import { tap, expect } from '@git.zone/tstest/tapbundle';
import { SmartProxy } from '../ts/index.js';
import * as http from 'http';
import WebSocket, { WebSocketServer } from 'ws';
import { findFreePorts, assertPortsFree } from './helpers/port-allocator.js';

/**
 * Helper: create a WebSocket client that connects through the proxy.
 * Registers the message handler BEFORE awaiting open to avoid race conditions.
 */
function connectWs(
  url: string,
  headers: Record<string, string> = {},
  opts: WebSocket.ClientOptions = {},
): { ws: WebSocket; messages: string[]; opened: Promise<void> } {
  const messages: string[] = [];
  const ws = new WebSocket(url, { headers, ...opts });

  // Register message handler immediately — before open fires
  ws.on('message', (data) => {
    messages.push(data.toString());
  });

  const opened = new Promise<void>((resolve, reject) => {
    const timeout = setTimeout(() => reject(new Error('WebSocket open timeout')), 5000);
    ws.on('open', () => { clearTimeout(timeout); resolve(); });
    ws.on('error', (err) => { clearTimeout(timeout); reject(err); });
  });

  return { ws, messages, opened };
}

/** Wait until `predicate` returns true, with a hard timeout. */
function waitFor(predicate: () => boolean, timeoutMs = 5000): Promise<void> {
  return new Promise((resolve, reject) => {
    const deadline = setTimeout(() => reject(new Error('waitFor timeout')), timeoutMs);
    const check = () => {
      if (predicate()) { clearTimeout(deadline); resolve(); }
      else setTimeout(check, 30);
    };
    check();
  });
}

/** Graceful close helper */
function closeWs(ws: WebSocket): Promise<void> {
  return new Promise((resolve) => {
    if (ws.readyState === WebSocket.CLOSED) return resolve();
    ws.on('close', () => resolve());
    ws.close();
    setTimeout(resolve, 2000); // fallback
  });
}

// ─── Test 1: Basic WebSocket upgrade and bidirectional messaging ───
tap.test('should proxy WebSocket connections with bidirectional messaging', async () => {
  const [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);

  // Backend: echoes messages with prefix, sends greeting on connect
  const backendServer = http.createServer();
  const wss = new WebSocketServer({ server: backendServer });
  const backendMessages: string[] = [];

  wss.on('connection', (ws) => {
    ws.on('message', (data) => {
      const msg = data.toString();
      backendMessages.push(msg);
      ws.send(`echo: ${msg}`);
    });
    ws.send('hello from backend');
  });

  await new Promise<void>((resolve) => {
    backendServer.listen(BACKEND_PORT, '127.0.0.1', () => resolve());
  });

  const proxy = new SmartProxy({
    routes: [{
      name: 'ws-test-route',
      match: { ports: PROXY_PORT },
      action: {
        type: 'forward',
        targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
        websocket: { enabled: true },
      },
    }],
  });
  await proxy.start();

  // Connect client — message handler registered before open
  const { ws, messages, opened } = connectWs(
    `ws://127.0.0.1:${PROXY_PORT}/`,
    { Host: 'test.local' },
  );
  await opened;

  // Wait for the backend greeting
  await waitFor(() => messages.length >= 1);
  expect(messages[0]).toEqual('hello from backend');

  // Send 3 messages, expect 3 echoes
  ws.send('ping 1');
  ws.send('ping 2');
  ws.send('ping 3');

  await waitFor(() => messages.length >= 4);

  expect(messages).toContain('echo: ping 1');
  expect(messages).toContain('echo: ping 2');
  expect(messages).toContain('echo: ping 3');
  expect(backendMessages).toInclude('ping 1');
  expect(backendMessages).toInclude('ping 2');
  expect(backendMessages).toInclude('ping 3');

  await closeWs(ws);
  await proxy.stop();
  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
  await new Promise((r) => setTimeout(r, 500));
  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
});

