fix: stabilize local subtitle startup and pause release

src/main/runtime/local-subtitle-selection.ts

@@ -0,0 +1,261 @@
+import path from 'node:path';
+
+import { isRemoteMediaPath } from '../../jimaku/utils';
+import { normalizeYoutubeLangCode } from '../../core/services/youtube/labels';
+
+const DEFAULT_PRIMARY_SUBTITLE_LANGUAGES = ['ja', 'jpn'];
+const DEFAULT_SECONDARY_SUBTITLE_LANGUAGES = ['en', 'eng', 'english', 'enus', 'en-us'];
+const HEARING_IMPAIRED_PATTERN = /\b(hearing impaired|sdh|closed captions?|cc)\b/i;
+
+type SubtitleTrackLike = {
+  type?: unknown;
+  id?: unknown;
+  lang?: unknown;
+  title?: unknown;
+  external?: unknown;
+  selected?: unknown;
+};
+
+type NormalizedSubtitleTrack = {
+  id: number;
+  lang: string;
+  title: string;
+  external: boolean;
+  selected: boolean;
+};
+
+export type ManagedLocalSubtitleSelection = {
+  primaryTrackId: number | null;
+  secondaryTrackId: number | null;
+  hasPrimaryMatch: boolean;
+  hasSecondaryMatch: boolean;
+};
+
+function parseTrackId(value: unknown): number | null {
+  if (typeof value === 'number' && Number.isInteger(value)) {
+    return value;
+  }
+  if (typeof value === 'string') {
+    const parsed = Number(value.trim());
+    return Number.isInteger(parsed) ? parsed : null;
+  }
+  return null;
+}
+
+function normalizeTrack(entry: unknown): NormalizedSubtitleTrack | null {
+  if (!entry || typeof entry !== 'object') {
+    return null;
+  }
+  const track = entry as SubtitleTrackLike;
+  const id = parseTrackId(track.id);
+  if (id === null || (track.type !== undefined && track.type !== 'sub')) {
+    return null;
+  }
+  return {
+    id,
+    lang: String(track.lang || '').trim(),
+    title: String(track.title || '').trim(),
+    external: track.external === true,
+    selected: track.selected === true,
+  };
+}
+
+function normalizeLanguageList(values: string[], fallback: string[]): string[] {
+  const normalized = values
+    .map((value) => normalizeYoutubeLangCode(value))
+    .filter((value, index, items) => value.length > 0 && items.indexOf(value) === index);
+  if (normalized.length > 0) {
+    return normalized;
+  }
+  return fallback
+    .map((value) => normalizeYoutubeLangCode(value))
+    .filter((value, index, items) => value.length > 0 && items.indexOf(value) === index);
+}
+
+function resolveLanguageRank(language: string, preferredLanguages: string[]): number {
+  const normalized = normalizeYoutubeLangCode(language);
+  if (!normalized) {
+    return Number.POSITIVE_INFINITY;
+  }
+  const directIndex = preferredLanguages.indexOf(normalized);
+  if (directIndex >= 0) {
+    return directIndex;
+  }
+  const base = normalized.split('-')[0] || normalized;
+  const baseIndex = preferredLanguages.indexOf(base);
+  return baseIndex >= 0 ? baseIndex : Number.POSITIVE_INFINITY;
+}
+
+function isLikelyHearingImpaired(title: string): boolean {
+  return HEARING_IMPAIRED_PATTERN.test(title);
+}
+
+function pickBestTrackId(
+  tracks: NormalizedSubtitleTrack[],
+  preferredLanguages: string[],
+  excludeId: number | null = null,
+): { trackId: number | null; hasMatch: boolean } {
+  const ranked = tracks
+    .filter((track) => track.id !== excludeId)
+    .map((track) => ({
+      track,
+      languageRank: resolveLanguageRank(track.lang, preferredLanguages),
+    }))
+    .filter(({ languageRank }) => Number.isFinite(languageRank))
+    .sort((left, right) => {
+      if (left.languageRank !== right.languageRank) {
+        return left.languageRank - right.languageRank;
+      }
+      if (left.track.external !== right.track.external) {
+        return left.track.external ? -1 : 1;
+      }
+      if (isLikelyHearingImpaired(left.track.title) !== isLikelyHearingImpaired(right.track.title)) {
+        return isLikelyHearingImpaired(left.track.title) ? 1 : -1;
+      }
+      if (/\bdefault\b/i.test(left.track.title) !== /\bdefault\b/i.test(right.track.title)) {
+        return /\bdefault\b/i.test(left.track.title) ? -1 : 1;
+      }
+      return left.track.id - right.track.id;
+    });
+
+  return {
+    trackId: ranked[0]?.track.id ?? null,
+    hasMatch: ranked.length > 0,
+  };
+}
+
+export function resolveManagedLocalSubtitleSelection(input: {
+  trackList: unknown[] | null;
+  primaryLanguages: string[];
+  secondaryLanguages: string[];
+}): ManagedLocalSubtitleSelection {
