4 files changed, 167 insertions, 0 deletions
diff --git a/app/services/draft_notes/base_service.rb b/app/services/draft_notes/base_service.rb
new file mode 100644
index 00000000000..89daae0e8f4
--- /dev/null
+++ b/app/services/draft_notes/base_service.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module DraftNotes
+  class BaseService < ::BaseService
+    attr_accessor :merge_request, :current_user, :params
+
+    def initialize(merge_request, current_user, params = nil)
+      @merge_request, @current_user, @params = merge_request, current_user, params.dup
+    end
+
+    private
+
+    def draft_notes
+      @draft_notes ||= merge_request.draft_notes.order_id_asc.authored_by(current_user)
+    end
+
+    def project
+      merge_request.target_project
+    end
+  end
+end
diff --git a/app/services/draft_notes/create_service.rb b/app/services/draft_notes/create_service.rb
new file mode 100644
index 00000000000..501778b7d5f
--- /dev/null
+++ b/app/services/draft_notes/create_service.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module DraftNotes
+  class CreateService < DraftNotes::BaseService
+    attr_accessor :in_draft_mode, :in_reply_to_discussion_id
+
+    def initialize(merge_request, current_user, params = nil)
+      @in_reply_to_discussion_id = params.delete(:in_reply_to_discussion_id)
+      super
+    end
+
+    def execute
+      if in_reply_to_discussion_id.present?
+        unless discussion
+          return base_error(_('Thread to reply to cannot be found'))
+        end
+
+        params[:discussion_id] = discussion.reply_id
+      end
+
+      if params[:resolve_discussion] && !can_resolve_discussion?
+        return base_error(_('User is not allowed to resolve thread'))
+      end
+
+      draft_note = DraftNote.new(params)
+      draft_note.merge_request = merge_request
+      draft_note.author = current_user
+      draft_note.save
+
+      if in_reply_to_discussion_id.blank? && draft_note.diff_file&.unfolded?
+        merge_request.diffs.clear_cache
+      end
+
+      draft_note
+    end
+
+    private
+
+    def base_error(text)
+      DraftNote.new.tap do |draft|
+        draft.errors.add(:base, text)
+      end
+    end
+
+    def discussion
+      @discussion ||= merge_request.notes.find_discussion(in_reply_to_discussion_id)
+    end
+
+    def can_resolve_discussion?
+      note = discussion&.notes&.first
+      return false unless note
+
+      current_user && Ability.allowed?(current_user, :resolve_note, note)
+    end
+  end
+end
diff --git a/app/services/draft_notes/destroy_service.rb b/app/services/draft_notes/destroy_service.rb
new file mode 100644
index 00000000000..ddca0debb03
--- /dev/null
+++ b/app/services/draft_notes/destroy_service.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module DraftNotes
+  class DestroyService < DraftNotes::BaseService
+    # If no `draft` is given it fallsback to all
+    # draft notes of the given merge request and user.
+    def execute(draft = nil)
+      drafts = draft || draft_notes
+
+      clear_highlight_diffs_cache(Array.wrap(drafts))
+
+      drafts.is_a?(DraftNote) ? drafts.destroy! : drafts.delete_all
+    end
+
+    private
+
+    def clear_highlight_diffs_cache(drafts)
+      if drafts.any? { |draft| draft.diff_file&.unfolded? }
+        merge_request.diffs.clear_cache
+      end
+    end
+  end
+end
diff --git a/app/services/draft_notes/publish_service.rb b/app/services/draft_notes/publish_service.rb
new file mode 100644
index 00000000000..a9a7304e5ed
--- /dev/null
+++ b/app/services/draft_notes/publish_service.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module DraftNotes
+  class PublishService < DraftNotes::BaseService
+    def execute(draft = nil)
+      return error('Not allowed to create notes') unless can?(current_user, :create_note, merge_request)
+
+      if draft
+        publish_draft_note(draft)
+      else
+        publish_draft_notes
+      end
+
+      success
+    rescue ActiveRecord::RecordInvalid => e
+      message = "Unable to save #{e.record.class.name}: #{e.record.errors.full_messages.join(", ")} "
+      error(message)
+    end
+
+    private
+
+    def publish_draft_note(draft)
+      create_note_from_draft(draft)
+      draft.delete
+
+      MergeRequests::ResolvedDiscussionNotificationService.new(project, current_user).execute(merge_request)
+    end
+
+    def publish_draft_notes
+      return if draft_notes.empty?
+
+      review = Review.create!(author: current_user, merge_request: merge_request, project: project)
+
+      draft_notes.map do |draft_note|
+        draft_note.review = review
+        create_note_from_draft(draft_note)
+      end
+      draft_notes.delete_all
+
+      notification_service.async.new_review(review)
+      MergeRequests::ResolvedDiscussionNotificationService.new(project, current_user).execute(merge_request)
+    end
+
+    def create_note_from_draft(draft)
+      # Make sure the diff file is unfolded in order to find the correct line
+      # codes.
+      draft.diff_file&.unfold_diff_lines(draft.original_position)
+
+      note = Notes::CreateService.new(draft.project, draft.author, draft.publish_params).execute
+      set_discussion_resolve_status(note, draft)
+
+      note
+    end
+
+    def set_discussion_resolve_status(note, draft_note)
+      return unless draft_note.discussion_id.present?
+
+      discussion = note.discussion
+
+      if draft_note.resolve_discussion && discussion.can_resolve?(current_user)
+        discussion.resolve!(current_user)
+      else
+        discussion.unresolve!
+      end
+    end
+  end
+end