// ─── Test 2: Multiple concurrent WebSocket connections ───
tap.test('should handle multiple concurrent WebSocket connections', async () => {
  const [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);

  const backendServer = http.createServer();
  const wss = new WebSocketServer({ server: backendServer });

  let connectionCount = 0;
  wss.on('connection', (ws) => {
    const id = ++connectionCount;
    ws.on('message', (data) => {
      ws.send(`conn${id}: ${data.toString()}`);
    });
  });

  await new Promise<void>((resolve) => {
    backendServer.listen(BACKEND_PORT, '127.0.0.1', () => resolve());
  });

  const proxy = new SmartProxy({
    routes: [{
      name: 'ws-multi-route',
      match: { ports: PROXY_PORT },
      action: {
        type: 'forward',
        targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
        websocket: { enabled: true },
      },
    }],
  });
  await proxy.start();

  const NUM_CLIENTS = 5;
  const clients: { ws: WebSocket; messages: string[] }[] = [];

  for (let i = 0; i < NUM_CLIENTS; i++) {
    const c = connectWs(
      `ws://127.0.0.1:${PROXY_PORT}/`,
      { Host: 'test.local' },
    );
    await c.opened;
    clients.push(c);
  }

  // Each client sends a unique message
  for (let i = 0; i < NUM_CLIENTS; i++) {
    clients[i].ws.send(`hello from client ${i}`);
  }

  // Wait for all replies
  await waitFor(() => clients.every((c) => c.messages.length >= 1));

  for (let i = 0; i < NUM_CLIENTS; i++) {
    expect(clients[i].messages.length).toBeGreaterThanOrEqual(1);
    expect(clients[i].messages[0]).toInclude(`hello from client ${i}`);
  }
  expect(connectionCount).toEqual(NUM_CLIENTS);

  for (const c of clients) await closeWs(c.ws);
  await proxy.stop();
  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
  await new Promise((r) => setTimeout(r, 500));
  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
});

// ─── Test 3: WebSocket with binary data ───
tap.test('should proxy binary WebSocket frames', async () => {
  const [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);

  const backendServer = http.createServer();
  const wss = new WebSocketServer({ server: backendServer });

  wss.on('connection', (ws) => {
    ws.on('message', (data) => {
      ws.send(data, { binary: true });
    });
  });

  await new Promise<void>((resolve) => {
    backendServer.listen(BACKEND_PORT, '127.0.0.1', () => resolve());
  });

  const proxy = new SmartProxy({
    routes: [{
      name: 'ws-binary-route',
      match: { ports: PROXY_PORT },
      action: {
        type: 'forward',
        targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
        websocket: { enabled: true },
      },
    }],
  });
  await proxy.start();

  const receivedBuffers: Buffer[] = [];
  const ws = new WebSocket(`ws://127.0.0.1:${PROXY_PORT}/`, {
    headers: { Host: 'test.local' },
  });
  ws.on('message', (data) => {
    receivedBuffers.push(Buffer.from(data as ArrayBuffer));
  });

  await new Promise<void>((resolve, reject) => {
    const timeout = setTimeout(() => reject(new Error('timeout')), 5000);
    ws.on('open', () => { clearTimeout(timeout); resolve(); });
    ws.on('error', (err) => { clearTimeout(timeout); reject(err); });
  });

  // Send a 256-byte buffer with known content
  const sentBuffer = Buffer.alloc(256);
  for (let i = 0; i < 256; i++) sentBuffer[i] = i;
  ws.send(sentBuffer);

  await waitFor(() => receivedBuffers.length >= 1);

  expect(receivedBuffers[0].length).toEqual(256);
  expect(Buffer.compare(receivedBuffers[0], sentBuffer)).toEqual(0);

  await closeWs(ws);
  await proxy.stop();
  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
  await new Promise((r) => setTimeout(r, 500));
  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
});

// ─── Test 4: WebSocket path and query string preserved ───
tap.test('should preserve path and query string through proxy', async () => {
  const [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);

  const backendServer = http.createServer();
  const wss = new WebSocketServer({ server: backendServer });

  let receivedUrl = '';
  wss.on('connection', (ws, req) => {
    receivedUrl = req.url || '';
    ws.send(`url: ${receivedUrl}`);
  });

  await new Promise<void>((resolve) => {
    backendServer.listen(BACKEND_PORT, '127.0.0.1', () => resolve());
  });