+  const tracks = Array.isArray(input.trackList)
+    ? input.trackList.map(normalizeTrack).filter((track): track is NormalizedSubtitleTrack => track !== null)
+    : [];
+  const preferredPrimaryLanguages = normalizeLanguageList(
+    input.primaryLanguages,
+    DEFAULT_PRIMARY_SUBTITLE_LANGUAGES,
+  );
+  const preferredSecondaryLanguages = normalizeLanguageList(
+    input.secondaryLanguages,
+    DEFAULT_SECONDARY_SUBTITLE_LANGUAGES,
+  );
+
+  const primary = pickBestTrackId(tracks, preferredPrimaryLanguages);
+  const secondary = pickBestTrackId(tracks, preferredSecondaryLanguages, primary.trackId);
+
+  return {
+    primaryTrackId: primary.trackId,
+    secondaryTrackId: secondary.trackId,
+    hasPrimaryMatch: primary.hasMatch,
+    hasSecondaryMatch: secondary.hasMatch,
+  };
+}
+
+function normalizeLocalMediaPath(mediaPath: string | null | undefined): string | null {
+  if (typeof mediaPath !== 'string') {
+    return null;
+  }
+  const trimmed = mediaPath.trim();
+  if (!trimmed || isRemoteMediaPath(trimmed)) {
+    return null;
+  }
+  return path.resolve(trimmed);
+}
+
+export function createManagedLocalSubtitleSelectionRuntime(deps: {
+  getCurrentMediaPath: () => string | null;
+  getMpvClient: () =>
+    | {
+        connected?: boolean;
+        requestProperty?: (name: string) => Promise<unknown>;
+      }
+    | null;
+  getPrimarySubtitleLanguages: () => string[];
+  getSecondarySubtitleLanguages: () => string[];
+  sendMpvCommand: (command: ['set_property', 'sid' | 'secondary-sid', number]) => void;
+  schedule: (callback: () => void, delayMs: number) => ReturnType<typeof setTimeout>;
+  clearScheduled: (timer: ReturnType<typeof setTimeout>) => void;
+  delayMs?: number;
+}) {
+  const delayMs = deps.delayMs ?? 400;
+  let currentMediaPath: string | null = null;
+  let appliedMediaPath: string | null = null;
+  let pendingTimer: ReturnType<typeof setTimeout> | null = null;
+
+  const clearPendingTimer = (): void => {
+    if (!pendingTimer) {
+      return;
+    }
+    deps.clearScheduled(pendingTimer);
+    pendingTimer = null;
+  };
+
+  const maybeApplySelection = (trackList: unknown[] | null): void => {
+    if (!currentMediaPath || appliedMediaPath === currentMediaPath) {
+      return;
+    }
+    const selection = resolveManagedLocalSubtitleSelection({
+      trackList,
+      primaryLanguages: deps.getPrimarySubtitleLanguages(),
+      secondaryLanguages: deps.getSecondarySubtitleLanguages(),
+    });
+    if (!selection.hasPrimaryMatch && !selection.hasSecondaryMatch) {
+      return;
+    }
+    if (selection.primaryTrackId !== null) {
+      deps.sendMpvCommand(['set_property', 'sid', selection.primaryTrackId]);
+    }
+    if (selection.secondaryTrackId !== null) {
+      deps.sendMpvCommand(['set_property', 'secondary-sid', selection.secondaryTrackId]);
+    }
+    appliedMediaPath = currentMediaPath;
+    clearPendingTimer();
+  };
+
+  const refreshFromMpv = async (): Promise<void> => {
+    const client = deps.getMpvClient();
+    if (!client?.connected || !client.requestProperty) {
+      return;
+    }
+    const mediaPath = normalizeLocalMediaPath(deps.getCurrentMediaPath());
+    if (!mediaPath || mediaPath !== currentMediaPath) {
+      return;
+    }
+    try {
+      const trackList = await client.requestProperty('track-list');
+      maybeApplySelection(Array.isArray(trackList) ? trackList : null);
+    } catch {
+      // Skip selection when mpv track inspection fails.
+    }
+  };
+
+  const scheduleRefresh = (): void => {
+    clearPendingTimer();
+    if (!currentMediaPath || appliedMediaPath === currentMediaPath) {
+      return;
+    }
+    pendingTimer = deps.schedule(() => {
+      pendingTimer = null;
+      void refreshFromMpv();
+    }, delayMs);
+  };
+
+  return {
+    handleMediaPathChange: (mediaPath: string | null | undefined): void => {
+      const normalizedPath = normalizeLocalMediaPath(mediaPath);
+      if (normalizedPath !== currentMediaPath) {
+        appliedMediaPath = null;
+      }
+      currentMediaPath = normalizedPath;
+      if (!currentMediaPath) {
+        clearPendingTimer();
+        return;
+      }
+      scheduleRefresh();
+    },
+    handleSubtitleTrackListChange: (trackList: unknown[] | null): void => {
+      maybeApplySelection(trackList);
+    },
+  };
+}