1 files changed, 85 insertions, 0 deletions
diff --git a/app/services/work_items/related_work_item_links/destroy_service.rb b/app/services/work_items/related_work_item_links/destroy_service.rb
new file mode 100644
index 00000000000..6d1920d01b2
--- /dev/null
+++ b/app/services/work_items/related_work_item_links/destroy_service.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+module WorkItems
+  module RelatedWorkItemLinks
+    class DestroyService < BaseService
+      def initialize(work_item, user, params)
+        @work_item = work_item
+        @current_user = user
+        @params = params.dup
+        @failed_ids = []
+        @removed_ids = []
+      end
+
+      def execute
+        return error(_('No work item found.'), 403) unless can?(current_user, :admin_work_item_link, work_item)
+        return error(_('No work item IDs provided.'), 409) if params[:item_ids].empty?
+
+        destroy_links_for(params[:item_ids])
+
+        if removed_ids.any?
+          success(message: response_message, items_removed: removed_ids, items_with_errors: failed_ids.flatten)
+        else
+          error(error_message)
+        end
+      end
+
+      private
+
+      attr_reader :work_item, :current_user, :failed_ids, :removed_ids
+
+      def destroy_links_for(item_ids)
+        destroy_links(source: work_item, target: item_ids, direction: :target)
+        destroy_links(source: item_ids, target: work_item, direction: :source)
+      end
+
+      def destroy_links(source:, target:, direction:)
+        WorkItems::RelatedWorkItemLink.for_source_and_target(source, target).each do |link|
+          linked_item = link.try(direction)
+
+          if can?(current_user, :admin_work_item_link, linked_item)
+            link.destroy!
+            removed_ids << linked_item.id
+            create_notes(link)
+          else
+            failed_ids << linked_item.id
+          end
+        end
+      end
+
+      def create_notes(link)
+        SystemNoteService.unrelate_issuable(link.source, link.target, current_user)
+        SystemNoteService.unrelate_issuable(link.target, link.source, current_user)
+      end
+
+      def error_message
+        not_linked = params[:item_ids] - (removed_ids + failed_ids)
+        error_messages = []
+
+        if failed_ids.any?
+          error_messages << format(
+            _('%{item_ids} could not be removed due to insufficient permissions'), item_ids: failed_ids.to_sentence
+          )
+        end
+
+        if not_linked.any?
+          error_messages << format(
+            _('%{item_ids} could not be removed due to not being linked'), item_ids: not_linked.to_sentence
+          )
+        end
+
+        return '' unless error_messages.any?
+
+        format(_('IDs with errors: %{error_messages}.'), error_messages: error_messages.join(', '))
+      end
+
+      def response_message
+        success_message = format(_('Successfully unlinked IDs: %{item_ids}.'), item_ids: removed_ids.to_sentence)
+
+        return success_message unless error_message.present?
+
+        "#{success_message} #{error_message}"
+      end
+    end
+  end
+end