps}
+}
+
+// ListenAndServe registers all routes and starts the HTTP server.
+// It blocks until ctx is cancelled, then performs a graceful shutdown.
+func (s *Server) ListenAndServe(ctx context.Context) error {
+	mux := http.NewServeMux()
+
+	// Health / version
+	mux.HandleFunc("GET /health", s.handleHealth)
+	mux.HandleFunc("GET /api/version", s.handleVersion)
+
+	// Scrape task creation (202 Accepted — runner executes asynchronously)
+	mux.HandleFunc("POST /scrape", s.handleScrapeCatalogue)
+	mux.HandleFunc("POST /scrape/book", s.handleScrapeBook)
+	mux.HandleFunc("POST /scrape/book/range", s.handleScrapeBookRange)
+
+	// Scrape task status / history
+	mux.HandleFunc("GET /api/scrape/status", s.handleScrapeStatus)
+	mux.HandleFunc("GET /api/scrape/tasks", s.handleScrapeTasks)
+
+	// Cancel a pending task (scrape or audio)
+	mux.HandleFunc("POST /api/cancel-task/{id}", s.handleCancelTask)
+
+	// Browse & search (live novelfire.net)
+	mux.HandleFunc("GET /api/browse", s.handleBrowse)
+	mux.HandleFunc("GET /api/search", s.handleSearch)
+
+	// Ranking (from PocketBase)
+	mux.HandleFunc("GET /api/ranking", s.handleGetRanking)
+
+	// Cover proxy (live URL redirect)
+	mux.HandleFunc("GET /api/cover/{domain}/{slug}", s.handleGetCover)
+
+	// Book preview (enqueues scrape task if not in library; returns stored data if already scraped)
+	mux.HandleFunc("GET /api/book-preview/{slug}", s.handleBookPreview)
+
+	// Chapter text (served from MinIO via PocketBase index)
+	mux.HandleFunc("GET /api/chapter-text/{slug}/{n}", s.handleChapterText)
+	// Raw markdown chapter content — served directly from MinIO by the backend.
+	// Use this instead of presign+fetch to avoid SvelteKit→MinIO network path.
+	mux.HandleFunc("GET /api/chapter-markdown/{slug}/{n}", s.handleChapterMarkdown)
+
+	// Reindex chapters_idx from MinIO
+	mux.HandleFunc("POST /api/reindex/{slug}", s.handleReindex)
+
+	// Audio task creation (backend creates task; runner executes)
+	mux.HandleFunc("POST /api/audio/{slug}/{n}", s.handleAudioGenerate)
+	mux.HandleFunc("GET /api/audio/status/{slug}/{n}", s.handleAudioStatus)
+	mux.HandleFunc("GET /api/audio-proxy/{slug}/{n}", s.handleAudioProxy)
+
+	// Voices list
+	mux.HandleFunc("GET /api/voices", s.handleVoices)
+
+	// Presigned URLs
+	mux.HandleFunc("GET /api/presign/chapter/{slug}/{n}", s.handlePresignChapter)
+	mux.HandleFunc("GET /api/presign/audio/{slug}/{n}", s.handlePresignAudio)
+	mux.HandleFunc("GET /api/presign/voice-sample/{voice}", s.handlePresignVoiceSample)
+	mux.HandleFunc("GET /api/presign/avatar-upload/{userId}", s.handlePresignAvatarUpload)
+	mux.HandleFunc("GET /api/presign/avatar/{userId}", s.handlePresignAvatar)
+
+	// Reading progress
+	mux.HandleFunc("GET /api/progress", s.handleGetProgress)
+	mux.HandleFunc("POST /api/progress/{slug}", s.handleSetProgress)
+	mux.HandleFunc("DELETE /api/progress/{slug}", s.handleDeleteProgress)
+
+	srv := &http.Server{
+		Addr:         s.cfg.Addr,
+		Handler:      mux,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 60 * time.Second,
+		IdleTimeout:  60 * time.Second,
+	}
+
+	errCh := make(chan error, 1)
+	go func() { errCh <- srv.ListenAndServe() }()
+	s.deps.Log.Info("backend: HTTP server listening", "addr", s.cfg.Addr)
+
+	select {
+	case <-ctx.Done():
+		s.deps.Log.Info("backend: context cancelled, starting graceful shutdown")
+		shutCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer cancel()
+		if err := srv.Shutdown(shutCtx); err != nil {
+			s.deps.Log.Error("backend: graceful shutdown failed", "err", err)
+			return err
+		}
+		s.deps.Log.Info("backend: shutdown complete")
+		return nil
+	case err := <-errCh:
+		return err
+	}
+}
+
+// ── Session cookie helpers ─────────────────────────────────────────────────────
+
+const sessionCookieName = "libnovel_session"
+
+func sessionID(r *http.Request) string {
+	c, err := r.Cookie(sessionCookieName)
+	if err != nil {
+		return ""
+	}
+	return c.Value
+}
+
+func newSessionID() (string, error) {
+	b := make([]byte, 16)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(b), nil
+}
+
+func ensureSession(w http.ResponseWriter, r *http.Request) string {
+	if id := sessionID(r); id != "" {
+		return id
+	}
+	id, err := newSessionID()
+	if err != nil {
+		id = fmt.Sprintf("fallback-%d", time.Now().UnixNano())
+	}
+	http.SetCookie(w, &http.Cookie{
+		Name:     sessionCookieName,
+		Value:    id,
+		Path:     "/",
+		HttpOnly: true,
+		SameSite: http.SameSiteLaxMode,
+		MaxAge:   365 * 24 * 60 * 60,
+	})
+	return id
+}
+
+// ── Utility helpers ────────────────────────────────────────────────────────────
+
+// writeJSON writes v as a JSON response with status code. Status 0 → 200.
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	if status != 0 {
+		w.WriteHeader(status)
+	}
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+// jsonError writes a JSON error body and the given status code.
+func jsonError(w http.ResponseWriter, status int, msg string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(map[string]string{"error": msg})
+}
+
+// voices returns the list of available Kokoro voices. On the first call it
+// fetches from the Kokoro service and caches the result. Falls back to the
+// hardcoded list on error.
+func (s *Server) voices(ctx context.Context) []string {
+	s.voiceMu.RLock()
+	cached := s.cachedVoices
+	s.voiceMu.RUnlock()
+	if len(cached) > 0 {
+		return cached
+	}
+
+	if s.deps.Kokoro == nil {
+		return kokoroVoices
+	}
+
+	fetchCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
+	defer cancel()
+	list, err := s.deps.Kokoro.ListVoices(fetchCtx)
+	if err != nil || len(list) == 0 {
+		s.deps.Log.Warn("backend: could not fetch kokoro voices, using built-in list", "err", err)
+		return kokoroVoices
+	}
+
+	s.voiceMu.Lock()
+	s.cachedVoices = list
+	s.voiceMu.Unlock()
+	s.deps.Log.Info("backend: fetched kokoro voices", "count", len(list))
+	return list
+}
+
+// handleHealth handles GET /health.
+func (s *Server) handleHealth(w http.ResponseWriter, _ *http.Request) {
+	writeJSON(w, 0, map[string]string{
+		"status":  "ok",
+		"version": s.cfg.Version,
+		"commit":  s.cfg.Commit,
+	})
+}
+
+// handleVersion handles GET /api/version.
+func (s *Server) handleVersion(w http.ResponseWriter, _ *http.Request) {
+	writeJSON(w, 0, map[string]string{
+		"version": s.cfg.Version,
+		"commit":  s.cfg.Commit,
+	})
+}

backend/internal/bookstore/bookstore.go

@@ -0,0 +1,125 @@
+// Package bookstore defines the segregated read/write interfaces for book,
+// chapter, ranking, progress, audio, and presign data.
+//
+// Interface segregation:
+//   - BookWriter   — used by the runner to persist scraped data.
+//   - BookReader   — used by the backend to serve book/chapter data.
+//   - RankingStore — used by both runner (write) and backend (read).
+//   - PresignStore — used only by the backend for URL signing.
+//   - AudioStore   — used by the runner to store audio; backend for presign.
+//   - ProgressStore— used only by the backend for reading progress.
+//
+// Concrete implementations live in internal/storage.
+package bookstore
+
+import (
+	"context"
+	"time"
+
+	"github.com/libnovel/backend/internal/domain"
+)
+
+// BookWriter is the write side used by the runner after scraping a book.
+type BookWriter interface {
+	// WriteMetadata upserts all bibliographic fields for a book.
+	WriteMetadata(ctx context.Context, meta domain.BookMeta) error
+
+	// WriteChapter stores a fully-scraped chapter's text in MinIO and
+	// updates the chapters_idx record in PocketBase.
+	WriteChapter(ctx context.Context, slug string, chapter domain.Chapter) error
+
+	// WriteChapterRefs persists chapter metadata (number + title) into
+	// chapters_idx without fetching or storing chapter text.
+	WriteChapterRefs(ctx context.Context, slug string, refs []domain.ChapterRef) error
+
+	// ChapterExists returns true if the markdown object for ref already exists.
+	ChapterExists(ctx context.Context, slug string, ref domain.ChapterRef) bool
+}
+
+// BookReader is the read side used by the backend to serve content.
+type BookReader interface {
+	// ReadMetadata returns the metadata for slug.
+	// Returns (zero, false, nil) when not found.
+	ReadMetadata(ctx context.Context, slug string) (domain.BookMeta, bool, error)
+
+	// ListBooks returns all books sorted alphabetically by title.
+	ListBooks(ctx context.Context) ([]domain.BookMeta, error)
+
+	// LocalSlugs returns the set of slugs that have metadata stored.
+	LocalSlugs(ctx context.Context) (map[string]bool, error)
+
+	// MetadataMtime returns the Unix-second mtime of the metadata record, or 0.
+	MetadataMtime(ctx context.Context, slug string) int64
+
+	// ReadChapter returns the raw markdown for chapter number n.
+	ReadChapter(ctx context.Context, slug string, n int) (string, error)
+
+	// ListChapters returns all stored chapters for slug, sorted by number.
+	ListChapters(ctx context.Context, slug string) ([]domain.ChapterInfo, error)
+
+	// CountChapters returns the count of stored chapters.
+	CountChapters(ctx context.Context, slug string) int
+
+	// ReindexChapters rebuilds chapters_idx from MinIO objects for slug.
+	ReindexChapters(ctx context.Context, slug string) (int, error)
+}
+
+// RankingStore covers ranking reads and writes.
+type RankingStore interface {
+	// WriteRankingItem upserts a single ranking entry (keyed on Slug).
+	WriteRankingItem(ctx context.Context, item domain.RankingItem) error
+
+	// ReadRankingItems returns all ranking items sorted by rank ascending.
+	ReadRankingItems(ctx context.Context) ([]domain.RankingItem, error)
+
+	// RankingFreshEnough returns true when ranking rows exist and the most
+	// recent Updated timestamp is within maxAge.
+	RankingFreshEnough(ctx context.Context, maxAge time.Duration) (bool, error)
+}
+
+// AudioStore covers audio object storage (runner writes; backend reads).
+type AudioStore interface {
+	// AudioObjectKey returns the MinIO object key for a cached audio file.
+	AudioObjectKey(slug string, n int, voice string) string
+
+	// AudioExists returns true when the audio object is present in MinIO.
+	AudioExists(ctx context.Context, key string) bool
+
+	// PutAudio stores raw audio bytes under the given MinIO object key.
+	PutAudio(ctx context.Context, key string, data []byte) error
+}
+
+// PresignStore generates short-lived URLs — used exclusively by the backend.
+type PresignStore interface {
+	// PresignChapter returns a presigned GET URL for a chapter markdown object.
+	PresignChapter(ctx context.Context, slug string, n int, expires time.Duration) (string, error)
+
+	// PresignAudio returns a presigned GET URL for an audio object.
+	PresignAudio(ctx context.Context, key string, expires time.Duration) (string, error)
+
+	// PresignAvatarUpload returns a short-lived presigned PUT URL for uploading
+	// an avatar image. ext should be "jpg", "png", or "webp".
+	PresignAvatarUpload(ctx context.Context, userID, ext string) (uploadURL, key string, err error)
+
+	// PresignAvatarURL returns a presigned GET URL for a user's avatar.
+	// Returns ("", false, nil) when no avatar exists.
+	PresignAvatarURL(ctx context.Context, userID string) (string, bool, error)
+
+	// DeleteAvatar removes all avatar objects for a user.
+	DeleteAvatar(ctx context.Context, userID string) error
+}
+
+// ProgressStore covers per-session reading progress — backend only.
+type ProgressStore interface {
+	// GetProgress returns the reading progress for the given session + slug.
+	GetProgress(ctx context.Context, sessionID, slug string) (domain.ReadingProgress, bool)
+
+	// SetProgress saves or updates reading progress.
+	SetProgress(ctx context.Context, sessionID string, p domain.ReadingProgress) error
+
+	// AllProgress returns all progress entries for a session.
+	AllProgress(ctx context.Context, sessionID string) ([]domain.ReadingProgress, error)
+
+	// DeleteProgress removes progress for a specific slug.
+	DeleteProgress(ctx context.Context, sessionID, slug string) error
+}

backend/internal/bookstore/bookstore_test.go

@@ -0,0 +1,138 @@
+package bookstore_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/bookstore"
+	"github.com/libnovel/backend/internal/domain"
+)
+
+// ── Mock that satisfies all bookstore interfaces ──────────────────────────────
+
+type mockStore struct{}
+
+// BookWriter
+func (m *mockStore) WriteMetadata(_ context.Context, _ domain.BookMeta) error         { return nil }
+func (m *mockStore) WriteChapter(_ context.Context, _ string, _ domain.Chapter) error { return nil }
+func (m *mockStore) WriteChapterRefs(_ context.Context, _ string, _ []domain.ChapterRef) error {
+	return nil
+}
+func (m *mockStore) ChapterExists(_ context.Context, _ string, _ domain.ChapterRef) bool {
+	return false
+}
+
+// BookReader
+func (m *mockStore) ReadMetadata(_ context.Context, _ string) (domain.BookMeta, bool, error) {
+	return domain.BookMeta{}, false, nil
+}
+func (m *mockStore) ListBooks(_ context.Context) ([]domain.BookMeta, error) { return nil, nil }
+func (m *mockStore) LocalSlugs(_ context.Context) (map[string]bool, error) {
+	return map[string]bool{}, nil
+}
+func (m *mockStore) MetadataMtime(_ context.Context, _ string) int64 { return 0 }
+func (m *mockStore) ReadChapter(_ context.Context, _ string, _ int) (string, error) {
+	return "", nil
+}
+func (m *mockStore) ListChapters(_ context.Context, _ string) ([]domain.ChapterInfo, error) {
+	return nil, nil
+}
+func (m *mockStore) CountChapters(_ context.Context, _ string) int            { return 0 }
+func (m *mockStore) ReindexChapters(_ context.Context, _ string) (int, error) { return 0, nil }
+
+// RankingStore
+func (m *mockStore) WriteRankingItem(_ context.Context, _ domain.RankingItem) error { return nil }
+func (m *mockStore) ReadRankingItems(_ context.Context) ([]domain.RankingItem, error) {
+	return nil, nil
+}
+func (m *mockStore) RankingFreshEnough(_ context.Context, _ time.Duration) (bool, error) {
+	return false, nil
+}
+
+// AudioStore
+func (m *mockStore) AudioObjectKey(_ string, _ int, _ string) string      { return "" }
+func (m *mockStore) AudioExists(_ context.Context, _ string) bool         { return false }
+func (m *mockStore) PutAudio(_ context.Context, _ string, _ []byte) error { return nil }
+
+// PresignStore
+func (m *mockStore) PresignChapter(_ context.Context, _ string, _ int, _ time.Duration) (string, error) {
+	return "", nil
+}
+func (m *mockStore) PresignAudio(_ context.Context, _ string, _ time.Duration) (string, error) {
+	return "", nil
+}
+func (m *mockStore) PresignAvatarUpload(_ context.Context, _, _ string) (string, string, error) {
+	return "", "", nil
+}
+func (m *mockStore) PresignAvatarURL(_ context.Context, _ string) (string, bool, error) {
+	return "", false, nil
+}
+func (m *mockStore) DeleteAvatar(_ context.Context, _ string) error { return nil }
+
+// ProgressStore
+func (m *mockStore) GetProgress(_ context.Context, _, _ string) (domain.ReadingProgress, bool) {
+	return domain.ReadingProgress{}, false
+}
+func (m *mockStore) SetProgress(_ context.Context, _ string, _ domain.ReadingProgress) error {
+	return nil
+}
+func (m *mockStore) AllProgress(_ context.Context, _ string) ([]domain.ReadingProgress, error) {
+	return nil, nil
+}
+func (m *mockStore) DeleteProgress(_ context.Context, _, _ string) error { return nil }
+
+// ── Compile-time interface satisfaction ───────────────────────────────────────
+
+var _ bookstore.BookWriter = (*mockStore)(nil)
+var _ bookstore.BookReader = (*mockStore)(nil)
+var _ bookstore.RankingStore = (*mockStore)(nil)
+var _ bookstore.AudioStore = (*mockStore)(nil)
+var _ bookstore.PresignStore = (*mockStore)(nil)
+var _ bookstore.ProgressStore = (*mockStore)(nil)
+
+// ── Behavioural tests ─────────────────────────────────────────────────────────
+
+func TestBookWriter_WriteMetadata_ReturnsNilError(t *testing.T) {
+	var w bookstore.BookWriter = &mockStore{}
+	if err := w.WriteMetadata(context.Background(), domain.BookMeta{Slug: "test"}); err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestBookReader_ReadMetadata_NotFound(t *testing.T) {
+	var r bookstore.BookReader = &mockStore{}
+	_, found, err := r.ReadMetadata(context.Background(), "unknown")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if found {
+		t.Error("expected not found")
+	}
+}
+
+func TestRankingStore_RankingFreshEnough_ReturnsFalse(t *testing.T) {
+	var s bookstore.RankingStore = &mockStore{}
+	fresh, err := s.RankingFreshEnough(context.Background(), time.Hour)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if fresh {
+		t.Error("expected false")
+	}
+}
+
+func TestAudioStore_AudioExists_ReturnsFalse(t *testing.T) {
+	var s bookstore.AudioStore = &mockStore{}
+	if s.AudioExists(context.Background(), "audio/slug/1/af_bella.mp3") {
+		t.Error("expected false")
+	}
+}
+
+func TestProgressStore_GetProgress_NotFound(t *testing.T) {
+	var s bookstore.ProgressStore = &mockStore{}
+	_, found := s.GetProgress(context.Background(), "session-1", "slug")
+	if found {
+		t.Error("expected not found")
+	}
+}

backend/internal/browser/browser.go

@@ -0,0 +1,206 @@
+// Package browser provides a rate-limited HTTP client for web scraping.
+// The Client interface is the only thing the rest of the codebase depends on;
+// the concrete DirectClient can be swapped for any other implementation
+// (e.g. a Browserless-backed client) without touching callers.
+package browser
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"sync"
+	"time"
+)
+
+// ErrRateLimit is returned by GetContent when the server responds with 429.
+// It carries the suggested retry delay (from Retry-After header, or a default).
+var ErrRateLimit = errors.New("rate limited (429)")
+
+// RateLimitError wraps ErrRateLimit and carries the suggested wait duration.
+type RateLimitError struct {
+	// RetryAfter is how long the caller should wait before retrying.
+	// Derived from the Retry-After response header when present; otherwise a default.
+	RetryAfter time.Duration
+}
+
+func (e *RateLimitError) Error() string {
+	return fmt.Sprintf("rate limited (429): retry after %s", e.RetryAfter)
+}
+
+func (e *RateLimitError) Is(target error) bool { return target == ErrRateLimit }
+
+// defaultRateLimitDelay is used when the server returns 429 with no Retry-After header.
+const defaultRateLimitDelay = 60 * time.Second
+
+// Client is the interface used by scrapers to fetch raw page HTML.
+// Implementations must be safe for concurrent use.
+type Client interface {
+	// GetContent fetches the URL and returns the full response body as a string.
+	// It should respect the provided context for cancellation and timeouts.
+	GetContent(ctx context.Context, pageURL string) (string, error)
+}
+
+// Config holds tunable parameters for the direct HTTP client.
+type Config struct {
+	// MaxConcurrent limits the number of simultaneous in-flight requests.
+	// Defaults to 5 when 0.
+	MaxConcurrent int
+	// Timeout is the per-request deadline. Defaults to 90s when 0.
+	Timeout time.Duration
+	// ProxyURL is an optional outbound proxy, e.g. "http://user:pass@host:3128".
+	// Falls back to HTTP_PROXY / HTTPS_PROXY environment variables when empty.
+	ProxyURL string
+}
+
+// DirectClient is a plain net/http-based Client with a concurrency semaphore.
+type DirectClient struct {
+	http      *http.Client
+	semaphore chan struct{}
+}
+
+// NewDirectClient returns a DirectClient configured by cfg.
+func NewDirectClient(cfg Config) *DirectClient {
+	if cfg.MaxConcurrent <= 0 {
+		cfg.MaxConcurrent = 5
+	}
+	if cfg.Timeout <= 0 {
+		cfg.Timeout = 90 * time.Second
+	}
+
+	transport := &http.Transport{
+		MaxIdleConnsPerHost: cfg.MaxConcurrent * 2,
+		DisableCompression:  false,
+	}
+	if cfg.ProxyURL != "" {
+		proxyParsed, err := url.Parse(cfg.ProxyURL)
+		if err == nil {
+			transport.Proxy = http.ProxyURL(proxyParsed)
+		}
+	} else {
+		transport.Proxy = http.ProxyFromEnvironment
+	}
+
+	return &DirectClient{
+		http: &http.Client{
+			Transport: transport,
+			Timeout:   cfg.Timeout,
+		},
+		semaphore: make(chan struct{}, cfg.MaxConcurrent),
+	}
+}
+
+// GetContent fetches pageURL respecting the concurrency limit.
+func (c *DirectClient) GetContent(ctx context.Context, pageURL string) (string, error) {
+	// Acquire semaphore slot.
+	select {
+	case c.semaphore <- struct{}{}:
+	case <-ctx.Done():
+		return "", ctx.Err()
+	}
+	defer func() { <-c.semaphore }()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, pageURL, nil)
+	if err != nil {
+		return "", fmt.Errorf("browser: build request %s: %w", pageURL, err)
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; libnovel-runner/2)")
+	req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+	req.Header.Set("Accept-Language", "en-US,en;q=0.5")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("browser: GET %s: %w", pageURL, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode == http.StatusTooManyRequests {
+		delay := defaultRateLimitDelay
+		if ra := resp.Header.Get("Retry-After"); ra != "" {
+			if secs, err := strconv.Atoi(ra); err == nil && secs > 0 {
+				delay = time.Duration(secs) * time.Second
+			}
+		}
+		return "", &RateLimitError{RetryAfter: delay}
+	}
+
+	if resp.StatusCode >= 400 {
+		return "", fmt.Errorf("browser: GET %s returned %d", pageURL, resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("browser: read body %s: %w", pageURL, err)
+	}
+	return string(body), nil
+}
+
+// Do implements httputil.Client so DirectClient can be passed to RetryGet.
+func (c *DirectClient) Do(req *http.Request) (*http.Response, error) {
+	select {
+	case c.semaphore <- struct{}{}:
+	case <-req.Context().Done():
+		return nil, req.Context().Err()
+	}
+	defer func() { <-c.semaphore }()
+	return c.http.Do(req)
+}
+
+// ── Stub for testing ──────────────────────────────────────────────────────────
+
+// StubClient is a test double for Client. It returns pre-configured responses
+// keyed on URL. Calls to unknown URLs return an error.
+type StubClient struct {
+	mu      sync.Mutex
+	pages   map[string]string
+	errors  map[string]error
+	callLog []string
+}
+
+// NewStub creates a StubClient with no pages pre-loaded.
+func NewStub() *StubClient {
+	return &StubClient{
+		pages:  make(map[string]string),
+		errors: make(map[string]error),
+	}
+}
+
+// SetPage registers a URL → HTML body mapping.
+func (s *StubClient) SetPage(u, html string) {
+	s.mu.Lock()
+	s.pages[u] = html
+	s.mu.Unlock()
+}
+
+// SetError registers a URL → error mapping (returned instead of a body).
+func (s *StubClient) SetError(u string, err error) {
+	s.mu.Lock()
+	s.errors[u] = err
+	s.mu.Unlock()
+}
+
+// CallLog returns the ordered list of URLs that were requested.
+func (s *StubClient) CallLog() []string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	out := make([]string, len(s.callLog))
+	copy(out, s.callLog)
+	return out
+}
+
+// GetContent returns the registered page or an error for the URL.
+func (s *StubClient) GetContent(_ context.Context, pageURL string) (string, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.callLog = append(s.callLog, pageURL)
+	if err, ok := s.errors[pageURL]; ok {
+		return "", err
+	}
+	if html, ok := s.pages[pageURL]; ok {
+		return html, nil
+	}
+	return "", fmt.Errorf("stub: no page registered for %q", pageURL)
+}

