package storage

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"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 _ bookstore.CoverStore = (*Store)(nil)
var _ bookstore.TranslationStore = (*Store)(nil)
var _ bookstore.AIJobStore = (*Store)(nil)
var _ bookstore.ChapterImageStore = (*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,
		"rating":         meta.Rating,
	}
	// Upsert via filter: if exists PATCH, otherwise POST.
	// Use a conflict-retry pattern to handle concurrent scrapes racing to insert
	// the same slug: if POST fails (or another concurrent writer beat us to it),
	// re-fetch and PATCH instead.
	existing, err := s.getBookBySlug(ctx, meta.Slug)
	if err != nil && err != ErrNotFound {
		return fmt.Errorf("WriteMetadata: %w", err)
	}
	if err == ErrNotFound {
		postErr := s.pb.post(ctx, "/api/collections/books/records", payload, nil)
		if postErr == nil {
			return nil
		}
		// POST failed — a concurrent writer may have inserted the same slug.
		// Re-fetch and fall through to PATCH.
		existing, err = s.getBookBySlug(ctx, meta.Slug)
		if err != nil {
			return postErr // original POST error is more informative
		}
	}
	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 {
		// Set created timestamp on first insert so recentlyUpdatedBooks can sort by it.
		insertPayload := map[string]any{
			"slug":    slug,
			"number":  ref.Number,
			"title":   ref.Title,
			"created": time.Now().UTC().Format(time.RFC3339),
		}
		postErr := s.pb.post(ctx, "/api/collections/chapters_idx/records", insertPayload, nil)
		if postErr == nil {
			return nil
		}
		// POST failed — a concurrent writer may have inserted the same slug+number.
		// Re-fetch and fall through to PATCH (mirrors WriteMetadata retry pattern).
		items, err = s.pb.listAll(ctx, "chapters_idx", filter, "")
		if err != nil || len(items) == 0 {
			return postErr // original POST error is more informative
		}
	}
	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)
}

// DeduplicateChapters removes duplicate chapters_idx records for slug.
// For each chapter number that has more than one record, it keeps the record
// with the latest "updated" timestamp and deletes the rest.
// Returns the number of records deleted.
func (s *Store) DeduplicateChapters(ctx context.Context, slug string) (int, error) {
	filter := fmt.Sprintf(`slug=%q`, slug)
	items, err := s.pb.listAll(ctx, "chapters_idx", filter, "number")
	if err != nil {
		return 0, fmt.Errorf("DeduplicateChapters: list: %w", err)
	}

	type record struct {
		ID      string `json:"id"`
		Number  int    `json:"number"`
		Updated string `json:"updated"`
	}

	// Group records by chapter number.
	byNumber := make(map[int][]record)
	for _, raw := range items {
		var rec record
		if err := json.Unmarshal(raw, &rec); err != nil || rec.ID == "" {
			continue
		}
		byNumber[rec.Number] = append(byNumber[rec.Number], rec)
	}

	deleted := 0
	for _, recs := range byNumber {
		if len(recs) <= 1 {
			continue
		}
		// Keep the record with the latest Updated timestamp; delete the rest.
		keep := 0
		for i := 1; i < len(recs); i++ {
			if recs[i].Updated > recs[keep].Updated {
				keep = i
			}
		}
		for i, rec := range recs {
			if i == keep {
				continue
			}
			if delErr := s.pb.delete(ctx, fmt.Sprintf("/api/collections/chapters_idx/records/%s", rec.ID)); delErr != nil {
				s.log.Warn("DeduplicateChapters: delete failed", "slug", slug, "number", rec.Number, "id", rec.ID, "err", delErr)
				continue
			}
			deleted++
		}
	}
	return deleted, nil
}

// ── 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"`
	Rating        float64  `json:"rating"`
	Updated       string   `json:"updated"`
}

func (b pbBook) toDomain() domain.BookMeta {
	var metaUpdated int64
	if t, err := time.Parse(time.RFC3339, b.Updated); err == nil {
		metaUpdated = t.Unix()
	}
	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,
		Rating:        b.Rating,
		MetaUpdated:   metaUpdated,
	}
}

