Add spotify queue

app.py

@@ -314,6 +314,25 @@ def _mark_spotify_accounts(rooms: list):
         room["spotify_account"] = playing_on.get(_spotify_name(room["key"]))
 
 
+# How much of a room's Spotify queue its card unfolds to.
+QUEUE_LENGTH = 10
+def _queue_item(item: dict) -> dict:
+    """One queue entry in the same shape as a card's now-playing: a track
+    names its artists and its album's cover, a podcast episode its show."""
+    show = item.get("show") or {}
+    artist = ", ".join(a["name"] for a in item.get("artists") or [] if a.get("name")) or show.get("name")
+    images = (item.get("album") or {}).get("images") or item.get("images") or show.get("images") or []
+    # Spotify lists them widest first: the smallest still sharp on a retina phone, rather than a 640px cover squeezed into a thumbnail
+    sharp = [i for i in images if (i.get("width") or 0) >= 120]
+    image = (sharp[-1] if sharp else images[0] if images else {}).get("url")
+    return {
+        "song": item.get("name") or "",
+        "artist": artist or "",
+        "image": image,
+        "duration_ms": item.get("duration_ms")
+    }
+
+
 def _link_zidoo_poster(avr: dict):
     """Point the AVR's now-playing cover at our own copy of the Zidoo's
     poster: the panel is served over https, and the Zidoo only speaks plain
@@ -522,6 +541,23 @@ def api_spotify_devices():
     return jsonify(_spotify_from(request.args).devices())
 
 
+@app.get("/api/spotify/queue")
+@handle_errors
+def api_spotify_queue():
+    """What comes next in a room's Spotify stream (?target=lego_room), asked
+    of whichever of your accounts is playing there. Only fetched when a card
+    unfolds its queue, not on every poll."""
+    key = _target_from(request.args)
+    # Demo rooms are not on anyone's real Spotify, so they bring their own queue.
+    if _is_demo():
+        return jsonify({"target": key, "queue": controller.spotify_queue(key)[:QUEUE_LENGTH]})
+    account = _spotify_playing_on().get(_spotify_name(key))
+    if account is None:
+        raise ValueError("Only a Spotify stream one of your accounts is playing has a queue to show")
+    items = spotify[account].queue()[:QUEUE_LENGTH]
+    return jsonify({"target": key, "account": account, "queue": [_queue_item(i) for i in items]})
+
+
 @app.post("/api/spotify/resume")
 @handle_errors
 def api_spotify_resume():