Add service to move board lists

1 files changed, 52 insertions, 0 deletions

diff --git a/app/services/boards/lists/move_service.rb b/app/services/boards/lists/move_service.rb
new file mode 100644
index 00000000000..4a3000d1648
--- /dev/null
+++ b/app/services/boards/lists/move_service.rb
@@ -0,0 +1,52 @@
+module Boards
+  module Lists
+    class MoveService
+      def initialize(project, params = {})
+        @board  = project.board
+        @params = params.dup
+      end
+
+      def execute
+        return false if new_position.blank?
+        return false if new_position == old_position
+
+        list.with_lock do
+          reorder_intermediate_lists
+          update_list_position
+        end
+      end
+
+      private
+
+      attr_reader :board, :params
+
+      def list
+        @list ||= board.lists.find(params[:list_id])
+      end
+
+      def old_position
+        @old_position ||= list.position
+      end
+
+      def new_position
+        @new_position ||= params[:position]
+      end
+
+      def reorder_intermediate_lists
+        if old_position < new_position
+          board.lists.where('position > ?',  old_position)
+                     .where('position <= ?', new_position)
+                     .update_all('position = position - 1')
+        else
+          board.lists.where('position >= ?', new_position)
+                     .where('position < ?',  old_position)
+                     .update_all('position = position + 1')
+        end
+      end
+
+      def update_list_position
+        list.update_attribute(:position, new_position)
+      end
+    end
+  end
+end