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) AudioObjectKeyExt(slug string, n int, voice, ext string) string {
	return AudioObjectKeyExt(slug, n, voice, ext)
}

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)
}

func (s *Store) PutAudioStream(ctx context.Context, key string, r io.Reader, size int64, contentType string) error {
	return s.mc.putObjectStream(ctx, s.mc.bucketAudio, key, contentType, r, size)
}

// ── 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) PutAvatar(ctx context.Context, userID, ext, contentType string, data []byte) (string, error) {
	// Delete existing avatar objects for this user before writing the new one
	// so old extensions don't linger (e.g. old .png after uploading a .jpg).
	_ = s.mc.deleteObjects(ctx, s.mc.bucketAvatars, userID+"/")
	key := AvatarObjectKey(userID, ext)
	if err := s.mc.putObject(ctx, s.mc.bucketAvatars, key, contentType, data); err != nil {
		return "", fmt.Errorf("put avatar: %w", err)
	}
	return key, 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) CreateTranslationTask(ctx context.Context, slug string, chapter int, lang string) (string, error) {
	cacheKey := fmt.Sprintf("%s/%d/%s", slug, chapter, lang)
	payload := map[string]any{
		"cache_key": cacheKey,
		"slug":      slug,
		"chapter":   chapter,
		"lang":      lang,
		"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/translation_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, then translation_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
	}
	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id),
		map[string]string{"status": string(domain.TaskStatusCancelled)}); err == nil {
		return nil
	}
	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/translation_jobs/records/%s", id),
		map[string]string{"status": string(domain.TaskStatusCancelled)})
}

func (s *Store) CancelAudioTasksBySlug(ctx context.Context, slug string) (int, error) {
	filter := fmt.Sprintf(`slug='%s'&&(status='pending'||status='running')`, slug)
	items, err := s.pb.listAll(ctx, "audio_jobs", filter, "")
	if err != nil {
		return 0, fmt.Errorf("CancelAudioTasksBySlug list: %w", err)
	}
	cancelled := 0
	for _, raw := range items {
		var rec struct {
			ID string `json:"id"`
		}
		if json.Unmarshal(raw, &rec) == nil && rec.ID != "" {
			if patchErr := s.pb.patch(ctx,
				fmt.Sprintf("/api/collections/audio_jobs/records/%s", rec.ID),
				map[string]string{"status": string(domain.TaskStatusCancelled)}); patchErr == nil {
				cancelled++
			}
		}
	}
	return cancelled, nil
}

// ── 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) ClaimNextTranslationTask(ctx context.Context, workerID string) (domain.TranslationTask, bool, error) {
	raw, err := s.pb.claimRecord(ctx, "translation_jobs", workerID, nil)
	if err != nil {
		return domain.TranslationTask{}, false, err
	}
	if raw == nil {
		return domain.TranslationTask{}, false, nil
	}
	task, err := parseTranslationTask(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) FinishTranslationTask(ctx context.Context, id string, result domain.TranslationResult) error {
	status := string(domain.TaskStatusDone)
	if result.ErrorMessage != "" {
		status = string(domain.TaskStatusFailed)
	}
	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/translation_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
	}
	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id), payload); err == nil {
		return nil
	}
	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/translation_jobs/records/%s", id), payload)
}

// HeartbeatTask updates the heartbeat_at field on a running task.
// Tries scraping_tasks first, then audio_jobs, then translation_jobs.
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
	}
	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/audio_jobs/records/%s", id), payload); err == nil {
		return nil
	}
	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/translation_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 null OR heartbeat_at < threshold).
	// PocketBase datetime fields require `=null` not `=""` in filter expressions.
	filter := fmt.Sprintf(`status="running"&&(heartbeat_at=null||heartbeat_at<"%s")`, threshold)
	resetPayload := map[string]any{
		"status":       string(domain.TaskStatusPending),
		"worker_id":    "",
		"heartbeat_at": nil,
	}

	total := 0
	for _, collection := range []string{"scraping_tasks", "audio_jobs", "translation_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='%s'`, 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
}

