#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2018 the OpenProject Foundation (OPF)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
# Copyright (C) 2006-2017 Jean-Philippe Lang
# Copyright (C) 2010-2013 the ChiliProject Team
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
# See docs/COPYRIGHT.rdoc for more details.
#++

module API
  module V3
    module Utilities
      module Endpoints
        class Delete
          def default_instance_generator(model)
            ->(_params) do
              instance_variable_get("@#{model.name.demodulize.underscore}")
            end
          end

          def initialize(model:,
                         instance_generator: default_instance_generator(model),
                         process_service: nil)
            self.model = model
            self.instance_generator = instance_generator
            self.process_service = process_service || deduce_process_service
          end

          def mount
            delete = self

            -> do
              call = delete.process(current_user,
                                    instance_exec(params, &delete.instance_generator))

              delete.render(call) do
                status delete.success_status
              end
            end
          end

          def process(current_user, instance)
            process_service
              .new(user: current_user,
                   model: instance)
              .call
          end

          def render(call)
            if success?(call)
              yield
            else
              present_error(call)
            end
          end

          def success_status
            204
          end

          attr_accessor :model,
                        :instance_generator,
                        :process_service

          private

          def present_error(call)
            fail ::API::Errors::ErrorBase.create_and_merge_errors(call.errors)
          end

          def success?(call)
            call.success?
          end

          def deduce_process_service
            "::#{deduce_namespace}::DeleteService".constantize
          end

          def deduce_namespace
            demodulized_name.pluralize
          end

          def demodulized_name
            model.name.demodulize
          end
        end
      end
    end
  end
end