# frozen_string_literal: true

require "paper_trail/attribute_serializers/attribute_serializer_factory"

module PaperTrail
  # :nodoc:
  module AttributeSerializers
    # The `CastAttributeSerializer` (de)serializes model attribute values. For
    # example, the string "1.99" serializes into the integer `1` when assigned
    # to an attribute of type `ActiveRecord::Type::Integer`.
    #
    # This implementation depends on the `type_for_attribute` method, which was
    # introduced in rails 4.2. As of PT 8, we no longer support rails < 4.2.
    class CastAttributeSerializer
      def initialize(klass)
        @klass = klass
      end

      private

      # Returns a hash mapping attributes to hashes that map strings to
      # integers. Example:
      #
      # ```
      # { "status" => { "draft"=>0, "published"=>1, "archived"=>2 } }
      # ```
      #
      # ActiveRecord::Enum was added in AR 4.1
      # http://edgeguides.rubyonrails.org/4_1_release_notes.html#active-record-enums
      def defined_enums
        @defined_enums ||= (@klass.respond_to?(:defined_enums) ? @klass.defined_enums : {})
      end
    end

    # Uses AR 5's `serialize` and `deserialize`.
    class CastAttributeSerializer
      def serialize(attr, val)
        AttributeSerializerFactory.for(@klass, attr).serialize(val)
      end

      def deserialize(attr, val)
        if defined_enums[attr] && val.is_a?(::String)
          # Because PT 4 used to save the string version of enums to `object_changes`
          val
        else
          AttributeSerializerFactory.for(@klass, attr).deserialize(val)
        end
      end
    end
  end
end