import { NextRequest, NextResponse } from 'next/server';
import { locales, defaultLocale } from './lib/i18n';

export function middleware(request: NextRequest) {
    // 在静态导出模式下，中间件不会执行
    // 这个文件保留用于开发和服务器模式
    
    // 在静态导出模式下跳过中间件逻辑
    if (process.env.NODE_ENV === 'production' && process.env.NEXT_OUTPUT_MODE === 'export') {
        return NextResponse.next();
    }
    
    const pathname = request.nextUrl.pathname;

    // Check if there is any supported locale in the pathname
    const pathnameIsMissingLocale = locales.every(
        (locale) => !pathname.startsWith(`/${locale}/`) && pathname !== `/${locale}`,
    );

    // Redirect if there is no locale
    if (pathnameIsMissingLocale) {
        // Get locale from Accept-Language header or use default
        const locale = getLocaleFromRequest(request) || defaultLocale;

        // Don't redirect for default locale on root path
        if (locale === defaultLocale && pathname === '/') {
            return NextResponse.next();
        }

        // Redirect to locale-prefixed path for non-default locales
        if (locale !== defaultLocale) {
            return NextResponse.redirect(
                new URL(`/${locale}${pathname === '/' ? '' : pathname}`, request.url),
            );
        }
    }

    return NextResponse.next();
}

function getLocaleFromRequest(request: NextRequest): string | undefined {
    // Get locale from cookie first
    const localeCookie = request.cookies.get('locale')?.value;
    if (localeCookie && locales.includes(localeCookie as any)) {
        return localeCookie;
    }

    // Get locale from Accept-Language header
    const acceptLanguage = request.headers.get('accept-language');
    if (acceptLanguage) {
        const preferredLocale = acceptLanguage
            .split(',')
            .map((lang) => lang.split(';')[0].trim())
            .find((lang) => locales.includes(lang as any));

        if (preferredLocale) {
            return preferredLocale;
        }
    }

    return defaultLocale;
}

export const config = {
    matcher: [
        // Skip all internal paths (_next), static files, and manifest files
        '/((?!_next|api|favicon.ico|site.webmanifest|.*\\..*).*)',
    ],
};