Function migrateLegacyPreference

site/src/theme/themeMode.ts:73–107

(
	settings: AppearanceSettingsLike,
)

 * state, applying the one-time migration of legacy `auto-*` values.
 */
export const migrateLegacyPreference = (
	settings: AppearanceSettingsLike,
): ThemeModeState => {
	const mode = settings.theme_mode;

	if (mode === "sync") {
		return {
			mode: "sync",
			light: coerceConcrete(settings.theme_light, "light"),
			dark: coerceConcrete(settings.theme_dark, "dark"),
		};
	}

	if (mode === "single") {
		return {
			mode: "single",
			theme: coerceConcrete(settings.theme_preference, DEFAULT_THEME),
		};
	}

	// No recognized theme_mode. Inspect the legacy theme_preference.
	const legacySync = legacyAutoToSync(settings.theme_preference);
	if (legacySync) {
		return {
			mode: "sync",
			light: coerceConcrete(settings.theme_light, legacySync.light),
			dark: coerceConcrete(settings.theme_dark, legacySync.dark),
		};
	}

	return {
		mode: "single",
		theme: coerceConcrete(settings.theme_preference, DEFAULT_THEME),
	};
};

export const resolveActiveThemeName = (
	state: ThemeModeState,