ama-team / ruby-entity-mapper

require_relative 'reflection'

module AMA

  module Entity

    class Mapper

      module Mixin

        # This module provides Type and Attribute classes with shortcut

        # handler :name, :method method to register handlers

        module HandlerSupport

          class << self

            def included(klass)

              declare_namespace_method(klass)

              declare_handler_method(klass)

            end

            def declare_namespace_method(klass)

              klass.define_singleton_method(:handler_namespace) do |namespace|

                @handler_namespace = namespace

              end

            end

            def declare_handler_method(klass)

              processor = self

              klass.define_singleton_method(:handler) do |key, method|

                handler_name = key.capitalize

                handler_class = @handler_namespace.const_get(handler_name)

                processor.declare_handler_getter(klass, key, handler_class)

                processor.declare_handler_setter(klass, key, handler_class)

                processor.declare_handler_block_setter(klass, key, method)

              end

            end

            def declare_handler_getter(klass, handler_key, handler_class)

              instance = handler_class::INSTANCE

              klass.instance_eval do

                define_method(handler_key) do

                  instance_variable_get("@#{handler_key}") || instance

                end

              end

            end

            def declare_handler_block_setter(klass, handler_key, method)

              klass.instance_eval do

                include Mixin::Reflection

                define_method("#{handler_key}_block") do |&block|

                  send("#{handler_key}=", method_object(method, &block))

                end

              end

            end

          end

        end

      end

    end

  end

end