feat(stats): add v1 immersion stats dashboard (#19)

src/main/runtime/subtitle-prefetch-init.test.ts

@@ -0,0 +1,114 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import type { SubtitleCue } from '../../core/services/subtitle-cue-parser';
+import type { SubtitlePrefetchService } from '../../core/services/subtitle-prefetch';
+import { createSubtitlePrefetchInitController } from './subtitle-prefetch-init';
+
+function createDeferred<T>(): {
+  promise: Promise<T>;
+  resolve: (value: T) => void;
+  reject: (error: unknown) => void;
+} {
+  let resolve!: (value: T) => void;
+  let reject!: (error: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}
+
+function flushMicrotasks(): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, 0));
+}
+
+test('latest subtitle prefetch init wins over stale async loads', async () => {
+  const loads = new Map<string, ReturnType<typeof createDeferred<string>>>();
+  const started: string[] = [];
+  const stopped: string[] = [];
+  let currentService: SubtitlePrefetchService | null = null;
+
+  const controller = createSubtitlePrefetchInitController({
+    getCurrentService: () => currentService,
+    setCurrentService: (service) => {
+      currentService = service;
+    },
+    loadSubtitleSourceText: async (source) => {
+      const deferred = createDeferred<string>();
+      loads.set(source, deferred);
+      return await deferred.promise;
+    },
+    parseSubtitleCues: (_content, filename): SubtitleCue[] => [
+      { startTime: 0, endTime: 1, text: filename },
+    ],
+    createSubtitlePrefetchService: ({ cues }) => ({
+      start: () => {
+        started.push(cues[0]!.text);
+      },
+      stop: () => {
+        stopped.push(cues[0]!.text);
+      },
+      onSeek: () => {},
+      pause: () => {},
+      resume: () => {},
+    }),
+    tokenizeSubtitle: async () => null,
+    preCacheTokenization: () => {},
+    isCacheFull: () => false,
+    logInfo: () => {},
+    logWarn: () => {},
+  });
+
+  const firstInit = controller.initSubtitlePrefetch('old.ass', 1);
+  const secondInit = controller.initSubtitlePrefetch('new.ass', 2);
+
+  loads.get('new.ass')!.resolve('new');
+  await flushMicrotasks();
+
+  assert.deepEqual(started, ['new.ass']);
+
+  loads.get('old.ass')!.resolve('old');
+  await Promise.all([firstInit, secondInit]);
+
+  assert.deepEqual(started, ['new.ass']);
+  assert.deepEqual(stopped, []);
+});
+
+test('cancelPendingInit prevents an in-flight load from attaching a stale service', async () => {
+  const deferred = createDeferred<string>();
+  let currentService: SubtitlePrefetchService | null = null;
+  const started: string[] = [];
+
+  const controller = createSubtitlePrefetchInitController({
+    getCurrentService: () => currentService,
+    setCurrentService: (service) => {
+      currentService = service;
+    },
+    loadSubtitleSourceText: async () => await deferred.promise,
+    parseSubtitleCues: (_content, filename): SubtitleCue[] => [
+      { startTime: 0, endTime: 1, text: filename },
+    ],
+    createSubtitlePrefetchService: ({ cues }) => ({
+      start: () => {
+        started.push(cues[0]!.text);
+      },
+      stop: () => {},
+      onSeek: () => {},
+      pause: () => {},
+      resume: () => {},
+    }),
+    tokenizeSubtitle: async () => null,
+    preCacheTokenization: () => {},
+    isCacheFull: () => false,
+    logInfo: () => {},
+    logWarn: () => {},
+  });
+
+  const initPromise = controller.initSubtitlePrefetch('stale.ass', 1);
+  controller.cancelPendingInit();
+  deferred.resolve('stale');
+  await initPromise;
+
+  assert.equal(currentService, null);
+  assert.deepEqual(started, []);
+});