import http from 'node:http';
import type { AddressInfo } from 'node:net';
import express from 'express';
import type { NextFunction, Request, Response } from 'express';
import { afterAll, beforeAll, describe, expect, it } from 'vitest';
import {
  allowedBrowserPorts,
  configuredAllowedOrigins,
  isAllowedBrowserOrigin,
  isLocalSameOrigin,
} from '../src/origin-validation.js';

type TestRequestOptions = {
  origin?: string;
  headers?: http.OutgoingHttpHeaders;
};

type TestResponse = {
  status: number | undefined;
  body: string;
  headers: http.IncomingHttpHeaders;
};

function getListeningPort(server: http.Server): number {
  const address = server.address();
  if (address == null || typeof address === 'string') {
    throw new Error('Expected HTTP server to listen on a TCP port');
  }
  return (address as AddressInfo).port;
}

function closeServer(server: http.Server): Promise<void> {
  return new Promise((resolve, reject) => {
    server.close((error) => {
      if (error != null) {
        reject(error);
        return;
      }
      resolve();
    });
  });
}

function createOriginMiddleware(resolvedPort: number, host = '127.0.0.1') {
  const _NULL_ORIGIN_SAFE_GET_RE =
    /^\/projects\/[^/]+\/raw\/|^\/codex-pets\/[^/]+\/spritesheet$/;
  return (req: Request, res: Response, next: NextFunction) => {
    const origin = req.headers.origin;
    if (origin == null || origin === '') return next();
    if (origin === 'null') {
      const isSafeReadOnly =
        req.method === 'GET' && _NULL_ORIGIN_SAFE_GET_RE.test(req.path);
      if (!isSafeReadOnly) {
        return res.status(403).json({ error: 'Origin: null not allowed for this route' });
      }
      return next();
    }
    if (!resolvedPort) {
      return res.status(403).json({ error: 'Server initializing' });
    }
    const ports = allowedBrowserPorts(resolvedPort);
    const extraAllowedOrigins = configuredAllowedOrigins();
    if (!isAllowedBrowserOrigin(origin, req.headers.host, ports, host, extraAllowedOrigins)) {
      return res.status(403).json({ error: 'Cross-origin requests are not allowed' });
    }
    next();
  };
}

function makeTestApp(port: number, host = '127.0.0.1') {
  const app = express();
  app.use(express.json());
  app.use('/api', createOriginMiddleware(port, host));
  app.get('/api/health', (_req, res) => res.json({ ok: true }));
  app.get('/api/projects', (_req, res) => res.json({ projects: [] }));
  app.post('/api/active', (req, res) => {
    if (!isLocalSameOrigin(req, port)) {
      return res.status(403).json({ error: 'cross-origin request rejected' });
    }
    res.json({ active: true });
  });
  app.get('/api/projects/:id/raw/:name', (req, res) => {
    // Mimics the real raw-file route that sets CORS for Origin: null
    if (req.headers.origin === 'null') {
      res.header('Access-Control-Allow-Origin', '*');
    }
    res.json({ file: req.params.name });
  });
  app.post('/api/projects', (req, res) => res.json({ project: req.body }));
  app.delete('/api/projects/:id', (req, res) => res.json({ ok: true }));
  app.get('/api/codex-pets/:id/spritesheet', (req, res) => {
    // Mimics the real spritesheet route that sets CORS for Origin: null
    if (req.headers.origin === 'null') {
      res.header('Access-Control-Allow-Origin', 'null');
    }
    res.type('image/png').send(Buffer.from('fake-sprite'));
  });
  return app;
}

function request(
  port: number,
  method: string,
  path: string,
  { origin, headers = {} }: TestRequestOptions = {},
): Promise<TestResponse> {
  return new Promise((resolve, reject) => {
    const opts: http.RequestOptions = {
      hostname: '127.0.0.1',
      port,
      path,
      method,
      headers: {
        ...headers,
        ...(origin !== undefined ? { origin } : {}),
      },
    };
    const req = http.request(opts, (res) => {
      let body = '';
      res.setEncoding('utf8');
      res.on('data', (chunk: string) => (body += chunk));
      res.on('end', () => resolve({ status: res.statusCode, body, headers: res.headers }));
    });
    req.on('error', reject);
    req.end();
  });
}

