fix: harden AI subtitle fix response parsing

src/window-trackers/base-tracker.ts

@@ -21,13 +21,17 @@ import { WindowGeometry } from '../types';
 export type GeometryChangeCallback = (geometry: WindowGeometry) => void;
 export type WindowFoundCallback = (geometry: WindowGeometry) => void;
 export type WindowLostCallback = () => void;
+export type WindowFocusChangeCallback = (focused: boolean) => void;
 
 export abstract class BaseWindowTracker {
   protected currentGeometry: WindowGeometry | null = null;
   protected windowFound: boolean = false;
+  protected focusKnown: boolean = false;
+  protected windowFocused: boolean = false;
   public onGeometryChange: GeometryChangeCallback | null = null;
   public onWindowFound: WindowFoundCallback | null = null;
   public onWindowLost: WindowLostCallback | null = null;
+  public onWindowFocusChange: WindowFocusChangeCallback | null = null;
 
   abstract start(): void;
   abstract stop(): void;
@@ -40,6 +44,19 @@ export abstract class BaseWindowTracker {
     return this.windowFound;
   }
 
+  isFocused(): boolean {
+    return this.focusKnown ? this.windowFocused : this.windowFound;
+  }
+
+  protected updateFocus(focused: boolean): void {
+    const changed = !this.focusKnown || this.windowFocused !== focused;
+    this.focusKnown = true;
+    this.windowFocused = focused;
+    if (changed) {
+      this.onWindowFocusChange?.(focused);
+    }
+  }
+
   protected updateGeometry(newGeometry: WindowGeometry | null): void {
     if (newGeometry) {
       if (!this.windowFound) {
@@ -58,6 +75,12 @@ export abstract class BaseWindowTracker {
         if (this.onGeometryChange) this.onGeometryChange(newGeometry);
       }
     } else {
+      const focusChanged = this.focusKnown && this.windowFocused;
+      this.focusKnown = false;
+      this.windowFocused = false;
+      if (focusChanged) {
+        this.onWindowFocusChange?.(false);
+      }
       if (this.windowFound) {
         this.windowFound = false;
         this.currentGeometry = null;

src/window-trackers/macos-tracker.ts

@@ -22,9 +22,56 @@ import * as fs from 'fs';
 import * as os from 'os';
 import { BaseWindowTracker } from './base-tracker';
 import { createLogger } from '../logger';
+import type { WindowGeometry } from '../types';
 
 const log = createLogger('tracker').child('macos');
 
+export interface MacOSHelperWindowState {
+  geometry: WindowGeometry;
+  focused: boolean;
+}
+
+export function parseMacOSHelperOutput(result: string): MacOSHelperWindowState | null {
+  const trimmed = result.trim();
+  if (!trimmed || trimmed === 'not-found') {
+    return null;
+  }
+
+  const parts = trimmed.split(',');
+  if (parts.length !== 4 && parts.length !== 5) {
+    return null;
+  }
+
+  const x = parseInt(parts[0]!, 10);
+  const y = parseInt(parts[1]!, 10);
+  const width = parseInt(parts[2]!, 10);
+  const height = parseInt(parts[3]!, 10);
+  if (
+    !Number.isFinite(x) ||
+    !Number.isFinite(y) ||
+    !Number.isFinite(width) ||
+    !Number.isFinite(height) ||
+    width <= 0 ||
+    height <= 0
+  ) {
+    return null;
+  }
+
+  const focusedRaw = parts[4]?.trim().toLowerCase();
+  const focused =
+    focusedRaw === undefined ? true : focusedRaw === '1' || focusedRaw === 'true';
+
+  return {
+    geometry: {
+      x,
+      y,
+      width,
+      height,
+    },
+    focused,
+  };
+}
+
 export class MacOSWindowTracker extends BaseWindowTracker {
   private pollInterval: ReturnType<typeof setInterval> | null = null;
   private pollInFlight = false;
@@ -173,33 +220,12 @@ export class MacOSWindowTracker extends BaseWindowTracker {
           return;
         }
 
-        const result = (stdout || '').trim();
-        if (result && result !== 'not-found') {
-          const parts = result.split(',');
-          if (parts.length === 4) {
-            const x = parseInt(parts[0]!, 10);
-            const y = parseInt(parts[1]!, 10);
-            const width = parseInt(parts[2]!, 10);
-            const height = parseInt(parts[3]!, 10);
-
-            if (
-              Number.isFinite(x) &&
-              Number.isFinite(y) &&
-              Number.isFinite(width) &&
-              Number.isFinite(height) &&
-              width > 0 &&
-              height > 0
-            ) {
-              this.updateGeometry({
-                x,
-                y,
-                width,
-                height,
-              });
-              this.pollInFlight = false;
-              return;
-            }
-          }
+        const parsed = parseMacOSHelperOutput(stdout || '');
+        if (parsed) {
+          this.updateFocus(parsed.focused);
+          this.updateGeometry(parsed.geometry);
+          this.pollInFlight = false;
+          return;
         }
 
         this.updateGeometry(null);

src/window-trackers/x11-tracker.test.ts

@@ -1,6 +1,7 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { parseX11WindowGeometry, parseX11WindowPid, X11WindowTracker } from './x11-tracker';
+import { parseMacOSHelperOutput } from './macos-tracker';
 
 test('parseX11WindowGeometry parses xwininfo output', () => {
   const geometry = parseX11WindowGeometry(`
@@ -52,3 +53,27 @@ Height: 360`;
   release();
   await new Promise((resolve) => setTimeout(resolve, 0));
 });
+
+test('parseMacOSHelperOutput parses geometry and focused state', () => {
+  assert.deepEqual(parseMacOSHelperOutput('120,240,1280,720,1'), {
+    geometry: {
+      x: 120,
+      y: 240,
+      width: 1280,
+      height: 720,
+    },
+    focused: true,
+  });
+});
+
+test('parseMacOSHelperOutput tolerates unfocused helper output', () => {
+  assert.deepEqual(parseMacOSHelperOutput('120,240,1280,720,0'), {
+    geometry: {
+      x: 120,
+      y: 240,
+      width: 1280,
+      height: 720,
+    },
+    focused: false,
+  });
+});