Init

led_platform/services/scene_store.py

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+import json
+from pathlib import Path
+from threading import Lock
+
+from led_platform.core.clock import epoch_ms
+from led_platform.domain import Scene, SceneState
+
+
+class SceneStore:
+    def __init__(self, config_path: Path) -> None:
+        self.config_path = config_path
+        self._lock = Lock()
+        self._scenes: dict[str, Scene] = {}
+        self._state: SceneState | None = None
+        self.reload()
+
+    def reload(self) -> None:
+        data = json.loads(self.config_path.read_text(encoding="utf-8"))
+        scenes = [Scene(**item) for item in data["scenes"]]
+        if not scenes:
+            raise ValueError("At least one scene is required.")
+        default_scene_id = data.get("default_scene_id") or scenes[0].id
+        scene_map = {scene.id: scene for scene in scenes}
+        if default_scene_id not in scene_map:
+            raise ValueError(f"Default scene {default_scene_id!r} does not exist.")
+        default_scene = scene_map[default_scene_id]
+        with self._lock:
+            version = self._state.version + 1 if self._state else 1
+            self._scenes = scene_map
+            self._state = self._build_state(default_scene, version=version, apply_at_ms=None)
+
+    def list(self) -> list[Scene]:
+        with self._lock:
+            return list(self._scenes.values())
+
+    def get(self, scene_id: str) -> Scene:
+        with self._lock:
+            if scene_id not in self._scenes:
+                raise KeyError(scene_id)
+            return self._scenes[scene_id]
+
+    def state(self) -> SceneState:
+        with self._lock:
+            if self._state is None:
+                raise RuntimeError("Scene state is not initialized.")
+            return self._state
+
+    def switch(self, scene_id: str, apply_at_ms: int) -> SceneState:
+        with self._lock:
+            if scene_id not in self._scenes:
+                raise KeyError(scene_id)
+            version = self._state.version + 1 if self._state else 1
+            self._state = self._build_state(
+                self._scenes[scene_id],
+                version=version,
+                apply_at_ms=apply_at_ms,
+            )
+            return self._state
+
+    def action(self, action: str, apply_at_ms: int) -> SceneState:
+        with self._lock:
+            if self._state is None:
+                raise RuntimeError("Scene state is not initialized.")
+            self._state = self._state.model_copy(
+                update={
+                    "version": self._state.version + 1,
+                    "action": action,
+                    "apply_at_ms": apply_at_ms,
+                }
+            )
+            return self._state
+
+    @staticmethod
+    def _build_state(scene: Scene, version: int, apply_at_ms: int | None) -> SceneState:
+        return SceneState(
+            active_scene_id=scene.id,
+            active_view=scene.view,
+            active_url=str(scene.url),
+            version=version,
+            scene_started_at_ms=apply_at_ms or epoch_ms(),
+            apply_at_ms=apply_at_ms,
+        )