backend/internal/browser/browser_test.go

@@ -0,0 +1,141 @@
+package browser_test
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/browser"
+)
+
+func TestDirectClient_GetContent_Success(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("<html>hello</html>"))
+	}))
+	defer srv.Close()
+
+	c := browser.NewDirectClient(browser.Config{MaxConcurrent: 2, Timeout: 5 * time.Second})
+	body, err := c.GetContent(context.Background(), srv.URL)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if body != "<html>hello</html>" {
+		t.Errorf("want <html>hello</html>, got %q", body)
+	}
+}
+
+func TestDirectClient_GetContent_4xxReturnsError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer srv.Close()
+
+	c := browser.NewDirectClient(browser.Config{})
+	_, err := c.GetContent(context.Background(), srv.URL)
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestDirectClient_SemaphoreBlocksConcurrency(t *testing.T) {
+	const maxConcurrent = 2
+	var inflight atomic.Int32
+	var peak atomic.Int32
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		n := inflight.Add(1)
+		if int(n) > int(peak.Load()) {
+			peak.Store(n)
+		}
+		time.Sleep(20 * time.Millisecond)
+		inflight.Add(-1)
+		w.Write([]byte("ok"))
+	}))
+	defer srv.Close()
+
+	c := browser.NewDirectClient(browser.Config{MaxConcurrent: maxConcurrent, Timeout: 5 * time.Second})
+
+	var wg sync.WaitGroup
+	for i := 0; i < 8; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			c.GetContent(context.Background(), srv.URL)
+		}()
+	}
+	wg.Wait()
+
+	if int(peak.Load()) > maxConcurrent {
+		t.Errorf("concurrent requests exceeded limit: peak=%d, limit=%d", peak.Load(), maxConcurrent)
+	}
+}
+
+func TestDirectClient_ContextCancel(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(200 * time.Millisecond)
+		w.Write([]byte("ok"))
+	}))
+	defer srv.Close()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // cancel before making the request
+
+	c := browser.NewDirectClient(browser.Config{})
+	_, err := c.GetContent(ctx, srv.URL)
+	if err == nil {
+		t.Fatal("expected context cancellation error")
+	}
+}
+
+// ── StubClient ────────────────────────────────────────────────────────────────
+
+func TestStubClient_ReturnsRegisteredPage(t *testing.T) {
+	stub := browser.NewStub()
+	stub.SetPage("http://example.com/page1", "<html>page1</html>")
+
+	body, err := stub.GetContent(context.Background(), "http://example.com/page1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if body != "<html>page1</html>" {
+		t.Errorf("want page1 html, got %q", body)
+	}
+}
+
+func TestStubClient_ReturnsRegisteredError(t *testing.T) {
+	stub := browser.NewStub()
+	want := errors.New("network failure")
+	stub.SetError("http://example.com/bad", want)
+
+	_, err := stub.GetContent(context.Background(), "http://example.com/bad")
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestStubClient_UnknownURLReturnsError(t *testing.T) {
+	stub := browser.NewStub()
+	_, err := stub.GetContent(context.Background(), "http://unknown.example.com/")
+	if err == nil {
+		t.Fatal("expected error for unknown URL")
+	}
+}
+
+func TestStubClient_CallLog(t *testing.T) {
+	stub := browser.NewStub()
+	stub.SetPage("http://example.com/a", "a")
+	stub.SetPage("http://example.com/b", "b")
+
+	stub.GetContent(context.Background(), "http://example.com/a")
+	stub.GetContent(context.Background(), "http://example.com/b")
+
+	log := stub.CallLog()
+	if len(log) != 2 || log[0] != "http://example.com/a" || log[1] != "http://example.com/b" {
+		t.Errorf("unexpected call log: %v", log)
+	}
+}

backend/internal/config/config.go

@@ -0,0 +1,183 @@
+// Package config loads all service configuration from environment variables.
+// Both the runner and backend binaries call config.Load() at startup; each
+// uses only the sub-struct relevant to it.
+//
+// Every field has a documented default so the service starts sensibly without
+// any environment configuration (useful for local development).
+package config
+
+import (
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// PocketBase holds connection settings for the remote PocketBase instance.
+type PocketBase struct {
+	// URL is the base URL of the PocketBase instance, e.g. https://pb.libnovel.cc
+	URL string
+	// AdminEmail is the admin account email used for API authentication.
+	AdminEmail string
+	// AdminPassword is the admin account password.
+	AdminPassword string
+}
+
+// MinIO holds connection settings for the remote MinIO / S3-compatible store.
+type MinIO struct {
+	// Endpoint is the host:port of the MinIO S3 API, e.g. storage.libnovel.cc:443
+	Endpoint string
+	// PublicEndpoint is the browser-visible endpoint used for presigned URLs.
+	// Falls back to Endpoint when empty.
+	PublicEndpoint string
+	// AccessKey is the MinIO access key.
+	AccessKey string
+	// SecretKey is the MinIO secret key.
+	SecretKey string
+	// UseSSL enables TLS for the internal MinIO connection.
+	UseSSL bool
+	// PublicUseSSL enables TLS for presigned URL generation.
+	PublicUseSSL bool
+	// BucketChapters is the bucket that holds chapter markdown objects.
+	BucketChapters string
+	// BucketAudio is the bucket that holds generated audio MP3 objects.
+	BucketAudio string
+	// BucketAvatars is the bucket that holds user avatar images.
+	BucketAvatars string
+}
+
+// Kokoro holds connection settings for the Kokoro-FastAPI TTS service.
+type Kokoro struct {
+	// URL is the base URL of the Kokoro service, e.g. https://kokoro.libnovel.cc
+	// An empty string disables TTS generation.
+	URL string
+	// DefaultVoice is the voice used when none is specified.
+	DefaultVoice string
+}
+
+// HTTP holds settings for the HTTP server (backend only).
+type HTTP struct {
+	// Addr is the listen address, e.g. ":8080"
+	Addr string
+}
+
+// Runner holds settings specific to the runner/worker binary.
+type Runner struct {
+	// PollInterval is how often the runner checks PocketBase for pending tasks.
+	PollInterval time.Duration
+	// MaxConcurrentScrape limits simultaneous book-scrape goroutines.
+	MaxConcurrentScrape int
+	// MaxConcurrentAudio limits simultaneous audio-generation goroutines.
+	MaxConcurrentAudio int
+	// WorkerID is a unique identifier for this runner instance.
+	// Defaults to the system hostname.
+	WorkerID string
+	// Workers is the number of chapter-scraping goroutines per book.
+	Workers int
+	// Timeout is the per-request HTTP timeout for scraping.
+	Timeout time.Duration
+	// ProxyURL is an optional outbound proxy for scraper HTTP requests.
+	ProxyURL string
+}
+
+// Config is the top-level configuration struct consumed by both binaries.
+type Config struct {
+	PocketBase PocketBase
+	MinIO      MinIO
+	Kokoro     Kokoro
+	HTTP       HTTP
+	Runner     Runner
+	// LogLevel is one of "debug", "info", "warn", "error".
+	LogLevel string
+}
+
+// Load reads all configuration from environment variables and returns a
+// populated Config. Missing variables fall back to documented defaults.
+func Load() Config {
+	workerID, _ := os.Hostname()
+	if workerID == "" {
+		workerID = "runner-default"
+	}
+
+	return Config{
+		LogLevel: envOr("LOG_LEVEL", "info"),
+
+		PocketBase: PocketBase{
+			URL:           envOr("POCKETBASE_URL", "http://localhost:8090"),
+			AdminEmail:    envOr("POCKETBASE_ADMIN_EMAIL", "admin@libnovel.local"),
+			AdminPassword: envOr("POCKETBASE_ADMIN_PASSWORD", "changeme123"),
+		},
+
+		MinIO: MinIO{
+			Endpoint:       envOr("MINIO_ENDPOINT", "localhost:9000"),
+			PublicEndpoint: envOr("MINIO_PUBLIC_ENDPOINT", ""),
+			AccessKey:      envOr("MINIO_ACCESS_KEY", "admin"),
+			SecretKey:      envOr("MINIO_SECRET_KEY", "changeme123"),
+			UseSSL:         envBool("MINIO_USE_SSL", false),
+			PublicUseSSL:   envBool("MINIO_PUBLIC_USE_SSL", true),
+			BucketChapters: envOr("MINIO_BUCKET_CHAPTERS", "libnovel-chapters"),
+			BucketAudio:    envOr("MINIO_BUCKET_AUDIO", "libnovel-audio"),
+			BucketAvatars:  envOr("MINIO_BUCKET_AVATARS", "libnovel-avatars"),
+		},
+
+		Kokoro: Kokoro{
+			URL:          envOr("KOKORO_URL", ""),
+			DefaultVoice: envOr("KOKORO_VOICE", "af_bella"),
+		},
+
+		HTTP: HTTP{
+			Addr: envOr("BACKEND_HTTP_ADDR", ":8080"),
+		},
+
+		Runner: Runner{
+			PollInterval:        envDuration("RUNNER_POLL_INTERVAL", 30*time.Second),
+			MaxConcurrentScrape: envInt("RUNNER_MAX_CONCURRENT_SCRAPE", 1),
+			MaxConcurrentAudio:  envInt("RUNNER_MAX_CONCURRENT_AUDIO", 1),
+			WorkerID:            envOr("RUNNER_WORKER_ID", workerID),
+			Workers:             envInt("RUNNER_WORKERS", 0), // 0 → runtime.NumCPU()
+			Timeout:             envDuration("RUNNER_TIMEOUT", 90*time.Second),
+			ProxyURL:            envOr("SCRAPER_PROXY", ""),
+		},
+	}
+}
+
+// ── helpers ───────────────────────────────────────────────────────────────────
+
+func envOr(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}
+
+func envBool(key string, fallback bool) bool {
+	v := os.Getenv(key)
+	if v == "" {
+		return fallback
+	}
+	return strings.ToLower(v) == "true"
+}
+
+func envInt(key string, fallback int) int {
+	v := os.Getenv(key)
+	if v == "" {
+		return fallback
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil || n < 0 {
+		return fallback
+	}
+	return n
+}
+
+func envDuration(key string, fallback time.Duration) time.Duration {
+	v := os.Getenv(key)
+	if v == "" {
+		return fallback
+	}
+	d, err := time.ParseDuration(v)
+	if err != nil {
+		return fallback
+	}
+	return d
+}

backend/internal/config/config_test.go

@@ -0,0 +1,127 @@
+package config_test
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/config"
+)
+
+func TestLoad_Defaults(t *testing.T) {
+	// Unset all relevant vars so we test pure defaults.
+	unset := []string{
+		"LOG_LEVEL",
+		"POCKETBASE_URL", "POCKETBASE_ADMIN_EMAIL", "POCKETBASE_ADMIN_PASSWORD",
+		"MINIO_ENDPOINT", "MINIO_PUBLIC_ENDPOINT", "MINIO_ACCESS_KEY", "MINIO_SECRET_KEY",
+		"MINIO_USE_SSL", "MINIO_PUBLIC_USE_SSL",
+		"MINIO_BUCKET_CHAPTERS", "MINIO_BUCKET_AUDIO", "MINIO_BUCKET_AVATARS",
+		"KOKORO_URL", "KOKORO_VOICE",
+		"BACKEND_HTTP_ADDR",
+		"RUNNER_POLL_INTERVAL", "RUNNER_MAX_CONCURRENT_SCRAPE", "RUNNER_MAX_CONCURRENT_AUDIO",
+		"RUNNER_WORKER_ID", "RUNNER_WORKERS", "RUNNER_TIMEOUT", "SCRAPER_PROXY",
+	}
+	for _, k := range unset {
+		t.Setenv(k, "")
+	}
+
+	cfg := config.Load()
+
+	if cfg.LogLevel != "info" {
+		t.Errorf("LogLevel: want info, got %q", cfg.LogLevel)
+	}
+	if cfg.PocketBase.URL != "http://localhost:8090" {
+		t.Errorf("PocketBase.URL: want http://localhost:8090, got %q", cfg.PocketBase.URL)
+	}
+	if cfg.MinIO.BucketChapters != "libnovel-chapters" {
+		t.Errorf("MinIO.BucketChapters: want libnovel-chapters, got %q", cfg.MinIO.BucketChapters)
+	}
+	if cfg.MinIO.UseSSL != false {
+		t.Errorf("MinIO.UseSSL: want false, got %v", cfg.MinIO.UseSSL)
+	}
+	if cfg.MinIO.PublicUseSSL != true {
+		t.Errorf("MinIO.PublicUseSSL: want true, got %v", cfg.MinIO.PublicUseSSL)
+	}
+	if cfg.Kokoro.DefaultVoice != "af_bella" {
+		t.Errorf("Kokoro.DefaultVoice: want af_bella, got %q", cfg.Kokoro.DefaultVoice)
+	}
+	if cfg.HTTP.Addr != ":8080" {
+		t.Errorf("HTTP.Addr: want :8080, got %q", cfg.HTTP.Addr)
+	}
+	if cfg.Runner.PollInterval != 30*time.Second {
+		t.Errorf("Runner.PollInterval: want 30s, got %v", cfg.Runner.PollInterval)
+	}
+	if cfg.Runner.MaxConcurrentScrape != 1 {
+		t.Errorf("Runner.MaxConcurrentScrape: want 1, got %d", cfg.Runner.MaxConcurrentScrape)
+	}
+	if cfg.Runner.MaxConcurrentAudio != 1 {
+		t.Errorf("Runner.MaxConcurrentAudio: want 1, got %d", cfg.Runner.MaxConcurrentAudio)
+	}
+}
+
+func TestLoad_EnvOverride(t *testing.T) {
+	t.Setenv("LOG_LEVEL", "debug")
+	t.Setenv("POCKETBASE_URL", "https://pb.libnovel.cc")
+	t.Setenv("MINIO_USE_SSL", "true")
+	t.Setenv("MINIO_PUBLIC_USE_SSL", "false")
+	t.Setenv("RUNNER_POLL_INTERVAL", "1m")
+	t.Setenv("RUNNER_MAX_CONCURRENT_SCRAPE", "5")
+	t.Setenv("RUNNER_WORKER_ID", "homelab-01")
+	t.Setenv("BACKEND_HTTP_ADDR", ":9090")
+	t.Setenv("KOKORO_URL", "https://kokoro.libnovel.cc")
+
+	cfg := config.Load()
+
+	if cfg.LogLevel != "debug" {
+		t.Errorf("LogLevel: want debug, got %q", cfg.LogLevel)
+	}
+	if cfg.PocketBase.URL != "https://pb.libnovel.cc" {
+		t.Errorf("PocketBase.URL: want https://pb.libnovel.cc, got %q", cfg.PocketBase.URL)
+	}
+	if !cfg.MinIO.UseSSL {
+		t.Error("MinIO.UseSSL: want true")
+	}
+	if cfg.MinIO.PublicUseSSL {
+		t.Error("MinIO.PublicUseSSL: want false")
+	}
+	if cfg.Runner.PollInterval != time.Minute {
+		t.Errorf("Runner.PollInterval: want 1m, got %v", cfg.Runner.PollInterval)
+	}
+	if cfg.Runner.MaxConcurrentScrape != 5 {
+		t.Errorf("Runner.MaxConcurrentScrape: want 5, got %d", cfg.Runner.MaxConcurrentScrape)
+	}
+	if cfg.Runner.WorkerID != "homelab-01" {
+		t.Errorf("Runner.WorkerID: want homelab-01, got %q", cfg.Runner.WorkerID)
+	}
+	if cfg.HTTP.Addr != ":9090" {
+		t.Errorf("HTTP.Addr: want :9090, got %q", cfg.HTTP.Addr)
+	}
+	if cfg.Kokoro.URL != "https://kokoro.libnovel.cc" {
+		t.Errorf("Kokoro.URL: want https://kokoro.libnovel.cc, got %q", cfg.Kokoro.URL)
+	}
+}
+
+func TestLoad_InvalidInt_FallsToDefault(t *testing.T) {
+	t.Setenv("RUNNER_MAX_CONCURRENT_SCRAPE", "notanumber")
+	cfg := config.Load()
+	if cfg.Runner.MaxConcurrentScrape != 1 {
+		t.Errorf("want default 1, got %d", cfg.Runner.MaxConcurrentScrape)
+	}
+}
+
+func TestLoad_InvalidDuration_FallsToDefault(t *testing.T) {
+	t.Setenv("RUNNER_POLL_INTERVAL", "notaduration")
+	cfg := config.Load()
+	if cfg.Runner.PollInterval != 30*time.Second {
+		t.Errorf("want default 30s, got %v", cfg.Runner.PollInterval)
+	}
+}
+
+func TestLoad_WorkerID_FallsToHostname(t *testing.T) {
+	t.Setenv("RUNNER_WORKER_ID", "")
+	cfg := config.Load()
+	host, _ := os.Hostname()
+	if host != "" && cfg.Runner.WorkerID != host {
+		t.Errorf("want hostname %q, got %q", host, cfg.Runner.WorkerID)
+	}
+}

backend/internal/domain/domain.go

@@ -0,0 +1,131 @@
+// Package domain contains the core value types shared across all packages
+// in this module. It has zero internal imports — only the standard library.
+// Every other package imports domain; domain imports nothing from this module.
+package domain
+
+import "time"
+
+// ── Book types ────────────────────────────────────────────────────────────────
+
+// BookMeta carries all bibliographic information about a novel.
+type BookMeta struct {
+	Slug          string   `json:"slug"`
+	Title         string   `json:"title"`
+	Author        string   `json:"author"`
+	Cover         string   `json:"cover,omitempty"`
+	Status        string   `json:"status,omitempty"`
+	Genres        []string `json:"genres,omitempty"`
+	Summary       string   `json:"summary,omitempty"`
+	TotalChapters int      `json:"total_chapters,omitempty"`
+	SourceURL     string   `json:"source_url"`
+	Ranking       int      `json:"ranking,omitempty"`
+}
+
+// CatalogueEntry is a lightweight book reference returned by catalogue pages.
+type CatalogueEntry struct {
+	Title string `json:"title"`
+	URL   string `json:"url"`
+}
+
+// ChapterRef is a reference to a single chapter returned by chapter-list pages.
+type ChapterRef struct {
+	Number int    `json:"number"`
+	Title  string `json:"title"`
+	URL    string `json:"url"`
+	Volume int    `json:"volume,omitempty"`
+}
+
+// Chapter contains the fully-extracted text of a single chapter.
+type Chapter struct {
+	Ref  ChapterRef `json:"ref"`
+	Text string     `json:"text"`
+}
+
+// RankingItem represents a single entry in the novel ranking list.
+type RankingItem struct {
+	Rank      int       `json:"rank"`
+	Slug      string    `json:"slug"`
+	Title     string    `json:"title"`
+	Author    string    `json:"author,omitempty"`
+	Cover     string    `json:"cover,omitempty"`
+	Status    string    `json:"status,omitempty"`
+	Genres    []string  `json:"genres,omitempty"`
+	SourceURL string    `json:"source_url,omitempty"`
+	Updated   time.Time `json:"updated,omitempty"`
+}
+
+// ── Storage record types ──────────────────────────────────────────────────────
+
+// ChapterInfo is a lightweight chapter descriptor stored in the index.
+type ChapterInfo struct {
+	Number int    `json:"number"`
+	Title  string `json:"title"`
+	Date   string `json:"date,omitempty"`
+}
+
+// ReadingProgress holds a single user's reading position for one book.
+type ReadingProgress struct {
+	Slug      string    `json:"slug"`
+	Chapter   int       `json:"chapter"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+// ── Task record types ─────────────────────────────────────────────────────────
+
+// TaskStatus enumerates the lifecycle states of any task.
+type TaskStatus string
+
+const (
+	TaskStatusPending   TaskStatus = "pending"
+	TaskStatusRunning   TaskStatus = "running"
+	TaskStatusDone      TaskStatus = "done"
+	TaskStatusFailed    TaskStatus = "failed"
+	TaskStatusCancelled TaskStatus = "cancelled"
+)
+
+// ScrapeTask represents a book-scraping job stored in PocketBase.
+type ScrapeTask struct {
+	ID              string     `json:"id"`
+	Kind            string     `json:"kind"`       // "catalogue" | "book" | "book_range"
+	TargetURL       string     `json:"target_url"` // non-empty for single-book tasks
+	FromChapter     int        `json:"from_chapter,omitempty"`
+	ToChapter       int        `json:"to_chapter,omitempty"`
+	WorkerID        string     `json:"worker_id,omitempty"`
+	Status          TaskStatus `json:"status"`
+	BooksFound      int        `json:"books_found"`
+	ChaptersScraped int        `json:"chapters_scraped"`
+	ChaptersSkipped int        `json:"chapters_skipped"`
+	Errors          int        `json:"errors"`
+	Started         time.Time  `json:"started"`
+	Finished        time.Time  `json:"finished,omitempty"`
+	ErrorMessage    string     `json:"error_message,omitempty"`
+}
+
+// ScrapeResult is the outcome reported by the runner after finishing a ScrapeTask.
+type ScrapeResult struct {
+	BooksFound      int    `json:"books_found"`
+	ChaptersScraped int    `json:"chapters_scraped"`
+	ChaptersSkipped int    `json:"chapters_skipped"`
+	Errors          int    `json:"errors"`
+	ErrorMessage    string `json:"error_message,omitempty"`
+}
+
+// AudioTask represents an audio-generation job stored in PocketBase.
+type AudioTask struct {
+	ID           string     `json:"id"`
+	CacheKey     string     `json:"cache_key"` // "slug/chapter/voice"
+	Slug         string     `json:"slug"`
+	Chapter      int        `json:"chapter"`
+	Voice        string     `json:"voice"`
+	WorkerID     string     `json:"worker_id,omitempty"`
+	Status       TaskStatus `json:"status"`
+	ErrorMessage string     `json:"error_message,omitempty"`
+	Started      time.Time  `json:"started"`
+	Finished     time.Time  `json:"finished,omitempty"`
+}
+
+// AudioResult is the outcome reported by the runner after finishing an AudioTask.
+type AudioResult struct {
+	ObjectKey    string `json:"object_key,omitempty"`
+	ErrorMessage string `json:"error_message,omitempty"`
+}

backend/internal/domain/domain_test.go

@@ -0,0 +1,104 @@
+package domain_test
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/domain"
+)
+
+func TestBookMeta_JSONRoundtrip(t *testing.T) {
+	orig := domain.BookMeta{
+		Slug:          "a-great-novel",
+		Title:         "A Great Novel",
+		Author:        "Jane Doe",
+		Cover:         "https://example.com/cover.jpg",
+		Status:        "Ongoing",
+		Genres:        []string{"Fantasy", "Action"},
+		Summary:       "A thrilling tale.",
+		TotalChapters: 120,
+		SourceURL:     "https://novelfire.net/book/a-great-novel",
+		Ranking:       3,
+	}
+
+	b, err := json.Marshal(orig)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	var got domain.BookMeta
+	if err := json.Unmarshal(b, &got); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if got.Slug != orig.Slug {
+		t.Errorf("Slug: want %q, got %q", orig.Slug, got.Slug)
+	}
+	if got.TotalChapters != orig.TotalChapters {
+		t.Errorf("TotalChapters: want %d, got %d", orig.TotalChapters, got.TotalChapters)
+	}
+	if len(got.Genres) != len(orig.Genres) {
+		t.Errorf("Genres len: want %d, got %d", len(orig.Genres), len(got.Genres))
+	}
+}
+
+func TestChapterRef_JSONRoundtrip(t *testing.T) {
+	orig := domain.ChapterRef{Number: 42, Title: "The Battle", URL: "https://example.com/ch-42", Volume: 2}
+	b, _ := json.Marshal(orig)
+	var got domain.ChapterRef
+	json.Unmarshal(b, &got)
+	if got != orig {
+		t.Errorf("want %+v, got %+v", orig, got)
+	}
+}
+
+func TestRankingItem_JSONRoundtrip(t *testing.T) {
+	now := time.Now().Truncate(time.Second)
+	orig := domain.RankingItem{
+		Rank:      1,
+		Slug:      "top-novel",
+		Title:     "Top Novel",
+		SourceURL: "https://novelfire.net/book/top-novel",
+		Updated:   now,
+	}
+	b, _ := json.Marshal(orig)
+	var got domain.RankingItem
+	json.Unmarshal(b, &got)
+	if got.Rank != orig.Rank || got.Slug != orig.Slug {
+		t.Errorf("want %+v, got %+v", orig, got)
+	}
+}
+
+func TestScrapeResult_JSONRoundtrip(t *testing.T) {
+	orig := domain.ScrapeResult{BooksFound: 10, ChaptersScraped: 200, ChaptersSkipped: 5, Errors: 1, ErrorMessage: "one error"}
+	b, _ := json.Marshal(orig)
+	var got domain.ScrapeResult
+	json.Unmarshal(b, &got)
+	if got != orig {
+		t.Errorf("want %+v, got %+v", orig, got)
+	}
+}
+
+func TestAudioResult_JSONRoundtrip(t *testing.T) {
+	orig := domain.AudioResult{ObjectKey: "audio/slug/1/af_bella.mp3"}
+	b, _ := json.Marshal(orig)
+	var got domain.AudioResult
+	json.Unmarshal(b, &got)
+	if got != orig {
+		t.Errorf("want %+v, got %+v", orig, got)
+	}
+}
+
+func TestTaskStatus_Values(t *testing.T) {
+	cases := []domain.TaskStatus{
+		domain.TaskStatusPending,
+		domain.TaskStatusRunning,
+		domain.TaskStatusDone,
+		domain.TaskStatusFailed,
+		domain.TaskStatusCancelled,
+	}
+	for _, s := range cases {
+		if s == "" {
+			t.Errorf("TaskStatus constant must not be empty")
+		}
+	}
+}

