fix(osd): show subtitle-annotation loading status during tokenization

src/main/runtime/composers/mpv-runtime-composer.ts

@@ -87,6 +87,7 @@ export type MpvRuntimeComposerResult<
   tokenizeSubtitle: (text: string) => Promise<TTokenizedSubtitle>;
   createMecabTokenizerAndCheck: () => Promise<void>;
   prewarmSubtitleDictionaries: () => Promise<void>;
+  startTokenizationWarmups: () => Promise<void>;
   launchBackgroundWarmupTask: ReturnType<typeof createLaunchBackgroundWarmupTaskFromStartup>;
   startBackgroundWarmups: ReturnType<typeof createStartBackgroundWarmupsFromStartup>;
 }>;
@@ -132,12 +133,23 @@ export function composeMpvRuntimeHandlers<
   const prewarmSubtitleDictionaries = createPrewarmSubtitleDictionariesMainHandler(
     options.tokenizer.prewarmSubtitleDictionariesMainDeps,
   );
-  const tokenizeSubtitle = async (text: string): Promise<TTokenizedSubtitle> => {
-    await options.warmups.startBackgroundWarmupsMainDeps.ensureYomitanExtensionLoaded();
-    if (!options.tokenizer.createMecabTokenizerAndCheckMainDeps.getMecabTokenizer()) {
-      await createMecabTokenizerAndCheck().catch(() => {});
+  let tokenizationWarmupInFlight: Promise<void> | null = null;
+  const startTokenizationWarmups = (): Promise<void> => {
+    if (!tokenizationWarmupInFlight) {
+      tokenizationWarmupInFlight = (async () => {
+        await options.warmups.startBackgroundWarmupsMainDeps.ensureYomitanExtensionLoaded();
+        if (!options.tokenizer.createMecabTokenizerAndCheckMainDeps.getMecabTokenizer()) {
+          await createMecabTokenizerAndCheck().catch(() => {});
+        }
+    await prewarmSubtitleDictionaries({ showLoadingOsd: true });
+      })().finally(() => {
+        tokenizationWarmupInFlight = null;
+      });
     }
-    await prewarmSubtitleDictionaries();
+    return tokenizationWarmupInFlight;
+  };
+  const tokenizeSubtitle = async (text: string): Promise<TTokenizedSubtitle> => {
+    await startTokenizationWarmups();
     return options.tokenizer.tokenizeSubtitle(
       text,
       options.tokenizer.createTokenizerRuntimeDeps(buildTokenizerDepsHandler()),
@@ -165,6 +177,7 @@ export function composeMpvRuntimeHandlers<
     tokenizeSubtitle,
     createMecabTokenizerAndCheck: () => createMecabTokenizerAndCheck(),
     prewarmSubtitleDictionaries: () => prewarmSubtitleDictionaries(),
+    startTokenizationWarmups,
     launchBackgroundWarmupTask: (label, task) => launchBackgroundWarmupTask(label, task),
     startBackgroundWarmups: () => startBackgroundWarmups(),
   };

src/main/runtime/subtitle-tokenization-main-deps.test.ts

@@ -6,6 +6,17 @@ import {
   createPrewarmSubtitleDictionariesMainHandler,
 } from './subtitle-tokenization-main-deps';
 
+function createDeferred(): {
+  promise: Promise<void>;
+  resolve: () => void;
+} {
+  let resolve!: () => void;
+  const promise = new Promise<void>((nextResolve) => {
+    resolve = nextResolve;
+  });
+  return { promise, resolve };
+}
+
 test('tokenizer deps builder records known-word lookups and maps readers', () => {
   const calls: string[] = [];
   const deps = createBuildTokenizerDepsMainHandler({
@@ -77,3 +88,93 @@ test('dictionary prewarm runs both dictionary loaders', async () => {
   await prewarm();
   assert.deepEqual(calls.sort(), ['freq', 'jlpt']);
 });
+
+test('dictionary prewarm shows OSD spinner while loading and completion when loaded', async () => {
+  const osdMessages: string[] = [];
+  const clearedTimers: unknown[] = [];
+  let tick: (() => void) | null = null;
+  const jlptDeferred = createDeferred();
+  const freqDeferred = createDeferred();
+
+  const prewarm = createPrewarmSubtitleDictionariesMainHandler({
+    ensureJlptDictionaryLookup: async () => jlptDeferred.promise,
+    ensureFrequencyDictionaryLookup: async () => freqDeferred.promise,
+    shouldShowOsdNotification: () => true,
+    showMpvOsd: (message) => {
+      osdMessages.push(message);
+    },
+    setInterval: (callback) => {
+      tick = callback;
+      return 1;
+    },
+    clearInterval: (timer) => {
+      clearedTimers.push(timer);
+    },
+  });
+
+  const prewarmPromise = prewarm({ showLoadingOsd: true });
+  assert.deepEqual(osdMessages, ['Loading subtitle annotations |']);
+
+  if (!tick) {
+    throw new Error('expected loading spinner tick callback');
+  }
+  const tickCallback: () => void = tick;
+  tickCallback();
+  assert.deepEqual(osdMessages, ['Loading subtitle annotations |', 'Loading subtitle annotations /']);
+
+  jlptDeferred.resolve();
+  freqDeferred.resolve();
+  await prewarmPromise;
+
+  assert.deepEqual(osdMessages, [
+    'Loading subtitle annotations |',
+    'Loading subtitle annotations /',
+    'Subtitle annotations loaded',
+  ]);
+  assert.deepEqual(clearedTimers, [1]);
+});
+
+test('dictionary prewarm can show OSD while awaiting background-started load', async () => {
+  const osdMessages: string[] = [];
+  const jlptDeferred = createDeferred();
+  const freqDeferred = createDeferred();
+
+  const prewarm = createPrewarmSubtitleDictionariesMainHandler({
+    ensureJlptDictionaryLookup: async () => jlptDeferred.promise,
+    ensureFrequencyDictionaryLookup: async () => freqDeferred.promise,
+    shouldShowOsdNotification: () => true,
+    showMpvOsd: (message) => {
+      osdMessages.push(message);
+    },
+    setInterval: () => 1,
+    clearInterval: () => undefined,
+  });
+
+  const backgroundWarmupPromise = prewarm();
+  const tokenizationWarmupPromise = prewarm({ showLoadingOsd: true });
+  assert.deepEqual(osdMessages, ['Loading subtitle annotations |']);
+
+  jlptDeferred.resolve();
+  freqDeferred.resolve();
+  await backgroundWarmupPromise;
+  await tokenizationWarmupPromise;
+
+  assert.deepEqual(osdMessages, ['Loading subtitle annotations |', 'Subtitle annotations loaded']);
+});
+
+test('dictionary prewarm does not show OSD when notifications are disabled', async () => {
+  const osdMessages: string[] = [];
+
+  const prewarm = createPrewarmSubtitleDictionariesMainHandler({
+    ensureJlptDictionaryLookup: async () => undefined,
+    ensureFrequencyDictionaryLookup: async () => undefined,
+    shouldShowOsdNotification: () => false,
+    showMpvOsd: (message) => {
+      osdMessages.push(message);
+    },
+  });
+
+  await prewarm({ showLoadingOsd: true });
+
+  assert.deepEqual(osdMessages, []);
+});

