va-oauth.html

<dom-module id="va-oauth">
  
  <template>
    
    <va-cordova-oauth id="cordovaAuth"></va-cordova-oauth>
    
  </template>
  
  <script>
    Polymer({
      
      is: 'va-oauth',
      
      properties: {
        
        account: {
          type: Object
        }
      },
      
      link: function (provider) {
        var that = this;
        var promise;

        if (window.cordova) {
          var url = this.resolveUrl('../va-cordova-oauth/va-cordova-oauth.html', null, null, true);
          promise = Promise.resolve();

          this.importHref(url, function () {
            that.$.cordovaAuth.signIn(provider).then(function () {
              var credential;

              switch (provider) {
                case 'google':
                  credential = firebase.auth.GoogleAuthProvider.credential(arguments[0], null);
                  break;
                case 'facebook':
                  credential = firebase.auth.FacebookAuthProvider.credential(arguments[0]);
                  break;
                case 'twitter':
                  credential = firebase.auth.TwitterAuthProvider.credential(arguments[0], arguments[1]);
                  break;
              }

              that.account.link(credential).then(function () {
                promise.resolve();
              });
            });
          });
        } else {
          promise = this.$.auth.signInWithPopup(provider).then(function (result) {
            that.account.link(result.credential);
          });
        }
        
        return promise;
      },
      
      hasGoogleAccount: function () {
        return this._findAccountByProvider('google.com');
      },
      
      hasFacebookAccount: function () {
        return this._findAccountByProvider('facebook.com');
      },
      
      hasTwitterAccount: function () {
        return this._findAccountByProvider('twitter.com');
      },
      
      _findAccountByProvider: function (provider) {
        for (var i in this.account.providerData) {
          if (this.account.providerData[i].providerId === provider) {
            return true;
          }
        }
        return false;
      }
      
    });
  </script>
  
</dom-module>