backend/internal/httputil/httputil.go

@@ -0,0 +1,124 @@
+// Package httputil provides shared HTTP helpers used by both the runner and
+// backend binaries. It has no imports from this module — only the standard
+// library — so it is safe to import from anywhere in the dependency graph.
+package httputil
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+// Client is the minimal interface for making HTTP GET requests.
+// *http.Client satisfies this interface.
+type Client interface {
+	Do(req *http.Request) (*http.Response, error)
+}
+
+// ErrMaxRetries is returned when RetryGet exhausts all attempts.
+var ErrMaxRetries = errors.New("httputil: max retries exceeded")
+
+// errClientError is returned by doGet for 4xx responses; it signals that the
+// request should NOT be retried (the client is at fault).
+var errClientError = errors.New("httputil: client error")
+
+// RetryGet fetches url using client, retrying on network errors or 5xx
+// responses with exponential backoff. It returns the full response body as a
+// string on success.
+//
+//   - maxAttempts: total number of attempts (must be >= 1)
+//   - baseDelay:   initial wait before the second attempt; doubles each retry
+func RetryGet(ctx context.Context, client Client, url string, maxAttempts int, baseDelay time.Duration) (string, error) {
+	if maxAttempts < 1 {
+		maxAttempts = 1
+	}
+	delay := baseDelay
+
+	var lastErr error
+	for attempt := 0; attempt < maxAttempts; attempt++ {
+		if attempt > 0 {
+			select {
+			case <-ctx.Done():
+				return "", ctx.Err()
+			case <-time.After(delay):
+			}
+			delay *= 2
+		}
+
+		body, err := doGet(ctx, client, url)
+		if err == nil {
+			return body, nil
+		}
+		lastErr = err
+
+		// Do not retry on context cancellation.
+		if ctx.Err() != nil {
+			return "", ctx.Err()
+		}
+		// Do not retry on 4xx — the client is at fault.
+		if errors.Is(err, errClientError) {
+			return "", err
+		}
+	}
+
+	return "", fmt.Errorf("%w after %d attempts: %w", ErrMaxRetries, maxAttempts, lastErr)
+}
+
+func doGet(ctx context.Context, client Client, url string) (string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return "", fmt.Errorf("build request: %w", err)
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; libnovel-runner/2)")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("GET %s: %w", url, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 500 {
+		return "", fmt.Errorf("GET %s: server error %d", url, resp.StatusCode)
+	}
+	if resp.StatusCode >= 400 {
+		return "", fmt.Errorf("%w: GET %s: client error %d", errClientError, url, resp.StatusCode)
+	}
+
+	raw, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("read body %s: %w", url, err)
+	}
+	return string(raw), nil
+}
+
+// WriteJSON writes v as JSON to w with the given HTTP status code and sets the
+// Content-Type header to application/json.
+func WriteJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+// WriteError writes a JSON error object {"error": msg} with the given status.
+func WriteError(w http.ResponseWriter, status int, msg string) {
+	WriteJSON(w, status, map[string]string{"error": msg})
+}
+
+// maxBodyBytes is the limit applied by DecodeJSON to prevent unbounded reads.
+const maxBodyBytes = 1 << 20 // 1 MiB
+
+// DecodeJSON decodes a JSON request body into v. It enforces a 1 MiB size
+// limit and returns a descriptive error on any failure.
+func DecodeJSON(r *http.Request, v any) error {
+	r.Body = http.MaxBytesReader(nil, r.Body, maxBodyBytes)
+	dec := json.NewDecoder(r.Body)
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(v); err != nil {
+		return fmt.Errorf("decode JSON body: %w", err)
+	}
+	return nil
+}

backend/internal/httputil/httputil_test.go

@@ -0,0 +1,181 @@
+package httputil_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/httputil"
+)
+
+// ── RetryGet ──────────────────────────────────────────────────────────────────
+
+func TestRetryGet_ImmediateSuccess(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("hello"))
+	}))
+	defer srv.Close()
+
+	body, err := httputil.RetryGet(context.Background(), srv.Client(), srv.URL, 3, time.Millisecond)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if body != "hello" {
+		t.Errorf("want hello, got %q", body)
+	}
+}
+
+func TestRetryGet_RetriesOn5xx(t *testing.T) {
+	calls := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		calls++
+		if calls < 3 {
+			w.WriteHeader(http.StatusServiceUnavailable)
+			return
+		}
+		w.Write([]byte("ok"))
+	}))
+	defer srv.Close()
+
+	body, err := httputil.RetryGet(context.Background(), srv.Client(), srv.URL, 5, time.Millisecond)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if body != "ok" {
+		t.Errorf("want ok, got %q", body)
+	}
+	if calls != 3 {
+		t.Errorf("want 3 calls, got %d", calls)
+	}
+}
+
+func TestRetryGet_MaxAttemptsExceeded(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+	}))
+	defer srv.Close()
+
+	_, err := httputil.RetryGet(context.Background(), srv.Client(), srv.URL, 3, time.Millisecond)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+}
+
+func TestRetryGet_ContextCancelDuringBackoff(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}))
+	defer srv.Close()
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Cancel after first failed attempt hits the backoff wait.
+	go func() { time.Sleep(5 * time.Millisecond); cancel() }()
+
+	_, err := httputil.RetryGet(ctx, srv.Client(), srv.URL, 10, 500*time.Millisecond)
+	if err == nil {
+		t.Fatal("expected context cancellation error")
+	}
+}
+
+func TestRetryGet_NoRetryOn4xx(t *testing.T) {
+	calls := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		calls++
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer srv.Close()
+
+	_, err := httputil.RetryGet(context.Background(), srv.Client(), srv.URL, 5, time.Millisecond)
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+	// 4xx is NOT retried — should be exactly 1 call.
+	if calls != 1 {
+		t.Errorf("want 1 call for 4xx, got %d", calls)
+	}
+}
+
+// ── WriteJSON ─────────────────────────────────────────────────────────────────
+
+func TestWriteJSON_SetsHeadersAndStatus(t *testing.T) {
+	rr := httptest.NewRecorder()
+	httputil.WriteJSON(rr, http.StatusCreated, map[string]string{"key": "val"})
+
+	if rr.Code != http.StatusCreated {
+		t.Errorf("status: want 201, got %d", rr.Code)
+	}
+	if ct := rr.Header().Get("Content-Type"); ct != "application/json" {
+		t.Errorf("Content-Type: want application/json, got %q", ct)
+	}
+	var got map[string]string
+	if err := json.NewDecoder(rr.Body).Decode(&got); err != nil {
+		t.Fatalf("decode body: %v", err)
+	}
+	if got["key"] != "val" {
+		t.Errorf("body key: want val, got %q", got["key"])
+	}
+}
+
+// ── WriteError ────────────────────────────────────────────────────────────────
+
+func TestWriteError_Format(t *testing.T) {
+	rr := httptest.NewRecorder()
+	httputil.WriteError(rr, http.StatusBadRequest, "bad input")
+
+	if rr.Code != http.StatusBadRequest {
+		t.Errorf("status: want 400, got %d", rr.Code)
+	}
+	var got map[string]string
+	json.NewDecoder(rr.Body).Decode(&got)
+	if got["error"] != "bad input" {
+		t.Errorf("error field: want bad input, got %q", got["error"])
+	}
+}
+
+// ── DecodeJSON ────────────────────────────────────────────────────────────────
+
+func TestDecodeJSON_HappyPath(t *testing.T) {
+	body := `{"name":"test","value":42}`
+	req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(body))
+	req.Header.Set("Content-Type", "application/json")
+
+	var payload struct {
+		Name  string `json:"name"`
+		Value int    `json:"value"`
+	}
+	if err := httputil.DecodeJSON(req, &payload); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if payload.Name != "test" || payload.Value != 42 {
+		t.Errorf("unexpected payload: %+v", payload)
+	}
+}
+
+func TestDecodeJSON_UnknownFieldReturnsError(t *testing.T) {
+	body := `{"name":"test","unknown_field":"boom"}`
+	req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(body))
+
+	var payload struct {
+		Name string `json:"name"`
+	}
+	if err := httputil.DecodeJSON(req, &payload); err == nil {
+		t.Fatal("expected error for unknown field, got nil")
+	}
+}
+
+func TestDecodeJSON_BodyTooLarge(t *testing.T) {
+	// Build a body > 1 MiB.
+	big := bytes.Repeat([]byte("a"), 2<<20)
+	req := httptest.NewRequest(http.MethodPost, "/", bytes.NewReader(big))
+
+	var payload map[string]any
+	if err := httputil.DecodeJSON(req, &payload); err == nil {
+		t.Fatal("expected error for oversized body, got nil")
+	}
+}

backend/internal/kokoro/client.go

@@ -0,0 +1,160 @@
+// Package kokoro provides a client for the Kokoro-FastAPI TTS service.
+//
+// The Kokoro API is an OpenAI-compatible audio speech API that returns a
+// download link (X-Download-Path header) instead of streaming audio directly.
+// GenerateAudio handles the two-step flow: POST /v1/audio/speech → GET /v1/download/{file}.
+package kokoro
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// Client is the interface for interacting with the Kokoro TTS service.
+type Client interface {
+	// GenerateAudio synthesises text using voice and returns raw MP3 bytes.
+	GenerateAudio(ctx context.Context, text, voice string) ([]byte, error)
+
+	// ListVoices returns the available voice IDs. Falls back to an empty slice
+	// on error — callers should treat an empty list as "service unavailable".
+	ListVoices(ctx context.Context) ([]string, error)
+}
+
+// httpClient is the concrete Kokoro HTTP client.
+type httpClient struct {
+	baseURL string
+	http    *http.Client
+}
+
+// New returns a Kokoro Client targeting baseURL (e.g. "https://kokoro.example.com").
+func New(baseURL string) Client {
+	return &httpClient{
+		baseURL: strings.TrimRight(baseURL, "/"),
+		http:    &http.Client{Timeout: 10 * time.Minute},
+	}
+}
+
+// GenerateAudio calls POST /v1/audio/speech (return_download_link=true) and then
+// downloads the resulting MP3 from GET /v1/download/{filename}.
+func (c *httpClient) GenerateAudio(ctx context.Context, text, voice string) ([]byte, error) {
+	if text == "" {
+		return nil, fmt.Errorf("kokoro: empty text")
+	}
+	if voice == "" {
+		voice = "af_bella"
+	}
+
+	// ── Step 1: request generation ────────────────────────────────────────────
+	reqBody, err := json.Marshal(map[string]any{
+		"model":                "kokoro",
+		"input":                text,
+		"voice":                voice,
+		"response_format":      "mp3",
+		"speed":                1.0,
+		"stream":               false,
+		"return_download_link": true,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: marshal request: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
+		c.baseURL+"/v1/audio/speech", bytes.NewReader(reqBody))
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: build speech request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: speech request: %w", err)
+	}
+	defer resp.Body.Close()
+	_, _ = io.Copy(io.Discard, resp.Body)
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("kokoro: speech returned %d", resp.StatusCode)
+	}
+
+	dlPath := resp.Header.Get("X-Download-Path")
+	if dlPath == "" {
+		return nil, fmt.Errorf("kokoro: no X-Download-Path header in response")
+	}
+	filename := dlPath
+	if idx := strings.LastIndex(dlPath, "/"); idx >= 0 {
+		filename = dlPath[idx+1:]
+	}
+	if filename == "" {
+		return nil, fmt.Errorf("kokoro: empty filename in X-Download-Path: %q", dlPath)
+	}
+
+	// ── Step 2: download the generated file ───────────────────────────────────
+	dlURL := c.baseURL + "/v1/download/" + filename
+	dlReq, err := http.NewRequestWithContext(ctx, http.MethodGet, dlURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: build download request: %w", err)
+	}
+
+	dlResp, err := c.http.Do(dlReq)
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: download request: %w", err)
+	}
+	defer dlResp.Body.Close()
+
+	if dlResp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("kokoro: download returned %d", dlResp.StatusCode)
+	}
+
+	data, err := io.ReadAll(dlResp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: read download body: %w", err)
+	}
+	return data, nil
+}
+
+// ListVoices calls GET /v1/audio/voices and returns the list of voice IDs.
+func (c *httpClient) ListVoices(ctx context.Context) ([]string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet,
+		c.baseURL+"/v1/audio/voices", nil)
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: build voices request: %w", err)
+	}
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("kokoro: voices request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		_, _ = io.Copy(io.Discard, resp.Body)
+		return nil, fmt.Errorf("kokoro: voices returned %d", resp.StatusCode)
+	}
+
+	var result struct {
+		Voices []string `json:"voices"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		return nil, fmt.Errorf("kokoro: decode voices response: %w", err)
+	}
+	return result.Voices, nil
+}
+
+// VoiceSampleKey returns the MinIO object key for a voice sample MP3.
+// Key: _voice-samples/{voice}.mp3 (sanitised).
+func VoiceSampleKey(voice string) string {
+	safe := strings.Map(func(r rune) rune {
+		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') ||
+			(r >= '0' && r <= '9') || r == '_' || r == '-' {
+			return r
+		}
+		return '_'
+	}, voice)
+	return fmt.Sprintf("_voice-samples/%s.mp3", safe)
+}

backend/internal/kokoro/client_test.go

@@ -0,0 +1,291 @@
+package kokoro_test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/libnovel/backend/internal/kokoro"
+)
+
+// ── VoiceSampleKey ────────────────────────────────────────────────────────────
+
+func TestVoiceSampleKey(t *testing.T) {
+	tests := []struct {
+		voice string
+		want  string
+	}{
+		{"af_bella", "_voice-samples/af_bella.mp3"},
+		{"am_echo", "_voice-samples/am_echo.mp3"},
+		{"voice with spaces", "_voice-samples/voice_with_spaces.mp3"},
+		{"special!@#chars", "_voice-samples/special___chars.mp3"},
+		{"", "_voice-samples/.mp3"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.voice, func(t *testing.T) {
+			got := kokoro.VoiceSampleKey(tt.voice)
+			if got != tt.want {
+				t.Errorf("VoiceSampleKey(%q) = %q, want %q", tt.voice, got, tt.want)
+			}
+		})
+	}
+}
+
+// ── GenerateAudio ─────────────────────────────────────────────────────────────
+
+func TestGenerateAudio_EmptyText(t *testing.T) {
+	srv := httptest.NewServer(http.NotFoundHandler())
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	_, err := c.GenerateAudio(context.Background(), "", "af_bella")
+	if err == nil {
+		t.Fatal("expected error for empty text, got nil")
+	}
+	if !strings.Contains(err.Error(), "empty text") {
+		t.Errorf("expected 'empty text' in error, got: %v", err)
+	}
+}
+
+func TestGenerateAudio_DefaultVoice(t *testing.T) {
+	// Tracks that the voice defaults to af_bella when empty.
+	var capturedBody string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/speech" {
+			buf := make([]byte, 512)
+			n, _ := r.Body.Read(buf)
+			capturedBody = string(buf[:n])
+			w.Header().Set("X-Download-Path", "/download/test_file.mp3")
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		if strings.HasPrefix(r.URL.Path, "/v1/download/") {
+			w.WriteHeader(http.StatusOK)
+			_, _ = w.Write([]byte("fake-mp3-data"))
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	data, err := c.GenerateAudio(context.Background(), "hello world", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(data) != "fake-mp3-data" {
+		t.Errorf("unexpected data: %q", string(data))
+	}
+	if !strings.Contains(capturedBody, `"af_bella"`) {
+		t.Errorf("expected default voice af_bella in request body, got: %s", capturedBody)
+	}
+}
+
+func TestGenerateAudio_SpeechNon200(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/speech" {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	_, err := c.GenerateAudio(context.Background(), "text", "af_bella")
+	if err == nil {
+		t.Fatal("expected error for non-200 speech response")
+	}
+	if !strings.Contains(err.Error(), "500") {
+		t.Errorf("expected 500 in error, got: %v", err)
+	}
+}
+
+func TestGenerateAudio_NoDownloadPathHeader(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/speech" {
+			// No X-Download-Path header
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	_, err := c.GenerateAudio(context.Background(), "text", "af_bella")
+	if err == nil {
+		t.Fatal("expected error for missing X-Download-Path")
+	}
+	if !strings.Contains(err.Error(), "X-Download-Path") {
+		t.Errorf("expected X-Download-Path in error, got: %v", err)
+	}
+}
+
+func TestGenerateAudio_DownloadFails(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/speech" {
+			w.Header().Set("X-Download-Path", "/v1/download/speech.mp3")
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		if strings.HasPrefix(r.URL.Path, "/v1/download/") {
+			w.WriteHeader(http.StatusNotFound)
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	_, err := c.GenerateAudio(context.Background(), "text", "af_bella")
+	if err == nil {
+		t.Fatal("expected error for failed download")
+	}
+	if !strings.Contains(err.Error(), "404") {
+		t.Errorf("expected 404 in error, got: %v", err)
+	}
+}
+
+func TestGenerateAudio_FullPath(t *testing.T) {
+	// X-Download-Path with a full path: extract just filename.
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/speech" {
+			w.Header().Set("X-Download-Path", "/some/nested/path/audio_abc123.mp3")
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		if r.URL.Path == "/v1/download/audio_abc123.mp3" {
+			_, _ = w.Write([]byte("audio-bytes"))
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	data, err := c.GenerateAudio(context.Background(), "text", "af_bella")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(data) != "audio-bytes" {
+		t.Errorf("unexpected data: %q", string(data))
+	}
+}
+
+func TestGenerateAudio_ContextCancelled(t *testing.T) {
+	// Server that hangs — context should cancel before we get a response.
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Never respond.
+		select {}
+	}))
+	defer srv.Close()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // cancel immediately
+
+	c := kokoro.New(srv.URL)
+	_, err := c.GenerateAudio(ctx, "text", "af_bella")
+	if err == nil {
+		t.Fatal("expected error for cancelled context")
+	}
+}
+
+// ── ListVoices ────────────────────────────────────────────────────────────────
+
+func TestListVoices_Success(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/voices" {
+			w.Header().Set("Content-Type", "application/json")
+			_, _ = w.Write([]byte(`{"voices":["af_bella","am_adam","bf_emma"]}`))
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	voices, err := c.ListVoices(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(voices) != 3 {
+		t.Errorf("expected 3 voices, got %d: %v", len(voices), voices)
+	}
+	if voices[0] != "af_bella" {
+		t.Errorf("expected first voice to be af_bella, got %q", voices[0])
+	}
+}
+
+func TestListVoices_Non200(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	_, err := c.ListVoices(context.Background())
+	if err == nil {
+		t.Fatal("expected error for non-200 response")
+	}
+	if !strings.Contains(err.Error(), "503") {
+		t.Errorf("expected 503 in error, got: %v", err)
+	}
+}
+
+func TestListVoices_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte(`not-json`))
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	_, err := c.ListVoices(context.Background())
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestListVoices_EmptyVoices(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"voices":[]}`))
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL)
+	voices, err := c.ListVoices(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(voices) != 0 {
+		t.Errorf("expected 0 voices, got %d", len(voices))
+	}
+}
+
+// ── New ───────────────────────────────────────────────────────────────────────
+
+func TestNew_TrailingSlashStripped(t *testing.T) {
+	// Verify that a trailing slash on baseURL doesn't produce double-slash paths.
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/v1/audio/voices" {
+			w.Header().Set("Content-Type", "application/json")
+			_, _ = w.Write([]byte(`{"voices":["af_bella"]}`))
+			return
+		}
+		http.NotFound(w, r)
+	}))
+	defer srv.Close()
+
+	c := kokoro.New(srv.URL + "/") // trailing slash
+	voices, err := c.ListVoices(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(voices) == 0 {
+		t.Error("expected at least one voice")
+	}
+}

