'use strict';

/* global LazyLoader */
/* global oauth2 */
/* global oauthflow */

var fb = window.fb || {};

if (typeof fb.msg === 'undefined') {
  LazyLoader.load('/shared/pages/import/js/parameters.js', () => {
    (function(document) {
      var Msg = fb.msg = {};
      var to;
      var message;
      var params = oauthflow.params.facebook;
      var appId = params.applicationId;
      var redirectURI = params.redirectMsg;

      Msg.CID_PARAM = 'contactid';

      // Only needed if we decide to craft our own UI
      Msg.wallPost = function(uid, msg) {
        to = uid || to;
        message = msg || message;
        oauth2.getAccessToken(doWallPost, 'wallPost', 'facebook');
      };

      Msg.sendPrivate = function(uid, msg) {
        // TODO: To be implemented (if we decide to craft our custom UI)
      };

      // This code is for posting to user's wall. Only will be necessary if
      // we decide to craft our own UI for posting to the wall
      function doWallPost(token) {
        var msgWallService = 'https://graph.facebook.com/#/feed?method=POST';

        msgWallService = msgWallService.replace(/#/, to);

        var params = [
          'access_token' + '=' + token,
          'message' + '=' + message,
          'callback' + '=' + 'fb.msg.ui.wallPosted'
        ];

        var q = params.join('&');

        var jsonp = document.createElement('script');
        jsonp.src = msgWallService + '&' + q;

        document.body.appendChild(jsonp);
      }

      var UI = Msg.ui = {};

      function getFbContactUid(contactId, callback) {
         var req = fb.utils.getContactData(contactId);

        req.onsuccess = function() {
          var fbContact = new fb.Contact(req.result);
          callback(fbContact.uid);
        };

        req.onerror = function() {
          window.console.error('Contacts: Contact not found!');
          callback(null);
        };
      }

      function openMsgDialog(dialogURI, uid) {
        var params = [
          'app_id' + '=' + appId,
          'to' + '=' + uid,
          'redirect_uri' + '=' + encodeURIComponent(redirectURI)
        ];

        var target = dialogURI + params.join('&');
        window.open(fb.utils.getNonCacheableUrl(target), '', 'dialog');
      }

      // Use the FB Dialogs functionality for posting to the wall
      UI.wallPost = function(contactId) {
        getFbContactUid(contactId, function ui_wallPost(uid) {
          if (uid) {
            var dialogURI = 'https://m.facebook.com/dialog/feed?';
            openMsgDialog(dialogURI, uid);
          }
        });
      };

      // Use a Web view from Facebook for sending private messages
      // TODO: Check with Facebook why the send message dialog seems not to be
      // working on mobile
      UI.sendPrivateMsg = function(contactId) {
        getFbContactUid(contactId, function ui_sendMsg(uid) {
          if (uid) {
            var url = 'https://m.facebook.com/compose_message/?uid=' + uid;
            window.open(fb.utils.getNonCacheableUrl(url),
              '', 'dialog');
          }
        });
      };

      UI.wallPosted = function(result) {
        UI.end();
        window.console.log(JSON.stringify(result));
      };

    })(document);
  });
}