require 'active_model'
require 'active_support/concern'
#require 'active_support/hash_with_indifferent_access'

module IB

  # Module adds prop Macro and
  module BaseProperties
    extend ActiveSupport::Concern

    ### Instance methods

    # Default presentation
    def to_human
      "<#{self.class.to_s.demodulize}: " + attributes.map do |attr, value|
        "#{attr}: #{value}" unless value.nil?
      end.compact.sort.join(' ') + ">"
    end

    # Comparison support
    def content_attributes
      #HashWithIndifferentAccess[attributes.reject do |(attr, _)|
			#NoMethodError if a Hash is assigned to an attribute
      Hash[attributes.reject do |(attr, _)|
                                  attr.to_s =~ /(_count)\z/ ||
                                    [:created_at, :updated_at, :type,
                                     :id, :order_id, :contract_id].include?(attr.to_sym)
      end]
    end

=begin
Remove all Time-Stamps from the list of Attributes
=end
		def invariant_attributes
				attributes.reject{|x| x =~ /_at/}
		end

    # Update nil attributes from given Hash or model
    def update_missing attrs
      attrs = attrs.content_attributes unless attrs.kind_of?(Hash)

      attrs.each { |attr, val| send "#{attr}=", val if send(attr).blank? }
      self # for chaining
    end

    # Default Model comparison
    def == other
      case other
      when String # Probably a Rails URI, delegate to AR::Base
        super(other)
      else
        content_attributes.keys.inject(true) { |res, key|
          res && other.respond_to?(key) && (send(key) == other.send(key)) }
      end
    end

    ### Default attributes support

    def default_attributes
      {:created_at => Time.now
     #  :updated_at => Time.now,
       }
    end

    def set_attribute_defaults
      default_attributes.each do |key, val|
        self.send("#{key}=", val) if self.send(key).nil?
        # self.send("#{key}=", val) if self[key].nil? # Problems with association defaults
      end
    end

    included do

      after_initialize :set_attribute_defaults

      ### Class macros

      def self.prop *properties
        prop_hash = properties.last.is_a?(Hash) ? properties.pop : {}

        properties.each { |names| define_property names, nil }
        prop_hash.each { |names, type| define_property names, type }
      end

      def self.define_property names, body
        aliases = [names].flatten
        name = aliases.shift
        instance_eval do

          define_property_methods name, body

          aliases.each do |ali|
            alias_method "#{ali}", name
            alias_method "#{ali}=", "#{name}="
          end
        end
      end

      def self.define_property_methods name, body={}
        #p name, body
        case body
        when '' # default getter and setter
          define_property_methods name

        when Array # [setter, getter, validators]
          define_property_methods name,
            :get => body[0],
            :set => body[1],
            :validate => body[2]

        when Hash # recursion base case
          getter = case # Define getter
          when body[:get].respond_to?(:call)
            body[:get]
          when body[:get]
            proc { self[name].send "to_#{body[:get]}" }
          when VALUES[name] # property is encoded
            proc { VALUES[name][self[name]] }
          else
            proc { self[name] }
          end
          define_method name, &getter if getter

          setter = case # Define setter
          when body[:set].respond_to?(:call)
            body[:set]
          when body[:set]
            proc { |value| self[name] = value.send "to_#{body[:set]}" }
          when CODES[name] # property is encoded
            proc { |value| self[name] = CODES[name][value] || value }
          else
            proc { |value| self[name] = value } # p name, value;
          end
          define_method "#{name}=", &setter if setter

          # Define validator(s)
          [body[:validate]].flatten.compact.each do |validator|
            case validator
            when Proc
              validates_each name, &validator
            when Hash
              validates name, validator.dup
            end
          end

          # TODO define self[:name] accessors for :virtual and :flag properties

        else # setter given
          define_property_methods name, :set => body, :get => body
        end
      end

      # Timestamps in lightweight models
      unless defined?(ActiveRecord::Base) && ancestors.include?(ActiveRecord::Base)
        prop :created_at #, :updated_at
      end

    end # included
  end # module BaseProperties
end