backend/internal/novelfire/htmlutil/htmlutil.go

@@ -0,0 +1,228 @@
+// Package htmlutil provides helper functions for parsing HTML with
+// golang.org/x/net/html and extracting values by Selector descriptors.
+package htmlutil
+
+import (
+	"net/url"
+	"regexp"
+	"strings"
+
+	"github.com/libnovel/backend/internal/scraper"
+	"golang.org/x/net/html"
+)
+
+// ResolveURL returns an absolute URL. If href is already absolute it is
+// returned unchanged. Otherwise it is resolved against base.
+func ResolveURL(base, href string) string {
+	if strings.HasPrefix(href, "http://") || strings.HasPrefix(href, "https://") {
+		return href
+	}
+	b, err := url.Parse(base)
+	if err != nil {
+		return base + href
+	}
+	ref, err := url.Parse(href)
+	if err != nil {
+		return base + href
+	}
+	return b.ResolveReference(ref).String()
+}
+
+// ParseHTML parses raw HTML and returns the root node.
+func ParseHTML(raw string) (*html.Node, error) {
+	return html.Parse(strings.NewReader(raw))
+}
+
+// selectorMatches reports whether node n matches sel.
+func selectorMatches(n *html.Node, sel scraper.Selector) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+	if sel.Tag != "" && n.Data != sel.Tag {
+		return false
+	}
+	if sel.ID != "" {
+		for _, a := range n.Attr {
+			if a.Key == "id" && a.Val == sel.ID {
+				goto checkClass
+			}
+		}
+		return false
+	}
+checkClass:
+	if sel.Class != "" {
+		for _, a := range n.Attr {
+			if a.Key == "class" {
+				for _, cls := range strings.Fields(a.Val) {
+					if cls == sel.Class {
+						goto matched
+					}
+				}
+			}
+		}
+		return false
+	}
+matched:
+	return true
+}
+
+// AttrVal returns the value of attribute key from node n.
+func AttrVal(n *html.Node, key string) string {
+	for _, a := range n.Attr {
+		if a.Key == key {
+			return a.Val
+		}
+	}
+	return ""
+}
+
+// TextContent returns the concatenated text content of all descendant text nodes.
+func TextContent(n *html.Node) string {
+	var sb strings.Builder
+	var walk func(*html.Node)
+	walk = func(cur *html.Node) {
+		if cur.Type == html.TextNode {
+			sb.WriteString(cur.Data)
+		}
+		for c := cur.FirstChild; c != nil; c = c.NextSibling {
+			walk(c)
+		}
+	}
+	walk(n)
+	return strings.TrimSpace(sb.String())
+}
+
+// FindFirst returns the first node matching sel within root.
+func FindFirst(root *html.Node, sel scraper.Selector) *html.Node {
+	var found *html.Node
+	var walk func(*html.Node) bool
+	walk = func(n *html.Node) bool {
+		if selectorMatches(n, sel) {
+			found = n
+			return true
+		}
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			if walk(c) {
+				return true
+			}
+		}
+		return false
+	}
+	walk(root)
+	return found
+}
+
+// FindAll returns all nodes matching sel within root.
+func FindAll(root *html.Node, sel scraper.Selector) []*html.Node {
+	var results []*html.Node
+	var walk func(*html.Node)
+	walk = func(n *html.Node) {
+		if selectorMatches(n, sel) {
+			results = append(results, n)
+		}
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			walk(c)
+		}
+	}
+	walk(root)
+	return results
+}
+
+// ExtractText extracts a string value from node n using sel.
+// If sel.Attr is set the attribute value is returned; otherwise the inner text.
+func ExtractText(n *html.Node, sel scraper.Selector) string {
+	if sel.Attr != "" {
+		return AttrVal(n, sel.Attr)
+	}
+	return TextContent(n)
+}
+
+// ExtractFirst locates the first match in root and returns its text/attr value.
+func ExtractFirst(root *html.Node, sel scraper.Selector) string {
+	n := FindFirst(root, sel)
+	if n == nil {
+		return ""
+	}
+	return ExtractText(n, sel)
+}
+
+// ExtractAll locates all matches in root and returns their text/attr values.
+func ExtractAll(root *html.Node, sel scraper.Selector) []string {
+	nodes := FindAll(root, sel)
+	out := make([]string, 0, len(nodes))
+	for _, n := range nodes {
+		if v := ExtractText(n, sel); v != "" {
+			out = append(out, v)
+		}
+	}
+	return out
+}
+
+// NodeToMarkdown converts the children of an HTML node to a plain-text/Markdown
+// representation suitable for chapter storage.
+func NodeToMarkdown(n *html.Node) string {
+	var sb strings.Builder
+	nodeToMD(n, &sb)
+	out := multiBlankLine.ReplaceAllString(sb.String(), "\n\n")
+	return strings.TrimSpace(out)
+}
+
+var multiBlankLine = regexp.MustCompile(`\n(\s*\n){2,}`)
+
+var blockElements = map[string]bool{
+	"p": true, "div": true, "br": true, "h1": true, "h2": true,
+	"h3": true, "h4": true, "h5": true, "h6": true, "li": true,
+	"blockquote": true, "pre": true, "hr": true,
+}
+
+func nodeToMD(n *html.Node, sb *strings.Builder) {
+	switch n.Type {
+	case html.TextNode:
+		sb.WriteString(n.Data)
+	case html.ElementNode:
+		tag := n.Data
+		switch tag {
+		case "br":
+			sb.WriteString("\n")
+		case "hr":
+			sb.WriteString("\n---\n")
+		case "h1", "h2", "h3", "h4", "h5", "h6":
+			level := int(tag[1] - '0')
+			sb.WriteString("\n" + strings.Repeat("#", level) + " ")
+			for c := n.FirstChild; c != nil; c = c.NextSibling {
+				nodeToMD(c, sb)
+			}
+			sb.WriteString("\n\n")
+			return
+		case "p", "div", "blockquote":
+			sb.WriteString("\n")
+			for c := n.FirstChild; c != nil; c = c.NextSibling {
+				nodeToMD(c, sb)
+			}
+			sb.WriteString("\n")
+			return
+		case "em", "i":
+			sb.WriteString("*")
+			for c := n.FirstChild; c != nil; c = c.NextSibling {
+				nodeToMD(c, sb)
+			}
+			sb.WriteString("*")
+			return
+		case "strong", "b":
+			sb.WriteString("**")
+			for c := n.FirstChild; c != nil; c = c.NextSibling {
+				nodeToMD(c, sb)
+			}
+			sb.WriteString("**")
+			return
+		case "script", "style", "noscript":
+			return // drop
+		}
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			nodeToMD(c, sb)
+		}
+		if blockElements[tag] {
+			sb.WriteString("\n")
+		}
+	}
+}

backend/internal/novelfire/scraper.go

@@ -0,0 +1,498 @@
+// Package novelfire provides a NovelScraper implementation for novelfire.net.
+//
+// Site structure (as of 2025):
+//
+//	Catalogue : https://novelfire.net/genre-all/sort-new/status-all/all-novel?page=N
+//	Book page : https://novelfire.net/book/{slug}
+//	Chapters  : https://novelfire.net/book/{slug}/chapters?page=N
+//	Chapter   : https://novelfire.net/book/{slug}/{chapter-slug}
+package novelfire
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/url"
+	"path"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/libnovel/backend/internal/browser"
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/novelfire/htmlutil"
+	"github.com/libnovel/backend/internal/scraper"
+	"golang.org/x/net/html"
+)
+
+const (
+	baseURL       = "https://novelfire.net"
+	cataloguePath = "/genre-all/sort-new/status-all/all-novel"
+	rankingPath   = "/genre-all/sort-popular/status-all/all-novel"
+)
+
+// Scraper is the novelfire.net implementation of scraper.NovelScraper.
+type Scraper struct {
+	client browser.Client
+	log    *slog.Logger
+}
+
+// Compile-time interface check.
+var _ scraper.NovelScraper = (*Scraper)(nil)
+
+// New returns a new novelfire Scraper backed by client.
+func New(client browser.Client, log *slog.Logger) *Scraper {
+	if log == nil {
+		log = slog.Default()
+	}
+	return &Scraper{client: client, log: log}
+}
+
+// SourceName implements NovelScraper.
+func (s *Scraper) SourceName() string { return "novelfire.net" }
+
+// ── CatalogueProvider ─────────────────────────────────────────────────────────
+
+// ScrapeCatalogue streams all CatalogueEntry values across all catalogue pages.
+func (s *Scraper) ScrapeCatalogue(ctx context.Context) (<-chan domain.CatalogueEntry, <-chan error) {
+	entries := make(chan domain.CatalogueEntry, 64)
+	errs := make(chan error, 16)
+
+	go func() {
+		defer close(entries)
+		defer close(errs)
+
+		pageURL := baseURL + cataloguePath
+		page := 1
+
+		for pageURL != "" {
+			select {
+			case <-ctx.Done():
+				return
+			default:
+			}
+
+			s.log.Info("scraping catalogue page", "page", page, "url", pageURL)
+			raw, err := s.client.GetContent(ctx, pageURL)
+			if err != nil {
+				errs <- fmt.Errorf("catalogue page %d: %w", page, err)
+				return
+			}
+
+			root, err := htmlutil.ParseHTML(raw)
+			if err != nil {
+				errs <- fmt.Errorf("catalogue page %d parse: %w", page, err)
+				return
+			}
+
+			cards := htmlutil.FindAll(root, scraper.Selector{Tag: "li", Class: "novel-item", Multiple: true})
+			if len(cards) == 0 {
+				s.log.Warn("no novel cards found, stopping pagination", "page", page)
+				return
+			}
+
+			for _, card := range cards {
+				linkNode := htmlutil.FindFirst(card, scraper.Selector{Tag: "a", Attr: "href"})
+				titleNode := htmlutil.FindFirst(card, scraper.Selector{Tag: "h4", Class: "novel-title"})
+
+				var title, href string
+				if linkNode != nil {
+					href = htmlutil.ExtractText(linkNode, scraper.Selector{Tag: "a", Attr: "href"})
+				}
+				if titleNode != nil {
+					title = strings.TrimSpace(htmlutil.ExtractText(titleNode, scraper.Selector{}))
+				}
+				if href == "" || title == "" {
+					continue
+				}
+
+				bookURL := resolveURL(baseURL, href)
+				select {
+				case <-ctx.Done():
+					return
+				case entries <- domain.CatalogueEntry{Title: title, URL: bookURL}:
+				}
+			}
+
+			if !hasNextPageLink(root) {
+				break
+			}
+			nextHref := ""
+			for _, a := range htmlutil.FindAll(root, scraper.Selector{Tag: "a", Multiple: true}) {
+				if htmlutil.AttrVal(a, "rel") == "next" {
+					nextHref = htmlutil.AttrVal(a, "href")
+					break
+				}
+			}
+			if nextHref == "" {
+				break
+			}
+			pageURL = resolveURL(baseURL, nextHref)
+			page++
+		}
+	}()
+
+	return entries, errs
+}
+
+// ── MetadataProvider ──────────────────────────────────────────────────────────
+
+// ScrapeMetadata fetches and parses book metadata from the book's landing page.
+func (s *Scraper) ScrapeMetadata(ctx context.Context, bookURL string) (domain.BookMeta, error) {
+	s.log.Debug("metadata fetch starting", "url", bookURL)
+
+	raw, err := s.client.GetContent(ctx, bookURL)
+	if err != nil {
+		return domain.BookMeta{}, fmt.Errorf("metadata fetch %s: %w", bookURL, err)
+	}
+
+	root, err := htmlutil.ParseHTML(raw)
+	if err != nil {
+		return domain.BookMeta{}, fmt.Errorf("metadata parse %s: %w", bookURL, err)
+	}
+
+	title := htmlutil.ExtractFirst(root, scraper.Selector{Tag: "h1", Class: "novel-title"})
+	author := htmlutil.ExtractFirst(root, scraper.Selector{Tag: "span", Class: "author"})
+
+	var cover string
+	if fig := htmlutil.FindFirst(root, scraper.Selector{Tag: "figure", Class: "cover"}); fig != nil {
+		cover = htmlutil.ExtractFirst(fig, scraper.Selector{Tag: "img", Attr: "src"})
+		if cover != "" && !strings.HasPrefix(cover, "http") {
+			cover = baseURL + cover
+		}
+	}
+
+	status := htmlutil.ExtractFirst(root, scraper.Selector{Tag: "span", Class: "status"})
+
+	genresNode := htmlutil.FindFirst(root, scraper.Selector{Tag: "div", Class: "genres"})
+	var genres []string
+	if genresNode != nil {
+		genres = htmlutil.ExtractAll(genresNode, scraper.Selector{Tag: "a", Multiple: true})
+	}
+
+	summary := htmlutil.ExtractFirst(root, scraper.Selector{Tag: "div", Class: "summary"})
+	totalStr := htmlutil.ExtractFirst(root, scraper.Selector{Tag: "span", Class: "chapter-count"})
+	totalChapters := parseChapterCount(totalStr)
+
+	slug := slugFromURL(bookURL)
+
+	meta := domain.BookMeta{
+		Slug:          slug,
+		Title:         title,
+		Author:        author,
+		Cover:         cover,
+		Status:        status,
+		Genres:        genres,
+		Summary:       summary,
+		TotalChapters: totalChapters,
+		SourceURL:     bookURL,
+	}
+	s.log.Debug("metadata parsed", "slug", meta.Slug, "title", meta.Title)
+	return meta, nil
+}
+
+// ── ChapterListProvider ───────────────────────────────────────────────────────
+
+// ScrapeChapterList returns all chapter references for a book, ordered ascending.
+func (s *Scraper) ScrapeChapterList(ctx context.Context, bookURL string) ([]domain.ChapterRef, error) {
+	var refs []domain.ChapterRef
+	baseChapterURL := strings.TrimRight(bookURL, "/") + "/chapters"
+	page := 1
+
+	for {
+		select {
+		case <-ctx.Done():
+			return refs, ctx.Err()
+		default:
+		}
+
+		pageURL := fmt.Sprintf("%s?page=%d", baseChapterURL, page)
+		s.log.Info("scraping chapter list", "page", page, "url", pageURL)
+
+		raw, err := s.client.GetContent(ctx, pageURL)
+		if err != nil {
+			return refs, fmt.Errorf("chapter list page %d: %w", page, err)
+		}
+
+		root, err := htmlutil.ParseHTML(raw)
+		if err != nil {
+			return refs, fmt.Errorf("chapter list page %d parse: %w", page, err)
+		}
+
+		chapterList := htmlutil.FindFirst(root, scraper.Selector{Class: "chapter-list"})
+		if chapterList == nil {
+			s.log.Debug("chapter list container not found, stopping pagination", "page", page)
+			break
+		}
+
+		items := htmlutil.FindAll(chapterList, scraper.Selector{Tag: "li"})
+		if len(items) == 0 {
+			break
+		}
+
+		for _, item := range items {
+			linkNode := htmlutil.FindFirst(item, scraper.Selector{Tag: "a"})
+			if linkNode == nil {
+				continue
+			}
+			href := htmlutil.ExtractText(linkNode, scraper.Selector{Attr: "href"})
+			chTitle := htmlutil.ExtractText(linkNode, scraper.Selector{})
+			if href == "" {
+				continue
+			}
+			chURL := resolveURL(baseURL, href)
+			num := chapterNumberFromURL(chURL)
+			if num <= 0 {
+				num = len(refs) + 1
+				s.log.Warn("chapter number not parseable from URL, falling back to position",
+					"url", chURL, "position", num)
+			}
+			refs = append(refs, domain.ChapterRef{
+				Number: num,
+				Title:  strings.TrimSpace(chTitle),
+				URL:    chURL,
+			})
+		}
+
+		page++
+	}
+
+	return refs, nil
+}
+
+// ── ChapterTextProvider ───────────────────────────────────────────────────────
+
+// ScrapeChapterText fetches and parses a single chapter page.
+func (s *Scraper) ScrapeChapterText(ctx context.Context, ref domain.ChapterRef) (domain.Chapter, error) {
+	s.log.Debug("chapter text fetch starting", "chapter", ref.Number, "url", ref.URL)
+
+	raw, err := retryGet(ctx, s.log, s.client, ref.URL, 9, 6*time.Second)
+	if err != nil {
+		return domain.Chapter{}, fmt.Errorf("chapter %d fetch: %w", ref.Number, err)
+	}
+
+	root, err := htmlutil.ParseHTML(raw)
+	if err != nil {
+		return domain.Chapter{}, fmt.Errorf("chapter %d parse: %w", ref.Number, err)
+	}
+
+	container := htmlutil.FindFirst(root, scraper.Selector{ID: "content"})
+	if container == nil {
+		return domain.Chapter{}, fmt.Errorf("chapter %d: #content container not found in %s", ref.Number, ref.URL)
+	}
+
+	text := htmlutil.NodeToMarkdown(container)
+
+	s.log.Debug("chapter text parsed", "chapter", ref.Number, "text_bytes", len(text))
+
+	return domain.Chapter{Ref: ref, Text: text}, nil
+}
+
+// ── RankingProvider ───────────────────────────────────────────────────────────
+
+// ScrapeRanking pages through up to maxPages pages of the popular-novels listing.
+// maxPages <= 0 means all pages. The caller decides whether to persist items.
+func (s *Scraper) ScrapeRanking(ctx context.Context, maxPages int) (<-chan domain.BookMeta, <-chan error) {
+	entries := make(chan domain.BookMeta, 32)
+	errs := make(chan error, 16)
+
+	go func() {
+		defer close(entries)
+		defer close(errs)
+
+		rank := 1
+
+		for page := 1; maxPages <= 0 || page <= maxPages; page++ {
+			select {
+			case <-ctx.Done():
+				return
+			default:
+			}
+
+			pageURL := fmt.Sprintf("%s%s?page=%d", baseURL, rankingPath, page)
+			s.log.Info("scraping popular ranking page", "page", page, "url", pageURL)
+
+			raw, err := s.client.GetContent(ctx, pageURL)
+			if err != nil {
+				errs <- fmt.Errorf("ranking page %d: %w", page, err)
+				return
+			}
+
+			root, err := htmlutil.ParseHTML(raw)
+			if err != nil {
+				errs <- fmt.Errorf("ranking page %d parse: %w", page, err)
+				return
+			}
+
+			cards := htmlutil.FindAll(root, scraper.Selector{Tag: "li", Class: "novel-item", Multiple: true})
+			if len(cards) == 0 {
+				break
+			}
+
+			for _, card := range cards {
+				linkNode := htmlutil.FindFirst(card, scraper.Selector{Tag: "a"})
+				if linkNode == nil {
+					continue
+				}
+				href := htmlutil.ExtractText(linkNode, scraper.Selector{Tag: "a", Attr: "href"})
+				bookURL := resolveURL(baseURL, href)
+				if bookURL == "" {
+					continue
+				}
+
+				title := strings.TrimSpace(htmlutil.ExtractFirst(card, scraper.Selector{Tag: "h4", Class: "novel-title"}))
+				if title == "" {
+					title = strings.TrimSpace(htmlutil.ExtractText(linkNode, scraper.Selector{Tag: "a", Attr: "title"}))
+				}
+				if title == "" {
+					continue
+				}
+
+				var cover string
+				if fig := htmlutil.FindFirst(card, scraper.Selector{Tag: "figure", Class: "novel-cover"}); fig != nil {
+					cover = htmlutil.ExtractFirst(fig, scraper.Selector{Tag: "img", Attr: "data-src"})
+					if cover == "" {
+						cover = htmlutil.ExtractFirst(fig, scraper.Selector{Tag: "img", Attr: "src"})
+					}
+					if strings.HasPrefix(cover, "data:") {
+						cover = ""
+					}
+					if cover != "" && !strings.HasPrefix(cover, "http") {
+						cover = baseURL + cover
+					}
+				}
+
+				meta := domain.BookMeta{
+					Slug:      slugFromURL(bookURL),
+					Title:     title,
+					Cover:     cover,
+					SourceURL: bookURL,
+					Ranking:   rank,
+				}
+				rank++
+
+				select {
+				case <-ctx.Done():
+					return
+				case entries <- meta:
+				}
+			}
+
+			if !hasNextPageLink(root) {
+				break
+			}
+		}
+	}()
+
+	return entries, errs
+}
+
+// ── helpers ───────────────────────────────────────────────────────────────────
+
+func resolveURL(base, href string) string { return htmlutil.ResolveURL(base, href) }
+
+func hasNextPageLink(root *html.Node) bool {
+	links := htmlutil.FindAll(root, scraper.Selector{Tag: "a", Multiple: true})
+	for _, a := range links {
+		for _, attr := range a.Attr {
+			if attr.Key == "rel" && attr.Val == "next" {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func slugFromURL(bookURL string) string {
+	u, err := url.Parse(bookURL)
+	if err != nil {
+		return bookURL
+	}
+	parts := strings.Split(strings.Trim(u.Path, "/"), "/")
+	if len(parts) >= 2 && parts[0] == "book" {
+		return parts[1]
+	}
+	if len(parts) > 0 {
+		return parts[len(parts)-1]
+	}
+	return ""
+}
+
+func parseChapterCount(s string) int {
+	s = strings.ReplaceAll(s, ",", "")
+	fields := strings.Fields(s)
+	if len(fields) == 0 {
+		return 0
+	}
+	n, _ := strconv.Atoi(fields[0])
+	return n
+}
+
+func chapterNumberFromURL(chapterURL string) int {
+	u, err := url.Parse(chapterURL)
+	if err != nil {
+		return 0
+	}
+	seg := path.Base(u.Path)
+	seg = strings.TrimPrefix(seg, "chapter-")
+	seg = strings.TrimPrefix(seg, "chap-")
+	seg = strings.TrimPrefix(seg, "ch-")
+	digits := strings.FieldsFunc(seg, func(r rune) bool {
+		return r < '0' || r > '9'
+	})
+	if len(digits) == 0 {
+		return 0
+	}
+	n, _ := strconv.Atoi(digits[0])
+	return n
+}
+
+// retryGet calls client.GetContent up to maxAttempts times with exponential backoff.
+// If the server returns 429 (ErrRateLimit), the suggested Retry-After delay is used
+// instead of the geometric backoff delay.
+func retryGet(
+	ctx context.Context,
+	log *slog.Logger,
+	client browser.Client,
+	pageURL string,
+	maxAttempts int,
+	baseDelay time.Duration,
+) (string, error) {
+	var lastErr error
+	delay := baseDelay
+	for attempt := 1; attempt <= maxAttempts; attempt++ {
+		raw, err := client.GetContent(ctx, pageURL)
+		if err == nil {
+			return raw, nil
+		}
+		lastErr = err
+		if ctx.Err() != nil {
+			return "", err
+		}
+		if attempt < maxAttempts {
+			// If the server is rate-limiting us, honour its Retry-After delay.
+			waitFor := delay
+			var rlErr *browser.RateLimitError
+			if errors.As(err, &rlErr) {
+				waitFor = rlErr.RetryAfter
+				if log != nil {
+					log.Warn("rate limited, backing off",
+						"url", pageURL, "attempt", attempt, "retry_in", waitFor)
+				}
+			} else {
+				if log != nil {
+					log.Warn("fetch failed, retrying",
+						"url", pageURL, "attempt", attempt, "retry_in", delay, "err", err)
+				}
+				delay *= 2
+			}
+			select {
+			case <-ctx.Done():
+				return "", ctx.Err()
+			case <-time.After(waitFor):
+			}
+		}
+	}
+	return "", lastErr
+}

backend/internal/novelfire/scraper_test.go

@@ -0,0 +1,129 @@
+package novelfire
+
+import (
+	"context"
+	"testing"
+)
+
+func TestSlugFromURL(t *testing.T) {
+	cases := []struct {
+		url  string
+		want string
+	}{
+		{"https://novelfire.net/book/shadow-slave", "shadow-slave"},
+		{"https://novelfire.net/book/a-dragon-against-the-whole-world", "a-dragon-against-the-whole-world"},
+		{"https://novelfire.net/book/foo/chapter-1", "foo"},
+		{"https://novelfire.net/", ""},
+		{"not-a-url", "not-a-url"},
+	}
+	for _, c := range cases {
+		got := slugFromURL(c.url)
+		if got != c.want {
+			t.Errorf("slugFromURL(%q) = %q, want %q", c.url, got, c.want)
+		}
+	}
+}
+
+func TestChapterNumberFromURL(t *testing.T) {
+	cases := []struct {
+		url  string
+		want int
+	}{
+		{"https://novelfire.net/book/shadow-slave/chapter-42", 42},
+		{"https://novelfire.net/book/shadow-slave/chapter-1000", 1000},
+		{"https://novelfire.net/book/shadow-slave/chap-7", 7},
+		{"https://novelfire.net/book/shadow-slave/ch-3", 3},
+		{"https://novelfire.net/book/shadow-slave/42", 42},
+		{"https://novelfire.net/book/shadow-slave/no-number-here", 0},
+		{"not-a-url", 0},
+	}
+	for _, c := range cases {
+		got := chapterNumberFromURL(c.url)
+		if got != c.want {
+			t.Errorf("chapterNumberFromURL(%q) = %d, want %d", c.url, got, c.want)
+		}
+	}
+}
+
+func TestParseChapterCount(t *testing.T) {
+	cases := []struct {
+		in   string
+		want int
+	}{
+		{"123 Chapters", 123},
+		{"1,234 Chapters", 1234},
+		{"0", 0},
+		{"", 0},
+		{"500", 500},
+	}
+	for _, c := range cases {
+		got := parseChapterCount(c.in)
+		if got != c.want {
+			t.Errorf("parseChapterCount(%q) = %d, want %d", c.in, got, c.want)
+		}
+	}
+}
+
+func TestRetryGet_ContextCancellation(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // cancel immediately
+
+	stub := newStubClient()
+	stub.setError("https://example.com/page", context.Canceled)
+
+	_, err := retryGet(ctx, nil, stub, "https://example.com/page", 3, 0)
+	if err == nil {
+		t.Fatal("expected error on cancelled context")
+	}
+}
+
+func TestRetryGet_EventualSuccess(t *testing.T) {
+	stub := newStubClient()
+	calls := 0
+	stub.setFn("https://example.com/page", func() (string, error) {
+		calls++
+		if calls < 3 {
+			return "", context.DeadlineExceeded
+		}
+		return "<html>ok</html>", nil
+	})
+
+	got, err := retryGet(context.Background(), nil, stub, "https://example.com/page", 5, 0)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "<html>ok</html>" {
+		t.Errorf("got %q, want html", got)
+	}
+	if calls != 3 {
+		t.Errorf("expected 3 calls, got %d", calls)
+	}
+}
+
+// ── minimal stub client for tests ─────────────────────────────────────────────
+
+type stubClient struct {
+	errors map[string]error
+	fns    map[string]func() (string, error)
+}
+
+func newStubClient() *stubClient {
+	return &stubClient{
+		errors: make(map[string]error),
+		fns:    make(map[string]func() (string, error)),
+	}
+}
+
+func (s *stubClient) setError(u string, err error) { s.errors[u] = err }
+
+func (s *stubClient) setFn(u string, fn func() (string, error)) { s.fns[u] = fn }
+
+func (s *stubClient) GetContent(_ context.Context, pageURL string) (string, error) {
+	if fn, ok := s.fns[pageURL]; ok {
+		return fn()
+	}
+	if err, ok := s.errors[pageURL]; ok {
+		return "", err
+	}
+	return "", context.DeadlineExceeded
+}

