import { existsSync, mkdirSync, rmSync, writeFileSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { dirname, join, resolve } from 'node:path';
import { spawn } from 'node:child_process';

const BASE_URL = process.env.WENFAN_HELP_BASE_URL || 'http://localhost:3000';
const VIEWPORT = { width: 1440, height: 1000 };
const OUTPUT_DIR = resolve('apps/web/public/help/wenfan-xiaobao');

const AUTH_USER = {
  id: 'm-8',
  name: '超级管理员',
  roleId: 'role-admin',
  departmentId: 'dept-1',
  phone: '13200132008',
  email: 'admin@company.com',
};

const SCREENSHOTS = [
  { file: 'product-create.png', route: '/products' },
  { file: 'project-create.png', route: '/projects' },
  { file: 'version-create.png', route: '/versions' },
  { file: 'requirement-pool.png', route: '/requirements' },
  { file: 'version-requirement-include.png', route: '/versions' },
  { file: 'research-plan.png', route: '/versions' },
  { file: 'product-plan.png', route: '/versions' },
  { file: 'ai-decompose.png', route: '/versions' },
  { file: 'ui-design-plan.png', route: '/versions' },
  { file: 'dev-task-workflow.png', route: '/versions' },
  { file: 'test-case-workflow.png', route: '/versions' },
  { file: 'bug-workflow.png', route: '/versions' },
  { file: 'activity-logs.png', route: '/workspace' },
  { file: 'xiaobao-warning.png', route: '/xiaobao-warning' },
];

function findBrowser() {
  const candidates = [
    process.env.CHROME_PATH,
    'C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe',
    'C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe',
    'C:\\Program Files\\Microsoft\\Edge\\Application\\msedge.exe',
    'C:\\Program Files (x86)\\Microsoft\\Edge\\Application\\msedge.exe',
    '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
    '/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge',
    '/usr/bin/google-chrome',
    '/usr/bin/chromium',
    '/usr/bin/chromium-browser',
  ].filter(Boolean);

  return candidates.find((candidate) => existsSync(candidate));
}

function delay(ms) {
  return new Promise((resolveDelay) => setTimeout(resolveDelay, ms));
}

async function assertServerAvailable() {
  try {
    const response = await fetch(BASE_URL);
    if (!response.ok) throw new Error(`HTTP ${response.status}`);
  } catch (error) {
    throw new Error(`本地页面不可访问：${BASE_URL}。请先启动前端 dev server。`);
  }
}

function launchBrowser(browserPath, userDataDir) {
  const child = spawn(
    browserPath,
    [
      '--headless=new',
      '--disable-gpu',
      '--no-first-run',
      '--no-default-browser-check',
      '--remote-debugging-port=0',
      `--user-data-dir=${userDataDir}`,
      `--window-size=${VIEWPORT.width},${VIEWPORT.height}`,
      'about:blank',
    ],
    { stdio: ['ignore', 'pipe', 'pipe'] },
  );

  return child;
}

function waitForDevtools(child) {
  return new Promise((resolveDevtools, rejectDevtools) => {
    const timer = setTimeout(() => rejectDevtools(new Error('Chrome DevTools 启动超时。')), 15000);

    function onData(data) {
      const text = data.toString();
      const match = text.match(/DevTools listening on (ws:\/\/[^\s]+)/);
      if (!match) return;
      clearTimeout(timer);
      child.stdout.off('data', onData);
      child.stderr.off('data', onData);
      resolveDevtools(match[1]);
    }

    child.stdout.on('data', onData);
    child.stderr.on('data', onData);
    child.once('exit', (code) => {
      clearTimeout(timer);
      rejectDevtools(new Error(`浏览器提前退出，退出码：${code}`));
    });
  });
}

async function getPageWebSocketUrl(wsEndpoint) {
  const url = new URL(wsEndpoint);
  const listUrl = `http://${url.hostname}:${url.port}/json/list`;

  for (let i = 0; i < 30; i += 1) {
    const response = await fetch(listUrl);
    const targets = await response.json();
    const page = targets.find((target) => target.type === 'page' && target.webSocketDebuggerUrl);
    if (page) return page.webSocketDebuggerUrl;
    await delay(200);
  }

  throw new Error('没有找到可截图的 Chrome 页面 target。');
}

class CdpClient {
  constructor(webSocketUrl) {
    this.webSocketUrl = webSocketUrl;
    this.nextId = 1;
    this.pending = new Map();
    this.eventWaiters = new Map();
  }

