fix birdseye reordering widget in settings

cameras are only sorted while the layout is built, so a config change that reorders them needs a fresh layout even when the active set is unchanged, which is always the case in continuous mode

frigate/test/test_birdseye.py

@@ -1,8 +1,10 @@
 """Test camera user and password cleanup."""
 
+import multiprocessing as mp
 import unittest
 
-from frigate.output.birdseye import get_canvas_shape
+from frigate.config import FrigateConfig
+from frigate.output.birdseye import BirdsEyeFrameManager, get_canvas_shape
 
 
 class TestBirdseye(unittest.TestCase):
@@ -45,3 +47,70 @@ class TestBirdseye(unittest.TestCase):
         canvas_width, canvas_height = get_canvas_shape(width, height)
         assert canvas_width == width  # width will be the same
         assert canvas_height != height
+
+
+class TestBirdseyeCameraOrder(unittest.TestCase):
+    """Test that birdseye reacts to camera order changes without a restart."""
+
+    def setUp(self):
+        config = {
+            "mqtt": {"enabled": False},
+            "birdseye": {"enabled": True, "mode": "continuous"},
+            "cameras": {
+                camera: {
+                    "ffmpeg": {
+                        "inputs": [
+                            {"path": "rtsp://10.0.0.1:554/video", "roles": ["detect"]}
+                        ]
+                    },
+                    "detect": {"height": 1080, "width": 1920, "fps": 5},
+                }
+                for camera in ("back", "front", "side")
+            },
+        }
+        self.config = FrigateConfig(**config)
+        self.manager = BirdsEyeFrameManager(self.config, mp.Event())
+
+        # mark every camera as continuously active with no frame to draw, which
+        # exercises the layout without needing real yuv frames
+        for camera_data in self.manager.cameras.values():
+            camera_data["current_frame"] = None
+            camera_data["current_frame_time"] = 1.0
+            camera_data["last_active_frame"] = 1.0
+
+    def layout_order(self) -> list[str]:
+        """Return the cameras in the order the current layout renders them."""
+        return [position[0] for row in self.manager.camera_layout for position in row]
+
+    def test_layout_uses_configured_order(self):
+        """Test the layout is sorted by order, then by name when tied."""
+        self.config.cameras["side"].birdseye.order = 0
+        self.config.cameras["back"].birdseye.order = 10
+        self.config.cameras["front"].birdseye.order = 20
+
+        self.manager.update_frame()
+
+        assert self.layout_order() == ["side", "back", "front"]
+
+    def test_order_change_rebuilds_layout(self):
+        """Test a reorder relayouts even though the active cameras are unchanged."""
+        self.manager.update_frame()
+        assert self.layout_order() == ["back", "front", "side"]
+
+        # a stable active set means only an order change can reset the layout,
+        # which is what a settings reorder publishes to this process
+        self.config.cameras["side"].birdseye.order = -10
+
+        _, layout_changed = self.manager.update_frame()
+
+        assert layout_changed
+        assert self.layout_order() == ["side", "back", "front"]
+
+    def test_unchanged_order_keeps_layout(self):
+        """Test a repeat update with no order change doesn't reset the layout."""
+        self.manager.update_frame()
+
+        _, layout_changed = self.manager.update_frame()
+
+        assert not layout_changed
+        assert self.layout_order() == ["back", "front", "side"]