import { existsSync, mkdirSync, readdirSync, symlinkSync } from 'node:fs';
import { homedir } from 'node:os';
import path from 'node:path';
import { getOpenClawConfigDir } from './paths';

const PLAYWRIGHT_BROWSERS_DIR = 'ms-playwright';
const PLAYWRIGHT_LOCKS_DIR = 'locks';
const PLAYWRIGHT_COMPLETE_MARKER = 'INSTALLATION_COMPLETE';

function resolveDefaultPlaywrightBrowsersPath(): string | null {
  if (process.platform === 'darwin') {
    return path.join(homedir(), 'Library', 'Caches', 'ms-playwright');
  }
  if (process.platform === 'win32') {
    const localAppData = process.env.LOCALAPPDATA?.trim();
    return localAppData ? path.join(localAppData, 'ms-playwright') : null;
  }
  return path.join(homedir(), '.cache', 'ms-playwright');
}

export function resolveYinianPlaywrightBrowsersPath(): string {
  return path.join(getOpenClawConfigDir(), 'runtime', PLAYWRIGHT_BROWSERS_DIR);
}

export function resolveYinianPlaywrightInstallLockPath(): string {
  return path.join(getOpenClawConfigDir(), 'runtime', PLAYWRIGHT_LOCKS_DIR, 'playwright-chromium-install.lock');
}

function mirrorCompletedDefaultBrowsers(targetRoot: string): void {
  const defaultRoot = resolveDefaultPlaywrightBrowsersPath();
  if (!defaultRoot || defaultRoot === targetRoot || !existsSync(defaultRoot)) return;

  let entries;
  try {
    entries = readdirSync(defaultRoot, { withFileTypes: true });
  } catch {
    return;
  }

  for (const entry of entries) {
    if (!entry.isDirectory() || !entry.name.startsWith('chromium')) continue;

    const sourceDir = path.join(defaultRoot, entry.name);
    if (!existsSync(path.join(sourceDir, PLAYWRIGHT_COMPLETE_MARKER))) continue;

    const targetDir = path.join(targetRoot, entry.name);
    if (existsSync(targetDir)) continue;

    try {
      symlinkSync(sourceDir, targetDir, process.platform === 'win32' ? 'junction' : 'dir');
    } catch {
      // Best effort. A missing browser remains a warning-level diagnostic.
    }
  }
}

export function ensureYinianPlaywrightRuntimeDirs(): void {
  const browsersPath = resolveYinianPlaywrightBrowsersPath();
  mkdirSync(browsersPath, { recursive: true });
  mkdirSync(path.dirname(resolveYinianPlaywrightInstallLockPath()), { recursive: true });
  mirrorCompletedDefaultBrowsers(browsersPath);
}

export function buildPlaywrightRuntimeEnv(
  baseEnv: Record<string, string | undefined> = process.env as Record<string, string | undefined>,
): Record<string, string> {
  const explicitBrowsersPath = baseEnv.PLAYWRIGHT_BROWSERS_PATH?.trim();
  return {
    PLAYWRIGHT_BROWSERS_PATH: explicitBrowsersPath || resolveYinianPlaywrightBrowsersPath(),
    PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD: baseEnv.PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD ?? '1',
    YINIAN_PLAYWRIGHT_INSTALL_LOCK_PATH: baseEnv.YINIAN_PLAYWRIGHT_INSTALL_LOCK_PATH
      ?? resolveYinianPlaywrightInstallLockPath(),
  };
}