describe('daemon origin validation middleware', () => {
  let server: http.Server;
  let port: number;

  beforeAll(
    () =>
      new Promise<void>((resolve, reject) => {
        // Start on port 0 to get a dynamic port, then rebuild with real port
        const tempApp = makeTestApp(0);
        const tempServer = tempApp.listen(0, '127.0.0.1', () => {
          port = getListeningPort(tempServer);
          tempServer.close(() => {
            const realApp = makeTestApp(port);
            server = realApp.listen(port, '127.0.0.1', (err?: Error) => {
              if (err) reject(err);
              else resolve();
            });
          });
        });
      }),
  );

  afterAll(
    () => closeServer(server),
  );

  // --- Non-browser clients (no Origin) ---

  it('allows requests without Origin header (curl, CLI)', async () => {
    const res = await request(port, 'GET', '/api/health');
    expect(res.status).toBe(200);
  });

  // --- Same-origin (localhost) ---

  it('allows same-origin requests from http://127.0.0.1', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://127.0.0.1:${port}`,
    });
    expect(res.status).toBe(200);
  });

  it('allows same-origin requests from http://localhost', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://localhost:${port}`,
    });
    expect(res.status).toBe(200);
  });

  it('allows same-origin requests via HTTPS', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `https://127.0.0.1:${port}`,
    });
    expect(res.status).toBe(200);
  });

  it('allows same-origin requests from a private LAN address', async () => {
    const lanHost = `192.168.18.16:${port}`;
    const res = await request(port, 'POST', '/api/projects', {
      origin: `http://${lanHost}`,
      headers: {
        Host: lanHost,
        'content-type': 'application/json',
      },
    });
    expect(res.status).toBe(200);
  });

  it.each([
    '10.0.5.12',
    '172.16.0.1',
    '172.31.255.254',
    '169.254.10.20',
  ])('allows same-origin requests from private LAN range %s', async (host) => {
    const lanHost = `${host}:${port}`;
    const res = await request(port, 'POST', '/api/projects', {
      origin: `http://${lanHost}`,
      headers: {
        Host: lanHost,
        'content-type': 'application/json',
      },
    });
    expect(res.status).toBe(200);
  });

  it.each([
    '172.15.255.255',
    '172.32.0.1',
    '192.168.1.256',
  ])('blocks non-private or malformed LAN-like address %s', async (host) => {
    const lanHost = `${host}:${port}`;
    const res = await request(port, 'POST', '/api/projects', {
      origin: `http://${lanHost}`,
      headers: {
        Host: lanHost,
        'content-type': 'application/json',
      },
    });
    expect(res.status).toBe(403);
  });

  it('allows local guarded routes from a matching private LAN origin', async () => {
    const lanHost = `192.168.18.16:${port}`;
    const res = await request(port, 'POST', '/api/active', {
      origin: `http://${lanHost}`,
      headers: {
        Host: lanHost,
        'content-type': 'application/json',
      },
    });
    expect(res.status).toBe(200);
  });

  it('blocks private LAN origins when the request host differs', async () => {
    const res = await request(port, 'POST', '/api/projects', {
      origin: `http://192.168.18.16:${port}`,
      headers: {
        Host: `192.168.18.17:${port}`,
        'content-type': 'application/json',
      },
    });
    expect(res.status).toBe(403);
  });

  it('blocks local guarded routes when the private LAN host differs', async () => {
    const res = await request(port, 'POST', '/api/active', {
      origin: `http://192.168.18.16:${port}`,
      headers: {
        Host: `192.168.18.17:${port}`,
        'content-type': 'application/json',
      },
    });
    expect(res.status).toBe(403);
  });

  it('blocks local guarded routes without Origin when Host only matches a configured deployment origin', async () => {
    process.env.OD_ALLOWED_ORIGINS = 'https://od.example.com';
    try {
      const res = await request(port, 'POST', '/api/active', {
        headers: {
          Host: 'od.example.com',
          'content-type': 'application/json',
        },
      });
      expect(res.status).toBe(403);
    } finally {
      delete process.env.OD_ALLOWED_ORIGINS;
    }
  });

