module Neo4j
	module Rails
    # Handle all the created_at, updated_at, created_on, updated_on type stuff.
		module Timestamps
			extend ActiveSupport::Concern

			TIMESTAMP_PROPERTIES = [ :created_at, :created_on, :updated_at, :updated_on ]

      included do
        before_create :create_timestamp
        before_save :update_timestamp, :if => :new_or_changed?
      end
			# Set the timestamps for this model if timestamps is set to true in the config
			# and the model is set up with the correct property name, e.g.:
			#
			#   class Trackable < Neo4j::Rails::Model
			#     property :updated_at, :type => DateTime
			#   end
			def update_timestamp
				#definition provided whenever an :updated_at property is defined
			end

			# Set the timestamps for this model if timestamps is set to true in the config
			# and the model is set up with the correct property name, e.g.:
			#
			#   class Trackable < Neo4j::Rails::Model
			#     property :created_at, :type => DateTime
			#   end
			def create_timestamp
				#definition provided whenever an :created_at property is defined
			end

			# Write the timestamp as a Date, DateTime or Time depending on the property type
			def write_date_or_timestamp(attribute)
				value = case self.class._decl_props[attribute][:type].to_s
				when "DateTime"
					DateTime.now
				when "Date"
					Date.today
				when "Time"
					Time.now
				end

				send("#{attribute}=", value)
			end

      def new_or_changed?
        self.new? or self.changed?
      end

			module ClassMethods
				def property_setup(property, options)
					super
          define_timestamp_method(:create_timestamp,:created_at) if property == :created_at
				  define_timestamp_method(:update_timestamp,:updated_at) if property == :updated_at
					# ensure there's always a type on the timestamp properties
					if Neo4j::Config[:timestamps] && TIMESTAMP_PROPERTIES.include?(property)
						_decl_props[property][:type] ||= Time
					end
				end

				def define_timestamp_method(method_name, property)
					class_eval <<-RUBY, __FILE__, __LINE__
						def #{method_name}
							write_date_or_timestamp(:#{property}) if Neo4j::Config[:timestamps]
						end
          RUBY
			  end
			end
		end
	end
end