enum

# File activerecord/lib/active_record/enum.rb, line 150
    def enum(definitions)
      klass = self
      enum_prefix = definitions.delete(:_prefix)
      enum_suffix = definitions.delete(:_suffix)
      definitions.each do |name, values|
        # statuses = { }
        enum_values = ActiveSupport::HashWithIndifferentAccess.new
        name        = name.to_sym

        # def self.statuses() statuses end
        detect_enum_conflict!(name, name.to_s.pluralize, true)
        klass.singleton_class.send(:define_method, name.to_s.pluralize) { enum_values }

        detect_enum_conflict!(name, name)
        detect_enum_conflict!(name, "#{name}=")

        attr = attribute_alias?(name) ? attribute_alias(name) : name
        decorate_attribute_type(attr, :enum) do |subtype|
          EnumType.new(attr, enum_values, subtype)
        end

        _enum_methods_module.module_eval do
          pairs = values.respond_to?(:each_pair) ? values.each_pair : values.each_with_index
          pairs.each do |value, i|
            if enum_prefix == true
              prefix = "#{name}_"
            elsif enum_prefix
              prefix = "#{enum_prefix}_"
            end
            if enum_suffix == true
              suffix = "_#{name}"
            elsif enum_suffix
              suffix = "_#{enum_suffix}"
            end

            value_method_name = "#{prefix}#{value}#{suffix}"
            enum_values[value] = i

            # def active?() status == 0 end
            klass.send(:detect_enum_conflict!, name, "#{value_method_name}?")
            define_method("#{value_method_name}?") { self[attr] == value.to_s }

            # def active!() update! status: :active end
            klass.send(:detect_enum_conflict!, name, "#{value_method_name}!")
            define_method("#{value_method_name}!") { update!(attr => value) }

            # scope :active, -> { where status: 0 }
            klass.send(:detect_enum_conflict!, name, value_method_name, true)
            klass.scope value_method_name, -> { where(attr => value) }
          end
        end
        defined_enums[name.to_s] = enum_values
      end
    end