backend/internal/orchestrator/orchestrator.go

@@ -0,0 +1,205 @@
+// Package orchestrator coordinates metadata extraction, chapter-list fetching,
+// and parallel chapter scraping for a single book.
+//
+// Design:
+//   - RunBook scrapes one book (metadata + chapter list + chapter texts) end-to-end.
+//   - N worker goroutines pull chapter refs from a shared queue and call ScrapeChapterText.
+//   - The caller (runner poll loop) owns the outer task-claim / finish cycle.
+package orchestrator
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"runtime"
+	"sync"
+	"sync/atomic"
+
+	"github.com/libnovel/backend/internal/bookstore"
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/scraper"
+)
+
+// Config holds tunable parameters for the orchestrator.
+type Config struct {
+	// Workers is the number of goroutines used to scrape chapters in parallel.
+	// Defaults to runtime.NumCPU() when 0.
+	Workers int
+}
+
+// Orchestrator runs a single-book scrape pipeline.
+type Orchestrator struct {
+	novel   scraper.NovelScraper
+	store   bookstore.BookWriter
+	log     *slog.Logger
+	workers int
+}
+
+// New returns a new Orchestrator.
+func New(cfg Config, novel scraper.NovelScraper, store bookstore.BookWriter, log *slog.Logger) *Orchestrator {
+	if log == nil {
+		log = slog.Default()
+	}
+	workers := cfg.Workers
+	if workers <= 0 {
+		workers = runtime.NumCPU()
+	}
+	return &Orchestrator{novel: novel, store: store, log: log, workers: workers}
+}
+
+// RunBook scrapes a single book described by task. It handles:
+//  1. Metadata scrape + write
+//  2. Chapter list scrape + write
+//  3. Parallel chapter text scrape + write (worker pool)
+//
+// Returns a ScrapeResult with counters. The result's ErrorMessage is non-empty
+// if the run failed at the metadata or chapter-list level.
+func (o *Orchestrator) RunBook(ctx context.Context, task domain.ScrapeTask) domain.ScrapeResult {
+	o.log.Info("orchestrator: RunBook starting",
+		"task_id", task.ID,
+		"kind", task.Kind,
+		"url", task.TargetURL,
+		"workers", o.workers,
+	)
+
+	var result domain.ScrapeResult
+
+	if task.TargetURL == "" {
+		result.ErrorMessage = "task has no target URL"
+		return result
+	}
+
+	// ── Step 1: Metadata ──────────────────────────────────────────────────────
+	meta, err := o.novel.ScrapeMetadata(ctx, task.TargetURL)
+	if err != nil {
+		o.log.Error("metadata scrape failed", "url", task.TargetURL, "err", err)
+		result.ErrorMessage = fmt.Sprintf("metadata: %v", err)
+		result.Errors++
+		return result
+	}
+
+	if err := o.store.WriteMetadata(ctx, meta); err != nil {
+		o.log.Error("metadata write failed", "slug", meta.Slug, "err", err)
+		// non-fatal: continue to chapters
+		result.Errors++
+	} else {
+		result.BooksFound = 1
+	}
+
+	o.log.Info("metadata saved", "slug", meta.Slug, "title", meta.Title)
+
+	// ── Step 2: Chapter list ──────────────────────────────────────────────────
+	refs, err := o.novel.ScrapeChapterList(ctx, task.TargetURL)
+	if err != nil {
+		o.log.Error("chapter list scrape failed", "slug", meta.Slug, "err", err)
+		result.ErrorMessage = fmt.Sprintf("chapter list: %v", err)
+		result.Errors++
+		return result
+	}
+
+	o.log.Info("chapter list fetched", "slug", meta.Slug, "chapters", len(refs))
+
+	// Persist chapter refs (without text) so the index exists early.
+	if wErr := o.store.WriteChapterRefs(ctx, meta.Slug, refs); wErr != nil {
+		o.log.Warn("chapter refs write failed", "slug", meta.Slug, "err", wErr)
+	}
+
+	// ── Step 3: Chapter texts (worker pool) ───────────────────────────────────
+	type chapterJob struct {
+		slug  string
+		ref   domain.ChapterRef
+		total int // total chapters to scrape (for progress logging)
+	}
+	work := make(chan chapterJob, o.workers*4)
+
+	var scraped, skipped, errors atomic.Int64
+	var wg sync.WaitGroup
+
+	for i := 0; i < o.workers; i++ {
+		wg.Add(1)
+		go func(workerID int) {
+			defer wg.Done()
+			for job := range work {
+				select {
+				case <-ctx.Done():
+					return
+				default:
+				}
+
+				if o.store.ChapterExists(ctx, job.slug, job.ref) {
+					o.log.Debug("chapter already exists, skipping",
+						"slug", job.slug, "chapter", job.ref.Number)
+					skipped.Add(1)
+					continue
+				}
+
+				ch, err := o.novel.ScrapeChapterText(ctx, job.ref)
+				if err != nil {
+					o.log.Error("chapter scrape failed",
+						"slug", job.slug, "chapter", job.ref.Number, "err", err)
+					errors.Add(1)
+					continue
+				}
+
+				if err := o.store.WriteChapter(ctx, job.slug, ch); err != nil {
+					o.log.Error("chapter write failed",
+						"slug", job.slug, "chapter", job.ref.Number, "err", err)
+					errors.Add(1)
+					continue
+				}
+
+				n := scraped.Add(1)
+				// Log a progress summary every 25 chapters scraped.
+				if n%25 == 0 {
+					o.log.Info("scraping chapters",
+						"slug", job.slug, "scraped", n, "total", job.total)
+				}
+			}
+		}(i)
+	}
+
+	// Count how many chapters will actually be enqueued (for progress logging).
+	toScrape := 0
+	for _, ref := range refs {
+		if task.FromChapter > 0 && ref.Number < task.FromChapter {
+			continue
+		}
+		if task.ToChapter > 0 && ref.Number > task.ToChapter {
+			continue
+		}
+		toScrape++
+	}
+
+	// Enqueue chapter jobs respecting the optional range filter from the task.
+	for _, ref := range refs {
+		if task.FromChapter > 0 && ref.Number < task.FromChapter {
+			skipped.Add(1)
+			continue
+		}
+		if task.ToChapter > 0 && ref.Number > task.ToChapter {
+			skipped.Add(1)
+			continue
+		}
+		select {
+		case <-ctx.Done():
+			goto drain
+		case work <- chapterJob{slug: meta.Slug, ref: ref, total: toScrape}:
+		}
+	}
+
+drain:
+	close(work)
+	wg.Wait()
+
+	result.ChaptersScraped = int(scraped.Load())
+	result.ChaptersSkipped = int(skipped.Load())
+	result.Errors += int(errors.Load())
+
+	o.log.Info("book scrape finished",
+		"slug", meta.Slug,
+		"scraped", result.ChaptersScraped,
+		"skipped", result.ChaptersSkipped,
+		"errors", result.Errors,
+	)
+	return result
+}

backend/internal/orchestrator/orchestrator_test.go

@@ -0,0 +1,210 @@
+package orchestrator
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+
+	"github.com/libnovel/backend/internal/domain"
+)
+
+// ── stubs ─────────────────────────────────────────────────────────────────────
+
+type stubScraper struct {
+	meta     domain.BookMeta
+	metaErr  error
+	refs     []domain.ChapterRef
+	refsErr  error
+	chapters map[int]domain.Chapter
+	chapErr  map[int]error
+}
+
+func (s *stubScraper) SourceName() string { return "stub" }
+
+func (s *stubScraper) ScrapeCatalogue(ctx context.Context) (<-chan domain.CatalogueEntry, <-chan error) {
+	ch := make(chan domain.CatalogueEntry)
+	errs := make(chan error)
+	close(ch)
+	close(errs)
+	return ch, errs
+}
+
+func (s *stubScraper) ScrapeMetadata(_ context.Context, _ string) (domain.BookMeta, error) {
+	return s.meta, s.metaErr
+}
+
+func (s *stubScraper) ScrapeChapterList(_ context.Context, _ string) ([]domain.ChapterRef, error) {
+	return s.refs, s.refsErr
+}
+
+func (s *stubScraper) ScrapeChapterText(_ context.Context, ref domain.ChapterRef) (domain.Chapter, error) {
+	if s.chapErr != nil {
+		if err, ok := s.chapErr[ref.Number]; ok {
+			return domain.Chapter{}, err
+		}
+	}
+	if s.chapters != nil {
+		if ch, ok := s.chapters[ref.Number]; ok {
+			return ch, nil
+		}
+	}
+	return domain.Chapter{Ref: ref, Text: "text"}, nil
+}
+
+func (s *stubScraper) ScrapeRanking(ctx context.Context, maxPages int) (<-chan domain.BookMeta, <-chan error) {
+	ch := make(chan domain.BookMeta)
+	errs := make(chan error)
+	close(ch)
+	close(errs)
+	return ch, errs
+}
+
+type stubStore struct {
+	mu              sync.Mutex
+	metaWritten     []domain.BookMeta
+	chaptersWritten []domain.Chapter
+	existing        map[string]bool // "slug:N" → exists
+	writeMetaErr    error
+}
+
+func (s *stubStore) WriteMetadata(_ context.Context, meta domain.BookMeta) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.writeMetaErr != nil {
+		return s.writeMetaErr
+	}
+	s.metaWritten = append(s.metaWritten, meta)
+	return nil
+}
+
+func (s *stubStore) WriteChapter(_ context.Context, slug string, ch domain.Chapter) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.chaptersWritten = append(s.chaptersWritten, ch)
+	return nil
+}
+
+func (s *stubStore) WriteChapterRefs(_ context.Context, _ string, _ []domain.ChapterRef) error {
+	return nil
+}
+
+func (s *stubStore) ChapterExists(_ context.Context, slug string, ref domain.ChapterRef) bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	key := slug + ":" + string(rune('0'+ref.Number))
+	return s.existing[key]
+}
+
+// ── tests ──────────────────────────────────────────────────────────────────────
+
+func TestRunBook_HappyPath(t *testing.T) {
+	sc := &stubScraper{
+		meta: domain.BookMeta{Slug: "test-book", Title: "Test Book", SourceURL: "https://example.com/book/test-book"},
+		refs: []domain.ChapterRef{
+			{Number: 1, Title: "Ch 1", URL: "https://example.com/book/test-book/chapter-1"},
+			{Number: 2, Title: "Ch 2", URL: "https://example.com/book/test-book/chapter-2"},
+			{Number: 3, Title: "Ch 3", URL: "https://example.com/book/test-book/chapter-3"},
+		},
+	}
+	st := &stubStore{}
+	o := New(Config{Workers: 2}, sc, st, nil)
+
+	task := domain.ScrapeTask{
+		ID:        "t1",
+		Kind:      "book",
+		TargetURL: "https://example.com/book/test-book",
+	}
+
+	result := o.RunBook(context.Background(), task)
+
+	if result.ErrorMessage != "" {
+		t.Fatalf("unexpected error: %s", result.ErrorMessage)
+	}
+	if result.BooksFound != 1 {
+		t.Errorf("BooksFound = %d, want 1", result.BooksFound)
+	}
+	if result.ChaptersScraped != 3 {
+		t.Errorf("ChaptersScraped = %d, want 3", result.ChaptersScraped)
+	}
+}
+
+func TestRunBook_MetadataError(t *testing.T) {
+	sc := &stubScraper{metaErr: errors.New("404 not found")}
+	st := &stubStore{}
+	o := New(Config{Workers: 1}, sc, st, nil)
+
+	result := o.RunBook(context.Background(), domain.ScrapeTask{
+		ID:        "t2",
+		TargetURL: "https://example.com/book/missing",
+	})
+
+	if result.ErrorMessage == "" {
+		t.Fatal("expected ErrorMessage to be set")
+	}
+	if result.Errors != 1 {
+		t.Errorf("Errors = %d, want 1", result.Errors)
+	}
+}
+
+func TestRunBook_ChapterRange(t *testing.T) {
+	sc := &stubScraper{
+		meta: domain.BookMeta{Slug: "range-book", SourceURL: "https://example.com/book/range-book"},
+		refs: func() []domain.ChapterRef {
+			var refs []domain.ChapterRef
+			for i := 1; i <= 10; i++ {
+				refs = append(refs, domain.ChapterRef{Number: i, URL: "https://example.com/book/range-book/chapter-" + string(rune('0'+i))})
+			}
+			return refs
+		}(),
+	}
+	st := &stubStore{}
+	o := New(Config{Workers: 2}, sc, st, nil)
+
+	result := o.RunBook(context.Background(), domain.ScrapeTask{
+		ID:          "t3",
+		TargetURL:   "https://example.com/book/range-book",
+		FromChapter: 3,
+		ToChapter:   7,
+	})
+
+	if result.ErrorMessage != "" {
+		t.Fatalf("unexpected error: %s", result.ErrorMessage)
+	}
+	// chapters 3–7 = 5 scraped, chapters 1-2 and 8-10 = 5 skipped
+	if result.ChaptersScraped != 5 {
+		t.Errorf("ChaptersScraped = %d, want 5", result.ChaptersScraped)
+	}
+	if result.ChaptersSkipped != 5 {
+		t.Errorf("ChaptersSkipped = %d, want 5", result.ChaptersSkipped)
+	}
+}
+
+func TestRunBook_ContextCancellation(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	sc := &stubScraper{
+		meta: domain.BookMeta{Slug: "ctx-book", SourceURL: "https://example.com/book/ctx-book"},
+		refs: []domain.ChapterRef{
+			{Number: 1, URL: "https://example.com/book/ctx-book/chapter-1"},
+		},
+	}
+	st := &stubStore{}
+	o := New(Config{Workers: 1}, sc, st, nil)
+
+	// Should not panic; result may have errors or zero chapters.
+	result := o.RunBook(ctx, domain.ScrapeTask{
+		ID:        "t4",
+		TargetURL: "https://example.com/book/ctx-book",
+	})
+	_ = result
+}
+
+func TestRunBook_EmptyTargetURL(t *testing.T) {
+	o := New(Config{Workers: 1}, &stubScraper{}, &stubStore{}, nil)
+	result := o.RunBook(context.Background(), domain.ScrapeTask{ID: "t5"})
+	if result.ErrorMessage == "" {
+		t.Fatal("expected ErrorMessage for empty target URL")
+	}
+}

backend/internal/runner/helpers.go

@@ -0,0 +1,21 @@
+package runner
+
+import (
+	"regexp"
+	"strings"
+)
+
+// stripMarkdown removes common markdown syntax from src, returning plain text
+// suitable for TTS. Mirrors the helper in the scraper's server package.
+func stripMarkdown(src string) string {
+	src = regexp.MustCompile(`(?m)^#{1,6}\s+`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`\*{1,3}|_{1,3}`).ReplaceAllString(src, "")
+	src = regexp.MustCompile("(?s)```.*?```").ReplaceAllString(src, "")
+	src = regexp.MustCompile("`[^`]*`").ReplaceAllString(src, "")
+	src = regexp.MustCompile(`\[([^\]]+)\]\([^)]+\)`).ReplaceAllString(src, "$1")
+	src = regexp.MustCompile(`!\[[^\]]*\]\([^)]+\)`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`(?m)^>\s?`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`(?m)^[-*_]{3,}\s*$`).ReplaceAllString(src, "")
+	src = regexp.MustCompile(`\n{3,}`).ReplaceAllString(src, "\n\n")
+	return strings.TrimSpace(src)
+}

backend/internal/runner/runner.go

@@ -0,0 +1,386 @@
+// Package runner implements the worker loop that polls PocketBase for pending
+// scrape and audio tasks, executes them, and reports results back.
+//
+// Design:
+//   - Run(ctx) loops on a ticker; each tick claims and dispatches pending tasks.
+//   - Scrape tasks are dispatched to the Orchestrator (one goroutine per task,
+//     up to MaxConcurrentScrape).
+//   - Audio tasks fetch chapter text, call Kokoro, upload to MinIO, and report
+//     the result back (up to MaxConcurrentAudio goroutines).
+//   - The runner is stateless between ticks; all state lives in PocketBase.
+package runner
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/libnovel/backend/internal/bookstore"
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/kokoro"
+	"github.com/libnovel/backend/internal/orchestrator"
+	"github.com/libnovel/backend/internal/scraper"
+	"github.com/libnovel/backend/internal/taskqueue"
+)
+
+// Config tunes the runner behaviour.
+type Config struct {
+	// WorkerID uniquely identifies this runner instance in PocketBase records.
+	WorkerID string
+	// PollInterval is how often the runner checks for new tasks.
+	PollInterval time.Duration
+	// MaxConcurrentScrape limits simultaneous book-scrape goroutines.
+	MaxConcurrentScrape int
+	// MaxConcurrentAudio limits simultaneous audio-generation goroutines.
+	MaxConcurrentAudio int
+	// OrchestratorWorkers is the chapter-scraping parallelism inside each book run.
+	OrchestratorWorkers int
+	// HeartbeatInterval is how often active tasks PATCH their heartbeat_at
+	// timestamp to signal they are still alive. Defaults to 30s when 0.
+	HeartbeatInterval time.Duration
+	// StaleTaskThreshold is how old a heartbeat must be (or absent) before the
+	// task is considered orphaned and reset to pending. Defaults to 2m when 0.
+	StaleTaskThreshold time.Duration
+}
+
+// Dependencies are the external services the runner depends on.
+type Dependencies struct {
+	// Consumer claims tasks from PocketBase.
+	Consumer taskqueue.Consumer
+	// BookWriter persists scraped data (used by orchestrator).
+	BookWriter bookstore.BookWriter
+	// BookReader reads chapter text for audio generation.
+	BookReader bookstore.BookReader
+	// AudioStore persists generated audio and checks key existence.
+	AudioStore bookstore.AudioStore
+	// Novel is the scraper implementation.
+	Novel scraper.NovelScraper
+	// Kokoro is the TTS client.
+	Kokoro kokoro.Client
+	// Log is the structured logger.
+	Log *slog.Logger
+}
+
+// Runner is the main worker process.
+type Runner struct {
+	cfg  Config
+	deps Dependencies
+}
+
+// New creates a Runner from cfg and deps.
+// Any zero/nil field in deps will cause a panic at construction time to fail fast.
+func New(cfg Config, deps Dependencies) *Runner {
+	if cfg.PollInterval <= 0 {
+		cfg.PollInterval = 30 * time.Second
+	}
+	if cfg.MaxConcurrentScrape <= 0 {
+		cfg.MaxConcurrentScrape = 2
+	}
+	if cfg.MaxConcurrentAudio <= 0 {
+		cfg.MaxConcurrentAudio = 1
+	}
+	if cfg.WorkerID == "" {
+		cfg.WorkerID = "runner"
+	}
+	if cfg.HeartbeatInterval <= 0 {
+		cfg.HeartbeatInterval = 30 * time.Second
+	}
+	if cfg.StaleTaskThreshold <= 0 {
+		cfg.StaleTaskThreshold = 2 * time.Minute
+	}
+	if deps.Log == nil {
+		deps.Log = slog.Default()
+	}
+	return &Runner{cfg: cfg, deps: deps}
+}
+
+// livenessFile is the path written on every successful poll so that the Docker
+// healthcheck (CMD /healthcheck file /tmp/runner.alive <max_age>) can verify
+// the runner is still making progress.
+const livenessFile = "/tmp/runner.alive"
+
+// touchAlive writes the current UTC time to livenessFile. Errors are logged but
+// never fatal — liveness is best-effort and should not crash the runner.
+func (r *Runner) touchAlive() {
+	data := []byte(time.Now().UTC().Format(time.RFC3339))
+	if err := os.WriteFile(livenessFile, data, 0o644); err != nil {
+		r.deps.Log.Warn("runner: failed to write liveness file", "err", err)
+	}
+}
+
+// Run starts the poll loop, blocking until ctx is cancelled.
+// On each tick it claims and executes all available pending tasks.
+// Scrape and audio tasks run in separate goroutine pools bounded by
+// MaxConcurrentScrape and MaxConcurrentAudio respectively.
+func (r *Runner) Run(ctx context.Context) error {
+	r.deps.Log.Info("runner: starting",
+		"worker_id", r.cfg.WorkerID,
+		"poll_interval", r.cfg.PollInterval,
+		"max_scrape", r.cfg.MaxConcurrentScrape,
+		"max_audio", r.cfg.MaxConcurrentAudio,
+	)
+
+	scrapeSem := make(chan struct{}, r.cfg.MaxConcurrentScrape)
+	audioSem := make(chan struct{}, r.cfg.MaxConcurrentAudio)
+	var wg sync.WaitGroup
+
+	// Write liveness file immediately so the first healthcheck passes before
+	// the first poll completes.
+	r.touchAlive()
+
+	tick := time.NewTicker(r.cfg.PollInterval)
+	defer tick.Stop()
+
+	// Run one poll immediately on startup, then on each tick.
+	for {
+		r.poll(ctx, scrapeSem, audioSem, &wg)
+		r.touchAlive()
+
+		select {
+		case <-ctx.Done():
+			r.deps.Log.Info("runner: context cancelled, draining active tasks")
+			done := make(chan struct{})
+			go func() {
+				wg.Wait()
+				close(done)
+			}()
+			select {
+			case <-done:
+				r.deps.Log.Info("runner: all tasks drained, exiting")
+			case <-time.After(2 * time.Minute):
+				r.deps.Log.Warn("runner: drain timeout exceeded, forcing exit")
+			}
+			return nil
+		case <-tick.C:
+		}
+	}
+}
+
+// poll claims all available pending tasks and dispatches them to goroutines.
+// It claims tasks in a tight loop until no more are available.
+func (r *Runner) poll(ctx context.Context, scrapeSem, audioSem chan struct{}, wg *sync.WaitGroup) {
+	// ── Reap orphaned tasks ───────────────────────────────────────────────
+	if n, err := r.deps.Consumer.ReapStaleTasks(ctx, r.cfg.StaleTaskThreshold); err != nil {
+		r.deps.Log.Warn("runner: reap stale tasks failed", "err", err)
+	} else if n > 0 {
+		r.deps.Log.Info("runner: reaped stale tasks", "count", n)
+	}
+
+	// ── Scrape tasks ──────────────────────────────────────────────────────
+	for {
+		if ctx.Err() != nil {
+			return
+		}
+		task, ok, err := r.deps.Consumer.ClaimNextScrapeTask(ctx, r.cfg.WorkerID)
+		if err != nil {
+			r.deps.Log.Error("runner: ClaimNextScrapeTask failed", "err", err)
+			break
+		}
+		if !ok {
+			break // queue empty
+		}
+		// Acquire semaphore (non-blocking when full — leave task running).
+		select {
+		case scrapeSem <- struct{}{}:
+		default:
+			// Too many concurrent scrapes — the task stays claimed but we can't
+			// run it right now. Log and break; the next poll will pick it up if
+			// still running (it won't be re-claimed while status=running).
+			r.deps.Log.Warn("runner: scrape semaphore full, will retry next tick",
+				"task_id", task.ID)
+			break
+		}
+		wg.Add(1)
+		go func(t domain.ScrapeTask) {
+			defer wg.Done()
+			defer func() { <-scrapeSem }()
+			r.runScrapeTask(ctx, t)
+		}(task)
+	}
+
+	// ── Audio tasks ───────────────────────────────────────────────────────
+	for {
+		if ctx.Err() != nil {
+			return
+		}
+		task, ok, err := r.deps.Consumer.ClaimNextAudioTask(ctx, r.cfg.WorkerID)
+		if err != nil {
+			r.deps.Log.Error("runner: ClaimNextAudioTask failed", "err", err)
+			break
+		}
+		if !ok {
+			break // queue empty
+		}
+		select {
+		case audioSem <- struct{}{}:
+		default:
+			r.deps.Log.Warn("runner: audio semaphore full, will retry next tick",
+				"task_id", task.ID)
+			break
+		}
+		wg.Add(1)
+		go func(t domain.AudioTask) {
+			defer wg.Done()
+			defer func() { <-audioSem }()
+			r.runAudioTask(ctx, t)
+		}(task)
+	}
+}
+
+// runScrapeTask executes one scrape task end-to-end and reports the result.
+func (r *Runner) runScrapeTask(ctx context.Context, task domain.ScrapeTask) {
+	log := r.deps.Log.With("task_id", task.ID, "kind", task.Kind, "url", task.TargetURL)
+	log.Info("runner: scrape task starting")
+
+	// Heartbeat goroutine: periodically PATCH heartbeat_at so the reaper knows
+	// this task is still alive. Cancelled when the task finishes.
+	hbCtx, hbCancel := context.WithCancel(ctx)
+	defer hbCancel()
+	go func() {
+		tick := time.NewTicker(r.cfg.HeartbeatInterval)
+		defer tick.Stop()
+		for {
+			select {
+			case <-hbCtx.Done():
+				return
+			case <-tick.C:
+				if err := r.deps.Consumer.HeartbeatTask(ctx, task.ID); err != nil {
+					log.Warn("runner: heartbeat failed", "err", err)
+				}
+			}
+		}
+	}()
+
+	oCfg := orchestrator.Config{Workers: r.cfg.OrchestratorWorkers}
+	o := orchestrator.New(oCfg, r.deps.Novel, r.deps.BookWriter, r.deps.Log)
+
+	var result domain.ScrapeResult
+
+	switch task.Kind {
+	case "catalogue":
+		result = r.runCatalogueTask(ctx, task, o, log)
+	case "book", "book_range":
+		result = o.RunBook(ctx, task)
+	default:
+		result.ErrorMessage = fmt.Sprintf("unknown task kind: %q", task.Kind)
+		log.Warn("runner: unknown task kind")
+	}
+
+	if err := r.deps.Consumer.FinishScrapeTask(ctx, task.ID, result); err != nil {
+		log.Error("runner: FinishScrapeTask failed", "err", err)
+	}
+	log.Info("runner: scrape task finished",
+		"scraped", result.ChaptersScraped,
+		"skipped", result.ChaptersSkipped,
+		"errors", result.Errors,
+	)
+}
+
+// runCatalogueTask runs a full catalogue scrape by iterating catalogue entries
+// and running a book task for each one.
+func (r *Runner) runCatalogueTask(ctx context.Context, task domain.ScrapeTask, o *orchestrator.Orchestrator, log *slog.Logger) domain.ScrapeResult {
+	entries, errCh := r.deps.Novel.ScrapeCatalogue(ctx)
+	var result domain.ScrapeResult
+
+	for entry := range entries {
+		if ctx.Err() != nil {
+			break
+		}
+		bookTask := domain.ScrapeTask{
+			ID:        task.ID,
+			Kind:      "book",
+			TargetURL: entry.URL,
+		}
+		bookResult := o.RunBook(ctx, bookTask)
+		result.BooksFound += bookResult.BooksFound + 1
+		result.ChaptersScraped += bookResult.ChaptersScraped
+		result.ChaptersSkipped += bookResult.ChaptersSkipped
+		result.Errors += bookResult.Errors
+	}
+
+	if err := <-errCh; err != nil {
+		log.Warn("runner: catalogue scrape finished with error", "err", err)
+		result.Errors++
+		if result.ErrorMessage == "" {
+			result.ErrorMessage = err.Error()
+		}
+	}
+	return result
+}
+
+// runAudioTask executes one audio-generation task:
+//  1. Read chapter text from MinIO.
+//  2. Call Kokoro to generate audio.
+//  3. Upload MP3 to MinIO under the standard audio object key.
+//  4. Report result back to PocketBase.
+func (r *Runner) runAudioTask(ctx context.Context, task domain.AudioTask) {
+	log := r.deps.Log.With("task_id", task.ID, "slug", task.Slug, "chapter", task.Chapter, "voice", task.Voice)
+	log.Info("runner: audio task starting")
+
+	// Heartbeat goroutine: periodically PATCH heartbeat_at so the reaper knows
+	// this task is still alive. Cancelled when the task finishes.
+	hbCtx, hbCancel := context.WithCancel(ctx)
+	defer hbCancel()
+	go func() {
+		tick := time.NewTicker(r.cfg.HeartbeatInterval)
+		defer tick.Stop()
+		for {
+			select {
+			case <-hbCtx.Done():
+				return
+			case <-tick.C:
+				if err := r.deps.Consumer.HeartbeatTask(ctx, task.ID); err != nil {
+					log.Warn("runner: heartbeat failed", "err", err)
+				}
+			}
+		}
+	}()
+
+	fail := func(msg string) {
+		log.Error("runner: audio task failed", "reason", msg)
+		result := domain.AudioResult{ErrorMessage: msg}
+		if err := r.deps.Consumer.FinishAudioTask(ctx, task.ID, result); err != nil {
+			log.Error("runner: FinishAudioTask failed", "err", err)
+		}
+	}
+
+	// Step 1: read chapter text.
+	raw, err := r.deps.BookReader.ReadChapter(ctx, task.Slug, task.Chapter)
+	if err != nil {
+		fail(fmt.Sprintf("read chapter: %v", err))
+		return
+	}
+	text := stripMarkdown(raw)
+	if text == "" {
+		fail("chapter text is empty after stripping markdown")
+		return
+	}
+
+	// Step 2: generate audio.
+	if r.deps.Kokoro == nil {
+		fail("kokoro client not configured")
+		return
+	}
+	audioData, err := r.deps.Kokoro.GenerateAudio(ctx, text, task.Voice)
+	if err != nil {
+		fail(fmt.Sprintf("kokoro generate: %v", err))
+		return
+	}
+
+	// Step 3: upload to MinIO.
+	key := r.deps.AudioStore.AudioObjectKey(task.Slug, task.Chapter, task.Voice)
+	if err := r.deps.AudioStore.PutAudio(ctx, key, audioData); err != nil {
+		fail(fmt.Sprintf("put audio: %v", err))
+		return
+	}
+
+	// Step 4: report success.
+	result := domain.AudioResult{ObjectKey: key}
+	if err := r.deps.Consumer.FinishAudioTask(ctx, task.ID, result); err != nil {
+		log.Error("runner: FinishAudioTask failed", "err", err)
+	}
+	log.Info("runner: audio task finished", "key", key)
+}

