feat: watch playlists and download newly added tracks

internal/watcher/watcher.go

@@ -0,0 +1,72 @@
+package watcher
+
+import (
+	"context"
+	"errors"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/mathismqn/godeez/internal/config"
+	"github.com/mathismqn/godeez/internal/downloader"
+	"github.com/mathismqn/godeez/internal/logger"
+	"github.com/mathismqn/godeez/internal/store"
+)
+
+type Watcher struct {
+	appConfig *config.Config
+	logger    *logger.Logger
+}
+
+func New(appConfig *config.Config) *Watcher {
+	homeDir, _ := os.UserHomeDir()
+	logFile := filepath.Join(homeDir, ".godeez", "watcher.log")
+	file, err := os.OpenFile(logFile, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
+	if err != nil {
+		log.Fatalf("Failed to open log file: %v\n", err)
+	}
+
+	base := log.New(file, "", log.LstdFlags)
+	log := logger.New(base)
+
+	return &Watcher{
+		appConfig: appConfig,
+		logger:    log,
+	}
+}
+
+func (w *Watcher) Run(ctx context.Context, opts downloader.Options) {
+	w.logger.Infof("Starting watcher...")
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+			playlists, err := store.ListWatchedPlaylists()
+			if err != nil {
+				w.logger.Errorf("Failed to list watched playlists: %v\n", err)
+			} else {
+				for _, playlist := range playlists {
+					dl := downloader.New(w.appConfig, "playlist")
+					dl.Logger = w.logger
+					if err := dl.Run(ctx, opts, playlist.ID); err != nil {
+						if errors.Is(err, context.Canceled) {
+							return
+						}
+
+						w.logger.Errorf("Playlist %s: %v\n", playlist.ID, err)
+					}
+				}
+			}
+
+			select {
+			case <-ctx.Done():
+				return
+			case <-time.After(15 * time.Minute):
+				// Continue to the next iteration to check for updates
+			}
+		}
+	}
+}