Full Page Screenshot

#!/usr/bin/env node
// full-page-screenshot.mjs — Standalone full-page screenshot tool via Chrome CDP
//
// Modes:
//   --check                          Check environment (Node.js 22+, Chrome debugging port)
//   --list                           List open browser tabs as JSON
//   --url <URL> [output] [options]   Screenshot a URL (create tab → wait → capture → close)
//   <targetId>  [output] [options]   Screenshot an existing tab by target ID
//
// Options:
//   --width N    Viewport width in CSS pixels (default: 1200)
//   --dpr N      Device pixel ratio (default: 1)
//   --wait N     Page load timeout in ms, --url mode only (default: 15000)
//
// Requires: Node.js 22+, Chrome with remote debugging enabled

import fs from 'fs';
import net from 'net';
import path from 'path';
import { platform, homedir } from 'os';

// ─── Argument parsing ───────────────────────────────────────────────────────

const args = process.argv.slice(2);
const flags = {};
const positional = [];
const boolFlags = new Set(['check', 'list']);

for (let i = 0; i < args.length; i++) {
  if (args[i].startsWith('--')) {
    const key = args[i].slice(2);
    if (boolFlags.has(key)) {
      flags[key] = true;
    } else if (i + 1 < args.length) {
      flags[key] = args[++i];
    }
  } else {
    positional.push(args[i]);
  }
}

const vpWidth = parseInt(flags.width || '1200', 10);
const dpr = parseInt(flags.dpr || '1', 10);
const loadTimeout = parseInt(flags.wait || '15000', 10);
const customCss = flags.css || '';

// ─── Chrome discovery ───────────────────────────────────────────────────────

function getDevToolsActivePortPaths() {
  const home = homedir();
  if (platform() === 'darwin') {
    return [
      path.join(home, 'Library/Application Support/Google/Chrome/DevToolsActivePort'),
      path.join(home, 'Library/Application Support/Google/Chrome Canary/DevToolsActivePort'),
      path.join(home, 'Library/Application Support/Chromium/DevToolsActivePort'),
    ];
  } else if (platform() === 'linux') {
    return [
      path.join(home, '.config/google-chrome/DevToolsActivePort'),
      path.join(home, '.config/chromium/DevToolsActivePort'),
    ];
  } else if (platform() === 'win32') {
    const local = process.env.LOCALAPPDATA || '';
    return [
      path.join(local, 'Google/Chrome/User Data/DevToolsActivePort'),
      path.join(local, 'Chromium/User Data/DevToolsActivePort'),
    ];
  }
  return [];
}

function checkPort(port) {
  return new Promise((resolve) => {
    const socket = net.createConnection(port, '127.0.0.1');
    const timer = setTimeout(() => { socket.destroy(); resolve(false); }, 2000);
    socket.once('connect', () => { clearTimeout(timer); socket.destroy(); resolve(true); });
    socket.once('error', () => { clearTimeout(timer); resolve(false); });
  });
}

async function discoverChrome() {
  // 1. Try DevToolsActivePort file
  for (const p of getDevToolsActivePortPaths()) {
    try {
      const lines = fs.readFileSync(p, 'utf-8').trim().split('\n');
      const port = parseInt(lines[0], 10);
      if (port > 0 && port < 65536) {
        const ok = await checkPort(port);
        if (ok) {
          const wsPath = lines[1] || '/devtools/browser';
          return { port, wsUrl: `ws://127.0.0.1:${port}${wsPath}` };
        }
      }
    } catch { /* try next */ }
  }

  // 2. Fallback: probe common debugging ports
  for (const port of [9222, 9229, 9333]) {
    const ok = await checkPort(port);
    if (ok) {
      return { port, wsUrl: `ws://127.0.0.1:${port}/devtools/browser` };
    }
  }

  return null;
}

// ─── CDP WebSocket helpers ──────────────────────────────────────────────────

let msgId = 0;
const pending = new Map();
let ws;

function send(method, params = {}, sessionId = null, timeoutMs = 60000) {
  return new Promise((resolve, reject) => {
    const id = ++msgId;
    const msg = { id, method, params };
    if (sessionId) msg.sessionId = sessionId;
    pending.set(id, resolve);
    ws.send(JSON.stringify(msg));
    setT