  it('allows local guarded routes from a matching configured deployment origin', async () => {
    process.env.OD_ALLOWED_ORIGINS = 'https://od.example.com';
    try {
      const res = await request(port, 'POST', '/api/active', {
        origin: 'https://od.example.com',
        headers: {
          Host: 'od.example.com',
          'content-type': 'application/json',
        },
      });
      expect(res.status).toBe(200);
    } finally {
      delete process.env.OD_ALLOWED_ORIGINS;
    }
  });

  it('allows local guarded routes without Origin when Host matches a configured non-loopback IP origin', async () => {
    const lanHost = `100.86.154.169:${port}`;
    process.env.OD_ALLOWED_ORIGINS = `http://${lanHost}`;
    try {
      const res = await request(port, 'POST', '/api/active', {
        headers: {
          Host: lanHost,
          'content-type': 'application/json',
        },
      });
      expect(res.status).toBe(200);
    } finally {
      delete process.env.OD_ALLOWED_ORIGINS;
    }
  });

  // --- Origin: null (sandboxed iframe previews) ---

  it('allows Origin: null for GET raw-file preview routes', async () => {
    const res = await request(port, 'GET', '/api/projects/abc/raw/design.html', {
      origin: 'null',
    });
    expect(res.status).toBe(200);
    expect(res.headers['access-control-allow-origin']).toBe('*');
  });

  it('allows Origin: null for GET codex-pet spritesheet routes', async () => {
    const res = await request(port, 'GET', '/api/codex-pets/my-pet/spritesheet', {
      origin: 'null',
    });
    expect(res.status).toBe(200);
    expect(res.headers['access-control-allow-origin']).toBe('null');
  });

  it('rejects Origin: null on POST to state-changing endpoints', async () => {
    const res = await request(port, 'POST', '/api/projects', {
      origin: 'null',
      headers: { 'content-type': 'application/json' },
    });
    expect(res.status).toBe(403);
    expect(JSON.parse(res.body)).toEqual({ error: 'Origin: null not allowed for this route' });
  });

  it('rejects Origin: null on DELETE endpoints', async () => {
    const res = await request(port, 'DELETE', '/api/projects/abc', {
      origin: 'null',
    });
    expect(res.status).toBe(403);
  });

  it('rejects Origin: null on non-raw-file GET routes', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: 'null',
    });
    expect(res.status).toBe(403);
  });

  it('allows explicitly configured deployment origins', async () => {
    process.env.OD_ALLOWED_ORIGINS = `https://od.example.com,http://203.0.113.10:${port}`;
    try {
      const res = await request(port, 'GET', '/api/projects', {
        origin: 'https://od.example.com',
      });
      expect(res.status).toBe(200);
    } finally {
      delete process.env.OD_ALLOWED_ORIGINS;
    }
  });

  // --- Cross-origin rejection ---

  it('blocks cross-origin requests from external domains', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: 'http://evil.com',
    });
    expect(res.status).toBe(403);
    expect(JSON.parse(res.body)).toEqual({ error: 'Cross-origin requests are not allowed' });
  });

  it('blocks cross-origin requests from other local ports', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://127.0.0.1:9999`,
    });
    expect(res.status).toBe(403);
  });

  it('blocks cross-origin POST to state-changing endpoints', async () => {
    const res = await request(port, 'POST', '/api/projects', {
      origin: 'http://attacker.local',
      headers: { 'content-type': 'application/json' },
    });
    expect(res.status).toBe(403);
  });

  // --- OD_WEB_PORT (split-port proxy) ---

  it('allows requests from OD_WEB_PORT (web proxy port)', async () => {
    const webPort = port + 1000;
    process.env.OD_WEB_PORT = String(webPort);
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://127.0.0.1:${webPort}`,
    });
    delete process.env.OD_WEB_PORT;
    expect(res.status).toBe(200);
  });

  it('blocks requests from unknown ports even with OD_WEB_PORT set', async () => {
    const webPort = port + 1000;
    process.env.OD_WEB_PORT = String(webPort);
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://127.0.0.1:${port + 2000}`,
    });
    delete process.env.OD_WEB_PORT;
    expect(res.status).toBe(403);
  });

