ama-team / ruby-entity-mapper

require_relative '../../mixin/reflection'

require_relative '../../mixin/errors'

module AMA

  module Entity

    class Mapper

      module Handler

        module Entity

          # Default attribute injector

          class Injector

            include Mixin::Reflection

            INSTANCE = new

            # @param [Object] entity

            # @param [AMA::Entity::Mapper::Type] _type

            # @param [AMA::Entity::Mapper::Type::Attribute] attribute

            # @param [Object] value

            # @param [AMA::Entity::Mapper::Context] _context

            class << self

              include Mixin::Reflection

              # @param [Injector] implementation

              # @return [Injector]

              def wrap(implementation)

                handler = handler_factory(implementation, INSTANCE)

                description = "Safety wrapper for #{implementation}"

                wrapper = method_object(:inject, to_s: description, &handler)

                wrapper.singleton_class.instance_eval do

                  include Mixin::Errors

                end

                wrapper

              end

              private

              # @param [Injector] impl

              # @param [Injector] fallback

              # @return [Injector]

              def handler_factory(impl, fallback)

                lambda do |entity, type, attr, val, ctx|

                  begin

                    impl.inject(entity, type, attr, val, ctx) do |e, t, a, v, c|

                      fallback.inject(e, t, a, v, c)

                    end

                  rescue StandardError => e

                    raise_if_internal(e)

                    message = "Unexpected error from injector #{impl}"

                    signature = '(entity, type, attr, val, ctx)'

                    options = { parent: e, context: ctx, signature: signature }

                    compliance_error(message, options)

                  end

                end

              end

            end

          end

        end

      end

    end

  end

end