'use strict';

var rscheme = /^(?:[a-z\u00a1-\uffff0-9-+]+)(?::(?:\/\/)?)/i;

var UrlHelper = {

  // Placeholder anchor tag to format URLs.
  a: null,

  getUrlFromInput: function urlHelper_getUrlFromInput(input) {
    this.a = this.a || document.createElement('a');
    this.a.href = input;
    return this.a.href;
  },

  _getScheme: function(input) {
    // This function returns one of followings
    // - scheme + ':' (ex. http:)
    // - scheme + '://' (ex. http://)
    // - null
    return (rscheme.exec(input) || [])[0];
  },

  hasScheme: function(input) {
    return !!this._getScheme(input);
  },

  isURL: function urlHelper_isURL(input) {
    return !UrlHelper.isNotURL(input);
  },

  isNotURL: function urlHelper_isNotURL(input) {
    // in bug 904731, we use <input type='url' value=''> to
    // validate url. However, there're still some cases
    // need extra validation. We'll remove it til bug fixed
    // for native form validation.
    //
    // for cases, ?abc and "a? b" which should searching query
    var case1Reg = /^(\?)|(\?.+\s)/;
    // for cases, pure string
    var case2Reg = /[\?\.\s\:]/;
    // for cases, data:uri and view-source:uri
    var case3Reg = /^(data|view-source)\:/;

    var str = input.trim();
    if (case1Reg.test(str) || !case2Reg.test(str) ||
        this._getScheme(str) === str) {
      return true;
    }
    if (case3Reg.test(str)) {
      return false;
    }
    // require basic scheme before form validation
    if (!this.hasScheme(str)) {
      str = 'http://' + str;
    }
    if (!this.urlValidate) {
      this.urlValidate = document.createElement('input');
      this.urlValidate.setAttribute('type', 'url');
    }
    this.urlValidate.setAttribute('value', str);
    return !this.urlValidate.validity.valid;
  },

  /**
   * Resolve a URL against a base URL.
   *
   * @param url String URL to resolve.
   * @param baseURL String Base URL to resolve against.
   * @returns String resolved URL or null.
   */
  resolveUrl: function urlHelper_resolveURL(url, baseUrl) {
    if (!url) {
      return null;
    }
    try {
      return new URL(url, baseUrl).href;
    } catch(e) {
      return null;
    }
  },

  /**
   * Get the hostname from a URL.
   *
   * @param String URL to process.
   * @returns String hostname of URL.
   */
  getHostname: function urlHelper_getHostname(url) {
    try {
      return new URL(url).hostname;
    } catch(e) {
      return null;
    }
  }
};