func (s *Store) ListTranslationTasks(ctx context.Context) ([]domain.TranslationTask, error) {
	items, err := s.pb.listAll(ctx, "translation_jobs", "", "-started")
	if err != nil {
		return nil, err
	}
	tasks := make([]domain.TranslationTask, 0, len(items))
	for _, raw := range items {
		t, err := parseTranslationTask(raw)
		if err == nil {
			tasks = append(tasks, t)
		}
	}
	return tasks, nil
}

func (s *Store) GetTranslationTask(ctx context.Context, cacheKey string) (domain.TranslationTask, bool, error) {
	filter := fmt.Sprintf(`cache_key='%s'`, cacheKey)
	items, err := s.pb.listAll(ctx, "translation_jobs", filter, "-started")
	if err != nil || len(items) == 0 {
		return domain.TranslationTask{}, false, err
	}
	t, err := parseTranslationTask(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
}

func parseTranslationTask(raw json.RawMessage) (domain.TranslationTask, error) {
	var rec struct {
		ID           string `json:"id"`
		CacheKey     string `json:"cache_key"`
		Slug         string `json:"slug"`
		Chapter      int    `json:"chapter"`
		Lang         string `json:"lang"`
		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.TranslationTask{}, err
	}
	started, _ := time.Parse(time.RFC3339, rec.Started)
	finished, _ := time.Parse(time.RFC3339, rec.Finished)
	return domain.TranslationTask{
		ID:           rec.ID,
		CacheKey:     rec.CacheKey,
		Slug:         rec.Slug,
		Chapter:      rec.Chapter,
		Lang:         rec.Lang,
		WorkerID:     rec.WorkerID,
		Status:       domain.TaskStatus(rec.Status),
		ErrorMessage: rec.ErrorMessage,
		Started:      started,
		Finished:     finished,
	}, nil
}

// ── CoverStore ─────────────────────────────────────────────────────────────────

func (s *Store) PutCover(ctx context.Context, slug string, data []byte, contentType string) error {
	key := CoverObjectKey(slug)
	if contentType == "" {
		contentType = coverContentType(data)
	}
	if err := s.mc.putCover(ctx, key, contentType, data); err != nil {
		return fmt.Errorf("PutCover: %w", err)
	}
	return nil
}

func (s *Store) GetCover(ctx context.Context, slug string) ([]byte, string, bool, error) {
	key := CoverObjectKey(slug)
	data, ok, err := s.mc.getCover(ctx, key)
	if err != nil {
		return nil, "", false, fmt.Errorf("GetCover: %w", err)
	}
	if !ok {
		return nil, "", false, nil
	}
	ct := coverContentType(data)
	return data, ct, true, nil
}

func (s *Store) CoverExists(ctx context.Context, slug string) bool {
	return s.mc.coverExists(ctx, CoverObjectKey(slug))
}

// ── ChapterImageStore ──────────────────────────────────────────────────────────

func (s *Store) PutChapterImage(ctx context.Context, slug string, n int, data []byte, contentType string) error {
	key := ChapterImageObjectKey(slug, n)
	if contentType == "" {
		contentType = coverContentType(data)
	}
	if err := s.mc.putChapterImage(ctx, key, contentType, data); err != nil {
		return fmt.Errorf("PutChapterImage: %w", err)
	}
	return nil
}

func (s *Store) GetChapterImage(ctx context.Context, slug string, n int) ([]byte, string, bool, error) {
	key := ChapterImageObjectKey(slug, n)
	data, ok, err := s.mc.getChapterImage(ctx, key)
	if err != nil {
		return nil, "", false, fmt.Errorf("GetChapterImage: %w", err)
	}
	if !ok {
		return nil, "", false, nil
	}
	ct := coverContentType(data)
	return data, ct, true, nil
}

func (s *Store) ChapterImageExists(ctx context.Context, slug string, n int) bool {
	return s.mc.chapterImageExists(ctx, ChapterImageObjectKey(slug, n))
}

