Fixed mentions in supergroups

Closes #1584

app/js/controllers.js

@@ -2512,8 +2512,14 @@ angular.module('myApp.controllers', ['myApp.i18n'])
       })
       var chatParticipantsPromise
       if (peerID < 0) {
-        chatParticipantsPromise = AppProfileManager.getChatFull(-peerID).then(function (chatFull) {
+        if (AppPeersManager.isChannel(peerID)) {
-          var participantsVector = (chatFull.participants || {}).participants || []
+          chatParticipantsPromise = AppProfileManager.getChannelParticipants(-peerID)
+        } else {
+          chatParticipantsPromise = AppProfileManager.getChatFull(-peerID).then(function (chatFull) {
+            return (chatFull.participants || {}).participants || []
+          })
+        }
+        chatParticipantsPromise = chatParticipantsPromise.then(function (participantsVector) {
           var ids = []
           angular.forEach(participantsVector, function (participant) {
             ids.push(participant.user_id)

app/js/services.js

@@ -1208,8 +1208,11 @@ angular.module('myApp.services', ['myApp.i18n', 'izhukov.utils'])
 
       if (filter._ == 'channelParticipantsRecent') {
         var chat = AppChatsManager.getChat(id)
-        if (chat.pFlags.kicked ||
+        if (chat &&
-            chat.pFlags.broadcast && !chat.pFlags.creator && !chat.admin_rights) {
+            chat.pFlags && (
+              chat.pFlags.kicked ||
+              chat.pFlags.broadcast && !chat.pFlags.creator && !chat.admin_rights
+            )) {
           return $q.reject()
         }
       }