Remove duplication in issue emails

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/mailers/emails/issues.rb

 module Emails
   module Issues
     def new_issue_email(recipient_id, issue_id)
-      @issue = Issue.find(issue_id)
-      @project = @issue.project
-      @target_url = namespace_project_issue_url(@project.namespace, @project, @issue)
-      mail_new_thread(@issue,
-                      from: sender(@issue.author_id),
-                      to: recipient(recipient_id),
-                      subject: subject("#{@issue.title} (##{@issue.iid})"))
-
-      SentNotification.record(@issue, recipient_id, reply_key)
+      mail_with_notification(issue_id, recipient_id) do
+        mail_new_thread(@issue, thread_options(@issue.author_id, recipient_id))
+      end
     end
 
     def reassigned_issue_email(recipient_id, issue_id, previous_assignee_id, updated_by_user_id)
-      @issue = Issue.find(issue_id)
+      mail_with_notification(issue_id, recipient_id) do
         @previous_assignee = User.find_by(id: previous_assignee_id) if previous_assignee_id
-      @project = @issue.project
-      @target_url = namespace_project_issue_url(@project.namespace, @project, @issue)
-      mail_answer_thread(@issue,
-                         from: sender(updated_by_user_id),
-                         to: recipient(recipient_id),
-                         subject: subject("#{@issue.title} (##{@issue.iid})"))
-
-      SentNotification.record(@issue, recipient_id, reply_key)
+        mail_answer_thread(@issue, thread_options(updated_by_user_id, recipient_id))
+      end
     end
 
     def closed_issue_email(recipient_id, issue_id, updated_by_user_id)
-      @issue = Issue.find issue_id
-      @project = @issue.project
+      mail_with_notification(issue_id, recipient_id) do
         @updated_by = User.find updated_by_user_id
-      @target_url = namespace_project_issue_url(@project.namespace, @project, @issue)
-      mail_answer_thread(@issue,
-                         from: sender(updated_by_user_id),
-                         to: recipient(recipient_id),
-                         subject: subject("#{@issue.title} (##{@issue.iid})"))
-
-      SentNotification.record(@issue, recipient_id, reply_key)
+        mail_answer_thread(@issue, thread_options(updated_by_user_id, recipient_id))
+      end
     end
 
     def issue_status_changed_email(recipient_id, issue_id, status, updated_by_user_id)
-      @issue = Issue.find issue_id
+      mail_with_notification(issue_id, recipient_id) do
         @issue_status = status
-      @project = @issue.project
         @updated_by = User.find updated_by_user_id
-      @target_url = namespace_project_issue_url(@project.namespace, @project, @issue)
-      mail_answer_thread(@issue,
-                         from: sender(updated_by_user_id),
+        mail_answer_thread(@issue, thread_options(updated_by_user_id, recipient_id))
+      end
+    end
+
+    def thread_options(sender_id, recipient_id)
+      {
+        from: sender(sender_id),
         to: recipient(recipient_id),
-                         subject: subject("#{@issue.title} (##{@issue.iid})"))
+        subject: subject("#{@issue.title} (##{@issue.iid})")
+      }
+    end
+
+    def mail_with_notification(issue_id, recipient_id)
+      @issue = Issue.find(issue_id)
+      @project = @issue.project
+      @target_url = namespace_project_issue_url(@project.namespace, @project, @issue)
+
+      yield
 
       SentNotification.record(@issue, recipient_id, reply_key)
     end