  async connect() {
    this.ws = new WebSocket(this.webSocketUrl);
    this.ws.addEventListener('message', (event) => this.handleMessage(event.data));
    await new Promise((resolveOpen, rejectOpen) => {
      this.ws.addEventListener('open', resolveOpen, { once: true });
      this.ws.addEventListener('error', rejectOpen, { once: true });
    });
  }

  handleMessage(raw) {
    const message = JSON.parse(raw);
    if (message.id && this.pending.has(message.id)) {
      const { resolve: resolvePending, reject } = this.pending.get(message.id);
      this.pending.delete(message.id);
      if (message.error) reject(new Error(message.error.message));
      else resolvePending(message.result);
      return;
    }

    if (message.method && this.eventWaiters.has(message.method)) {
      const waiters = this.eventWaiters.get(message.method);
      this.eventWaiters.delete(message.method);
      for (const waiter of waiters) waiter(message.params);
    }
  }

  send(method, params = {}) {
    const id = this.nextId;
    this.nextId += 1;
    const payload = JSON.stringify({ id, method, params });

    return new Promise((resolveSend, rejectSend) => {
      this.pending.set(id, { resolve: resolveSend, reject: rejectSend });
      this.ws.send(payload);
    });
  }

  waitForEvent(method, timeoutMs = 15000) {
    return new Promise((resolveEvent, rejectEvent) => {
      const timer = setTimeout(() => rejectEvent(new Error(`等待 ${method} 超时。`)), timeoutMs);
      const waiters = this.eventWaiters.get(method) || [];
      waiters.push((params) => {
        clearTimeout(timer);
        resolveEvent(params);
      });
      this.eventWaiters.set(method, waiters);
    });
  }

  close() {
    this.ws?.close();
  }
}

async function navigateAndWait(client, url) {
  const loadPromise = client.waitForEvent('Page.loadEventFired').catch(() => undefined);
  await client.send('Page.navigate', { url });
  await loadPromise;
  await delay(1200);
}

async function authenticate(client) {
  await navigateAndWait(client, `${BASE_URL}/login`);
  const serialized = JSON.stringify(AUTH_USER).replace(/\\/g, '\\\\').replace(/'/g, "\\'");
  await client.send('Runtime.evaluate', {
    expression: `
      sessionStorage.setItem('ftb_auth_session', '${serialized}');
      localStorage.setItem('ftb_auth_persist', '${serialized}');
    `,
  });
}

async function capture(client, route, outputPath) {
  await navigateAndWait(client, `${BASE_URL}${route}`);
  await client.send('Emulation.setDeviceMetricsOverride', {
    width: VIEWPORT.width,
    height: VIEWPORT.height,
    deviceScaleFactor: 1,
    mobile: false,
  });
  const screenshot = await client.send('Page.captureScreenshot', {
    format: 'png',
    fromSurface: true,
    captureBeyondViewport: true,
  });
  writeFileSync(outputPath, Buffer.from(screenshot.data, 'base64'));
}

async function terminateBrowser(browser) {
  if (browser.exitCode !== null) return;

  const exited = new Promise((resolveExit) => {
    browser.once('exit', resolveExit);
  });
  browser.kill();
  await Promise.race([exited, delay(2000)]);
}

async function main() {
  const browserPath = findBrowser();
  if (!browserPath) {
    throw new Error('未找到 Chrome 或 Edge，请安装浏览器，或通过 CHROME_PATH 指定浏览器路径。');
  }

  await assertServerAvailable();
  mkdirSync(OUTPUT_DIR, { recursive: true });

  const userDataDir = join(tmpdir(), `wenfan-help-screenshots-${Date.now()}`);
  const browser = launchBrowser(browserPath, userDataDir);
  let client;

  try {
    const browserWsEndpoint = await waitForDevtools(browser);
    const pageWsEndpoint = await getPageWebSocketUrl(browserWsEndpoint);
    client = new CdpClient(pageWsEndpoint);
    await client.connect();
    await client.send('Page.enable');
    await client.send('Runtime.enable');
    await authenticate(client);

    for (const item of SCREENSHOTS) {
      const outputPath = join(OUTPUT_DIR, item.file);
      await capture(client, item.route, outputPath);
      console.log(`saved ${outputPath}`);
    }
  } finally {
    client?.close();
    await terminateBrowser(browser);
    try {
      rmSync(userDataDir, { recursive: true, force: true });
    } catch {
      console.warn(`临时浏览器目录未能立即清理，可稍后手动删除：${userDataDir}`);
    }
  }
}

main().catch((error) => {
  console.error(error.message);
  process.exit(1);
});