feat: migrate playback module to modular domain pattern

internal/playback/service/service.go

@@ -0,0 +1,66 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"mal/internal/db"
+	"mal/internal/domain"
+	"strconv"
+)
+
+type playbackService struct {
+	repo      domain.PlaybackRepository
+	providers []domain.Provider
+}
+
+func NewPlaybackService(repo domain.PlaybackRepository, providers []domain.Provider) domain.PlaybackService {
+	return &playbackService{repo: repo, providers: providers}
+}
+
+func (s *playbackService) BuildWatchData(ctx context.Context, animeID int, titleCandidates []string, episode string, mode string, userID string) (map[string]any, error) {
+	// Minimal implementation for now to show the pattern
+	var result *domain.StreamResult
+	var err error
+
+	for _, p := range s.providers {
+		result, err = p.GetStreams(ctx, animeID, episode, mode)
+		if err == nil && result != nil {
+			break
+		}
+	}
+
+	if result == nil {
+		return nil, fmt.Errorf("no streams found")
+	}
+
+	startTime := 0.0
+	if userID != "" {
+		entry, err := s.repo.GetWatchListEntry(ctx, db.GetWatchListEntryParams{
+			UserID:  userID,
+			AnimeID: int64(animeID),
+		})
+		if err == nil {
+			if entry.CurrentEpisode.Valid && strconv.FormatInt(entry.CurrentEpisode.Int64, 10) == episode {
+				startTime = entry.CurrentTimeSeconds
+			}
+		}
+	}
+
+	return map[string]any{
+		"URL":        result.URL,
+		"Referer":    result.Referer,
+		"StartTime":  startTime,
+		"Subtitles":  result.Subtitles,
+		"Qualities":  result.Qualities,
+	}, nil
+}
+
+func (s *playbackService) SaveProgress(ctx context.Context, userID string, animeID int64, episode int, timeSeconds float64) error {
+	params := db.SaveWatchProgressParams{
+		UserID:             userID,
+		AnimeID:            animeID,
+		CurrentEpisode:     sql.NullInt64{Int64: int64(episode), Valid: true},
+		CurrentTimeSeconds: timeSeconds,
+	}
+	return s.repo.SaveWatchProgress(ctx, params)
+}