1 files changed, 40 insertions, 0 deletions
diff --git a/app/graphql/mutations/notes/create/note.rb b/app/graphql/mutations/notes/create/note.rb
new file mode 100644
index 00000000000..5236e48026e
--- /dev/null
+++ b/app/graphql/mutations/notes/create/note.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Mutations
+  module Notes
+    module Create
+      class Note < Base
+        graphql_name 'CreateNote'
+
+        argument :discussion_id,
+                  GraphQL::ID_TYPE,
+                  required: false,
+                  description: 'The global id of the discussion this note is in reply to'
+
+        private
+
+        def create_note_params(noteable, args)
+          discussion_id = nil
+
+          if args[:discussion_id]
+            discussion = GitlabSchema.object_from_id(args[:discussion_id])
+            authorize_discussion!(discussion)
+
+            discussion_id = discussion.id
+          end
+
+          super(noteable, args).merge({
+            in_reply_to_discussion_id: discussion_id
+          })
+        end
+
+        def authorize_discussion!(discussion)
+          unless Ability.allowed?(current_user, :read_note, discussion, scope: :user)
+            raise Gitlab::Graphql::Errors::ResourceNotAvailable,
+              "The discussion does not exist or you don't have permission to perform this action"
+          end
+        end
+      end
+    end
+  end
+end