1 files changed, 106 insertions, 0 deletions
diff --git a/lib/gitlab/email/receiver.rb b/lib/gitlab/email/receiver.rb
new file mode 100644
index 00000000000..355fbd27898
--- /dev/null
+++ b/lib/gitlab/email/receiver.rb
@@ -0,0 +1,106 @@
+# Inspired in great part by Discourse's Email::Receiver
+module Gitlab
+  module Email
+    class Receiver
+      class ProcessingError < StandardError; end
+      class EmailUnparsableError < ProcessingError; end
+      class SentNotificationNotFoundError < ProcessingError; end
+      class EmptyEmailError < ProcessingError; end
+      class AutoGeneratedEmailError < ProcessingError; end
+      class UserNotFoundError < ProcessingError; end
+      class UserBlockedError < ProcessingError; end
+      class UserNotAuthorizedError < ProcessingError; end
+      class NoteableNotFoundError < ProcessingError; end
+      class InvalidNoteError < ProcessingError; end
+
+      def initialize(raw)
+        @raw = raw
+      end
+
+      def execute
+        raise EmptyEmailError if @raw.blank?
+
+        raise SentNotificationNotFoundError unless sent_notification
+
+        raise AutoGeneratedEmailError if message.header.to_s =~ /auto-(generated|replied)/
+
+        author = sent_notification.recipient
+
+        raise UserNotFoundError unless author
+
+        raise UserBlockedError if author.blocked?
+
+        project = sent_notification.project
+
+        raise UserNotAuthorizedError unless project && author.can?(:create_note, project)
+
+        raise NoteableNotFoundError unless sent_notification.noteable
+
+        reply = ReplyParser.new(message).execute.strip
+
+        raise EmptyEmailError if reply.blank?
+
+        reply = add_attachments(reply)
+
+        note = create_note(reply)
+
+        unless note.persisted?
+          message = "The comment could not be created for the following reasons:"
+          note.errors.full_messages.each do |error|
+            message << "\n\n- #{error}"
+          end
+
+          raise InvalidNoteError, message
+        end
+      end
+
+      private
+
+      def message
+        @message ||= Mail::Message.new(@raw)
+      rescue Encoding::UndefinedConversionError, Encoding::InvalidByteSequenceError => e
+        raise EmailUnparsableError, e
+      end
+
+      def reply_key
+        reply_key = nil
+        message.to.each do |address|
+          reply_key = Gitlab::ReplyByEmail.reply_key_from_address(address)
+          break if reply_key
+        end
+
+        reply_key
+      end
+
+      def sent_notification
+        return nil unless reply_key
+        
+        SentNotification.for(reply_key)
+      end
+
+      def add_attachments(reply)
+        attachments = Email::AttachmentUploader.new(message).execute(sent_notification.project)
+
+        attachments.each do |link|
+          text = "[#{link[:alt]}](#{link[:url]})"
+          text.prepend("!") if link[:is_image]
+
+          reply << "\n\n#{text}"
+        end
+
+        reply
+      end
+
+      def create_note(reply)
+        Notes::CreateService.new(
+          sent_notification.project,
+          sent_notification.recipient,
+          note:           reply,
+          noteable_type:  sent_notification.noteable_type,
+          noteable_id:    sent_notification.noteable_id,
+          commit_id:      sent_notification.commit_id
+        ).execute
+      end
+    end
+  end
+end