fix: Update email message_id parsing order (#3073)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/mailboxes/application_mailbox.rb

@@ -1,19 +1,18 @@
 class ApplicationMailbox < ActionMailbox::Base
+  include MailboxHelper
+
   # Last part is the regex for the UUID
   # Eg: email should be something like : reply+6bdc3f4d-0bec-4515-a284-5d916fdde489@domain.com
-  REPLY_EMAIL_USERNAME_PATTERN = /^reply\+([0-9a-f]{8}\b-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-\b[0-9a-f]{12})$/i
+  REPLY_EMAIL_UUID_PATTERN = /^reply\+([0-9a-f]{8}\b-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-\b[0-9a-f]{12})$/i
+  CONVERSATION_MESSAGE_ID_PATTERN = %r{conversation/([a-zA-Z0-9\-]*?)/messages/(\d+?)@(\w+\.\w+)}
 
   def self.reply_mail?
     proc do |inbound_mail_obj|
       is_a_reply_email = false
       inbound_mail_obj.mail.to&.each do |email|
-        username = email.split('@')[0]
-        match_result = username.match(REPLY_EMAIL_USERNAME_PATTERN)
-        if match_result
-          is_a_reply_email = true
-          break
-        end
+        is_a_reply_email = true if reply_uuid_mail?(email)
       end
+      is_a_reply_email = true if in_reply_to_mail?(inbound_mail_obj, is_a_reply_email)
       is_a_reply_email
     end
   end
@@ -36,6 +35,30 @@ class ApplicationMailbox < ActionMailbox::Base
     proc { |_mail| true }
   end
 
+  # checks if follow this pattern then send it to reply_mailbox
+  # <account/#{@account.id}/conversation/#{@conversation.uuid}@#{@account.inbound_email_domain}>
+  def self.in_reply_to_mail?(inbound_mail_obj, is_a_reply_email)
+    return if is_a_reply_email
+
+    in_reply_to = inbound_mail_obj.mail['In-Reply-To'].value
+
+    return false if in_reply_to.blank?
+
+    return true if in_reply_to.match(CONVERSATION_MESSAGE_ID_PATTERN)
+
+    message = Message.find_by(source_id: in_reply_to)
+    return true if message.present?
+
+    false
+  end
+
+  # checks if follow this pattern  send it to reply_mailbox
+  # reply+<conversation-uuid>@<mailer-domain.com>
+  def self.reply_uuid_mail?(email)
+    conversation_uuid = email.split('@')[0]
+    conversation_uuid.match(REPLY_EMAIL_UUID_PATTERN)
+  end
+
   # routing should be defined below the referenced procs
 
   # routes as a reply to existing conversations