import { existsSync } from 'node:fs';
import {
  MIDSCENE_CHROME_PATH,
  MIDSCENE_MCP_CHROME_PATH,
  globalConfigManager,
} from '../env';
import { getDebug } from '../logger';

const warnChromePath = getDebug('agent-tools:chrome-path', { console: true });
let hasWarnedLegacyChromePath = false;
let cachedSystemChromePath: string | undefined;

export function getSystemChromePath(): string | undefined {
  if (cachedSystemChromePath !== undefined) {
    return cachedSystemChromePath;
  }

  const platform = process.platform;

  const chromePaths: Record<string, string[]> = {
    darwin: [
      '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
      '/Applications/Chromium.app/Contents/MacOS/Chromium',
    ],
    win32: [
      'C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe',
      'C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe',
      `C:\\Users\\${process.env.USERNAME ?? process.env.USER}\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe`,
    ],
    linux: [
      // Prefer actual binaries over wrapper scripts.
      // Wrappers in /usr/bin may strip --user-data-dir, causing
      // "DevTools remote debugging requires a non-default data directory" errors.
      '/opt/google/chrome/chrome',
      '/opt/google/chrome/google-chrome',
      '/usr/bin/google-chrome-stable',
      '/usr/bin/google-chrome',
      '/usr/bin/chromium-browser',
      '/usr/bin/chromium',
      '/snap/bin/chromium',
    ],
  };

  const paths = chromePaths[platform] ?? [];
  const foundPath = paths.find((p) => existsSync(p));
  if (foundPath) {
    cachedSystemChromePath = foundPath;
  }
  return foundPath;
}

export function resolveChromePath(): string {
  const primaryEnvPath =
    globalConfigManager.getEnvConfigValue(MIDSCENE_CHROME_PATH);
  const legacyEnvPath = globalConfigManager.getEnvConfigValue(
    MIDSCENE_MCP_CHROME_PATH,
  );
  const envPath = primaryEnvPath || legacyEnvPath;
  if (!primaryEnvPath && legacyEnvPath && !hasWarnedLegacyChromePath) {
    warnChromePath(
      'MIDSCENE_MCP_CHROME_PATH is deprecated. Use MIDSCENE_CHROME_PATH instead.',
    );
    hasWarnedLegacyChromePath = true;
  }
  if (envPath && envPath !== 'auto' && existsSync(envPath)) {
    return envPath;
  }
  const systemPath = getSystemChromePath();
  if (systemPath) return systemPath;

  throw new Error(
    'Chrome not found. Install Google Chrome or set MIDSCENE_CHROME_PATH environment variable.',
  );
}