First working POC

src/lib/services/favorites.ts

@@ -0,0 +1,55 @@
+// Favorites service - Handles toggling favorite status with optimistic updates
+
+import { invoke } from "@tauri-apps/api/core";
+import { auth } from "$lib/stores/auth";
+
+/**
+ * Toggle the favorite status of an item.
+ *
+ * Flow:
+ * 1. Update local database immediately (optimistic update)
+ * 2. Sync to Jellyfin server
+ * 3. Mark as synced on success, or leave pending_sync flag on failure
+ *
+ * @param itemId - The Jellyfin item ID
+ * @param currentIsFavorite - The current favorite status
+ * @returns The new favorite status
+ * @throws Error if not authenticated or database update fails
+ */
+export async function toggleFavorite(
+  itemId: string,
+  currentIsFavorite: boolean
+): Promise<boolean> {
+  const userId = auth.getUserId();
+  if (!userId) {
+    throw new Error("Not authenticated");
+  }
+
+  const newIsFavorite = !currentIsFavorite;
+
+  // 1. Update local database first (optimistic update)
+  await invoke("storage_toggle_favorite", {
+    userId,
+    itemId,
+    isFavorite: newIsFavorite,
+  });
+
+  // 2. Sync to Jellyfin server
+  try {
+    const repo = auth.getRepository();
+    if (newIsFavorite) {
+      await repo.markFavorite(itemId);
+    } else {
+      await repo.unmarkFavorite(itemId);
+    }
+
+    // 3. Mark as synced
+    await invoke("storage_mark_synced", { userId, itemId });
+  } catch (error) {
+    console.error("Failed to sync favorite to server:", error);
+    // Favorite is stored locally and will be synced later
+    // via sync queue (when implemented)
+  }
+
+  return newIsFavorite;
+}