feat(RECIPE-0009): complete iteration 0 — deduplication, notifications, UI improvements

src/lib/server/queue/QueueManager.ts

@@ -47,6 +47,21 @@ export class QueueManager {
 	/** Set of subscriber callbacks */
 	private subscribers: Set<QueueUpdateCallback> = new Set();
 
+	/**
+	 * Find queue item by URL
+	 *
+	 * @param url - Instagram URL to search for
+	 * @returns Existing queue item or undefined
+	 */
+	findByUrl(url: string): QueueItem | undefined {
+		for (const item of this.items.values()) {
+			if (item.url === url) {
+				return item;
+			}
+		}
+		return undefined;
+	}
+
 	/**
 	 * Add URL to processing queue
 	 *
@@ -60,6 +75,13 @@ export class QueueManager {
 	 * ```
 	 */
 	enqueue(url: string): QueueItem {
+		// Check for duplicate URL
+		const existingItem = this.findByUrl(url);
+		if (existingItem) {
+			console.log(`[QueueManager] Duplicate URL detected: ${url}, returning existing item ${existingItem.id}`);
+			return existingItem;
+		}
+
 		const now = new Date().toISOString();
 		const item: QueueItem = {
 			id: uuidv4(),