package server

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"github.com/libnovel/scraper/internal/storage"
)

// ─── Reading progress API ─────────────────────────────────────────────────────

// handleGetProgress handles GET /api/progress.
// Returns JSON: {"slug": chapterNum, ...} merged with {"slug_ts": timestampMs, ...}
func (s *Server) handleGetProgress(w http.ResponseWriter, r *http.Request) {
	sid := ensureSession(w, r)
	entries, err := s.store.AllProgress(r.Context(), sid)
	if err != nil {
		s.log.Error("AllProgress failed", "err", err)
		entries = nil
	}

	progress := make(map[string]interface{}, len(entries)*2)
	for _, p := range entries {
		progress[p.Slug] = p.Chapter
		progress[p.Slug+"_ts"] = p.UpdatedAt.UnixMilli()
	}

	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(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 == "" {
		http.Error(w, `{"error":"missing slug"}`, http.StatusBadRequest)
		return
	}

	var body struct {
		Chapter int `json:"chapter"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.Chapter < 1 {
		http.Error(w, `{"error":"invalid body"}`, http.StatusBadRequest)
		return
	}

	p := storage.ReadingProgress{
		Slug:      slug,
		Chapter:   body.Chapter,
		UpdatedAt: time.Now(),
	}
	if err := s.store.SetProgress(r.Context(), sid, p); err != nil {
		s.log.Error("SetProgress failed", "slug", slug, "err", err)
		http.Error(w, `{"error":"store error"}`, http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(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 == "" {
		http.Error(w, `{"error":"missing slug"}`, http.StatusBadRequest)
		return
	}

	if err := s.store.DeleteProgress(r.Context(), sid, slug); err != nil {
		s.log.Error("DeleteProgress failed", "slug", slug, "err", err)
		// Non-fatal — treat as success.
	}

	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(map[string]string{})
}

// handleChapterText returns the plain text of a chapter (markdown stripped)
// for server-side audio generation. Called by handleAudioGenerate internally.
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.store.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))
}