refactor: split jikan client into transport/cache/rate subpackages

integrations/jikan/cache/store.go

@@ -0,0 +1,86 @@
+package cache
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+
+	"mal/internal/db"
+	"mal/internal/observability"
+)
+
+type Store struct {
+	db      db.Querier
+	metrics *observability.Metrics
+}
+
+func NewStore(queries db.Querier, metrics *observability.Metrics) *Store {
+	return &Store{db: queries, metrics: metrics}
+}
+
+// Get retrieves a fresh cached value by key.
+func (s *Store) Get(parentCtx context.Context, key string, out any) bool {
+	ctx, cancel := context.WithTimeout(parentCtx, 2*time.Second)
+	defer cancel()
+
+	data, err := s.db.GetJikanCache(ctx, key)
+	if err != nil {
+		s.metrics.ObserveCache("jikan", "miss")
+		return false
+	}
+
+	if err := json.Unmarshal([]byte(data), out); err != nil {
+		s.metrics.ObserveCache("jikan", "miss")
+		return false
+	}
+
+	s.metrics.ObserveCache("jikan", "hit")
+	return true
+}
+
+// GetStale retrieves an expired-but-available cached value by key.
+func (s *Store) GetStale(parentCtx context.Context, key string, out any) bool {
+	ctx, cancel := context.WithTimeout(parentCtx, 2*time.Second)
+	defer cancel()
+
+	data, err := s.db.GetJikanCacheStale(ctx, key)
+	if err != nil {
+		s.metrics.ObserveCache("jikan_stale", "miss")
+		return false
+	}
+
+	if err := json.Unmarshal([]byte(data), out); err != nil {
+		s.metrics.ObserveCache("jikan_stale", "miss")
+		return false
+	}
+
+	s.metrics.ObserveCache("jikan_stale", "hit")
+	return true
+}
+
+// Set stores data in cache with the specified TTL.
+func (s *Store) Set(parentCtx context.Context, key string, data any, ttl time.Duration) {
+	ctx, cancel := context.WithTimeout(parentCtx, 2*time.Second)
+	defer cancel()
+
+	bytes, err := json.Marshal(data)
+	if err != nil {
+		return
+	}
+
+	err = s.db.SetJikanCache(ctx, db.SetJikanCacheParams{
+		Key:       key,
+		Data:      string(bytes),
+		ExpiresAt: time.Now().Add(ttl),
+	})
+	if err != nil {
+		observability.LogJSON(
+			observability.LogLevelError,
+			"jikan_cache_set",
+			"jikan",
+			"",
+			map[string]any{"cache_key": key},
+			err,
+		)
+	}
+}