Split async/sync parts of viewer.

src/resolved-media.ts

@@ -0,0 +1,57 @@
+import { HomeAssistant } from 'custom-card-helpers';
+import { homeAssistantWSRequest } from './common.js';
+import {
+  BrowseMediaSource,
+  ExtendedHomeAssistant,
+  ResolvedMedia,
+  resolvedMediaSchema,
+} from './types.js';
+
+export class ResolvedMediaCache {
+  protected _cache: Record<string, ResolvedMedia>;
+
+  constructor() {
+    this._cache = {};
+  }
+
+  public has(id: string): boolean {
+    return id in this._cache;
+  }
+
+  public get(id: string): ResolvedMedia | undefined {
+    return this._cache[id];
+  }
+
+  public set(id: string, resolvedMedia: ResolvedMedia): void {
+    this._cache[id] = resolvedMedia;
+  }
+}
+
+export class ResolvedMediaUtil {
+  static async resolveMedia(
+    hass: HomeAssistant & ExtendedHomeAssistant,
+    mediaSource?: BrowseMediaSource,
+    cache?: ResolvedMediaCache,
+  ): Promise<ResolvedMedia | null> {
+    if (!mediaSource) {
+      return null;
+    }
+    const cachedValue = cache ? cache.get(mediaSource.media_content_id) : undefined;
+    if (cachedValue) {
+      return cachedValue;
+    }
+    const request = {
+      type: 'media_source/resolve_media',
+      media_content_id: mediaSource.media_content_id,
+    };
+    const resolvedMedia = await homeAssistantWSRequest(
+      hass,
+      resolvedMediaSchema,
+      request,
+    );
+    if (cache && resolvedMedia) {
+      cache.set(mediaSource.media_content_id, resolvedMedia);
+    }
+    return resolvedMedia;
+  }
+}