backend/internal/runner/runner_test.go

@@ -0,0 +1,365 @@
+package runner_test
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/runner"
+)
+
+// ── Stub types ────────────────────────────────────────────────────────────────
+
+// stubConsumer is a test double for taskqueue.Consumer.
+type stubConsumer struct {
+	scrapeQueue []domain.ScrapeTask
+	audioQueue  []domain.AudioTask
+	scrapeIdx   int
+	audioIdx    int
+	finished    []string
+	failCalled  []string
+	claimErr    error
+}
+
+func (s *stubConsumer) ClaimNextScrapeTask(_ context.Context, _ string) (domain.ScrapeTask, bool, error) {
+	if s.claimErr != nil {
+		return domain.ScrapeTask{}, false, s.claimErr
+	}
+	if s.scrapeIdx >= len(s.scrapeQueue) {
+		return domain.ScrapeTask{}, false, nil
+	}
+	t := s.scrapeQueue[s.scrapeIdx]
+	s.scrapeIdx++
+	return t, true, nil
+}
+
+func (s *stubConsumer) ClaimNextAudioTask(_ context.Context, _ string) (domain.AudioTask, bool, error) {
+	if s.claimErr != nil {
+		return domain.AudioTask{}, false, s.claimErr
+	}
+	if s.audioIdx >= len(s.audioQueue) {
+		return domain.AudioTask{}, false, nil
+	}
+	t := s.audioQueue[s.audioIdx]
+	s.audioIdx++
+	return t, true, nil
+}
+
+func (s *stubConsumer) FinishScrapeTask(_ context.Context, id string, _ domain.ScrapeResult) error {
+	s.finished = append(s.finished, id)
+	return nil
+}
+
+func (s *stubConsumer) FinishAudioTask(_ context.Context, id string, _ domain.AudioResult) error {
+	s.finished = append(s.finished, id)
+	return nil
+}
+
+func (s *stubConsumer) FailTask(_ context.Context, id, _ string) error {
+	s.failCalled = append(s.failCalled, id)
+	return nil
+}
+
+func (s *stubConsumer) HeartbeatTask(_ context.Context, _ string) error { return nil }
+
+func (s *stubConsumer) ReapStaleTasks(_ context.Context, _ time.Duration) (int, error) {
+	return 0, nil
+}
+
+// stubBookWriter satisfies bookstore.BookWriter (no-op).
+type stubBookWriter struct{}
+
+func (s *stubBookWriter) WriteMetadata(_ context.Context, _ domain.BookMeta) error { return nil }
+func (s *stubBookWriter) WriteChapter(_ context.Context, _ string, _ domain.Chapter) error {
+	return nil
+}
+func (s *stubBookWriter) WriteChapterRefs(_ context.Context, _ string, _ []domain.ChapterRef) error {
+	return nil
+}
+func (s *stubBookWriter) ChapterExists(_ context.Context, _ string, _ domain.ChapterRef) bool {
+	return false
+}
+
+// stubBookReader satisfies bookstore.BookReader — returns a single chapter.
+type stubBookReader struct {
+	text    string
+	readErr error
+}
+
+func (s *stubBookReader) ReadChapter(_ context.Context, _ string, _ int) (string, error) {
+	return s.text, s.readErr
+}
+func (s *stubBookReader) ReadMetadata(_ context.Context, _ string) (domain.BookMeta, bool, error) {
+	return domain.BookMeta{}, false, nil
+}
+func (s *stubBookReader) ListBooks(_ context.Context) ([]domain.BookMeta, error) { return nil, nil }
+func (s *stubBookReader) LocalSlugs(_ context.Context) (map[string]bool, error)  { return nil, nil }
+func (s *stubBookReader) MetadataMtime(_ context.Context, _ string) int64        { return 0 }
+func (s *stubBookReader) ListChapters(_ context.Context, _ string) ([]domain.ChapterInfo, error) {
+	return nil, nil
+}
+func (s *stubBookReader) CountChapters(_ context.Context, _ string) int { return 0 }
+func (s *stubBookReader) ReindexChapters(_ context.Context, _ string) (int, error) {
+	return 0, nil
+}
+
+// stubAudioStore satisfies bookstore.AudioStore.
+type stubAudioStore struct {
+	putCalled atomic.Int32
+	putErr    error
+}
+
+func (s *stubAudioStore) AudioObjectKey(slug string, n int, voice string) string {
+	return slug + "/" + string(rune('0'+n)) + "/" + voice + ".mp3"
+}
+func (s *stubAudioStore) AudioExists(_ context.Context, _ string) bool { return false }
+func (s *stubAudioStore) PutAudio(_ context.Context, _ string, _ []byte) error {
+	s.putCalled.Add(1)
+	return s.putErr
+}
+
+// stubNovelScraper satisfies scraper.NovelScraper minimally.
+type stubNovelScraper struct {
+	entries  []domain.CatalogueEntry
+	metaErr  error
+	chapters []domain.ChapterRef
+}
+
+func (s *stubNovelScraper) ScrapeCatalogue(_ context.Context) (<-chan domain.CatalogueEntry, <-chan error) {
+	ch := make(chan domain.CatalogueEntry, len(s.entries))
+	errCh := make(chan error, 1)
+	for _, e := range s.entries {
+		ch <- e
+	}
+	close(ch)
+	close(errCh)
+	return ch, errCh
+}
+
+func (s *stubNovelScraper) ScrapeMetadata(_ context.Context, _ string) (domain.BookMeta, error) {
+	if s.metaErr != nil {
+		return domain.BookMeta{}, s.metaErr
+	}
+	return domain.BookMeta{Slug: "test-book", Title: "Test Book", SourceURL: "https://example.com/book/test-book"}, nil
+}
+
+func (s *stubNovelScraper) ScrapeChapterList(_ context.Context, _ string) ([]domain.ChapterRef, error) {
+	return s.chapters, nil
+}
+
+func (s *stubNovelScraper) ScrapeChapterText(_ context.Context, ref domain.ChapterRef) (domain.Chapter, error) {
+	return domain.Chapter{Ref: ref, Text: "# Chapter\n\nSome text."}, nil
+}
+
+func (s *stubNovelScraper) ScrapeRanking(_ context.Context, _ int) (<-chan domain.BookMeta, <-chan error) {
+	ch := make(chan domain.BookMeta)
+	errCh := make(chan error, 1)
+	close(ch)
+	close(errCh)
+	return ch, errCh
+}
+
+func (s *stubNovelScraper) SourceName() string { return "stub" }
+
+// stubKokoro satisfies kokoro.Client.
+type stubKokoro struct {
+	data   []byte
+	genErr error
+	called atomic.Int32
+}
+
+func (s *stubKokoro) GenerateAudio(_ context.Context, _, _ string) ([]byte, error) {
+	s.called.Add(1)
+	return s.data, s.genErr
+}
+
+func (s *stubKokoro) ListVoices(_ context.Context) ([]string, error) {
+	return []string{"af_bella"}, nil
+}
+
+// ── stripMarkdown helper ──────────────────────────────────────────────────────
+
+func TestStripMarkdownViaAudioTask(t *testing.T) {
+	// Verify markdown is stripped before sending to Kokoro.
+	// We inject chapter text with markdown; the kokoro stub verifies data flows.
+	consumer := &stubConsumer{
+		audioQueue: []domain.AudioTask{
+			{ID: "a1", Slug: "book", Chapter: 1, Voice: "af_bella", Status: domain.TaskStatusRunning},
+		},
+	}
+	bookReader := &stubBookReader{text: "## Chapter 1\n\nPlain **text** here."}
+	audioStore := &stubAudioStore{}
+	kokoroStub := &stubKokoro{data: []byte("mp3")}
+
+	cfg := runner.Config{
+		WorkerID:     "test",
+		PollInterval: time.Hour, // long poll — we'll cancel manually
+	}
+	deps := runner.Dependencies{
+		Consumer:   consumer,
+		BookWriter: &stubBookWriter{},
+		BookReader: bookReader,
+		AudioStore: audioStore,
+		Novel:      &stubNovelScraper{},
+		Kokoro:     kokoroStub,
+	}
+
+	r := runner.New(cfg, deps)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_ = r.Run(ctx)
+
+	if kokoroStub.called.Load() != 1 {
+		t.Errorf("expected Kokoro.GenerateAudio called once, got %d", kokoroStub.called.Load())
+	}
+	if audioStore.putCalled.Load() != 1 {
+		t.Errorf("expected PutAudio called once, got %d", audioStore.putCalled.Load())
+	}
+}
+
+func TestAudioTask_ReadChapterError(t *testing.T) {
+	consumer := &stubConsumer{
+		audioQueue: []domain.AudioTask{
+			{ID: "a2", Slug: "book", Chapter: 2, Voice: "af_bella", Status: domain.TaskStatusRunning},
+		},
+	}
+	bookReader := &stubBookReader{readErr: errors.New("chapter not found")}
+	audioStore := &stubAudioStore{}
+	kokoroStub := &stubKokoro{data: []byte("mp3")}
+
+	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
+	deps := runner.Dependencies{
+		Consumer:   consumer,
+		BookWriter: &stubBookWriter{},
+		BookReader: bookReader,
+		AudioStore: audioStore,
+		Novel:      &stubNovelScraper{},
+		Kokoro:     kokoroStub,
+	}
+
+	r := runner.New(cfg, deps)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_ = r.Run(ctx)
+
+	// Kokoro should not be called; FinishAudioTask should be called with error.
+	if kokoroStub.called.Load() != 0 {
+		t.Errorf("expected Kokoro not called, got %d", kokoroStub.called.Load())
+	}
+	if len(consumer.finished) != 1 {
+		t.Errorf("expected FinishAudioTask called once, got %d", len(consumer.finished))
+	}
+}
+
+func TestAudioTask_KokoroError(t *testing.T) {
+	consumer := &stubConsumer{
+		audioQueue: []domain.AudioTask{
+			{ID: "a3", Slug: "book", Chapter: 3, Voice: "af_bella", Status: domain.TaskStatusRunning},
+		},
+	}
+	bookReader := &stubBookReader{text: "Chapter text."}
+	audioStore := &stubAudioStore{}
+	kokoroStub := &stubKokoro{genErr: errors.New("tts failed")}
+
+	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
+	deps := runner.Dependencies{
+		Consumer:   consumer,
+		BookWriter: &stubBookWriter{},
+		BookReader: bookReader,
+		AudioStore: audioStore,
+		Novel:      &stubNovelScraper{},
+		Kokoro:     kokoroStub,
+	}
+
+	r := runner.New(cfg, deps)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_ = r.Run(ctx)
+
+	if audioStore.putCalled.Load() != 0 {
+		t.Errorf("expected PutAudio not called, got %d", audioStore.putCalled.Load())
+	}
+	if len(consumer.finished) != 1 {
+		t.Errorf("expected FinishAudioTask called once, got %d", len(consumer.finished))
+	}
+}
+
+func TestScrapeTask_BookKind(t *testing.T) {
+	consumer := &stubConsumer{
+		scrapeQueue: []domain.ScrapeTask{
+			{ID: "s1", Kind: "book", TargetURL: "https://example.com/book/test-book", Status: domain.TaskStatusRunning},
+		},
+	}
+
+	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
+	deps := runner.Dependencies{
+		Consumer:   consumer,
+		BookWriter: &stubBookWriter{},
+		BookReader: &stubBookReader{},
+		AudioStore: &stubAudioStore{},
+		Novel:      &stubNovelScraper{},
+		Kokoro:     &stubKokoro{},
+	}
+
+	r := runner.New(cfg, deps)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_ = r.Run(ctx)
+
+	if len(consumer.finished) != 1 || consumer.finished[0] != "s1" {
+		t.Errorf("expected task s1 finished, got %v", consumer.finished)
+	}
+}
+
+func TestScrapeTask_UnknownKind(t *testing.T) {
+	consumer := &stubConsumer{
+		scrapeQueue: []domain.ScrapeTask{
+			{ID: "s2", Kind: "unknown_kind", Status: domain.TaskStatusRunning},
+		},
+	}
+
+	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
+	deps := runner.Dependencies{
+		Consumer:   consumer,
+		BookWriter: &stubBookWriter{},
+		BookReader: &stubBookReader{},
+		AudioStore: &stubAudioStore{},
+		Novel:      &stubNovelScraper{},
+		Kokoro:     &stubKokoro{},
+	}
+
+	r := runner.New(cfg, deps)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_ = r.Run(ctx)
+
+	// Unknown kind still finishes the task (with error message in result).
+	if len(consumer.finished) != 1 || consumer.finished[0] != "s2" {
+		t.Errorf("expected task s2 finished, got %v", consumer.finished)
+	}
+}
+
+func TestRun_CancelImmediately(t *testing.T) {
+	consumer := &stubConsumer{}
+	cfg := runner.Config{WorkerID: "test", PollInterval: 10 * time.Millisecond}
+	deps := runner.Dependencies{
+		Consumer:   consumer,
+		BookWriter: &stubBookWriter{},
+		BookReader: &stubBookReader{},
+		AudioStore: &stubAudioStore{},
+		Novel:      &stubNovelScraper{},
+		Kokoro:     &stubKokoro{},
+	}
+
+	r := runner.New(cfg, deps)
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // cancel before Run
+
+	err := r.Run(ctx)
+	if err != nil {
+		t.Errorf("expected nil on graceful shutdown, got %v", err)
+	}
+}

backend/internal/scraper/scraper.go

@@ -0,0 +1,58 @@
+// Package scraper defines the NovelScraper interface and its sub-interfaces.
+// Domain types live in internal/domain — this package only defines the scraping
+// contract so that novelfire and any future scrapers can be swapped freely.
+package scraper
+
+import (
+	"context"
+
+	"github.com/libnovel/backend/internal/domain"
+)
+
+// CatalogueProvider can enumerate every novel available on a source site.
+type CatalogueProvider interface {
+	ScrapeCatalogue(ctx context.Context) (<-chan domain.CatalogueEntry, <-chan error)
+}
+
+// MetadataProvider can extract structured book metadata from a novel's landing page.
+type MetadataProvider interface {
+	ScrapeMetadata(ctx context.Context, bookURL string) (domain.BookMeta, error)
+}
+
+// ChapterListProvider can enumerate all chapters of a book.
+type ChapterListProvider interface {
+	ScrapeChapterList(ctx context.Context, bookURL string) ([]domain.ChapterRef, error)
+}
+
+// ChapterTextProvider can extract the readable text from a single chapter page.
+type ChapterTextProvider interface {
+	ScrapeChapterText(ctx context.Context, ref domain.ChapterRef) (domain.Chapter, error)
+}
+
+// RankingProvider can enumerate novels from a ranking page.
+type RankingProvider interface {
+	// ScrapeRanking pages through up to maxPages ranking pages.
+	// maxPages <= 0 means all pages.
+	ScrapeRanking(ctx context.Context, maxPages int) (<-chan domain.BookMeta, <-chan error)
+}
+
+// NovelScraper is the full interface a concrete novel source must implement.
+type NovelScraper interface {
+	CatalogueProvider
+	MetadataProvider
+	ChapterListProvider
+	ChapterTextProvider
+	RankingProvider
+
+	// SourceName returns the human-readable name of this scraper, e.g. "novelfire.net".
+	SourceName() string
+}
+
+// Selector describes how to locate an element in an HTML document.
+type Selector struct {
+	Tag      string
+	Class    string
+	ID       string
+	Attr     string
+	Multiple bool
+}

backend/internal/storage/minio.go

@@ -0,0 +1,194 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/url"
+	"path"
+	"strings"
+	"time"
+
+	minio "github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+
+	"github.com/libnovel/backend/internal/config"
+)
+
+// minioClient wraps the official minio-go client with bucket names.
+type minioClient struct {
+	client         *minio.Client // internal — all read/write operations
+	pubClient      *minio.Client // presign-only — initialised against the public endpoint
+	bucketChapters string
+	bucketAudio    string
+	bucketAvatars  string
+}
+
+func newMinioClient(cfg config.MinIO) (*minioClient, error) {
+	creds := credentials.NewStaticV4(cfg.AccessKey, cfg.SecretKey, "")
+
+	internal, err := minio.New(cfg.Endpoint, &minio.Options{
+		Creds:  creds,
+		Secure: cfg.UseSSL,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("minio: init internal client: %w", err)
+	}
+
+	// Presigned URLs must be signed with the hostname the browser will use
+	// (PUBLIC_MINIO_PUBLIC_URL), because AWS Signature V4 includes the Host
+	// header in the canonical request — a URL signed against "minio:9000" will
+	// return SignatureDoesNotMatch when the browser fetches it from
+	// "localhost:9000".
+	//
+	// However, minio-go normally makes a live BucketLocation HTTP call before
+	// signing, which would fail from inside the container when the public
+	// endpoint is externally-facing (e.g. "localhost:9000" is unreachable from
+	// within Docker).  We prevent this by:
+	//   1. Setting Region: "us-east-1" — minio-go skips getBucketLocation when
+	//      the region is already known (bucket-cache.go:49).
+	//   2. Setting BucketLookup: BucketLookupPath — forces path-style URLs
+	//      (e.g. host/bucket/key), matching MinIO's default behaviour and
+	//      avoiding any virtual-host DNS probing.
+	//
+	// When no public endpoint is configured (or it equals the internal one),
+	// fall back to the internal client so presigning still works.
+	publicEndpoint := cfg.PublicEndpoint
+	if u, err2 := url.Parse(publicEndpoint); err2 == nil && u.Host != "" {
+		publicEndpoint = u.Host // strip scheme so minio.New is happy
+	}
+	pubUseSSL := cfg.PublicUseSSL
+	if publicEndpoint == "" || publicEndpoint == cfg.Endpoint {
+		publicEndpoint = cfg.Endpoint
+		pubUseSSL = cfg.UseSSL
+	}
+	pub, err := minio.New(publicEndpoint, &minio.Options{
+		Creds:        creds,
+		Secure:       pubUseSSL,
+		Region:       "us-east-1", // skip live BucketLocation preflight
+		BucketLookup: minio.BucketLookupPath,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("minio: init public client: %w", err)
+	}
+
+	return &minioClient{
+		client:         internal,
+		pubClient:      pub,
+		bucketChapters: cfg.BucketChapters,
+		bucketAudio:    cfg.BucketAudio,
+		bucketAvatars:  cfg.BucketAvatars,
+	}, nil
+}
+
+// ensureBuckets creates all required buckets if they don't already exist.
+func (m *minioClient) ensureBuckets(ctx context.Context) error {
+	for _, bucket := range []string{m.bucketChapters, m.bucketAudio, m.bucketAvatars} {
+		exists, err := m.client.BucketExists(ctx, bucket)
+		if err != nil {
+			return fmt.Errorf("minio: check bucket %q: %w", bucket, err)
+		}
+		if !exists {
+			if err := m.client.MakeBucket(ctx, bucket, minio.MakeBucketOptions{}); err != nil {
+				return fmt.Errorf("minio: create bucket %q: %w", bucket, err)
+			}
+		}
+	}
+	return nil
+}
+
+// ── Key helpers ───────────────────────────────────────────────────────────────
+
+// ChapterObjectKey returns the MinIO object key for a chapter markdown file.
+// Format: {slug}/chapter-{n:06d}.md
+func ChapterObjectKey(slug string, n int) string {
+	return fmt.Sprintf("%s/chapter-%06d.md", slug, n)
+}
+
+// AudioObjectKey returns the MinIO object key for a cached audio file.
+// Format: {slug}/{n}/{voice}.mp3
+func AudioObjectKey(slug string, n int, voice string) string {
+	return fmt.Sprintf("%s/%d/%s.mp3", slug, n, voice)
+}
+
+// AvatarObjectKey returns the MinIO object key for a user avatar image.
+// Format: {userID}/{ext}.{ext}
+func AvatarObjectKey(userID, ext string) string {
+	return fmt.Sprintf("%s/%s.%s", userID, ext, ext)
+}
+
+// chapterNumberFromKey extracts the chapter number from a MinIO object key.
+// e.g. "my-book/chapter-000042.md" → 42
+func chapterNumberFromKey(key string) int {
+	base := path.Base(key)
+	base = strings.TrimPrefix(base, "chapter-")
+	base = strings.TrimSuffix(base, ".md")
+	var n int
+	fmt.Sscanf(base, "%d", &n)
+	return n
+}
+
+// ── Object operations ─────────────────────────────────────────────────────────
+
+func (m *minioClient) putObject(ctx context.Context, bucket, key, contentType string, data []byte) error {
+	_, err := m.client.PutObject(ctx, bucket, key,
+		strings.NewReader(string(data)),
+		int64(len(data)),
+		minio.PutObjectOptions{ContentType: contentType},
+	)
+	return err
+}
+
+func (m *minioClient) getObject(ctx context.Context, bucket, key string) ([]byte, error) {
+	obj, err := m.client.GetObject(ctx, bucket, key, minio.GetObjectOptions{})
+	if err != nil {
+		return nil, err
+	}
+	defer obj.Close()
+	return io.ReadAll(obj)
+}
+
+func (m *minioClient) objectExists(ctx context.Context, bucket, key string) bool {
+	_, err := m.client.StatObject(ctx, bucket, key, minio.StatObjectOptions{})
+	return err == nil
+}
+
+func (m *minioClient) presignGet(ctx context.Context, bucket, key string, expires time.Duration) (string, error) {
+	u, err := m.pubClient.PresignedGetObject(ctx, bucket, key, expires, nil)
+	if err != nil {
+		return "", fmt.Errorf("minio presign %s/%s: %w", bucket, key, err)
+	}
+	return u.String(), nil
+}
+
+func (m *minioClient) presignPut(ctx context.Context, bucket, key string, expires time.Duration) (string, error) {
+	u, err := m.pubClient.PresignedPutObject(ctx, bucket, key, expires)
+	if err != nil {
+		return "", fmt.Errorf("minio presign PUT %s/%s: %w", bucket, key, err)
+	}
+	return u.String(), nil
+}
+
+func (m *minioClient) deleteObjects(ctx context.Context, bucket, prefix string) error {
+	objCh := m.client.ListObjects(ctx, bucket, minio.ListObjectsOptions{Prefix: prefix})
+	for obj := range objCh {
+		if obj.Err != nil {
+			return obj.Err
+		}
+		if err := m.client.RemoveObject(ctx, bucket, obj.Key, minio.RemoveObjectOptions{}); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (m *minioClient) listObjectKeys(ctx context.Context, bucket, prefix string) ([]string, error) {
+	var keys []string
+	for obj := range m.client.ListObjects(ctx, bucket, minio.ListObjectsOptions{Prefix: prefix}) {
+		if obj.Err != nil {
+			return nil, obj.Err
+		}
+		keys = append(keys, obj.Key)
+	}
+	return keys, nil
+}

