nativefier/app/src/helpers/helpers.ts

import * as fs from 'fs';
import * as os from 'os';
import * as path from 'path';

import { BrowserWindow, OpenExternalOptions, shell } from 'electron';
import * as log from 'loglevel';

export const INJECT_DIR = path.join(__dirname, '..', 'inject');

/**
 * Helper to print debug messages from the main process in the browser window
 */
export function debugLog(browserWindow: BrowserWindow, message: string): void {
  // Need a delay, as it takes time for the preloaded js to be loaded by the window
  setTimeout(() => {
    browserWindow.webContents.send('debug', message);
  }, 3000);
  log.debug(message);
}

/**
 * Helper to determine domain-ish equality for many cases, the trivial ones
 * and the trickier ones, e.g. `blog.foo.com` and `shop.foo.com`,
 * in a way that is "good enough", and doesn't need a list of SLDs.
 * See chat at https://github.com/nativefier/nativefier/pull/1171#pullrequestreview-649132523
 */
function domainify(url: string): string {
  // So here's what we're doing here:
  // Get the hostname from the url
  const hostname = new URL(url).hostname;
  // Drop the first section if the domain
  const domain = hostname.split('.').slice(1).join('.');
  // Check the length, if it's too short, the hostname was probably the domain
  // Or if the domain doesn't have a . in it we went too far
  if (domain.length < 6 || domain.split('.').length === 0) {
    return hostname;
  }
  // This SHOULD be the domain, but nothing is 100% guaranteed
  return domain;
}

export function getAppIcon(): string | undefined {
  // Prefer ICO under Windows, see
  // https://www.electronjs.org/docs/api/browser-window#new-browserwindowoptions
  // https://www.electronjs.org/docs/api/native-image#supported-formats
  if (isWindows()) {
    const ico = path.join(__dirname, '..', 'icon.ico');
    if (fs.existsSync(ico)) {
      return ico;
    }
  }
  const png = path.join(__dirname, '..', 'icon.png');
  if (fs.existsSync(png)) {
    return png;
  }
}

export function getCounterValue(title: string): string | undefined {
  const itemCountRegex = /[([{]([\d.,]*)\+?[}\])]/;
  const match = itemCountRegex.exec(title);
  return match ? match[1] : undefined;
}

export function getCSSToInject(): string {
  let cssToInject = '';
  const cssFiles = fs
    .readdirSync(INJECT_DIR, { withFileTypes: true })
    .filter(
      (injectFile) => injectFile.isFile() && injectFile.name.endsWith('.css'),
    )
    .map((cssFileStat) =>
      path.resolve(path.join(INJECT_DIR, cssFileStat.name)),
    );
  for (const cssFile of cssFiles) {
    log.debug('Injecting CSS file', cssFile);
    const cssFileData = fs.readFileSync(cssFile);
    cssToInject += `/* ${cssFile} */\n\n ${cssFileData.toString()}\n\n`;
  }
  return cssToInject;
}

export function isOSX(): boolean {
  return os.platform() === 'darwin';
}

export function isLinux(): boolean {
  return os.platform() === 'linux';
}

export function isWindows(): boolean {
  return os.platform() === 'win32';
}

function isInternalLoginPage(url: string): boolean {
  // Making changes? Remember to update the tests in helpers.test.ts and in API.md
  const internalLoginPagesArray = [
    'amazon\\.[a-zA-Z\\.]*/[a-zA-Z\\/]*signin', // Amazon
    `facebook\\.[a-zA-Z\\.]*\\/login`, // Facebook
    'github\\.[a-zA-Z\\.]*\\/(?:login|session)', // GitHub
    'accounts\\.google\\.[a-zA-Z\\.]*', // Google
    'mail\\.google\\.[a-zA-Z\\.]*\\/accounts/SetOSID', // Google
    'linkedin\\.[a-zA-Z\\.]*/uas/login', // LinkedIn
    'login\\.live\\.[a-zA-Z\\.]*', // Microsoft
    'login\\.microsoftonline\\.[a-zA-Z\\.]*', // Microsoft
    'okta\\.[a-zA-Z\\.]*', // Okta
    'twitter\\.[a-zA-Z\\.]*/oauth/authenticate', // Twitter
    'appleid\\.apple\\.com/auth/authorize', // Apple
  ];
  // Making changes? Remember to update the tests in helpers.test.ts and in API.md
  const regex = RegExp(internalLoginPagesArray.join('|'));
  return regex.test(url);
}

export function linkIsInternal(
  currentUrl: string,
  newUrl: string,
  internalUrlRegex: string | RegExp | undefined,
): boolean {
  log.debug('linkIsInternal', { currentUrl, newUrl, internalUrlRegex });
  if (newUrl.split('#')[0] === 'about:blank') {
    return true;
  }

  if (isInternalLoginPage(newUrl)) {
    return true;
  }

  if (internalUrlRegex) {
    const regex = RegExp(internalUrlRegex);
    if (regex.test(newUrl)) {
      return true;
    }
  }

  try {
    // Consider as "same domain-ish", without TLD/SLD list:
    // 1. app.foo.com and foo.com
    // 2. www.foo.com and foo.com
    // 3. www.foo.com and app.foo.com

    // Only use the tld and the main domain for domain-ish test
    // Enables domain-ish equality for blog.foo.com and shop.foo.com
    return domainify(currentUrl) === domainify(newUrl);
  } catch (err: unknown) {
    log.error(
      'Failed to parse domains as determining if link is internal. From:',
      currentUrl,
      'To:',
      newUrl,
      err,
    );
    return false;
  }
}

export function nativeTabsSupported(): boolean {
  return isOSX();
}

export function openExternal(
  url: string,
  options?: OpenExternalOptions,
): Promise<void> {
  log.debug('openExternal', { url, options });
  return shell.openExternal(url, options);
}

export function removeUserAgentSpecifics(
  userAgentFallback: string,
  appName: string,
  appVersion: string,
): string {
  // Electron userAgentFallback is the user agent used if none is specified when creating a window.
  // For our purposes, it's useful because its format is similar enough to a real Chrome's user agent to not need
  // to infer the userAgent. userAgentFallback normally looks like this:
  // Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) app-nativefier-804458/1.0.0 Chrome/89.0.4389.128 Electron/12.0.7 Safari/537.36
  // We just need to strip out the appName/1.0.0 and Electron/electronVersion
  return userAgentFallback
    .replace(`Electron/${process.versions.electron} `, '')
    .replace(`${appName}/${appVersion} `, ' ');
}