module Moneta
  module Api
    module DataMapper
      def self.included(base)
        base.extend ClassMethods
      end

      module ClassMethods
        def property(name, type: nil, read_only: false)
          generate_accessors(name, read_only)

          # Сохраняем свойста и перезаписываем instance метод
          current_properties = instance_variable_get('@properties') || {}
          properties = instance_variable_set('@properties',
            current_properties.merge(parents_properties).merge(name => type)
          )

          send(:define_method, :properties) { properties }
        end

        def build(data)
          self.new.tap { |object| object.fill(data) }
        end

        private

        def parents_properties
          instance_variable_get('@parents_properties') ||
            instance_variable_set('@parents_properties', ancestors.each_with_object({}) do |klass, hash|
              if klass.name.match(/Moneta::Api::(Types|Requests|Responses)/)
                hash.merge!(klass.instance_variable_get('@properties') || {})
              end
            end
          )
        end

        def generate_accessors(name, read_only)
          attr_reader(name)
          attr_writer(name) unless read_only
        end
      end

      def fill(data)
        properties.each do |property, type|
          value = data[ property ]
          if value
            property_value = type.nil? ? value : build_complex_value(type, value)
            instance_variable_set("@#{ property }", property_value)
          end
        end

        self
      end

      def to_hash
        properties.each_with_object({}) do |(property, _), hash|
          value = send(property)
          unless value.nil?
            hash[ property.to_s.classify_with_lower ] = to_hash_complex_value(value)
          end
        end
      end

      private

      def build_complex_value(type, value)
        value.kind_of?(Array) ?
            value.map { |v| type.build(v) } :
            type.build(value)
      end

      def to_hash_complex_value(value)
        if value.kind_of?(Array)
          value.map(&:to_hash)
        elsif value.respond_to?(:to_hash)
          value.to_hash
        else
          value
        end
      end
    end
  end
end