refactor conversation handling in message builders

app/builders/messages/facebook/message_builder.rb

@@ -56,9 +56,13 @@ class Messages::Facebook::MessageBuilder < Messages::Messenger::MessageBuilder
     @conversation ||= set_conversation_based_on_inbox_config
   end
 
+  def facebook_direct_message_conversation
+    Conversation.where(conversation_params).order(created_at: :desc).first
+  end
+
   def set_conversation_based_on_inbox_config
     if @inbox.lock_to_single_conversation
-      Conversation.find_by(conversation_params) || build_conversation
+      facebook_direct_message_conversation || build_conversation
     else
       find_or_build_for_multiple_conversations
     end
@@ -66,10 +70,13 @@ class Messages::Facebook::MessageBuilder < Messages::Messenger::MessageBuilder
 
   def find_or_build_for_multiple_conversations
     # If lock to single conversation is disabled, we will create a new conversation if previous conversation is resolved
-    last_conversation = Conversation.where(conversation_params).where.not(status: :resolved).order(created_at: :desc).first
-    return build_conversation if last_conversation.nil?
+    last_conversation = facebook_direct_message_conversation
 
-    last_conversation
+    if last_conversation.nil? || last_conversation.resolved?
+      build_conversation
+    else
+      last_conversation
+    end
   end
 
   def build_conversation

app/builders/messages/instagram/message_builder.rb

@@ -74,19 +74,19 @@ class Messages::Instagram::MessageBuilder < Messages::Messenger::MessageBuilder
 
   def instagram_direct_message_conversation
     Conversation.where(conversation_params)
-                .where("additional_attributes ->> 'type' = 'instagram_direct_message'")
+                .where("additional_attributes ->> 'type' = 'instagram_direct_message'").order(created_at: :desc).first
   end
 
   def set_conversation_based_on_inbox_config
     if @inbox.lock_to_single_conversation
-      instagram_direct_message_conversation.first || build_conversation
+      instagram_direct_message_conversation || build_conversation
     else
       find_or_build_for_multiple_conversations
     end
   end
 
   def find_or_build_for_multiple_conversations
-    last_conversation = instagram_direct_message_conversation.order(created_at: :desc).first
+    last_conversation = instagram_direct_message_conversation
 
     if last_conversation.nil? || last_conversation.resolved?
       build_conversation