Add radio channel property with stereo/mono/left/right

server/app/item_catalog.py

@@ -20,7 +20,7 @@ ITEM_DEFINITIONS: dict[ItemType, ItemDefinition] = {
         default_title="radio",
         capabilities=("editable", "carryable", "deletable", "usable"),
         use_sound=None,
-        default_params={"streamUrl": "", "enabled": True, "volume": 50, "effect": "off", "effectValue": 50},
+        default_params={"streamUrl": "", "enabled": True, "channel": "stereo", "volume": 50, "effect": "off", "effectValue": 50},
     ),
     "dice": ItemDefinition(
         default_title="Dice",

server/app/server.py

@@ -49,6 +49,7 @@ LOGGER = logging.getLogger("chgrid.server")
 PACKET_LOGGER = logging.getLogger("chgrid.server.packet")
 CLIENT_PACKET_ADAPTER = TypeAdapter(ClientPacket)
 RADIO_EFFECT_IDS = {"reverb", "echo", "flanger", "high_pass", "low_pass", "off"}
+RADIO_CHANNEL_IDS = {"stereo", "mono", "left", "right"}
 
 
 class SignalingServer:
@@ -615,6 +616,18 @@ class SignalingServer:
                         return
                     next_params["effect"] = effect
 
+                    channel = str(next_params.get("channel", "stereo")).strip().lower()
+                    if channel not in RADIO_CHANNEL_IDS:
+                        await self._send_item_result(
+                            client,
+                            False,
+                            "update",
+                            "channel must be one of stereo, mono, left, right.",
+                            item.id,
+                        )
+                        return
+                    next_params["channel"] = channel
+
                     try:
                         effect_value = int(next_params.get("effectValue", 50))
                     except (TypeError, ValueError):

server/tests/test_item_use_cooldown.py

@@ -82,3 +82,38 @@ async def test_radio_use_toggles_enabled(monkeypatch: pytest.MonkeyPatch) -> Non
     assert send_payloads[-1].ok is True
 
     assert any(getattr(packet, "type", "") == "item_upsert" for packet in broadcast_payloads)
+
+
+@pytest.mark.asyncio
+async def test_radio_channel_update_validates(monkeypatch: pytest.MonkeyPatch) -> None:
+    server = SignalingServer("127.0.0.1", 8765, None, None)
+    ws = _fake_ws()
+    client = ClientConnection(websocket=ws, id="u1", nickname="tester", x=5, y=6)
+    server.clients[ws] = client
+    item = server.item_service.default_item(client, "radio_station")
+    server.item_service.add_item(item)
+
+    send_payloads: list[object] = []
+
+    async def fake_send(websocket: ServerConnection, packet: object) -> None:
+        send_payloads.append(packet)
+
+    async def fake_broadcast(packet: object, exclude: ServerConnection | None = None) -> None:
+        return
+
+    monkeypatch.setattr(server, "_send", fake_send)
+    monkeypatch.setattr(server, "_broadcast", fake_broadcast)
+
+    await server._handle_message(
+        client,
+        json.dumps({"type": "item_update", "itemId": item.id, "params": {"channel": "left"}}),
+    )
+    assert send_payloads[-1].ok is True
+    assert item.params.get("channel") == "left"
+
+    await server._handle_message(
+        client,
+        json.dumps({"type": "item_update", "itemId": item.id, "params": {"channel": "invalid"}}),
+    )
+    assert send_payloads[-1].ok is False
+    assert "channel must be one of" in send_payloads[-1].message.lower()