Skip adding reactions that is already posted

app/src/main/java/chat/rocket/android/chatroom/adapter/BaseViewHolder.kt

@@ -53,7 +53,9 @@ abstract class BaseViewHolder<T : BaseViewModel<*>>(
                     }
 
                     override fun onReactionAdded(messageId: String, emoji: Emoji) {
-                        reactionListener?.onReactionAdded(messageId, emoji)
+                        if (!adapter.contains(emoji.shortname)) {
+                            reactionListener?.onReactionAdded(messageId, emoji)
+                        }
                     }
                 }
                 val context = itemView.context

app/src/main/java/chat/rocket/android/chatroom/adapter/MessageReactionsAdapter.kt

@@ -71,6 +71,9 @@ class MessageReactionsAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>()
         notifyItemRangeRemoved(0, oldSize)
     }
 
+    fun contains(reactionShortname: String) =
+            reactions.firstOrNull { it.shortname ==  reactionShortname} != null
+
     class SingleReactionViewHolder(view: View,
                                    private val listener: EmojiReactionListener?)
         : RecyclerView.ViewHolder(view), View.OnClickListener {