module Gitlab
  module Database
    module RenameReservedPathsMigration
      module V1
        class RenameNamespaces < RenameBase
          include Gitlab::ShellAdapter

          def rename_namespaces(type:)
            namespaces_for_paths(type: type).each do |namespace|
              rename_namespace(namespace)
            end
          end

          def namespaces_for_paths(type:)
            namespaces = case type
                         when :child
                           MigrationClasses::Namespace.where.not(parent_id: nil)
                         when :top_level
                           MigrationClasses::Namespace.where(parent_id: nil)
                         end
            with_paths = MigrationClasses::Route.arel_table[:path].
                           matches_any(path_patterns)
            namespaces.joins(:route).where(with_paths)
          end

          def rename_namespace(namespace)
            old_full_path, new_full_path = rename_path_for_routable(namespace)

            move_repositories(namespace, old_full_path, new_full_path)
            move_uploads(old_full_path, new_full_path)
            move_pages(old_full_path, new_full_path)
            remove_cached_html_for_projects(projects_for_namespace(namespace).map(&:id))
          end

          def move_repositories(namespace, old_full_path, new_full_path)
            repo_paths_for_namespace(namespace).each do |repository_storage_path|
              # Ensure old directory exists before moving it
              gitlab_shell.add_namespace(repository_storage_path, old_full_path)

              unless gitlab_shell.mv_namespace(repository_storage_path, old_full_path, new_full_path)
                message = "Exception moving path #{repository_storage_path} \
                           from #{old_full_path} to #{new_full_path}"
                Rails.logger.error message
              end
            end
          end

          def repo_paths_for_namespace(namespace)
            projects_for_namespace(namespace).distinct.select(:repository_storage).
              map(&:repository_storage_path)
          end

          def projects_for_namespace(namespace)
            namespace_ids = child_ids_for_parent(namespace, ids: [namespace.id])
            namespace_or_children = MigrationClasses::Project.
                                      arel_table[:namespace_id].
                                      in(namespace_ids)
            MigrationClasses::Project.where(namespace_or_children)
          end

          def child_ids_for_parent(namespace, ids: [])
            namespace.children.each do |child|
              ids << child.id
              child_ids_for_parent(child, ids: ids) if child.children.any?
            end
            ids
          end
        end
      end
    end
  end
end
