feat(keybindings): cycle subtitle tracks on j/J with mpv-style OSD

docs/shortcuts.md

@@ -38,6 +38,8 @@ These control playback and subtitle display. They require overlay window focus.
 | Shortcut             | Action                                             |
 | -------------------- | -------------------------------------------------- |
 | `Space`              | Toggle mpv pause                                   |
+| `J`                  | Cycle primary subtitle track                       |
+| `Shift+J`            | Cycle secondary subtitle track                     |
 | `ArrowRight`         | Seek forward 5 seconds                             |
 | `ArrowLeft`          | Seek backward 5 seconds                            |
 | `ArrowUp`            | Seek forward 60 seconds                            |

src/config/definitions/domain-registry.test.ts

@@ -5,6 +5,7 @@ import {
   CONFIG_OPTION_REGISTRY,
   CONFIG_TEMPLATE_SECTIONS,
   DEFAULT_CONFIG,
+  DEFAULT_KEYBINDINGS,
   RUNTIME_OPTION_REGISTRY,
 } from '../definitions';
 import { buildCoreConfigOptionRegistry } from './options-core';
@@ -59,3 +60,9 @@ test('domain registry builders each contribute entries to composed registry', ()
     assert.ok(entries.some((entry) => composedPaths.has(entry.path)));
   }
 });
+
+test('default keybindings include primary and secondary subtitle track cycling on J keys', () => {
+  const keybindingMap = new Map(DEFAULT_KEYBINDINGS.map((binding) => [binding.key, binding.command]));
+  assert.deepEqual(keybindingMap.get('KeyJ'), ['cycle', 'sid']);
+  assert.deepEqual(keybindingMap.get('Shift+KeyJ'), ['cycle', 'secondary-sid']);
+});

src/config/definitions/shared.ts

@@ -48,6 +48,8 @@ export const SPECIAL_COMMANDS = {
 
 export const DEFAULT_KEYBINDINGS: NonNullable<ResolvedConfig['keybindings']> = [
   { key: 'Space', command: ['cycle', 'pause'] },
+  { key: 'KeyJ', command: ['cycle', 'sid'] },
+  { key: 'Shift+KeyJ', command: ['cycle', 'secondary-sid'] },
   { key: 'ArrowRight', command: ['seek', 5] },
   { key: 'ArrowLeft', command: ['seek', -5] },
   { key: 'ArrowUp', command: ['seek', 60] },

src/core/services/ipc-command.test.ts

@@ -0,0 +1,78 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { handleMpvCommandFromIpc } from './ipc-command';
+
+function createOptions(overrides: Partial<Parameters<typeof handleMpvCommandFromIpc>[1]> = {}) {
+  const calls: string[] = [];
+  const sentCommands: (string | number)[][] = [];
+  const osd: string[] = [];
+  const options: Parameters<typeof handleMpvCommandFromIpc>[1] = {
+    specialCommands: {
+      SUBSYNC_TRIGGER: '__subsync-trigger',
+      RUNTIME_OPTIONS_OPEN: '__runtime-options-open',
+      RUNTIME_OPTION_CYCLE_PREFIX: '__runtime-option-cycle:',
+      REPLAY_SUBTITLE: '__replay-subtitle',
+      PLAY_NEXT_SUBTITLE: '__play-next-subtitle',
+    },
+    triggerSubsyncFromConfig: () => {
+      calls.push('subsync');
+    },
+    openRuntimeOptionsPalette: () => {
+      calls.push('runtime-options');
+    },
+    runtimeOptionsCycle: () => ({ ok: true }),
+    showMpvOsd: (text) => {
+      osd.push(text);
+    },
+    mpvReplaySubtitle: () => {
+      calls.push('replay');
+    },
+    mpvPlayNextSubtitle: () => {
+      calls.push('next');
+    },
+    mpvSendCommand: (command) => {
+      sentCommands.push(command);
+    },
+    isMpvConnected: () => true,
+    hasRuntimeOptionsManager: () => true,
+    ...overrides,
+  };
+  return { options, calls, sentCommands, osd };
+}
+
+test('handleMpvCommandFromIpc forwards regular mpv commands', () => {
+  const { options, sentCommands, osd } = createOptions();
+  handleMpvCommandFromIpc(['cycle', 'pause'], options);
+  assert.deepEqual(sentCommands, [['cycle', 'pause']]);
+  assert.deepEqual(osd, []);
+});
+
+test('handleMpvCommandFromIpc emits osd for subtitle position keybinding proxies', () => {
+  const { options, sentCommands, osd } = createOptions();
+  handleMpvCommandFromIpc(['add', 'sub-pos', 1], options);
+  assert.deepEqual(sentCommands, [['add', 'sub-pos', 1]]);
+  assert.deepEqual(osd, ['Subtitle position: ${sub-pos}']);
+});
+
+test('handleMpvCommandFromIpc emits osd for primary subtitle track keybinding proxies', () => {
+  const { options, sentCommands, osd } = createOptions();
+  handleMpvCommandFromIpc(['cycle', 'sid'], options);
+  assert.deepEqual(sentCommands, [['cycle', 'sid']]);
+  assert.deepEqual(osd, ['Subtitle track: ${sid}']);
+});
+
+test('handleMpvCommandFromIpc emits osd for secondary subtitle track keybinding proxies', () => {
+  const { options, sentCommands, osd } = createOptions();
+  handleMpvCommandFromIpc(['set_property', 'secondary-sid', 'auto'], options);
+  assert.deepEqual(sentCommands, [['set_property', 'secondary-sid', 'auto']]);
+  assert.deepEqual(osd, ['Secondary subtitle track: ${secondary-sid}']);
+});
+
+test('handleMpvCommandFromIpc does not forward commands while disconnected', () => {
+  const { options, sentCommands, osd } = createOptions({
+    isMpvConnected: () => false,
+  });
+  handleMpvCommandFromIpc(['add', 'sub-pos', 1], options);
+  assert.deepEqual(sentCommands, []);
+  assert.deepEqual(osd, []);
+});

src/core/services/ipc-command.ts

@@ -24,6 +24,31 @@ export interface HandleMpvCommandFromIpcOptions {
   hasRuntimeOptionsManager: () => boolean;
 }
 
+const MPV_PROPERTY_COMMANDS = new Set([
+  'add',
+  'set',
+  'set_property',
+  'cycle',
+  'cycle-values',
+  'multiply',
+]);
+
+function resolveProxyCommandOsd(command: (string | number)[]): string | null {
+  const operation = typeof command[0] === 'string' ? command[0] : '';
+  const property = typeof command[1] === 'string' ? command[1] : '';
+  if (!MPV_PROPERTY_COMMANDS.has(operation)) return null;
+  if (property === 'sub-pos') {
+    return 'Subtitle position: ${sub-pos}';
+  }
+  if (property === 'sid') {
+    return 'Subtitle track: ${sid}';
+  }
+  if (property === 'secondary-sid') {
+    return 'Secondary subtitle track: ${secondary-sid}';
+  }
+  return null;
+}
+
 export function handleMpvCommandFromIpc(
   command: (string | number)[],
   options: HandleMpvCommandFromIpcOptions,
@@ -58,6 +83,10 @@ export function handleMpvCommandFromIpc(
       options.mpvPlayNextSubtitle();
     } else {
       options.mpvSendCommand(command);
+      const osd = resolveProxyCommandOsd(command);
+      if (osd) {
+        options.showMpvOsd(osd);
+      }
     }
   }
 }