feat: add episode service with background refresh worker

internal/episodes/worker.go

@@ -0,0 +1,44 @@
+package episodes
+
+import (
+	"context"
+	"log"
+	"mal/internal/domain"
+	"time"
+
+	"go.uber.org/fx"
+)
+
+const workerInterval = time.Minute
+
+func RegisterWorker(lc fx.Lifecycle, svc domain.EpisodeService) {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	lc.Append(fx.Hook{
+		OnStart: func(context.Context) error {
+			go func() {
+				log.Println("episodes: availability worker started")
+				ticker := time.NewTicker(workerInterval)
+				defer ticker.Stop()
+
+				for {
+					if err := svc.RefreshTrackedDue(ctx, 25); err != nil {
+						log.Printf("episodes: availability worker tick failed error=%v", err)
+					}
+
+					select {
+					case <-ticker.C:
+					case <-ctx.Done():
+						log.Println("episodes: availability worker stopped")
+						return
+					}
+				}
+			}()
+			return nil
+		},
+		OnStop: func(context.Context) error {
+			cancel()
+			return nil
+		},
+	})
+}