feat: implemented artwork fetching/downloading

app.py

@@ -615,6 +615,51 @@ def save_settings():
     return jsonify({"ok": True})
 
 
+# ---------------------------------------------------------------------------
+# Artwork routes
+# ---------------------------------------------------------------------------
+
+@app.route("/api/artwork", methods=["GET"])
+def get_artwork():
+    from monochrome.spotify_to_ids import parse_spotify_url, fetch_spotify_embed
+    spotify_url = request.args.get("url", "").strip()
+    if not spotify_url:
+        return jsonify({"error": "No URL provided"}), 400
+
+    sp_type, sp_id = parse_spotify_url(spotify_url)
+    if not sp_type:
+        return jsonify({"error": "Invalid Spotify URL"}), 400
+
+    embed_data = fetch_spotify_embed(sp_type, sp_id)
+    if not embed_data:
+        return jsonify({"error": "Could not fetch Spotify metadata"}), 502
+
+    try:
+        entity = embed_data["props"]["pageProps"]["state"]["data"]["entity"]
+    except (KeyError, TypeError):
+        return jsonify({"error": "Unexpected Spotify response format"}), 502
+
+    # entity.visualIdentity.image[] — confirmed structure from Spotify embed page
+    # Each entry: {"url": "https://image-cdn-ak.spotifycdn.com/image/...", "maxWidth": N, "maxHeight": N}
+    images = (entity.get("visualIdentity") or {}).get("image", [])
+    if not images:
+        app.logger.warning("Artwork not found. Entity keys: %s", list(entity.keys()))
+        return jsonify({"error": "No artwork found for this URL"}), 404
+
+    best = max(images, key=lambda img: img.get("maxWidth", 0))
+    url = best["url"]
+
+    # Upscale to 2000×2000 using the same CDN key technique as votify-fix.
+    # Spotify CDN filenames: first 16 hex chars = size key, remainder = image hash.
+    # Source: GladistonXD/votify-fix constants.py COVER_SIZE_X_KEY_MAPPING_SONG
+    EXTRA_LARGE_KEY = "ab67616d000082c1"
+    parts = url.rsplit("/", 1)
+    if len(parts) == 2 and len(parts[1]) >= 16:
+        url = parts[0] + "/" + EXTRA_LARGE_KEY + parts[1][16:]
+
+    return jsonify({"image_url": url})
+
+
 # ---------------------------------------------------------------------------
 # Job routes
 # ---------------------------------------------------------------------------