Function ThemeProvider

src/components/design-system/ThemeProvider.tsx:43–116

({
  children,
  initialState,
  onThemeSave = defaultSaveTheme
}: Props)

  }));
}
export function ThemeProvider({
  children,
  initialState,
  onThemeSave = defaultSaveTheme
}: Props) {
  const [themeSetting, setThemeSetting] = useState(initialState ?? defaultInitialTheme);
  const [previewTheme, setPreviewTheme] = useState<ThemeSetting | null>(null);

  // Track terminal theme for 'auto' resolution. Seeds from $COLORFGBG (or
  // 'dark' if unset); the OSC 11 watcher corrects it on first poll.
  const [systemTheme, setSystemTheme] = useState<SystemTheme>(() => (initialState ?? themeSetting) === 'auto' ? getSystemThemeName() : 'dark');

  // The setting currently in effect (preview wins while picker is open)
  const activeSetting = previewTheme ?? themeSetting;
  const {
    internal_querier
  } = useStdin();

  // Watch for live terminal theme changes while 'auto' is active.
  // Positive feature() pattern so the watcher import is dead-code-eliminated
  // in external builds.
  useEffect(() => {
    if (feature('AUTO_THEME')) {
      if (activeSetting !== 'auto' || !internal_querier) return;
      let cleanup: (() => void) | undefined;
      let cancelled = false;
      void import('../../utils/systemThemeWatcher.js').then(({
        watchSystemTheme
      }) => {
        if (cancelled) return;
        cleanup = watchSystemTheme(internal_querier, setSystemTheme);
      });
      return () => {
        cancelled = true;
        cleanup?.();
      };
    }
  }, [activeSetting, internal_querier]);
  const currentTheme: ThemeName = activeSetting === 'auto' ? systemTheme : activeSetting;
  const value = useMemo<ThemeContextValue>(() => ({
    themeSetting,
    setThemeSetting: (newSetting: ThemeSetting) => {
      setThemeSetting(newSetting);
      setPreviewTheme(null);
      // Switching to 'auto' restarts the watcher (activeSetting dep), whose
      // first poll fires immediately. Seed from the cache so the OSC
      // round-trip doesn't flash the wrong palette.
      if (newSetting === 'auto') {
        setSystemTheme(getSystemThemeName());
      }
      onThemeSave?.(newSetting);
    },
    setPreviewTheme: (newSetting_0: ThemeSetting) => {
      setPreviewTheme(newSetting_0);
      if (newSetting_0 === 'auto') {
        setSystemTheme(getSystemThemeName());
      }
    },