  const proxy = new SmartProxy({
    routes: [{
      name: 'ws-path-route',
      match: { ports: PROXY_PORT },
      action: {
        type: 'forward',
        targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
        websocket: { enabled: true },
      },
    }],
  });
  await proxy.start();

  const { ws, messages, opened } = connectWs(
    `ws://127.0.0.1:${PROXY_PORT}/chat/room1?token=abc123`,
    { Host: 'test.local' },
  );
  await opened;

  await waitFor(() => messages.length >= 1);

  expect(receivedUrl).toEqual('/chat/room1?token=abc123');
  expect(messages[0]).toEqual('url: /chat/room1?token=abc123');

  await closeWs(ws);
  await proxy.stop();
  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
  await new Promise((r) => setTimeout(r, 500));
  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
});

// ─── Test 5: Clean close propagation ───
tap.test('should handle clean WebSocket close from client', async () => {
  const [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);

  const backendServer = http.createServer();
  const wss = new WebSocketServer({ server: backendServer });

  let backendGotClose = false;
  let backendCloseCode = 0;
  wss.on('connection', (ws) => {
    ws.on('close', (code) => {
      backendGotClose = true;
      backendCloseCode = code;
    });
    ws.on('message', (data) => {
      ws.send(data);
    });
  });

  await new Promise<void>((resolve) => {
    backendServer.listen(BACKEND_PORT, '127.0.0.1', () => resolve());
  });

  const proxy = new SmartProxy({
    routes: [{
      name: 'ws-close-route',
      match: { ports: PROXY_PORT },
      action: {
        type: 'forward',
        targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
        websocket: { enabled: true },
      },
    }],
  });
  await proxy.start();

  const { ws, messages, opened } = connectWs(
    `ws://127.0.0.1:${PROXY_PORT}/`,
    { Host: 'test.local' },
  );
  await opened;

  // Confirm connection works with a round-trip
  ws.send('test');
  await waitFor(() => messages.length >= 1);

  // Close with code 1000
  let clientCloseCode = 0;
  const closed = new Promise<void>((resolve) => {
    ws.on('close', (code) => {
      clientCloseCode = code;
      resolve();
    });
    setTimeout(resolve, 3000);
  });
  ws.close(1000, 'done');
  await closed;

  // Wait for backend to register
  await waitFor(() => backendGotClose, 3000);

  expect(backendGotClose).toBeTrue();
  expect(clientCloseCode).toEqual(1000);

  await proxy.stop();
  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
  await new Promise((r) => setTimeout(r, 500));
  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
});

// ─── Test 6: Large messages ───
tap.test('should handle large WebSocket messages', async () => {
  const [PROXY_PORT, BACKEND_PORT] = await findFreePorts(2);

  const backendServer = http.createServer();
  const wss = new WebSocketServer({ server: backendServer, maxPayload: 5 * 1024 * 1024 });

  wss.on('connection', (ws) => {
    ws.on('message', (data) => {
      const buf = Buffer.from(data as ArrayBuffer);
      ws.send(`received ${buf.length} bytes`);
    });
  });

  await new Promise<void>((resolve) => {
    backendServer.listen(BACKEND_PORT, '127.0.0.1', () => resolve());
  });

  const proxy = new SmartProxy({
    routes: [{
      name: 'ws-large-route',
      match: { ports: PROXY_PORT },
      action: {
        type: 'forward',
        targets: [{ host: '127.0.0.1', port: BACKEND_PORT }],
        websocket: { enabled: true },
      },
    }],
  });
  await proxy.start();

  const { ws, messages, opened } = connectWs(
    `ws://127.0.0.1:${PROXY_PORT}/`,
    { Host: 'test.local' },
    { maxPayload: 5 * 1024 * 1024 },
  );
  await opened;

  // Send a 1MB message
  const largePayload = Buffer.alloc(1024 * 1024, 0x42);
  ws.send(largePayload);

  await waitFor(() => messages.length >= 1);
  expect(messages[0]).toEqual(`received ${1024 * 1024} bytes`);

  await closeWs(ws);
  await proxy.stop();
  await new Promise<void>((resolve) => backendServer.close(() => resolve()));
  await new Promise((r) => setTimeout(r, 500));
  await assertPortsFree([PROXY_PORT, BACKEND_PORT]);
});

export default tap.start();