fix(subtitles): follow mpv sub-delay in mining, sidebar, and navigation (#302)

src/main/runtime/autoplay-subtitle-priming-runtime.ts

@@ -1,3 +1,4 @@
+import { toSubtitleClock } from '../../core/services/subtitle-clock';
 import type { SubtitleCue, SubtitleData } from '../../types';
 import { selectAutoplayStartupCue } from './autoplay-subtitle-primer';
 import { primeVisibleOverlaySubtitleFromMpv } from './current-subtitle-snapshot';
@@ -12,6 +13,7 @@ type AutoplaySubtitlePrimingMpvClient = {
   requestProperty: (name: string) => Promise<unknown>;
   currentVideoPath?: string;
   currentTimePos?: number;
+  currentSubDelay?: number;
   currentSubText?: string;
   currentSecondarySubText?: string;
   setCurrentSecondarySubText?: (text: string) => void;
@@ -156,7 +158,7 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     const currentTimeSec = Number(client?.currentTimePos ?? deps.getLastObservedTimePos());
     return resolvePrimarySubtitleText({
       liveText: text,
-      currentTimeSec,
+      currentTimeSec: toSubtitleClock(currentTimeSec, client?.currentSubDelay ?? 0),
       cues: deps.getActiveParsedSubtitleCues(),
     });
   }
@@ -270,7 +272,10 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     const currentTimeSeconds = Number(
       timePosRaw ?? client?.currentTimePos ?? deps.getLastObservedTimePos() ?? 0,
     );
-    const resolvedTimeSeconds = Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0;
+    const resolvedTimeSeconds = toSubtitleClock(
+      Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0,
+      client?.currentSubDelay ?? 0,
+    );
     const cue = selectAutoplayStartupCue(
       cues,
       resolvedTimeSeconds,

src/main/runtime/mpv-main-event-main-deps.test.ts

@@ -176,6 +176,21 @@ test('subtitle-track transitions ignore stale parsed cues until replacement cues
   assert.deepEqual(recordedStarts.slice(-1), [20]);
 });
 
+test('subtitle timing history records lines on the video clock under sub-delay', () => {
+  const timing: Array<{ text: string; start: number; end: number }> = [];
+  const { handlers } = buildMainDeps({
+    mpvClient: { currentSubDelay: 2 },
+    subtitleTimingTracker: {
+      recordSubtitle: (text: string, start: number, end: number) =>
+        timing.push({ text, start, end }),
+    },
+  });
+
+  handlers.recordSubtitleTiming('食べる', 5, 8);
+
+  assert.deepEqual(timing, [{ text: '食べる', start: 7, end: 10 }]);
+});
+
 test('canonical ASS cues replace live glyph spam for display, history, and immersion', () => {
   const immersion: Array<{ text: string; start: number; end: number }> = [];
   const timing: Array<{ text: string; start: number; end: number }> = [];

src/main/runtime/mpv-main-event-main-deps.ts

@@ -1,3 +1,4 @@
+import { toSubtitleClock } from '../../core/services/subtitle-clock';
 import { createSubtitleLineDedupGate } from '../../core/services/subtitle-line-dedup-gate';
 import type { MergedToken, SubtitleCue, SubtitleData } from '../../types';
 import {
@@ -23,6 +24,7 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
       currentSubText?: string;
       currentSecondarySubText?: string;
       currentTimePos?: number;
+      currentSubDelay?: number;
       requestProperty?: (name: string) => Promise<unknown>;
     } | null;
     immersionTracker: {
@@ -161,7 +163,10 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
     resolveSubtitleText: (liveText: string) =>
       resolvePrimarySubtitleText({
         liveText,
-        currentTimeSec: Number(deps.appState.mpvClient?.currentTimePos),
+        currentTimeSec: toSubtitleClock(
+          Number(deps.appState.mpvClient?.currentTimePos),
+          deps.appState.mpvClient?.currentSubDelay ?? 0,
+        ),
         cues: deps.appState.activeParsedSubtitleCues,
       }),
     getCurrentLiveSubtitleText: () => deps.appState.mpvClient?.currentSubText ?? '',
@@ -231,6 +236,9 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
     hasSubtitleTimingTracker: () => Boolean(deps.appState.subtitleTimingTracker),
     recordSubtitleTiming: (text: string, start: number, end: number) => {
       const secondaryText = deps.appState.mpvClient?.currentSecondarySubText || undefined;
+      // The tracker feeds multi-line mining, so it stores video-clock times: the subtitle
+      // timings plus the `sub-delay` in effect while the line was on screen.
+      const subDelay = deps.appState.mpvClient?.currentSubDelay ?? 0;
       const canonical = resolveCanonicalSample(text, start);
       if (!canonical) {
         const recordableText = resolveTextForRecording(text, start);
@@ -239,8 +247,8 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
         }
         deps.appState.subtitleTimingTracker?.recordSubtitle?.(
           recordableText,
-          start,
-          end,
+          start + subDelay,
+          end + subDelay,
           secondaryText,
         );
         return;
@@ -253,8 +261,8 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
         recordedTimingCanonicalKeys.add(key);
         deps.appState.subtitleTimingTracker?.recordSubtitle?.(
           cue.text,
-          cue.startTime,
-          cue.endTime,
+          cue.startTime + subDelay,
+          cue.endTime + subDelay,
           secondaryText,
         );
       }