module MongoMapper
  module Plugins
    if defined?(ActiveModel)
      # Rails 3 stuff
      module Callbacks
        def self.configure(model)
          model.class_eval do
            extend ActiveModel::Callbacks
            define_model_callbacks  :create, :save, :update, :destroy, :validation,
                                    :validation_on_create, :validation_on_update
          end
        end

        module InstanceMethods
          def valid?
            action = new? ? 'create' : 'update'
            result = nil

            _run_validation_callbacks do
              self.send("_run_validation_on_#{action}_callbacks") do
                result = super
              end
            end

            result
          end

          def destroy
            result = nil

            _run_destroy_callbacks do
              result = super
            end

            result
          end

          private
            def create_or_update(*args)
              result = nil

              _run_save_callbacks do
                result = super
              end

              result
            end

            def create(*args)
              result = nil

              _run_create_callbacks do
                result = super
              end

              result
            end

            def update(*args)
              result = nil

              _run_update_callbacks do
                result = super
              end

              result
            end
        end
      end
    else
      module Callbacks
        def self.configure(model)
          model.class_eval do
            include ActiveSupport::Callbacks

            define_callbacks(
              :before_save, :after_save, 
              :before_create, :after_create, 
              :before_update, :after_update, 
              :before_validation, :after_validation, 
              :before_validation_on_create, :after_validation_on_create, 
              :before_validation_on_update, :after_validation_on_update, 
              :before_destroy, :after_destroy
            )
          end
        end
        
        module InstanceMethods
          def valid?
            action = new? ? 'create' : 'update'

            run_callbacks(:before_validation)
            run_callbacks("before_validation_on_#{action}".to_sym)
            result = super
            run_callbacks("after_validation_on_#{action}".to_sym)
            run_callbacks(:after_validation)

            result
          end

          def destroy
            run_callbacks(:before_destroy)
            result = super
            run_callbacks(:after_destroy)
            result
          end

          private
            def create_or_update(*args)
              run_callbacks(:before_save)
              if result = super
                run_callbacks(:after_save)
              end
              result
            end

            def create(*args)
              run_callbacks(:before_create)
              result = super
              run_callbacks(:after_create)
              result
            end

            def update(*args)
              run_callbacks(:before_update)
              result = super
              run_callbacks(:after_update)
              result
            end
        end
      end
    end
  end
end