/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {NormalizedUrl} from '../src/api';


/**
 * Determine whether the current environment provides all necessary APIs to run ServiceWorker tests.
 *
 * @return Whether ServiceWorker tests can be run in the current environment.
 */
export function envIsSupported(): boolean {
  if (typeof URL === 'function') {
    return true;
  }

  // If we're in a browser that doesn't support URL at this point, don't go any further
  // since browser builds use requirejs which will fail on the `require` call below.
  if (typeof window !== 'undefined' && window) {
    return false;
  }

  // In older Node.js versions, the `URL` global does not exist. We can use `url` instead.
  const url = (typeof require === 'function') && require('url');
  return url && (typeof url.parse === 'function') && (typeof url.resolve === 'function');
}

/**
 * Get a normalized representation of a URL relative to a provided base URL.
 *
 * More specifically:
 * 1. Resolve the URL relative to the provided base URL.
 * 2. If the URL is relative to the base URL, then strip the origin (and only return the path and
 *    search parts). Otherwise, return the full URL.
 *
 * @param url The raw URL.
 * @param relativeTo The base URL to resolve `url` relative to.
 *     (This is usually the ServiceWorker's origin or registration scope).
 * @return A normalized representation of the URL.
 */
export function normalizeUrl(url: string, relativeTo: string): NormalizedUrl {
  const {origin, path, search} = parseUrl(url, relativeTo);
  const {origin: relativeToOrigin} = parseUrl(relativeTo);

  return ((origin === relativeToOrigin) ? path + search : url) as NormalizedUrl;
}

/**
 * Parse a URL into its different parts, such as `origin`, `path` and `search`.
 */
export function parseUrl(
    url: string, relativeTo?: string): {origin: string, path: string, search: string} {
  const parsedUrl: URL = (typeof URL === 'function') ?
      (!relativeTo ? new URL(url) : new URL(url, relativeTo)) :
      require('url').parse(require('url').resolve(relativeTo || '', url));

  return {
    origin: parsedUrl.origin || `${parsedUrl.protocol}//${parsedUrl.host}`,
    path: parsedUrl.pathname,
    search: parsedUrl.search || '',
  };
}