// ── TranslationStore ───────────────────────────────────────────────────────────

func (s *Store) TranslationObjectKey(lang, slug string, n int) string {
	return TranslationObjectKey(lang, slug, n)
}

func (s *Store) TranslationExists(ctx context.Context, key string) bool {
	return s.mc.objectExists(ctx, s.mc.bucketTranslations, key)
}

func (s *Store) PutTranslation(ctx context.Context, key string, data []byte) error {
	return s.mc.putObject(ctx, s.mc.bucketTranslations, key, "text/markdown; charset=utf-8", data)
}

func (s *Store) GetTranslation(ctx context.Context, key string) (string, error) {
	data, err := s.mc.getObject(ctx, s.mc.bucketTranslations, key)
	if err != nil {
		return "", fmt.Errorf("GetTranslation: %w", err)
	}
	return string(data), nil
}

// ── AIJobStore ────────────────────────────────────────────────────────────────

func (s *Store) CreateAIJob(ctx context.Context, job domain.AIJob) (string, error) {
	payload := map[string]any{
		"kind":        job.Kind,
		"slug":        job.Slug,
		"status":      string(job.Status),
		"from_item":   job.FromItem,
		"to_item":     job.ToItem,
		"items_done":  job.ItemsDone,
		"items_total": job.ItemsTotal,
		"model":       job.Model,
		"payload":     job.Payload,
		"started":     job.Started.Format(time.RFC3339),
	}
	var out struct {
		ID string `json:"id"`
	}
	if err := s.pb.post(ctx, "/api/collections/ai_jobs/records", payload, &out); err != nil {
		return "", fmt.Errorf("CreateAIJob: %w", err)
	}
	return out.ID, nil
}

func (s *Store) GetAIJob(ctx context.Context, id string) (domain.AIJob, bool, error) {
	var raw json.RawMessage
	if err := s.pb.get(ctx, fmt.Sprintf("/api/collections/ai_jobs/records/%s", id), &raw); err != nil {
		if strings.Contains(err.Error(), "404") {
			return domain.AIJob{}, false, nil
		}
		return domain.AIJob{}, false, fmt.Errorf("GetAIJob: %w", err)
	}
	job, err := parseAIJob(raw)
	if err != nil {
		return domain.AIJob{}, false, err
	}
	return job, true, nil
}

func (s *Store) UpdateAIJob(ctx context.Context, id string, fields map[string]any) error {
	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/ai_jobs/records/%s", id), fields)
}

func (s *Store) ListAIJobs(ctx context.Context) ([]domain.AIJob, error) {
	items, err := s.pb.listAll(ctx, "ai_jobs", "", "-started")
	if err != nil {
		return nil, fmt.Errorf("ListAIJobs: %w", err)
	}
	out := make([]domain.AIJob, 0, len(items))
	for _, raw := range items {
		j, err := parseAIJob(raw)
		if err != nil {
			continue
		}
		out = append(out, j)
	}
	return out, nil
}

func parseAIJob(raw json.RawMessage) (domain.AIJob, error) {
	var r struct {
		ID           string `json:"id"`
		Kind         string `json:"kind"`
		Slug         string `json:"slug"`
		Status       string `json:"status"`
		FromItem     int    `json:"from_item"`
		ToItem       int    `json:"to_item"`
		ItemsDone    int    `json:"items_done"`
		ItemsTotal   int    `json:"items_total"`
		Model        string `json:"model"`
		Payload      string `json:"payload"`
		ErrorMessage string `json:"error_message"`
		Started      string `json:"started"`
		Finished     string `json:"finished"`
		HeartbeatAt  string `json:"heartbeat_at"`
	}
	if err := json.Unmarshal(raw, &r); err != nil {
		return domain.AIJob{}, fmt.Errorf("parseAIJob: %w", err)
	}
	parseT := func(s string) time.Time {
		if s == "" {
			return time.Time{}
		}
		t, _ := time.Parse(time.RFC3339, s)
		return t
	}
	return domain.AIJob{
		ID:           r.ID,
		Kind:         r.Kind,
		Slug:         r.Slug,
		Status:       domain.TaskStatus(r.Status),
		FromItem:     r.FromItem,
		ToItem:       r.ToItem,
		ItemsDone:    r.ItemsDone,
		ItemsTotal:   r.ItemsTotal,
		Model:        r.Model,
		Payload:      r.Payload,
		ErrorMessage: r.ErrorMessage,
		Started:      parseT(r.Started),
		Finished:     parseT(r.Finished),
		HeartbeatAt:  parseT(r.HeartbeatAt),
	}, nil
}