module RecordHistory
	module Model

		def self.included(base)
      base.send :extend, ClassMethods
    end

		module ClassMethods
			def has_record_history(options={})
				send :include, InstanceMethods

				attr_accessor :record_history_obj

				class_attribute :record_history_ignore
        self.record_history_ignore = ([options[:ignore]].flatten.compact || []).map{|attr| attr.to_s}

        class_attribute :record_history_only
        self.record_history_only = ([options[:only]].flatten.compact || []).map{|attr| attr.to_s}

        class_attribute :record_history_on
        self.record_history_on = ([options[:on] || ['create', 'update']].flatten.compact).map{|attr| attr.to_s}

				has_many :record_history,
                 :class_name => 'RecordHistoryModel',
                 :order      => "created_at DESC",
                 :as         => :item
        if self.record_history_on.include?('update')
          before_save  :build_history_on_update
          after_update :save_history_on_update
        end

        if self.record_history_on.include?('create')
          after_create :save_history_on_create
        end
			end

      def is_record_history_author(options={})
        has_many :written_history,
                 :class_name => 'RecordHistoryModel',
                 :order      => "created_at DESC",
                 :as         => :author
      end
		end

		module InstanceMethods


			def build_history_on_update
        return if self.new_record?
        self.record_history_obj = []
				self.class.new.attributes.keys.each do |attr_name|
					if (self.send("#{attr_name}_changed?"))
            next if self.class.record_history_only && !self.class.record_history_only.include?(attr_name)
            next if self.class.record_history_ignore && self.record_history_ignore.include?(attr_name)
						self.record_history_obj << RecordHistoryModel.new(
											:item_type => self.class.name,
                      :item_id => self.id,
                      :attr_name => attr_name,
                      :old_value => self.send("#{attr_name}_was"),
                      :new_value => self.send("#{attr_name}"),
                      :author => RecordHistory.author
						)
					end
				end
			end

			def save_history_on_update
        self.record_history_obj.each{|item| item.save}
			end

      def save_history_on_create
        RecordHistoryModel.create!(
          :item_type => self.class.name,
          :item_id => self.id,
          :author => RecordHistory.author
        )
      end
		end
	end
end