mjacobus / koine-attributes

require 'koine/attributes/adapter/base'

# provides the following API

#

# @example using attributes

#   class Person

#     include Koine::Attributes

#

#     attributes do

#       attribute :name, :string

#       attribute :birthday, :date

#

#       # or

#       attribute :birthday, Koine::Attributes::Adapter::Date.new

#     end

#   end

#

#   peson = Person.new

#   person.name = 'John Doe'

#   person.birtday = '2001-02-31' # Date Object can also be given

#

#   person.name # => 'John Doe'

#   person.birtday # => #<Date 2001-02-31>

#

# @example custom attribute options

#

#     attributes do

#       attribute :name, Koine::Attributes::Adapters::Date.new.with_default('guest')

#

#       # or

#       attribute :name, :string, ->(adapter) { adapter.with_default('guest') }

#     end

#

# @example Constructor for attributes

#

#   class Person

#     include Koine::Attributes

#

#     attributes initializer: true do

#       attribute :name, :string

#       attribute :birthday, :date

#     end

#   end

#

#   person = Person.new(name: 'John Doe', birthday: '2001-01-31')

#

#   # foo: attribute will raise error with strict mode

#   person = Person.new(name: 'John Doe', birthday: '2001-01-31', foo: :bar)

#

# @example Constructor for attributes withouth strict mode

#

#   class Person

#     include Koine::Attributes

#

#     attributes initializer: { strict: false } do

#       attribute :name, :string

#       attribute :birthday, :date

#     end

#   end

#

#   # foo will be ignored

#   person = Person.new(name: 'John Doe', birthday: '2001-01-31', foo: :bar)

#

# @example Override constructor

#

#   class Person

#     include Koine::Attributes

#

#     attr_reader :foo

#

#     attributes initializer: true do

#       attribute :name, :string

#       attribute :birthday, :date

#     end

#

#     def initialize(attributes = {})

#       @foo = attributes.delete(:foo)

#       self.attributes.set_values(attributes)

#     end

#   end

#

#   person = Person.new(name: 'John Doe', birthday: '2001-01-31', foo: :bar)

#   person.foo # => :bar

#

# @example

#  class Location

#    include Koine::Attributes

#

#    attributes initializer: { freeze: true } do

#      attribute :lat, :float

#      attribute :lon, :float

#    end

#  end

#

#  location = Location.new(lat: 1, lon: 2)

#  new_location = location.with_lon(3)

#

module Koine

  module Attributes

    autoload :Attributes, 'koine/attributes/attributes'

    autoload :AttributesFactory, 'koine/attributes/attributes_factory'

    module Adapter

      autoload :Any, 'koine/attributes/adapter/any'

      autoload :ArrayOf, 'koine/attributes/adapter/array_of'

      autoload :Boolean, 'koine/attributes/adapter/boolean'

      autoload :Date, 'koine/attributes/adapter/date'

      autoload :Float, 'koine/attributes/adapter/float'

      autoload :HashOf, 'koine/attributes/adapter/hash_of'

      autoload :Integer, 'koine/attributes/adapter/integer'

      autoload :String, 'koine/attributes/adapter/string'

      autoload :Symbol, 'koine/attributes/adapter/symbol'

      autoload :Time, 'koine/attributes/adapter/time'

    end

    Error = Class.new(StandardError)

    def self.included(base)

      base.extend(Forwardable)

      base.extend(ClassMethods)

    end

    module ClassMethods

      private

      def attributes(options = {}, &block)

        @builder = true

        @_attributes_factory ||= AttributesFactory.new(options)

        class_eval(&block)

        instance_eval do

          define_method :attributes do

            @_attributes ||= self.class.instance_variable_get(:@_attributes_factory).create(self)

          end

          private :attributes

          define_method(:initialize) { |*args| attributes.initialize_values(*args) }

        end

        @_attributes_factory.freeze

        @builder = nil

      end

      def array_of(item_adapter)

        adapter = @_attributes_factory.coerce_adapter(item_adapter)

        Adapter::ArrayOf.new(adapter)

      end

      def hash_of(key_adapter, value_adapter)

        key_adapter = @_attributes_factory.coerce_adapter(key_adapter)

        value_adapter = @_attributes_factory.coerce_adapter(value_adapter)

        Adapter::HashOf.new(key_adapter, value_adapter)

      end

    end

  end

end