src/main/runtime/subtitle-tokenization-main-deps.ts

@@ -66,8 +66,88 @@ export function createCreateMecabTokenizerAndCheckMainHandler<TMecab>(deps: {
 export function createPrewarmSubtitleDictionariesMainHandler(deps: {
   ensureJlptDictionaryLookup: () => Promise<void>;
   ensureFrequencyDictionaryLookup: () => Promise<void>;
+  showMpvOsd?: (message: string) => void;
+  shouldShowOsdNotification?: () => boolean;
+  setInterval?: (callback: () => void, delayMs: number) => unknown;
+  clearInterval?: (timer: unknown) => void;
 }) {
-  return async (): Promise<void> => {
-    await Promise.all([deps.ensureJlptDictionaryLookup(), deps.ensureFrequencyDictionaryLookup()]);
+  let prewarmed = false;
+  let prewarmPromise: Promise<void> | null = null;
+  let loadingOsdDepth = 0;
+  let loadingOsdFrame = 0;
+  let loadingOsdTimer: unknown = null;
+  const showMpvOsd = deps.showMpvOsd;
+  const shouldShowOsdNotification = deps.shouldShowOsdNotification ?? (() => false);
+  const setIntervalHandler =
+    deps.setInterval ??
+    ((callback: () => void, delayMs: number): unknown => setInterval(callback, delayMs));
+  const clearIntervalHandler =
+    deps.clearInterval ??
+    ((timer: unknown): void => clearInterval(timer as ReturnType<typeof setInterval>));
+  const spinnerFrames = ['|', '/', '-', '\\'];
+
+  const beginLoadingOsd = (): boolean => {
+    if (!showMpvOsd || !shouldShowOsdNotification()) {
+      return false;
+    }
+    loadingOsdDepth += 1;
+    if (loadingOsdDepth > 1) {
+      return true;
+    }
+
+    loadingOsdFrame = 0;
+    showMpvOsd(`Loading subtitle annotations ${spinnerFrames[loadingOsdFrame]}`);
+    loadingOsdFrame += 1;
+    loadingOsdTimer = setIntervalHandler(() => {
+      if (!showMpvOsd) {
+        return;
+      }
+      showMpvOsd(`Loading subtitle annotations ${spinnerFrames[loadingOsdFrame % spinnerFrames.length]}`);
+      loadingOsdFrame += 1;
+    }, 180);
+    return true;
+  };
+
+  const endLoadingOsd = (): void => {
+    if (!showMpvOsd || !shouldShowOsdNotification()) {
+      return;
+    }
+
+    loadingOsdDepth = Math.max(0, loadingOsdDepth - 1);
+    if (loadingOsdDepth > 0) {
+      return;
+    }
+
+    if (loadingOsdTimer) {
+      clearIntervalHandler(loadingOsdTimer);
+      loadingOsdTimer = null;
+    }
+    showMpvOsd('Subtitle annotations loaded');
+  };
+
+  return async (options?: { showLoadingOsd?: boolean }): Promise<void> => {
+    if (prewarmed) {
+      return;
+    }
+    const shouldTrackLoadingOsd = options?.showLoadingOsd === true;
+    const loadingOsdStarted = shouldTrackLoadingOsd ? beginLoadingOsd() : false;
+
+    if (!prewarmPromise) {
+      prewarmPromise = (async () => {
+        try {
+          await Promise.all([deps.ensureJlptDictionaryLookup(), deps.ensureFrequencyDictionaryLookup()]);
+          prewarmed = true;
+        } finally {
+          prewarmPromise = null;
+        }
+      })();
+    }
+    try {
+      await prewarmPromise;
+    } finally {
+      if (loadingOsdStarted) {
+        endLoadingOsd();
+      }
+    }
   };
 }