ama-team / ruby-entity-mapper

require 'logger'

module AMA

  module Entity

    class Mapper

      class Type

        # Holds all registered types

        class Registry

          attr_accessor :types

          # @param [AMA::Entity::Mapper::Type::Concrete] type

          def register(type)

            @types[type.type] = type

          end

          # @param [Class] klass

          def registered?(klass)

            @types.key?(klass)

          end

          def for(klass)

            find_class_types(klass) | find_module_types(klass)

          end

          private

          def inheritance_chain(klass)

            cursor = klass

            chain = []

            loop do

              chain.push(cursor)

              cursor = cursor.superclass

              break if cursor.nil?

            end

            chain

          end

          def find_class_types(klass)

            inheritance_chain(klass).each_with_object([]) do |entry, carrier|

              carrier.push(types[entry]) if types[entry]

            end

          end

          def find_module_types(klass)

            chain = inheritance_chain(klass).reverse

            result = chain.reduce([]) do |carrier, entry|

              ancestor_types = entry.ancestors.map do |candidate|

                types[candidate]

              end

              carrier | ancestor_types.reject(&:nil?)

            end

            result.reverse

          end

        end

      end

    end

  end

end