Allow camera engines to signal events to the card.

src/camera-manager/browse-media/camera.ts

@@ -0,0 +1,30 @@
+import { HomeAssistant } from '@dermotduffy/custom-card-helpers';
+import { localize } from '../../localize/localize';
+import { EntityRegistryManager } from '../../utils/ha/entity-registry';
+import { Entity } from '../../utils/ha/entity-registry/types';
+import { Camera } from '../camera';
+import { CameraInitializationError } from '../error';
+
+export class BrowseMediaCamera extends Camera {
+  protected _entity: Entity | null = null;
+
+  public async initialize(
+    hass: HomeAssistant,
+    entityRegistryManager: EntityRegistryManager,
+  ): Promise<Camera> {
+    const config = this.getConfig();
+    const entity = config.camera_entity
+      ? await entityRegistryManager.getEntity(hass, config.camera_entity)
+      : null;
+
+    if (!entity || !config.camera_entity) {
+      throw new CameraInitializationError(localize('error.no_camera_entity'), config);
+    }
+    this._entity = entity;
+    return this;
+  }
+
+  public getEntity(): Entity | null {
+    return this._entity;
+  }
+}