import path from 'node:path';
import { pathToFileURL } from 'node:url';

let playwrightPromise;

// Resolve project dependencies normally; an external installation is optional.
export async function loadPlaywright() {
  playwrightPromise ??= (async () => {
    const modulePath = process.env.ORGCHART_PLAYWRIGHT_MODULE?.trim();
    try {
      const runtime = await import(modulePath ? pathToFileURL(path.resolve(modulePath)).href : 'playwright');
      if (typeof runtime.chromium?.launch !== 'function') throw new Error('Module does not export chromium.launch');
      return runtime;
    } catch (cause) {
      throw new Error(
        `OrgChart browser verification cannot load Playwright (${modulePath || 'project module: playwright'}). ` +
        'Use an existing project Playwright installation, or set ORGCHART_PLAYWRIGHT_MODULE to an existing Playwright entry file.',
        { cause },
      );
    }
  })();
  return playwrightPromise;
}

export async function launchChromium(options = {}) {
  const { chromium } = await loadPlaywright();
  const executablePath = process.env.ORGCHART_CHROME?.trim();
  try {
    return await chromium.launch({ ...options, ...(executablePath ? { executablePath: path.resolve(executablePath) } : {}) });
  } catch (cause) {
    throw new Error(
      `OrgChart browser verification cannot launch Chromium (${executablePath || 'Playwright-managed browser'}). ` +
      'Ensure this Playwright installation has its Chromium browser, or set ORGCHART_CHROME to an existing browser executable.',
      { cause },
    );
  }
}