import type { NextConfig } from 'next';
import { existsSync } from 'node:fs';
import path from 'node:path';

// Monorepo: a single `.env` lives at the repository root; Next only reads the app directory.
for (const candidate of [path.resolve(process.cwd(), '../../.env'), path.resolve(process.cwd(), '.env')]) {
  if (existsSync(candidate)) {
    try {
      process.loadEnvFile(candidate);
    } catch {
      /* ignore malformed env */
    }
  }
}

// Dev: FastAPI on :8331 (see repo .env). Production sets API_URL=http://127.0.0.1:8321 in the mld manifest.
const API_URL = (process.env.API_URL ?? 'http://127.0.0.1:8331').replace(/\/$/, '');

const nextConfig: NextConfig = {
  // NEXT_DIST_DIR lets parallel dev servers / builds use separate output dirs (default .next)
  distDir: process.env.NEXT_DIST_DIR || '.next',
  reactStrictMode: true,
  poweredByHeader: false,
  allowedDevOrigins: ['127.0.0.1', 'localhost'],
  outputFileTracingRoot: path.resolve(__dirname, '../..'),
  experimental: {
    optimizePackageImports: ['lucide-react'],
  },
  // Browser-side fetches go to the same origin; the FastAPI service is loopback-only.
  async rewrites() {
    return [
      { source: '/api/v1/:path*', destination: `${API_URL}/api/v1/:path*` },
      { source: '/health', destination: `${API_URL}/health` },
    ];
  },
  async headers() {
    const PUBLIC_CACHE = { key: 'Cache-Control', value: 'public, s-maxage=300, stale-while-revalidate=3600' };
    const NO_STORE = { key: 'Cache-Control', value: 'private, no-store' };
    return [
      {
        source: '/(.*)',
        headers: [
          { key: 'X-Content-Type-Options', value: 'nosniff' },
          { key: 'Referrer-Policy', value: 'strict-origin-when-cross-origin' },
          { key: 'X-Frame-Options', value: 'SAMEORIGIN' },
          { key: 'Permissions-Policy', value: 'camera=(), microphone=(), geolocation=()' },
          { key: 'Strict-Transport-Security', value: 'max-age=31536000; includeSubDomains' },
        ],
      },
      { source: '/models/:path*', headers: [PUBLIC_CACHE] },
      { source: '/companies/:path*', headers: [PUBLIC_CACHE] },
      { source: '/papers/:path*', headers: [PUBLIC_CACHE] },
      { source: '/providers/:path*', headers: [PUBLIC_CACHE] },
      { source: '/benchmarks/:path*', headers: [PUBLIC_CACHE] },
      { source: '/hardware/:path*', headers: [PUBLIC_CACHE] },
      { source: '/api/:path*', headers: [NO_STORE] },
      { source: '/admin/:path*', headers: [NO_STORE] },
    ];
  },
};

export default nextConfig;