import { defaultLocale, locales } from '$lib/translations';
import type { Handle } from '@sveltejs/kit';

const routeRegex = new RegExp(/^\/[^.]*([?#].*)?$/);

const rtlLocales = ['ar'];

const isRTL = (locale: string): boolean => {
	return rtlLocales.includes(locale.toLowerCase());
};

/** @type {import('@sveltejs/kit').Handle} */
export const handle: Handle = async ({ event, resolve }) => {
	const { url } = event;
	const { pathname } = url;
	if (routeRegex.test(pathname)) {
		const supportedLocales = locales.get().map((l) => l.toLowerCase());

		// Try to get locale from `pathname`.
		let locale = supportedLocales.find((l) => l === `${pathname.match(/[^/]+?(?=\/|$)/)}`.toLowerCase());

		// We want to redirect the default locale to "no-locale" path
		if (!locale) {
			locale = defaultLocale;
		}

		const dir = isRTL(locale) ? 'rtl' : 'ltr';

		// Add html `lang` and `dir` attributes
		return resolve(
			{ ...event, locals: { lang: locale } },
			{
				transformPageChunk: ({ html }) => html.replace('%lang%', `${locale}`).replace('%dir%', dir),
			}
		);
	}

	return resolve(event);
};

// /** @type {import('@sveltejs/kit').HandleServerError} */
// export const handleError: ({
//   event,
// }: {
//   event: HandleServerError & { locals: { [name: string]: string } };
// }) => Promise<App.Locals> = async ({ event }) => {
//   const { locals } = event;
//   const { lang } = locals;
//
//   await loadTranslations(lang, 'error');
//
//   return locals;
// };