backend/internal/storage/pocketbase.go

@@ -0,0 +1,268 @@
+// Package storage provides the concrete implementations of all bookstore and
+// taskqueue interfaces backed by PocketBase (structured data) and MinIO (blobs).
+//
+// Entry point: NewStore(ctx, cfg, log) returns a *Store that satisfies every
+// interface defined in bookstore and taskqueue.
+package storage
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/libnovel/backend/internal/config"
+	"github.com/libnovel/backend/internal/domain"
+)
+
+// ErrNotFound is returned by single-record lookups when no record exists.
+var ErrNotFound = errors.New("storage: record not found")
+
+// pbClient is the internal PocketBase REST admin client.
+type pbClient struct {
+	baseURL  string
+	email    string
+	password string
+	log      *slog.Logger
+
+	mu    sync.Mutex
+	token string
+	exp   time.Time
+}
+
+func newPBClient(cfg config.PocketBase, log *slog.Logger) *pbClient {
+	return &pbClient{
+		baseURL:  strings.TrimRight(cfg.URL, "/"),
+		email:    cfg.AdminEmail,
+		password: cfg.AdminPassword,
+		log:      log,
+	}
+}
+
+// authToken returns a valid admin auth token, refreshing it when expired.
+func (c *pbClient) authToken(ctx context.Context) (string, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.token != "" && time.Now().Before(c.exp) {
+		return c.token, nil
+	}
+
+	body, _ := json.Marshal(map[string]string{
+		"identity": c.email,
+		"password": c.password,
+	})
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
+		c.baseURL+"/api/collections/_superusers/auth-with-password", bytes.NewReader(body))
+	if err != nil {
+		return "", fmt.Errorf("pb auth: build request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("pb auth: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		raw, _ := io.ReadAll(resp.Body)
+		return "", fmt.Errorf("pb auth: status %d: %s", resp.StatusCode, string(raw))
+	}
+
+	var payload struct {
+		Token string `json:"token"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&payload); err != nil {
+		return "", fmt.Errorf("pb auth: decode: %w", err)
+	}
+	c.token = payload.Token
+	c.exp = time.Now().Add(30 * time.Minute)
+	return c.token, nil
+}
+
+// do executes an authenticated PocketBase REST request.
+func (c *pbClient) do(ctx context.Context, method, path string, body io.Reader) (*http.Response, error) {
+	tok, err := c.authToken(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequestWithContext(ctx, method, c.baseURL+path, body)
+	if err != nil {
+		return nil, fmt.Errorf("pb: build request %s %s: %w", method, path, err)
+	}
+	req.Header.Set("Authorization", tok)
+	if body != nil {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("pb: %s %s: %w", method, path, err)
+	}
+	return resp, nil
+}
+
+// get is a convenience wrapper that decodes a JSON response into v.
+func (c *pbClient) get(ctx context.Context, path string, v any) error {
+	resp, err := c.do(ctx, http.MethodGet, path, nil)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode == http.StatusNotFound {
+		return ErrNotFound
+	}
+	if resp.StatusCode >= 400 {
+		raw, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("pb GET %s: status %d: %s", path, resp.StatusCode, string(raw))
+	}
+	return json.NewDecoder(resp.Body).Decode(v)
+}
+
+// post creates a record and decodes the created record into v.
+func (c *pbClient) post(ctx context.Context, path string, payload, v any) error {
+	b, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("pb: marshal: %w", err)
+	}
+	resp, err := c.do(ctx, http.MethodPost, path, bytes.NewReader(b))
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 400 {
+		raw, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("pb POST %s: status %d: %s", path, resp.StatusCode, string(raw))
+	}
+	if v != nil {
+		return json.NewDecoder(resp.Body).Decode(v)
+	}
+	return nil
+}
+
+// patch updates a record.
+func (c *pbClient) patch(ctx context.Context, path string, payload any) error {
+	b, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("pb: marshal: %w", err)
+	}
+	resp, err := c.do(ctx, http.MethodPatch, path, bytes.NewReader(b))
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 400 {
+		raw, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("pb PATCH %s: status %d: %s", path, resp.StatusCode, string(raw))
+	}
+	return nil
+}
+
+// delete removes a record.
+func (c *pbClient) delete(ctx context.Context, path string) error {
+	resp, err := c.do(ctx, http.MethodDelete, path, nil)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode == http.StatusNotFound {
+		return ErrNotFound
+	}
+	if resp.StatusCode >= 400 {
+		raw, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("pb DELETE %s: status %d: %s", path, resp.StatusCode, string(raw))
+	}
+	return nil
+}
+
+// listAll fetches all pages of a collection. PocketBase returns at most 200
+// records per page; we paginate until empty.
+func (c *pbClient) listAll(ctx context.Context, collection string, filter, sort string) ([]json.RawMessage, error) {
+	var all []json.RawMessage
+	page := 1
+	for {
+		q := url.Values{
+			"page":    {fmt.Sprintf("%d", page)},
+			"perPage": {"200"},
+		}
+		if filter != "" {
+			q.Set("filter", filter)
+		}
+		if sort != "" {
+			q.Set("sort", sort)
+		}
+		path := fmt.Sprintf("/api/collections/%s/records?%s", collection, q.Encode())
+
+		var result struct {
+			Items []json.RawMessage `json:"items"`
+			Page  int               `json:"page"`
+			Pages int               `json:"totalPages"`
+		}
+		if err := c.get(ctx, path, &result); err != nil {
+			return nil, err
+		}
+		all = append(all, result.Items...)
+		if result.Page >= result.Pages {
+			break
+		}
+		page++
+	}
+	return all, nil
+}
+
+// claimRecord atomically claims the first pending record matching collection.
+// It fetches the oldest pending record (filter + sort), then PATCHes it with
+// the claim payload. Returns (nil, nil) when the queue is empty.
+func (c *pbClient) claimRecord(ctx context.Context, collection, workerID string, extraClaim map[string]any) (json.RawMessage, error) {
+	q := url.Values{}
+	q.Set("filter", `status="pending"`)
+	q.Set("sort", "+started")
+	q.Set("perPage", "1")
+	path := fmt.Sprintf("/api/collections/%s/records?%s", collection, q.Encode())
+
+	var result struct {
+		Items []json.RawMessage `json:"items"`
+	}
+	if err := c.get(ctx, path, &result); err != nil {
+		return nil, fmt.Errorf("claimRecord list: %w", err)
+	}
+	if len(result.Items) == 0 {
+		return nil, nil // queue empty
+	}
+
+	var rec struct {
+		ID string `json:"id"`
+	}
+	if err := json.Unmarshal(result.Items[0], &rec); err != nil {
+		return nil, fmt.Errorf("claimRecord parse id: %w", err)
+	}
+
+	claim := map[string]any{
+		"status":    string(domain.TaskStatusRunning),
+		"worker_id": workerID,
+	}
+	for k, v := range extraClaim {
+		claim[k] = v
+	}
+
+	claimPath := fmt.Sprintf("/api/collections/%s/records/%s", collection, rec.ID)
+	if err := c.patch(ctx, claimPath, claim); err != nil {
+		return nil, fmt.Errorf("claimRecord patch: %w", err)
+	}
+
+	// Re-fetch the updated record so caller has current state.
+	var updated json.RawMessage
+	if err := c.get(ctx, claimPath, &updated); err != nil {
+		return nil, fmt.Errorf("claimRecord re-fetch: %w", err)
+	}
+	return updated, nil
+}

