import type { NextConfig } from "next";

// Enforcing, but deliberately permissive on script-src.
//
// A nonce-based script-src would mean reading headers() in the root layout,
// which opts every route out of static rendering — today `/` is served from
// cache with s-maxage=31536000. That trade is not worth it while the only
// inline script is the theme FOUC guard in src/app/layout.tsx and the XSS sink
// it would defend has already been removed (C-4 in .planning/SECURITY-SCAN.md).
//
// The remaining directives cost nothing and still close real avenues: no
// plugins, no <base> hijacking, no framing, no posting form data off-site, and
// no exfiltration channel to an arbitrary host.
const contentSecurityPolicy = [
  "default-src 'self'",
  "script-src 'self' 'unsafe-inline'",
  "style-src 'self' 'unsafe-inline'",
  "img-src 'self' data: https:",
  "font-src 'self' data:",
  "connect-src 'self'",
  "object-src 'none'",
  "base-uri 'self'",
  "form-action 'self'",
  "frame-ancestors 'none'",
  "upgrade-insecure-requests",
].join("; ");

const securityHeaders = [
  { key: "X-Frame-Options", value: "DENY" },
  { key: "X-Content-Type-Options", value: "nosniff" },
  { key: "Referrer-Policy", value: "strict-origin-when-cross-origin" },
  { key: "Permissions-Policy", value: "camera=(), microphone=(), geolocation=()" },
  { key: "X-DNS-Prefetch-Control", value: "on" },
  // Client dashboard tokens travel in the URL path, so an active downgrade
  // would expose them in cleartext — HSTS matters more here than usual.
  {
    key: "Strict-Transport-Security",
    value: "max-age=63072000; includeSubDomains; preload",
  },
  { key: "Content-Security-Policy", value: contentSecurityPolicy },
];

const nextConfig: NextConfig = {
  output: "standalone",
  async headers() {
    return [{ source: "/(.*)", headers: securityHeaders }];
  },
};

export default nextConfig;