/** @type {import('next').NextConfig} */
const nextConfig = {
  // Enable standalone output for Docker
  output: 'standalone',

  // The /api/* and /sitemap.xml proxies to the FastAPI backend are route
  // handlers (app/api/[...path]/route.ts, app/sitemap.xml/route.ts) rather
  // than rewrites, so the backend host is read from FASTAPI_URL at runtime
  // instead of being baked into the build.

  // Image optimization
  images: {
    remotePatterns: [
      { protocol: 'https', hostname: '*.tile.openstreetmap.org' },
      { protocol: 'https', hostname: 'tile.openstreetmap.org' },
      { protocol: 'https', hostname: 'cdnjs.cloudflare.com' },
    ],
    formats: ['image/avif', 'image/webp'],
    minimumCacheTTL: 31536000,
  },

  // Performance optimizations
  compiler: {
    // Remove console logs in production
    removeConsole: process.env.NODE_ENV === 'production',
  },

  // Compression
  compress: true,

  // React strict mode for better error detection
  reactStrictMode: true,

  // Power optimizations
  poweredByHeader: false,

  // Production source maps (disable for smaller bundles)
  productionBrowserSourceMaps: false,

  // Experimental features for performance
  experimental: {
    // Optimize package imports
    optimizePackageImports: ['chart.js', 'react-chartjs-2', 'leaflet'],
  },

  // Headers for caching and security
  async headers() {
    return [
      {
        source: '/:path*',
        headers: [
          {
            key: 'X-DNS-Prefetch-Control',
            value: 'on',
          },
          {
            // Allow the analytics subdomain (Umami heatmap/recorder) to embed
            // the site while blocking all other origins. frame-ancestors is the
            // modern replacement for X-Frame-Options, which cannot allow a
            // specific sibling subdomain (ALLOW-FROM is deprecated/ignored).
            key: 'Content-Security-Policy',
            value: "frame-ancestors 'self' https://analytics.schoolcompare.co.uk",
          },
          {
            key: 'X-Content-Type-Options',
            value: 'nosniff',
          },
          {
            key: 'Referrer-Policy',
            value: 'origin-when-cross-origin',
          },
        ],
      },
      {
        source: '/favicon.svg',
        headers: [
          {
            key: 'Cache-Control',
            value: 'public, max-age=31536000, immutable',
          },
        ],
      },
    ];
  },
};

module.exports = nextConfig;