ama-team / ruby-entity-mapper

require_relative '../../exception/mapping_error'

module AMA

  module Entity

    class Mapper

      class Engine

        class Denormalizer

          # Standard-interface denormalizer for denormalizing primitives.

          class Primitive

            MAPPING = {

              String => [],

              Symbol => [:to_sym],

              Numeric => %i[to_f to_i],

              TrueClass => [:to_bool],

              FalseClass => [:to_bool],

              Array => [:to_a],

              Hash => %i[to_h to_hash],

              NilClass => []

            }.freeze

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

            def supports(type)

              !downgrade_klass(type.type).nil?

            end

            # @param [Object] value

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

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

            def denormalize(value, _context, target_type)

              return value if value.is_a?(target_type.type)

              methods = MAPPING[downgrade_klass(target_type.type)]

              methods.each do |method|

                next unless value.respond_to?(method)

                begin

                  result = value.send(method)

                rescue ArgumentError

                  next

                end

                return result if result.is_a?(target_type.type)

              end

              message = "Can't denormalize #{target_type} out of #{value.class}"

              mapping_error(message)

            end

            private

            def downgrade_klass(klass)

              klass.ancestors.find do |ancestor|

                MAPPING.key?(ancestor)

              end

            end

        end

      end

    end

  end

end