const cdnDomain = process.env.CDN_DOMAIN || '';

const nextConfig = {
  output: 'standalone',
  // 默认 dist/；可用 NEXT_DIST_DIR 覆盖（CI 分环境输出，或本地需要避开既有构建产物）
  distDir: process.env.NEXT_DIST_DIR || 'dist',
  assetPrefix: cdnDomain || undefined,
  images: {
    // 有意关闭 Next 图片优化：产物经 Nginx 静态托管 + CDN 分发（见 docs/CDN_CONFIGURATION.md、
    // CLAUDE.md「Images are unoptimized (static export limitation)」）。
    // 不要仅因「性能」理由改为 false —— 在无 Node 运行时接管 /_next/image 的部署模式下会导致图片 404。
    unoptimized: true,
    // 注意：unoptimized 为 true 时下面这行不生效，仅在改回 false 后才会参与构建产物生成。
    formats: ['image/avif', 'image/webp'],
  },
  compress: true,
  poweredByHeader: false,
  reactStrictMode: true,
  experimental: {
    optimizePackageImports: ['lucide-react', 'framer-motion'],
  },
  compiler: {
    removeConsole: process.env.NODE_ENV === 'production',
  },
  generateEtags: true,
  httpAgentOptions: {
    keepAlive: true,
  },
  async headers() {
    return [
      {
        source: '/(.*)',
        headers: [
          { key: 'X-Content-Type-Options', value: 'nosniff' },
          { key: 'X-Frame-Options', value: 'DENY' },
          { key: 'X-XSS-Protection', value: '1; mode=block' },
          { key: 'Referrer-Policy', value: 'strict-origin-when-cross-origin' },
          {
            key: 'Content-Security-Policy',
            value: "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://www.googletagmanager.com https://ssl.google-analytics.com; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob: https://www.google-analytics.com https://ssl.google-analytics.com https://www.googletagmanager.com; font-src 'self'; connect-src 'self' https://www.google-analytics.com https://ssl.google-analytics.com https://www.googletagmanager.com; frame-src 'self'; object-src 'none'; base-uri 'self'; form-action 'self';",
          },
          { key: 'Permissions-Policy', value: 'camera=(), microphone=(), geolocation=(), interest-cohort=()' },
        ],
      },
    ];
  },
};

export default nextConfig;