feat: add episode classification enrichment implementation

internal/episodes/service/classifications.go

@@ -0,0 +1,81 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"strconv"
+
+	"mal/integrations/jikan"
+	"mal/internal/domain"
+	"mal/internal/observability"
+)
+
+func (s *EpisodeService) EnrichEpisodeClassifications(ctx context.Context, anime domain.Anime) (domain.CanonicalEpisodeList, error) {
+	payload, _, ok := s.cachedEpisodePayload(ctx, anime)
+	if !ok {
+		return domain.CanonicalEpisodeList{}, errors.New("episode classifications: episode availability is not cached")
+	}
+	if payload.ClassificationChecked {
+		return payload, nil
+	}
+	if s.jikan == nil {
+		return payload, errors.New("episode classifications: provider is not configured")
+	}
+
+	value, err, _ := s.classificationLoad.Do(strconv.Itoa(anime.MalID), func() (any, error) {
+		return s.loadEpisodeClassifications(ctx, anime)
+	})
+	if err != nil {
+		return payload, err
+	}
+	return value.(domain.CanonicalEpisodeList), nil
+}
+
+func (s *EpisodeService) loadEpisodeClassifications(ctx context.Context, anime domain.Anime) (domain.CanonicalEpisodeList, error) {
+	episodes, err := s.jikan.GetAllEpisodes(ctx, anime.MalID)
+	if err != nil {
+		return domain.CanonicalEpisodeList{}, err
+	}
+
+	s.cacheMu.Lock()
+	defer s.cacheMu.Unlock()
+
+	payload, row, ok := s.cachedEpisodePayload(ctx, anime)
+	if !ok {
+		return domain.CanonicalEpisodeList{}, errors.New("episode classifications: episode availability cache disappeared")
+	}
+	mergeEpisodeClassifications(payload.Episodes, episodes)
+	payload.ClassificationChecked = true
+	if err := s.storeEnrichedPayload(ctx, row, payload); err != nil {
+		return domain.CanonicalEpisodeList{}, err
+	}
+
+	observability.Info(
+		"episode_classifications_enriched",
+		"episodes",
+		"",
+		map[string]any{
+			"anime_id": anime.MalID,
+			"episodes": len(episodes),
+		},
+	)
+	return payload, nil
+}
+
+func mergeEpisodeClassifications(canonical []domain.CanonicalEpisode, episodes []jikan.Episode) {
+	byNumber := make(map[int]jikan.Episode, len(episodes))
+	for i, episode := range episodes {
+		number, ok := jikanEpisodeNumber(episode, i)
+		if ok {
+			byNumber[number] = episode
+		}
+	}
+	for i := range canonical {
+		classification, ok := byNumber[canonical[i].Number]
+		if !ok {
+			continue
+		}
+		canonical[i].Filler = classification.Filler
+		canonical[i].Recap = classification.Recap
+	}
+}