1 files changed, 73 insertions, 12 deletions
diff --git a/app/services/groups/transfer_service.rb b/app/services/groups/transfer_service.rb
index 58e8cca04bb..6f6f33c2903 100644
--- a/app/services/groups/transfer_service.rb
+++ b/app/services/groups/transfer_service.rb
@@ -1,8 +1,15 @@
 module Groups
   class TransferService < Groups::BaseService
-    include TransferErrorMessages
+    ERROR_MESSAGES = {
+      database_not_supported: 'Database is not supported.',
+      group_with_same_path: 'The parent group has a group with the same path.',
+      group_is_already_root: 'Group is already a root group.',
+      same_parent_as_current: 'Group is already associated to the parent group.',
+      invalid_policies: "You don't have enough permissions."
+    }.freeze
 
     TransferError = Class.new(StandardError)
+
     attr_reader :error
 
     def initialize(group, user, params = {})
@@ -10,24 +17,78 @@ module Groups
       @error = nil
     end
 
-    private
+    def execute(new_parent_group)
+      @new_parent_group = new_parent_group
+      ensure_allowed_transfer
+      proceed_to_transfer
 
-    def with_transfer_error_handling
-      yield
-    rescue TransferError => e
+    rescue TransferError, ActiveRecord::RecordInvalid, Gitlab::UpdatePathError => e
       @error = "Transfer failed: " + e.message
       false
-    rescue Gitlab::UpdatePathError
-      @error = friendly_update_path_error
-      false
     end
 
-    def raise_transfer_error(message)
-      if message.is_a?(Symbol)
-        raise TransferError, error_messages[message]
+    private
+
+    def proceed_to_transfer
+      Group.transaction do
+        update_children_and_projects_visibility if @new_parent_group.present?
+        update_group_attributes
+      end
+    end
+
+    def ensure_allowed_transfer
+      raise_transfer_error(:group_is_already_root) if group_is_already_root
+      raise_transfer_error(:database_not_supported) unless Group.supports_nested_groups?
+      raise_transfer_error(:same_parent_as_current) if same_parent?
+      raise_transfer_error(:group_with_same_path) if group_with_same_path?
+      raise_transfer_error(:invalid_policies) unless valid_policies?
+    end
+
+    def group_is_already_root
+      @new_parent_group.blank? && @group.parent.nil?
+    end
+
+    def same_parent?
+      @new_parent_group.present? && @new_parent_group.id == @group.parent_id
+    end
+
+    def valid_policies?
+      if @new_parent_group.present?
+        can?(current_user, :admin_group, @group) &&
+          can?(current_user, :create_subgroup, @new_parent_group)
       else
-        raise TransferError, message
+        can?(current_user, :admin_group, @group)
+      end
+    end
+
+    def group_with_same_path?
+      if @new_parent_group.present?
+        @new_parent_group.children.exists?(path: @group.path)
+      else
+        Group.exists?(path: @group.path, parent: nil)
+      end
+    end
+
+    def update_group_attributes
+      @group.visibility_level = @new_parent_group.visibility_level if @new_parent_group.present?
+      @group.parent = @new_parent_group
+      @group.save!
+    end
+
+    def update_children_and_projects_visibility
+      descendants = @group.descendants.where("visibility_level > ?", @new_parent_group.visibility_level)
+      descendants.each do |subgroup|
+        subgroup.update_column(:visibility_level, @new_parent_group.visibility_level)
       end
+
+      @group
+        .projects
+        .where("visibility_level > ?", @new_parent_group.visibility_level)
+        .update_all(visibility_level: @new_parent_group.visibility_level)
+    end
+
+    def raise_transfer_error(message)
+      raise TransferError, ERROR_MESSAGES[message]
     end
   end
 end