import { chromium, Browser, BrowserContext } from 'playwright';
import { config } from '../config';
import { logger } from '../utils/logger';

let browser: Browser | null = null;
let browserLaunchPromise: Promise<Browser> | null = null;

/**
 * Get or launch the shared browser instance.
 * Multiple callers waiting concurrently will share the same launch promise.
 */
export async function getBrowser(): Promise<Browser> {
  if (browser && browser.isConnected()) {
    return browser;
  }

  if (browserLaunchPromise) {
    return browserLaunchPromise;
  }

  browserLaunchPromise = launchBrowser();

  try {
    browser = await browserLaunchPromise;
    return browser;
  } finally {
    browserLaunchPromise = null;
  }
}

async function launchBrowser(): Promise<Browser> {
  logger.info('Launching Chromium browser', { headless: config.headless });

  const b = await chromium.launch({
    headless: config.headless,
    args: [
      '--no-sandbox',
      '--disable-setuid-sandbox',
      '--disable-dev-shm-usage',
      '--disable-gpu',
    ],
  });

  b.on('disconnected', () => {
    logger.warn('Browser disconnected');
    browser = null;
  });

  logger.info('Browser launched successfully');
  return b;
}

/**
 * Create a new isolated browser context for a job.
 * Optionally restore storage state from a previous session.
 */
export async function createContext(
  storageState?: string
): Promise<BrowserContext> {
  const b = await getBrowser();

  const contextOptions: Parameters<Browser['newContext']>[0] = {
    viewport: { width: 1280, height: 720 },
    userAgent:
      'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36',
    acceptDownloads: true,
  };

  if (storageState) {
    try {
      contextOptions.storageState = JSON.parse(storageState);
    } catch {
      logger.warn('Failed to parse storage state, starting fresh');
    }
  }

  const context = await b.newContext(contextOptions);

  // Set reasonable timeouts
  context.setDefaultTimeout(30000);
  context.setDefaultNavigationTimeout(60000);

  return context;
}

/**
 * Gracefully close the shared browser.
 */
export async function closeBrowser(): Promise<void> {
  if (browser) {
    try {
      await browser.close();
    } catch {
      // Ignore close errors
    }
    browser = null;
    logger.info('Browser closed');
  }
}

/**
 * Get count of active contexts (approximation of active jobs).
 */
export async function getActiveContextCount(): Promise<number> {
  if (!browser || !browser.isConnected()) return 0;
  return browser.contexts().length;
}