module MongoMapper
  module Plugins
    module Callbacks
      METHODS = ["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"]
      
      def self.configure(model)
        model.class_eval do
          include ActiveSupport::Callbacks

          define_callbacks *METHODS
          
          # If Rails 3, support the new callback syntax
          if metaclass.method_defined?(:set_callback)
            METHODS.each do |method|
              class_eval <<-"end_eval", __FILE__, __LINE__
                def self.#{method}(*methods, &block)
                  set_callback :#{method}, *methods, &block
                end
              end_eval
            end
          end
        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