  // Note: fail-closed coverage when port=0 is tested in the dedicated
  // describe block below ("fail-closed before port resolution").
});

describe('origin validation: fail-closed before port resolution', () => {
  let server: http.Server;
  let port: number;

  beforeAll(
    () =>
      new Promise<void>((resolve) => {
        const app = makeTestApp(0); // port=0 → not resolved
        server = app.listen(0, '127.0.0.1', () => {
          port = getListeningPort(server);
          resolve();
        });
      }),
  );

  afterAll(
    () => closeServer(server),
  );

  it('blocks browser origins when port is not resolved (fail-closed)', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://127.0.0.1:${port}`,
    });
    expect(res.status).toBe(403);
  });

  it('still allows non-browser clients when port is not resolved', async () => {
    const res = await request(port, 'GET', '/api/health');
    expect(res.status).toBe(200);
  });
});

describe('origin validation: non-loopback bind host', () => {
  let server: http.Server;
  let port: number;
  const nonLoopbackHost = '100.64.1.2'; // Tailscale-like address

  beforeAll(
    () =>
      new Promise<void>((resolve, reject) => {
        // Start on port 0 to get a dynamic port, then rebuild with real port
        const tempApp = makeTestApp(0, nonLoopbackHost);
        const tempServer = tempApp.listen(0, '127.0.0.1', () => {
          port = getListeningPort(tempServer);
          tempServer.close(() => {
            const realApp = makeTestApp(port, nonLoopbackHost);
            server = realApp.listen(port, '127.0.0.1', (err?: Error) => {
              if (err) reject(err);
              else resolve();
            });
          });
        });
      }),
  );

  afterAll(
    () => closeServer(server),
  );

  it('allows browser requests from the non-loopback bind host', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://${nonLoopbackHost}:${port}`,
    });
    expect(res.status).toBe(200);
  });

  it('still allows localhost origins alongside non-loopback host', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://127.0.0.1:${port}`,
    });
    expect(res.status).toBe(200);
  });

  it('blocks unknown external origins even with non-loopback host', async () => {
    const res = await request(port, 'GET', '/api/projects', {
      origin: `http://evil.com:${port}`,
    });
    expect(res.status).toBe(403);
  });
});

// Regression coverage for #1868. When the daemon runs behind a reverse
// proxy (Nginx, Caddy, Traefik, …), the Host header the daemon observes
// is the proxy upstream's address, not the browser-visible origin. The
// host check inside isLocalSameOrigin therefore rejects requests whose
// browser origin is explicitly listed in OD_ALLOWED_ORIGINS, because
// the Host header doesn't carry that origin's host. Trusting the Origin
// header when it matches an explicit allow-list entry restores the
// documented escape-hatch behavior of OD_ALLOWED_ORIGINS.
describe('isLocalSameOrigin: OD_ALLOWED_ORIGINS bypass for reverse-proxy deployments', () => {
  const ALLOWED = 'http://192.168.8.168:7457';
  const previousAllowedOrigins = process.env.OD_ALLOWED_ORIGINS;
  const env: NodeJS.ProcessEnv = {
    ...process.env,
    OD_ALLOWED_ORIGINS: ALLOWED,
    OD_BIND_HOST: '0.0.0.0',
  };

  beforeAll(() => {
    process.env.OD_ALLOWED_ORIGINS = ALLOWED;
  });
  afterAll(() => {
    if (previousAllowedOrigins === undefined) delete process.env.OD_ALLOWED_ORIGINS;
    else process.env.OD_ALLOWED_ORIGINS = previousAllowedOrigins;
  });

  it('accepts a request whose Origin matches OD_ALLOWED_ORIGINS even when the Host header is the proxy upstream', () => {
    const req = {
      headers: {
        host: '172.18.0.5:7457', // typical Nginx → daemon upstream (container IP)
        origin: ALLOWED,
      },
    };
    expect(isLocalSameOrigin(req, 7457, env)).toBe(true);
  });

  it('still rejects a request whose Origin is not in OD_ALLOWED_ORIGINS', () => {
    const req = {
      headers: {
        host: '172.18.0.5:7457',
        origin: 'http://evil.example.com',
      },
    };
    expect(isLocalSameOrigin(req, 7457, env)).toBe(false);
  });

