import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';
import { I18N_CONFIG } from '@nice/i18n';

// 使用统一的 i18n 配置
const { supportedLocales, defaultLocale } = I18N_CONFIG;
export type Locale = typeof supportedLocales[number];

function getLocale(request: NextRequest): string {
	// 从 Cookie 获取
	const cookieLocale = request.cookies.get('NEXT_LOCALE')?.value;
	if (cookieLocale && (supportedLocales as readonly string[]).includes(cookieLocale)) {
		return cookieLocale;
	}

	// 从 Accept-Language 头获取
	const acceptLanguage = request.headers.get('accept-language') || '';
	const browserLocales = acceptLanguage
		.split(',')
		.map(lang => lang.split(';')[0]?.trim())
		.filter(Boolean)
		.map(lang => lang?.split('-')[0])
		.filter(Boolean);

	for (const browserLocale of browserLocales) {
		if (browserLocale && (supportedLocales as readonly string[]).includes(browserLocale)) {
			return browserLocale;
		}
	}

	return defaultLocale;
}

export function middleware(request: NextRequest) {
	const { pathname, search } = request.nextUrl;

	// 跳过不需要处理的路径
	if (
		// API 路由
		pathname.startsWith('/api/') ||
		// Next.js 内部路径
		pathname.startsWith('/_next/') ||
		// 翻译文件路径
		pathname.startsWith('/locales/') ||
		// 静态文件
		pathname.includes('.') ||
		// 特定文件
		pathname === '/favicon.ico' ||
		pathname === '/sitemap.xml' ||
		pathname === '/robots.txt' ||
		// 图片文件
		/\.(jpg|jpeg|png|gif|svg|ico|webp)$/i.test(pathname) ||
		// CSS/JS 文件
		/\.(css|js|mjs)$/i.test(pathname)
	) {
		return NextResponse.next();
	}

	// 检查是否已经有语言前缀
	const hasLocalePrefix = supportedLocales.some(
		locale => pathname.startsWith(`/${locale}/`) || pathname === `/${locale}`
	);

	if (!hasLocalePrefix) {
		// 获取用户的语言偏好
		const locale = getLocale(request);

		// 重定向到带语言前缀的 URL
		const newUrl = new URL(`/${locale}${pathname}`, request.url);
		newUrl.search = search;

		const response = NextResponse.redirect(newUrl);

		// 设置 Cookie 保存语言偏好
		response.cookies.set('NEXT_LOCALE', locale, {
			maxAge: 365 * 24 * 60 * 60, // 1 year
			path: '/',
			sameSite: 'lax'
		});

		return response;
	}

	// 验证语言是否支持
	const pathLocale = pathname.split('/')[1];
	if (pathLocale && !(supportedLocales as readonly string[]).includes(pathLocale)) {
		// 不支持的语言，重定向到默认语言
		const newPathname = pathname.replace(`/${pathLocale}`, `/${defaultLocale}`);
		const newUrl = new URL(newPathname, request.url);
		newUrl.search = search;
		return NextResponse.redirect(newUrl);
	}

	// 添加语言信息到请求头，供服务端组件使用
	const requestHeaders = new Headers(request.headers);
	requestHeaders.set('x-pathname', pathname);

	return NextResponse.next({
		request: {
			headers: requestHeaders,
		}
	});
}


// Middleware matcher configuration
export const config = {
	matcher: [
		'/((?!api|_next/static|_next/image|favicon.ico|locales|.*\\..*).*)'
	],
};