backend/internal/storage/store.go

@@ -0,0 +1,769 @@
+package storage
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"strings"
+	"time"
+
+	"github.com/libnovel/backend/internal/bookstore"
+	"github.com/libnovel/backend/internal/config"
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/taskqueue"
+)
+
+// Store is the unified persistence implementation that satisfies all bookstore
+// and taskqueue interfaces. It routes structured data to PocketBase and binary
+// blobs to MinIO.
+type Store struct {
+	pb  *pbClient
+	mc  *minioClient
+	log *slog.Logger
+}
+
+// NewStore initialises PocketBase and MinIO connections and ensures all MinIO
+// buckets exist. Returns a ready-to-use Store.
+func NewStore(ctx context.Context, cfg config.Config, log *slog.Logger) (*Store, error) {
+	pb := newPBClient(cfg.PocketBase, log)
+	// Validate PocketBase connectivity by fetching an auth token.
+	if _, err := pb.authToken(ctx); err != nil {
+		return nil, fmt.Errorf("pocketbase: %w", err)
+	}
+
+	mc, err := newMinioClient(cfg.MinIO)
+	if err != nil {
+		return nil, fmt.Errorf("minio: %w", err)
+	}
+	if err := mc.ensureBuckets(ctx); err != nil {
+		return nil, fmt.Errorf("minio: ensure buckets: %w", err)
+	}
+
+	return &Store{pb: pb, mc: mc, log: log}, nil
+}
+
+// Compile-time interface satisfaction.
+var _ bookstore.BookWriter = (*Store)(nil)
+var _ bookstore.BookReader = (*Store)(nil)
+var _ bookstore.RankingStore = (*Store)(nil)
+var _ bookstore.AudioStore = (*Store)(nil)
+var _ bookstore.PresignStore = (*Store)(nil)
+var _ bookstore.ProgressStore = (*Store)(nil)
+var _ taskqueue.Producer = (*Store)(nil)
+var _ taskqueue.Consumer = (*Store)(nil)
+var _ taskqueue.Reader = (*Store)(nil)
+
+// ── BookWriter ────────────────────────────────────────────────────────────────
+
+func (s *Store) WriteMetadata(ctx context.Context, meta domain.BookMeta) error {
+	payload := map[string]any{
+		"slug":           meta.Slug,
+		"title":          meta.Title,
+		"author":         meta.Author,
+		"cover":          meta.Cover,
+		"status":         meta.Status,
+		"genres":         meta.Genres,
+		"summary":        meta.Summary,
+		"total_chapters": meta.TotalChapters,
+		"source_url":     meta.SourceURL,
+		"ranking":        meta.Ranking,
+	}
+	// Upsert via filter: if exists PATCH, otherwise POST.
+	existing, err := s.getBookBySlug(ctx, meta.Slug)
+	if err != nil && err != ErrNotFound {
+		return fmt.Errorf("WriteMetadata: %w", err)
+	}
+	if err == ErrNotFound {
+		return s.pb.post(ctx, "/api/collections/books/records", payload, nil)
+	}
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/books/records/%s", existing.ID), payload)
+}
+
+func (s *Store) WriteChapter(ctx context.Context, slug string, chapter domain.Chapter) error {
+	key := ChapterObjectKey(slug, chapter.Ref.Number)
+	if err := s.mc.putObject(ctx, s.mc.bucketChapters, key, "text/markdown", []byte(chapter.Text)); err != nil {
+		return fmt.Errorf("WriteChapter: minio: %w", err)
+	}
+	// Upsert the chapters_idx record in PocketBase.
+	return s.upsertChapterIdx(ctx, slug, chapter.Ref)
+}
+
+func (s *Store) WriteChapterRefs(ctx context.Context, slug string, refs []domain.ChapterRef) error {
+	for _, ref := range refs {
+		if err := s.upsertChapterIdx(ctx, slug, ref); err != nil {
+			s.log.Warn("WriteChapterRefs: upsert failed", "slug", slug, "chapter", ref.Number, "err", err)
+		}
+	}
+	return nil
+}
+
+func (s *Store) ChapterExists(ctx context.Context, slug string, ref domain.ChapterRef) bool {
+	return s.mc.objectExists(ctx, s.mc.bucketChapters, ChapterObjectKey(slug, ref.Number))
+}
+
+func (s *Store) upsertChapterIdx(ctx context.Context, slug string, ref domain.ChapterRef) error {
+	payload := map[string]any{
+		"slug":   slug,
+		"number": ref.Number,
+		"title":  ref.Title,
+	}
+	filter := fmt.Sprintf(`slug=%q&&number=%d`, slug, ref.Number)
+	items, err := s.pb.listAll(ctx, "chapters_idx", filter, "")
+	if err != nil && err != ErrNotFound {
+		return err
+	}
+	if len(items) == 0 {
+		return s.pb.post(ctx, "/api/collections/chapters_idx/records", payload, nil)
+	}
+	var rec struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(items[0], &rec)
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/chapters_idx/records/%s", rec.ID), payload)
+}
+
+// ── BookReader ────────────────────────────────────────────────────────────────
+
+type pbBook struct {
+	ID            string   `json:"id"`
+	Slug          string   `json:"slug"`
+	Title         string   `json:"title"`
+	Author        string   `json:"author"`
+	Cover         string   `json:"cover"`
+	Status        string   `json:"status"`
+	Genres        []string `json:"genres"`
+	Summary       string   `json:"summary"`
+	TotalChapters int      `json:"total_chapters"`
+	SourceURL     string   `json:"source_url"`
+	Ranking       int      `json:"ranking"`
+	Updated       string   `json:"updated"`
+}
+
+func (b pbBook) toDomain() domain.BookMeta {
+	return domain.BookMeta{
+		Slug:          b.Slug,
+		Title:         b.Title,
+		Author:        b.Author,
+		Cover:         b.Cover,
+		Status:        b.Status,
+		Genres:        b.Genres,
+		Summary:       b.Summary,
+		TotalChapters: b.TotalChapters,
+		SourceURL:     b.SourceURL,
+		Ranking:       b.Ranking,
+	}
+}
+
+func (s *Store) getBookBySlug(ctx context.Context, slug string) (pbBook, error) {
+	filter := fmt.Sprintf(`slug=%q`, slug)
+	items, err := s.pb.listAll(ctx, "books", filter, "")
+	if err != nil {
+		return pbBook{}, err
+	}
+	if len(items) == 0 {
+		return pbBook{}, ErrNotFound
+	}
+	var b pbBook
+	json.Unmarshal(items[0], &b)
+	return b, nil
+}
+
+func (s *Store) ReadMetadata(ctx context.Context, slug string) (domain.BookMeta, bool, error) {
+	b, err := s.getBookBySlug(ctx, slug)
+	if err == ErrNotFound {
+		return domain.BookMeta{}, false, nil
+	}
+	if err != nil {
+		return domain.BookMeta{}, false, err
+	}
+	return b.toDomain(), true, nil
+}
+
+func (s *Store) ListBooks(ctx context.Context) ([]domain.BookMeta, error) {
+	items, err := s.pb.listAll(ctx, "books", "", "title")
+	if err != nil {
+		return nil, err
+	}
+	books := make([]domain.BookMeta, 0, len(items))
+	for _, raw := range items {
+		var b pbBook
+		json.Unmarshal(raw, &b)
+		books = append(books, b.toDomain())
+	}
+	return books, nil
+}
+
+func (s *Store) LocalSlugs(ctx context.Context) (map[string]bool, error) {
+	items, err := s.pb.listAll(ctx, "books", "", "")
+	if err != nil {
+		return nil, err
+	}
+	slugs := make(map[string]bool, len(items))
+	for _, raw := range items {
+		var b struct {
+			Slug string `json:"slug"`
+		}
+		json.Unmarshal(raw, &b)
+		if b.Slug != "" {
+			slugs[b.Slug] = true
+		}
+	}
+	return slugs, nil
+}
+
+func (s *Store) MetadataMtime(ctx context.Context, slug string) int64 {
+	b, err := s.getBookBySlug(ctx, slug)
+	if err != nil {
+		return 0
+	}
+	t, err := time.Parse(time.RFC3339, b.Updated)
+	if err != nil {
+		return 0
+	}
+	return t.Unix()
+}
+
+func (s *Store) ReadChapter(ctx context.Context, slug string, n int) (string, error) {
+	data, err := s.mc.getObject(ctx, s.mc.bucketChapters, ChapterObjectKey(slug, n))
+	if err != nil {
+		return "", fmt.Errorf("ReadChapter: %w", err)
+	}
+	return string(data), nil
+}
+
+func (s *Store) ListChapters(ctx context.Context, slug string) ([]domain.ChapterInfo, error) {
+	filter := fmt.Sprintf(`slug=%q`, slug)
+	items, err := s.pb.listAll(ctx, "chapters_idx", filter, "number")
+	if err != nil {
+		return nil, err
+	}
+	chapters := make([]domain.ChapterInfo, 0, len(items))
+	for _, raw := range items {
+		var rec struct {
+			Number int    `json:"number"`
+			Title  string `json:"title"`
+		}
+		json.Unmarshal(raw, &rec)
+		chapters = append(chapters, domain.ChapterInfo{Number: rec.Number, Title: rec.Title})
+	}
+	return chapters, nil
+}
+
+func (s *Store) CountChapters(ctx context.Context, slug string) int {
+	chapters, err := s.ListChapters(ctx, slug)
+	if err != nil {
+		return 0
+	}
+	return len(chapters)
+}
+
+func (s *Store) ReindexChapters(ctx context.Context, slug string) (int, error) {
+	keys, err := s.mc.listObjectKeys(ctx, s.mc.bucketChapters, slug+"/")
+	if err != nil {
+		return 0, fmt.Errorf("ReindexChapters: list objects: %w", err)
+	}
+	count := 0
+	for _, key := range keys {
+		if !strings.HasSuffix(key, ".md") {
+			continue
+		}
+		n := chapterNumberFromKey(key)
+		if n == 0 {
+			continue
+		}
+		ref := domain.ChapterRef{Number: n}
+		if err := s.upsertChapterIdx(ctx, slug, ref); err != nil {
+			s.log.Warn("ReindexChapters: upsert failed", "key", key, "err", err)
+			continue
+		}
+		count++
+	}
+	return count, nil
+}
+
+// ── RankingStore ──────────────────────────────────────────────────────────────
+
+func (s *Store) WriteRankingItem(ctx context.Context, item domain.RankingItem) error {
+	payload := map[string]any{
+		"rank":       item.Rank,
+		"slug":       item.Slug,
+		"title":      item.Title,
+		"author":     item.Author,
+		"cover":      item.Cover,
+		"status":     item.Status,
+		"genres":     item.Genres,
+		"source_url": item.SourceURL,
+	}
+	filter := fmt.Sprintf(`slug=%q`, item.Slug)
+	items, err := s.pb.listAll(ctx, "ranking", filter, "")
+	if err != nil && err != ErrNotFound {
+		return err
+	}
+	if len(items) == 0 {
+		return s.pb.post(ctx, "/api/collections/ranking/records", payload, nil)
+	}
+	var rec struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(items[0], &rec)
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/ranking/records/%s", rec.ID), payload)
+}
+
+func (s *Store) ReadRankingItems(ctx context.Context) ([]domain.RankingItem, error) {
+	items, err := s.pb.listAll(ctx, "ranking", "", "rank")
+	if err != nil {
+		return nil, err
+	}
+	result := make([]domain.RankingItem, 0, len(items))
+	for _, raw := range items {
+		var rec struct {
+			Rank      int      `json:"rank"`
+			Slug      string   `json:"slug"`
+			Title     string   `json:"title"`
+			Author    string   `json:"author"`
+			Cover     string   `json:"cover"`
+			Status    string   `json:"status"`
+			Genres    []string `json:"genres"`
+			SourceURL string   `json:"source_url"`
+			Updated   string   `json:"updated"`
+		}
+		json.Unmarshal(raw, &rec)
+		t, _ := time.Parse(time.RFC3339, rec.Updated)
+		result = append(result, domain.RankingItem{
+			Rank:      rec.Rank,
+			Slug:      rec.Slug,
+			Title:     rec.Title,
+			Author:    rec.Author,
+			Cover:     rec.Cover,
+			Status:    rec.Status,
+			Genres:    rec.Genres,
+			SourceURL: rec.SourceURL,
+			Updated:   t,
+		})
+	}
+	return result, nil
+}
+
+func (s *Store) RankingFreshEnough(ctx context.Context, maxAge time.Duration) (bool, error) {
+	items, err := s.ReadRankingItems(ctx)
+	if err != nil || len(items) == 0 {
+		return false, err
+	}
+	var latest time.Time
+	for _, item := range items {
+		if item.Updated.After(latest) {
+			latest = item.Updated
+		}
+	}
+	return time.Since(latest) < maxAge, nil
+}
+
+// ── AudioStore ────────────────────────────────────────────────────────────────
+
+func (s *Store) AudioObjectKey(slug string, n int, voice string) string {
+	return AudioObjectKey(slug, n, voice)
+}
+
+func (s *Store) AudioExists(ctx context.Context, key string) bool {
+	return s.mc.objectExists(ctx, s.mc.bucketAudio, key)
+}
+
+func (s *Store) PutAudio(ctx context.Context, key string, data []byte) error {
+	return s.mc.putObject(ctx, s.mc.bucketAudio, key, "audio/mpeg", data)
+}
+
+// ── PresignStore ──────────────────────────────────────────────────────────────
+
+func (s *Store) PresignChapter(ctx context.Context, slug string, n int, expires time.Duration) (string, error) {
+	return s.mc.presignGet(ctx, s.mc.bucketChapters, ChapterObjectKey(slug, n), expires)
+}
+
+func (s *Store) PresignAudio(ctx context.Context, key string, expires time.Duration) (string, error) {
+	return s.mc.presignGet(ctx, s.mc.bucketAudio, key, expires)
+}
+
+func (s *Store) PresignAvatarUpload(ctx context.Context, userID, ext string) (uploadURL, key string, err error) {
+	key = AvatarObjectKey(userID, ext)
+	uploadURL, err = s.mc.presignPut(ctx, s.mc.bucketAvatars, key, 15*time.Minute)
+	return
+}
+
+func (s *Store) PresignAvatarURL(ctx context.Context, userID string) (string, bool, error) {
+	for _, ext := range []string{"jpg", "png", "webp"} {
+		key := AvatarObjectKey(userID, ext)
+		if s.mc.objectExists(ctx, s.mc.bucketAvatars, key) {
+			u, err := s.mc.presignGet(ctx, s.mc.bucketAvatars, key, 1*time.Hour)
+			return u, true, err
+		}
+	}
+	return "", false, nil
+}
+
+func (s *Store) DeleteAvatar(ctx context.Context, userID string) error {
+	return s.mc.deleteObjects(ctx, s.mc.bucketAvatars, userID+"/")
+}
+
+// ── ProgressStore ─────────────────────────────────────────────────────────────
+
+func (s *Store) GetProgress(ctx context.Context, sessionID, slug string) (domain.ReadingProgress, bool) {
+	filter := fmt.Sprintf(`session_id=%q&&slug=%q`, sessionID, slug)
+	items, err := s.pb.listAll(ctx, "progress", filter, "")
+	if err != nil || len(items) == 0 {
+		return domain.ReadingProgress{}, false
+	}
+	var rec struct {
+		Slug      string `json:"slug"`
+		Chapter   int    `json:"chapter"`
+		UpdatedAt string `json:"updated"`
+	}
+	json.Unmarshal(items[0], &rec)
+	t, _ := time.Parse(time.RFC3339, rec.UpdatedAt)
+	return domain.ReadingProgress{Slug: rec.Slug, Chapter: rec.Chapter, UpdatedAt: t}, true
+}
+
+func (s *Store) SetProgress(ctx context.Context, sessionID string, p domain.ReadingProgress) error {
+	payload := map[string]any{
+		"session_id": sessionID,
+		"slug":       p.Slug,
+		"chapter":    p.Chapter,
+	}
+	filter := fmt.Sprintf(`session_id=%q&&slug=%q`, sessionID, p.Slug)
+	items, err := s.pb.listAll(ctx, "progress", filter, "")
+	if err != nil && err != ErrNotFound {
+		return err
+	}
+	if len(items) == 0 {
+		return s.pb.post(ctx, "/api/collections/progress/records", payload, nil)
+	}
+	var rec struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(items[0], &rec)
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/progress/records/%s", rec.ID), payload)
+}
+
+func (s *Store) AllProgress(ctx context.Context, sessionID string) ([]domain.ReadingProgress, error) {
+	filter := fmt.Sprintf(`session_id=%q`, sessionID)
+	items, err := s.pb.listAll(ctx, "progress", filter, "-updated")
+	if err != nil {
+		return nil, err
+	}
+	result := make([]domain.ReadingProgress, 0, len(items))
+	for _, raw := range items {
+		var rec struct {
+			Slug      string `json:"slug"`
+			Chapter   int    `json:"chapter"`
+			UpdatedAt string `json:"updated"`
+		}
+		json.Unmarshal(raw, &rec)
+		t, _ := time.Parse(time.RFC3339, rec.UpdatedAt)
+		result = append(result, domain.ReadingProgress{Slug: rec.Slug, Chapter: rec.Chapter, UpdatedAt: t})
+	}
+	return result, nil
+}
+
+func (s *Store) DeleteProgress(ctx context.Context, sessionID, slug string) error {
+	filter := fmt.Sprintf(`session_id=%q&&slug=%q`, sessionID, slug)
+	items, err := s.pb.listAll(ctx, "progress", filter, "")
+	if err != nil || len(items) == 0 {
+		return nil
+	}
+	var rec struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(items[0], &rec)
+	return s.pb.delete(ctx, fmt.Sprintf("/api/collections/progress/records/%s", rec.ID))
+}
+
+// ── taskqueue.Producer ────────────────────────────────────────────────────────
+
+func (s *Store) CreateScrapeTask(ctx context.Context, kind, targetURL string, fromChapter, toChapter int) (string, error) {
+	payload := map[string]any{
+		"kind":         kind,
+		"target_url":   targetURL,
+		"from_chapter": fromChapter,
+		"to_chapter":   toChapter,
+		"status":       string(domain.TaskStatusPending),
+		"started":      time.Now().UTC().Format(time.RFC3339),
+	}
+	var rec struct {
+		ID string `json:"id"`
+	}
+	if err := s.pb.post(ctx, "/api/collections/scraping_tasks/records", payload, &rec); err != nil {
+		return "", err
+	}
+	return rec.ID, nil
+}
+
+func (s *Store) CreateAudioTask(ctx context.Context, slug string, chapter int, voice string) (string, error) {
+	cacheKey := fmt.Sprintf("%s/%d/%s", slug, chapter, voice)
+	payload := map[string]any{
+		"cache_key": cacheKey,
+		"slug":      slug,
+		"chapter":   chapter,
+		"voice":     voice,
+		"status":    string(domain.TaskStatusPending),
+		"started":   time.Now().UTC().Format(time.RFC3339),
+	}
+	var rec struct {
+		ID string `json:"id"`
+	}
+	if err := s.pb.post(ctx, "/api/collections/audio_jobs/records", payload, &rec); err != nil {
+		return "", err
+	}
+	return rec.ID, nil
+}
+
+func (s *Store) CancelTask(ctx context.Context, id string) error {
+	// Try scraping_tasks first, then audio_jobs.
+	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/scraping_tasks/records/%s", id),
+		map[string]string{"status": string(domain.TaskStatusCancelled)}); err == nil {
+		return nil
+	}
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id),
+		map[string]string{"status": string(domain.TaskStatusCancelled)})
+}
+
+// ── taskqueue.Consumer ────────────────────────────────────────────────────────
+
+func (s *Store) ClaimNextScrapeTask(ctx context.Context, workerID string) (domain.ScrapeTask, bool, error) {
+	raw, err := s.pb.claimRecord(ctx, "scraping_tasks", workerID, nil)
+	if err != nil {
+		return domain.ScrapeTask{}, false, err
+	}
+	if raw == nil {
+		return domain.ScrapeTask{}, false, nil
+	}
+	task, err := parseScrapeTask(raw)
+	return task, err == nil, err
+}
+
+func (s *Store) ClaimNextAudioTask(ctx context.Context, workerID string) (domain.AudioTask, bool, error) {
+	raw, err := s.pb.claimRecord(ctx, "audio_jobs", workerID, nil)
+	if err != nil {
+		return domain.AudioTask{}, false, err
+	}
+	if raw == nil {
+		return domain.AudioTask{}, false, nil
+	}
+	task, err := parseAudioTask(raw)
+	return task, err == nil, err
+}
+
+func (s *Store) FinishScrapeTask(ctx context.Context, id string, result domain.ScrapeResult) error {
+	status := string(domain.TaskStatusDone)
+	if result.ErrorMessage != "" {
+		status = string(domain.TaskStatusFailed)
+	}
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/scraping_tasks/records/%s", id), map[string]any{
+		"status":           status,
+		"books_found":      result.BooksFound,
+		"chapters_scraped": result.ChaptersScraped,
+		"chapters_skipped": result.ChaptersSkipped,
+		"errors":           result.Errors,
+		"error_message":    result.ErrorMessage,
+		"finished":         time.Now().UTC().Format(time.RFC3339),
+	})
+}
+
+func (s *Store) FinishAudioTask(ctx context.Context, id string, result domain.AudioResult) error {
+	status := string(domain.TaskStatusDone)
+	if result.ErrorMessage != "" {
+		status = string(domain.TaskStatusFailed)
+	}
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id), map[string]any{
+		"status":        status,
+		"error_message": result.ErrorMessage,
+		"finished":      time.Now().UTC().Format(time.RFC3339),
+	})
+}
+
+func (s *Store) FailTask(ctx context.Context, id, errMsg string) error {
+	payload := map[string]any{
+		"status":        string(domain.TaskStatusFailed),
+		"error_message": errMsg,
+		"finished":      time.Now().UTC().Format(time.RFC3339),
+	}
+	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/scraping_tasks/records/%s", id), payload); err == nil {
+		return nil
+	}
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id), payload)
+}
+
+// HeartbeatTask updates the heartbeat_at field on a running task.
+// Tries scraping_tasks first, then audio_jobs (same pattern as FailTask).
+func (s *Store) HeartbeatTask(ctx context.Context, id string) error {
+	payload := map[string]any{
+		"heartbeat_at": time.Now().UTC().Format(time.RFC3339),
+	}
+	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/scraping_tasks/records/%s", id), payload); err == nil {
+		return nil
+	}
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id), payload)
+}
+
+// ReapStaleTasks finds all running tasks whose heartbeat_at is either missing
+// or older than staleAfter, and resets them to pending so they can be
+// re-claimed. Returns the number of tasks reaped.
+func (s *Store) ReapStaleTasks(ctx context.Context, staleAfter time.Duration) (int, error) {
+	threshold := time.Now().UTC().Add(-staleAfter).Format(time.RFC3339)
+	// Match tasks that are running AND (heartbeat_at is empty OR heartbeat_at < threshold).
+	filter := fmt.Sprintf(`status="running"&&(heartbeat_at=""||heartbeat_at<"%s")`, threshold)
+	resetPayload := map[string]any{
+		"status":       string(domain.TaskStatusPending),
+		"worker_id":    "",
+		"heartbeat_at": "",
+	}
+
+	total := 0
+	for _, collection := range []string{"scraping_tasks", "audio_jobs"} {
+		items, err := s.pb.listAll(ctx, collection, filter, "")
+		if err != nil {
+			return total, fmt.Errorf("ReapStaleTasks list %s: %w", collection, err)
+		}
+		for _, raw := range items {
+			var rec struct {
+				ID string `json:"id"`
+			}
+			if err := json.Unmarshal(raw, &rec); err != nil || rec.ID == "" {
+				continue
+			}
+			path := fmt.Sprintf("/api/collections/%s/records/%s", collection, rec.ID)
+			if err := s.pb.patch(ctx, path, resetPayload); err != nil {
+				s.log.Warn("ReapStaleTasks: patch failed", "collection", collection, "id", rec.ID, "err", err)
+				continue
+			}
+			total++
+		}
+	}
+	return total, nil
+}
+
+// ── taskqueue.Reader ──────────────────────────────────────────────────────────
+
+func (s *Store) ListScrapeTasks(ctx context.Context) ([]domain.ScrapeTask, error) {
+	items, err := s.pb.listAll(ctx, "scraping_tasks", "", "-started")
+	if err != nil {
+		return nil, err
+	}
+	tasks := make([]domain.ScrapeTask, 0, len(items))
+	for _, raw := range items {
+		t, err := parseScrapeTask(raw)
+		if err == nil {
+			tasks = append(tasks, t)
+		}
+	}
+	return tasks, nil
+}
+
+func (s *Store) GetScrapeTask(ctx context.Context, id string) (domain.ScrapeTask, bool, error) {
+	var raw json.RawMessage
+	if err := s.pb.get(ctx, fmt.Sprintf("/api/collections/scraping_tasks/records/%s", id), &raw); err != nil {
+		if err == ErrNotFound {
+			return domain.ScrapeTask{}, false, nil
+		}
+		return domain.ScrapeTask{}, false, err
+	}
+	t, err := parseScrapeTask(raw)
+	return t, err == nil, err
+}
+
+func (s *Store) ListAudioTasks(ctx context.Context) ([]domain.AudioTask, error) {
+	items, err := s.pb.listAll(ctx, "audio_jobs", "", "-started")
+	if err != nil {
+		return nil, err
+	}
+	tasks := make([]domain.AudioTask, 0, len(items))
+	for _, raw := range items {
+		t, err := parseAudioTask(raw)
+		if err == nil {
+			tasks = append(tasks, t)
+		}
+	}
+	return tasks, nil
+}
+
+func (s *Store) GetAudioTask(ctx context.Context, cacheKey string) (domain.AudioTask, bool, error) {
+	filter := fmt.Sprintf(`cache_key=%q`, cacheKey)
+	items, err := s.pb.listAll(ctx, "audio_jobs", filter, "-started")
+	if err != nil || len(items) == 0 {
+		return domain.AudioTask{}, false, err
+	}
+	t, err := parseAudioTask(items[0])
+	return t, err == nil, err
+}
+
+// ── Parsers ───────────────────────────────────────────────────────────────────
+
+func parseScrapeTask(raw json.RawMessage) (domain.ScrapeTask, error) {
+	var rec struct {
+		ID              string `json:"id"`
+		Kind            string `json:"kind"`
+		TargetURL       string `json:"target_url"`
+		FromChapter     int    `json:"from_chapter"`
+		ToChapter       int    `json:"to_chapter"`
+		WorkerID        string `json:"worker_id"`
+		Status          string `json:"status"`
+		BooksFound      int    `json:"books_found"`
+		ChaptersScraped int    `json:"chapters_scraped"`
+		ChaptersSkipped int    `json:"chapters_skipped"`
+		Errors          int    `json:"errors"`
+		Started         string `json:"started"`
+		Finished        string `json:"finished"`
+		ErrorMessage    string `json:"error_message"`
+	}
+	if err := json.Unmarshal(raw, &rec); err != nil {
+		return domain.ScrapeTask{}, err
+	}
+	started, _ := time.Parse(time.RFC3339, rec.Started)
+	finished, _ := time.Parse(time.RFC3339, rec.Finished)
+	return domain.ScrapeTask{
+		ID:              rec.ID,
+		Kind:            rec.Kind,
+		TargetURL:       rec.TargetURL,
+		FromChapter:     rec.FromChapter,
+		ToChapter:       rec.ToChapter,
+		WorkerID:        rec.WorkerID,
+		Status:          domain.TaskStatus(rec.Status),
+		BooksFound:      rec.BooksFound,
+		ChaptersScraped: rec.ChaptersScraped,
+		ChaptersSkipped: rec.ChaptersSkipped,
+		Errors:          rec.Errors,
+		Started:         started,
+		Finished:        finished,
+		ErrorMessage:    rec.ErrorMessage,
+	}, nil
+}
+
+func parseAudioTask(raw json.RawMessage) (domain.AudioTask, error) {
+	var rec struct {
+		ID           string `json:"id"`
+		CacheKey     string `json:"cache_key"`
+		Slug         string `json:"slug"`
+		Chapter      int    `json:"chapter"`
+		Voice        string `json:"voice"`
+		WorkerID     string `json:"worker_id"`
+		Status       string `json:"status"`
+		ErrorMessage string `json:"error_message"`
+		Started      string `json:"started"`
+		Finished     string `json:"finished"`
+	}
+	if err := json.Unmarshal(raw, &rec); err != nil {
+		return domain.AudioTask{}, err
+	}
+	started, _ := time.Parse(time.RFC3339, rec.Started)
+	finished, _ := time.Parse(time.RFC3339, rec.Finished)
+	return domain.AudioTask{
+		ID:           rec.ID,
+		CacheKey:     rec.CacheKey,
+		Slug:         rec.Slug,
+		Chapter:      rec.Chapter,
+		Voice:        rec.Voice,
+		WorkerID:     rec.WorkerID,
+		Status:       domain.TaskStatus(rec.Status),
+		ErrorMessage: rec.ErrorMessage,
+		Started:      started,
+		Finished:     finished,
+	}, nil
+}

backend/internal/taskqueue/taskqueue.go

@@ -0,0 +1,84 @@
+// Package taskqueue defines the interfaces for creating and consuming
+// scrape/audio tasks stored in PocketBase.
+//
+// Interface segregation:
+//   - Producer is used only by the backend (creates tasks, cancels tasks).
+//   - Consumer is used only by the runner (claims tasks, reports results).
+//   - Reader is used by the backend for status/history endpoints.
+//
+// Concrete implementations live in internal/storage.
+package taskqueue
+
+import (
+	"context"
+	"time"
+
+	"github.com/libnovel/backend/internal/domain"
+)
+
+// Producer is the write side of the task queue used by the backend service.
+// It creates new tasks in PocketBase for the runner to pick up.
+type Producer interface {
+	// CreateScrapeTask inserts a new scrape task with status=pending and
+	// returns the assigned PocketBase record ID.
+	// kind is one of "catalogue", "book", or "book_range".
+	// targetURL is the book URL (empty for catalogue-wide tasks).
+	CreateScrapeTask(ctx context.Context, kind, targetURL string, fromChapter, toChapter int) (string, error)
+
+	// CreateAudioTask inserts a new audio task with status=pending and
+	// returns the assigned PocketBase record ID.
+	CreateAudioTask(ctx context.Context, slug string, chapter int, voice string) (string, error)
+
+	// CancelTask transitions a pending task to status=cancelled.
+	// Returns ErrNotFound if the task does not exist.
+	CancelTask(ctx context.Context, id string) error
+}
+
+// Consumer is the read/claim side of the task queue used by the runner.
+type Consumer interface {
+	// ClaimNextScrapeTask atomically finds the oldest pending scrape task,
+	// sets its status=running and worker_id=workerID, and returns it.
+	// Returns (zero, false, nil) when the queue is empty.
+	ClaimNextScrapeTask(ctx context.Context, workerID string) (domain.ScrapeTask, bool, error)
+
+	// ClaimNextAudioTask atomically finds the oldest pending audio task,
+	// sets its status=running and worker_id=workerID, and returns it.
+	// Returns (zero, false, nil) when the queue is empty.
+	ClaimNextAudioTask(ctx context.Context, workerID string) (domain.AudioTask, bool, error)
+
+	// FinishScrapeTask marks a running scrape task as done and records the result.
+	FinishScrapeTask(ctx context.Context, id string, result domain.ScrapeResult) error
+
+	// FinishAudioTask marks a running audio task as done and records the result.
+	FinishAudioTask(ctx context.Context, id string, result domain.AudioResult) error
+
+	// FailTask marks a task (scrape or audio) as failed with an error message.
+	FailTask(ctx context.Context, id, errMsg string) error
+
+	// HeartbeatTask updates the heartbeat_at timestamp on a running task.
+	// Should be called periodically by the runner while the task is active so
+	// the reaper knows the task is still alive.
+	HeartbeatTask(ctx context.Context, id string) error
+
+	// ReapStaleTasks finds all running tasks whose heartbeat_at is older than
+	// staleAfter (or was never set) and resets them to pending so they can be
+	// re-claimed by a healthy runner. Returns the number of tasks reaped.
+	ReapStaleTasks(ctx context.Context, staleAfter time.Duration) (int, error)
+}
+
+// Reader is the read-only side used by the backend for status pages.
+type Reader interface {
+	// ListScrapeTasks returns all scrape tasks sorted by started descending.
+	ListScrapeTasks(ctx context.Context) ([]domain.ScrapeTask, error)
+
+	// GetScrapeTask returns a single scrape task by ID.
+	// Returns (zero, false, nil) if not found.
+	GetScrapeTask(ctx context.Context, id string) (domain.ScrapeTask, bool, error)
+
+	// ListAudioTasks returns all audio tasks sorted by started descending.
+	ListAudioTasks(ctx context.Context) ([]domain.AudioTask, error)
+
+	// GetAudioTask returns the most recent audio task for cacheKey.
+	// Returns (zero, false, nil) if not found.
+	GetAudioTask(ctx context.Context, cacheKey string) (domain.AudioTask, bool, error)
+}

backend/internal/taskqueue/taskqueue_test.go

@@ -0,0 +1,138 @@
+package taskqueue_test
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/libnovel/backend/internal/domain"
+	"github.com/libnovel/backend/internal/taskqueue"
+)
+
+// ── Compile-time interface satisfaction ───────────────────────────────────────
+
+// stubStore satisfies all three taskqueue interfaces.
+// Any method that is called but not expected panics — making accidental
+// calls immediately visible in tests.
+type stubStore struct{}
+
+func (s *stubStore) CreateScrapeTask(_ context.Context, _, _ string, _, _ int) (string, error) {
+	return "task-1", nil
+}
+func (s *stubStore) CreateAudioTask(_ context.Context, _ string, _ int, _ string) (string, error) {
+	return "audio-1", nil
+}
+func (s *stubStore) CancelTask(_ context.Context, _ string) error { return nil }
+
+func (s *stubStore) ClaimNextScrapeTask(_ context.Context, _ string) (domain.ScrapeTask, bool, error) {
+	return domain.ScrapeTask{ID: "task-1", Status: domain.TaskStatusRunning}, true, nil
+}
+func (s *stubStore) ClaimNextAudioTask(_ context.Context, _ string) (domain.AudioTask, bool, error) {
+	return domain.AudioTask{ID: "audio-1", Status: domain.TaskStatusRunning}, true, nil
+}
+func (s *stubStore) FinishScrapeTask(_ context.Context, _ string, _ domain.ScrapeResult) error {
+	return nil
+}
+func (s *stubStore) FinishAudioTask(_ context.Context, _ string, _ domain.AudioResult) error {
+	return nil
+}
+func (s *stubStore) FailTask(_ context.Context, _, _ string) error { return nil }
+
+func (s *stubStore) HeartbeatTask(_ context.Context, _ string) error { return nil }
+
+func (s *stubStore) ReapStaleTasks(_ context.Context, _ time.Duration) (int, error) {
+	return 0, nil
+}
+
+func (s *stubStore) ListScrapeTasks(_ context.Context) ([]domain.ScrapeTask, error) { return nil, nil }
+func (s *stubStore) GetScrapeTask(_ context.Context, _ string) (domain.ScrapeTask, bool, error) {
+	return domain.ScrapeTask{}, false, nil
+}
+func (s *stubStore) ListAudioTasks(_ context.Context) ([]domain.AudioTask, error) { return nil, nil }
+func (s *stubStore) GetAudioTask(_ context.Context, _ string) (domain.AudioTask, bool, error) {
+	return domain.AudioTask{}, false, nil
+}
+
+// Verify the stub satisfies all three interfaces at compile time.
+var _ taskqueue.Producer = (*stubStore)(nil)
+var _ taskqueue.Consumer = (*stubStore)(nil)
+var _ taskqueue.Reader = (*stubStore)(nil)
+
+// ── Behavioural tests (using stub) ────────────────────────────────────────────
+
+func TestProducer_CreateScrapeTask(t *testing.T) {
+	var p taskqueue.Producer = &stubStore{}
+	id, err := p.CreateScrapeTask(context.Background(), "book", "https://example.com/book/slug", 0, 0)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if id == "" {
+		t.Error("expected non-empty task ID")
+	}
+}
+
+func TestConsumer_ClaimNextScrapeTask(t *testing.T) {
+	var c taskqueue.Consumer = &stubStore{}
+	task, ok, err := c.ClaimNextScrapeTask(context.Background(), "worker-1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !ok {
+		t.Fatal("expected a task to be claimed")
+	}
+	if task.Status != domain.TaskStatusRunning {
+		t.Errorf("want running, got %q", task.Status)
+	}
+}
+
+func TestConsumer_ClaimNextAudioTask(t *testing.T) {
+	var c taskqueue.Consumer = &stubStore{}
+	task, ok, err := c.ClaimNextAudioTask(context.Background(), "worker-1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !ok {
+		t.Fatal("expected an audio task to be claimed")
+	}
+	if task.ID == "" {
+		t.Error("expected non-empty task ID")
+	}
+}
+
+// ── domain.ScrapeResult / domain.AudioResult JSON shape ──────────────────────
+
+func TestScrapeResult_JSONRoundtrip(t *testing.T) {
+	cases := []domain.ScrapeResult{
+		{BooksFound: 5, ChaptersScraped: 100, ChaptersSkipped: 2, Errors: 0},
+		{BooksFound: 0, ChaptersScraped: 0, Errors: 1, ErrorMessage: "timeout"},
+	}
+	for _, orig := range cases {
+		b, err := json.Marshal(orig)
+		if err != nil {
+			t.Fatalf("marshal: %v", err)
+		}
+		var got domain.ScrapeResult
+		if err := json.Unmarshal(b, &got); err != nil {
+			t.Fatalf("unmarshal: %v", err)
+		}
+		if got != orig {
+			t.Errorf("want %+v, got %+v", orig, got)
+		}
+	}
+}
+
+func TestAudioResult_JSONRoundtrip(t *testing.T) {
+	cases := []domain.AudioResult{
+		{ObjectKey: "audio/slug/1/af_bella.mp3"},
+		{ErrorMessage: "kokoro unavailable"},
+	}
+	for _, orig := range cases {
+		b, _ := json.Marshal(orig)
+		var got domain.AudioResult
+		json.Unmarshal(b, &got)
+		if got != orig {
+			t.Errorf("want %+v, got %+v", orig, got)
+		}
+	}
+}