  it('preserves the no-Origin behavior — falls back to loopback host validation', () => {
    const reqLoopback = {
      headers: { host: '127.0.0.1:7457' },
    };
    expect(isLocalSameOrigin(reqLoopback, 7457, env)).toBe(true);

    const reqNonLoopback = {
      headers: { host: '172.18.0.5:7457' },
    };
    // 172.18.0.0/16 is private, so it actually passes isLoopbackOrPrivateLanHost;
    // demonstrate the more important invariant: an entirely external host fails.
    const reqExternal = {
      headers: { host: 'evil.example.com:7457' },
    };
    expect(isLocalSameOrigin(reqExternal, 7457, env)).toBe(false);
  });

  it('does not accept a partial match (origin must be exact)', () => {
    const req = {
      headers: {
        host: '172.18.0.5:7457',
        // Same hostname/port but trailing slash → not an exact match for the
        // allow-list entry, which the URL parser canonicalizes without one.
        origin: `${ALLOWED}/`,
      },
    };
    expect(isLocalSameOrigin(req, 7457, env)).toBe(false);
  });
});

// Firefox and Chrome omit the Origin header on same-origin GET requests per
// the Fetch spec. When the daemon runs behind a remote-access proxy whose
// public hostname is listed in OD_ALLOWED_ORIGINS, those legitimate
// same-origin GETs (e.g. /api/app-config) get rejected by the no-Origin
// host check because hostname entries in OD_ALLOWED_ORIGINS are only
// honored via the IP-literal subset in that branch. Sec-Fetch-Site is set
// by the browser and cannot be modified by JavaScript, so a value of
// "same-origin" is a trustworthy substitute for the missing Origin header.
describe('isLocalSameOrigin: Sec-Fetch-Site fallback for no-Origin same-origin GETs', () => {
  const ALLOWED = 'https://nas.example.ts.net';
  const previousAllowedOrigins = process.env.OD_ALLOWED_ORIGINS;
  const env: NodeJS.ProcessEnv = {
    ...process.env,
    OD_ALLOWED_ORIGINS: ALLOWED,
    OD_BIND_HOST: '127.0.0.1',
  };

  beforeAll(() => {
    process.env.OD_ALLOWED_ORIGINS = ALLOWED;
  });
  afterAll(() => {
    if (previousAllowedOrigins === undefined) delete process.env.OD_ALLOWED_ORIGINS;
    else process.env.OD_ALLOWED_ORIGINS = previousAllowedOrigins;
  });

  it('accepts a no-Origin request whose Host matches OD_ALLOWED_ORIGINS when Sec-Fetch-Site is same-origin', () => {
    const req = {
      headers: {
        host: 'nas.example.ts.net',
        'sec-fetch-site': 'same-origin',
      },
    };
    expect(isLocalSameOrigin(req, 7456, env)).toBe(true);
  });

  it('still rejects a no-Origin request whose Host matches the allow-list but Sec-Fetch-Site is cross-site', () => {
    const req = {
      headers: {
        host: 'nas.example.ts.net',
        'sec-fetch-site': 'cross-site',
      },
    };
    expect(isLocalSameOrigin(req, 7456, env)).toBe(false);
  });

  it('still rejects a no-Origin request whose Host matches the allow-list but Sec-Fetch-Site is same-site', () => {
    const req = {
      headers: {
        host: 'nas.example.ts.net',
        'sec-fetch-site': 'same-site',
      },
    };
    expect(isLocalSameOrigin(req, 7456, env)).toBe(false);
  });

  it('still rejects a no-Origin request whose Host is foreign even with Sec-Fetch-Site: same-origin (Host alone is forgeable)', () => {
    const req = {
      headers: {
        host: 'evil.example.com',
        'sec-fetch-site': 'same-origin',
      },
    };
    expect(isLocalSameOrigin(req, 7456, env)).toBe(false);
  });

  it('preserves no-Sec-Fetch-Site rejection (older / non-browser clients fall back to host-only check)', () => {
    const req = {
      headers: {
        host: 'nas.example.ts.net',
      },
    };
    expect(isLocalSameOrigin(req, 7456, env)).toBe(false);
  });
});
