[codex] Replace mpv fullscreen toggle with launch mode config (#48)

Co-authored-by: bee <autumn@skerritt.blog>

src/shared/mpv-launch-mode.test.ts

@@ -0,0 +1,15 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { buildMpvLaunchModeArgs, parseMpvLaunchMode } from './mpv-launch-mode';
+
+test('parseMpvLaunchMode normalizes valid string values', () => {
+  assert.equal(parseMpvLaunchMode(' fullscreen '), 'fullscreen');
+  assert.equal(parseMpvLaunchMode('MAXIMIZED'), 'maximized');
+  assert.equal(parseMpvLaunchMode('normal'), 'normal');
+});
+
+test('buildMpvLaunchModeArgs returns the expected mpv flags', () => {
+  assert.deepEqual(buildMpvLaunchModeArgs('normal'), []);
+  assert.deepEqual(buildMpvLaunchModeArgs('maximized'), ['--window-maximized=yes']);
+  assert.deepEqual(buildMpvLaunchModeArgs('fullscreen'), ['--fullscreen']);
+});

src/shared/mpv-launch-mode.ts

@@ -0,0 +1,24 @@
+import type { MpvLaunchMode } from '../types/config';
+
+export const MPV_LAUNCH_MODE_VALUES = ['normal', 'maximized', 'fullscreen'] as const satisfies
+  readonly MpvLaunchMode[];
+
+export function parseMpvLaunchMode(value: unknown): MpvLaunchMode | undefined {
+  if (typeof value !== 'string') {
+    return undefined;
+  }
+
+  const normalized = value.trim().toLowerCase();
+  return MPV_LAUNCH_MODE_VALUES.find((candidate) => candidate === normalized);
+}
+
+export function buildMpvLaunchModeArgs(launchMode: MpvLaunchMode): string[] {
+  switch (launchMode) {
+    case 'fullscreen':
+      return ['--fullscreen'];
+    case 'maximized':
+      return ['--window-maximized=yes'];
+    default:
+      return [];
+  }
+}