import { existsSync, readFileSync } from 'node:fs';
import { homedir } from 'node:os';
import { resolve } from 'node:path';

const browserPaths = [
  resolve(homedir(), 'Library/Application Support/Google/Chrome/DevToolsActivePort'),
  resolve(homedir(), 'Library/Application Support/Google/Chrome Beta/DevToolsActivePort'),
  resolve(homedir(), 'Library/Application Support/Chromium/DevToolsActivePort'),
  resolve(homedir(), 'Library/Application Support/Google/Chrome for Testing/DevToolsActivePort'),
  resolve(homedir(), '.config/google-chrome/DevToolsActivePort'),
  resolve(homedir(), '.config/chromium/DevToolsActivePort')
];

function browserWebSocketUrl() {
  const portFile = [process.env.CDP_PORT_FILE, ...browserPaths].filter(Boolean).find((path) => existsSync(path));
  if (!portFile) throw new Error('No DevToolsActivePort found; enable Chrome remote debugging first.');
  const lines = readFileSync(portFile, 'utf8').trim().split('\n');
  if (!lines[0] || !lines[1]) throw new Error(`Invalid DevToolsActivePort file: ${portFile}`);
  const host = process.env.CDP_HOST || '127.0.0.1';
  return `ws://${host}:${lines[0]}${lines[1]}`;
}

function request(wsUrl, method, params = {}) {
  return new Promise((resolve, reject) => {
    const ws = new WebSocket(wsUrl);
    let id = 0;
    let timer;
    const fail = (error) => {
      clearTimeout(timer);
      try { ws.close(); } catch {}
      reject(error);
    };
    ws.onerror = (event) => fail(new Error(event.message || event.type || 'Chrome DevTools WebSocket error'));
    ws.onopen = () => {
      id += 1;
      timer = setTimeout(() => fail(new Error(`Timeout: ${method}`)), 15000);
      ws.send(JSON.stringify({ id, method, params }));
    };
    ws.onmessage = (event) => {
      const message = JSON.parse(event.data);
      if (message.id !== id) return;
      clearTimeout(timer);
      try { ws.close(); } catch {}
      if (message.error) reject(new Error(message.error.message || `${method} failed`));
      else resolve(message.result || {});
    };
  });
}

export async function getTarget(port = '') {
  try {
    const response = await fetch(`http://127.0.0.1:${port}/json`);
    if (response.ok) {
      const targets = await response.json();
      const target = targets.find((item) => item.type === 'page' && item.url.includes('lwlt.hisy.cc'));
      if (target) return target;
    }
  } catch {}

  const wsUrl = browserWebSocketUrl();
  const result = await request(wsUrl, 'Target.getTargets');
  const target = (result.targetInfos || []).find((item) => item.type === 'page' && item.url.includes('lwlt.hisy.cc'));
  if (!target) throw new Error('No lwlt.hisy.cc page target on the Chrome DevTools connection.');
  return { webSocketDebuggerUrl: wsUrl, targetId: target.targetId };
}