ActiveRecord concern for accessing the date and time parts of a datetime attribute separately

date_time_splittable.rb

module DateTimeSplittable
  extend ActiveSupport::Concern

  included do
    def self.split_date_time(*attributes)
      attributes.each do |attribute|
        if self.type_for_attribute(attribute).type != :datetime
          raise ArgumentError.new("#{attribute} is not of type datetime")
        end

        attr_get = attribute.to_s
        attr_set = attribute.to_s + '='
        date_get = attr_get + '_date'
        date_set = attr_get + '_date='
        time_get = attr_get + '_time'
        time_set = attr_get + '_time='

        define_method(date_get) do
          self.instance_variable_get("@#{date_get}") || self.send(attr_get)&.to_date
        end

        define_method(date_set) do |value|
          if value.blank?
            self.send(attr_set, value)
            self.instance_variable_set("@#{date_get}", value)
            return value
          elsif self.send(attr_get).blank?
            self.send(attr_set, Time.zone.local(0)) # want time to be 0 in this case
          end

          if value.is_a?(String)
            value = Date.parse(value)
            self.instance_variable_set("@#{date_get}", value)
          end

          self.send(attr_set, self.send(attr_get).change(year: value&.year, month: value&.month, day: value&.day))
        end

        define_method(time_get) do
          self.instance_variable_get("@#{time_get}") || self.send(attr_get)&.to_time
        end

        define_method(time_set) do |value|
          if value.blank?
            self.send(attr_set, value)
            self.instance_variable_set("@#{time_get}", value)
            return value
          elsif self.send(attr_get).blank?
            self.send(attr_set, Time.zone.local(0)) # want time to be 0 in this case
          end

          if value.is_a?(String)
            value = Time.zone.parse(value)
            self.instance_variable_set("@#{time_get}", value)
          end

          self.send(attr_set, self.send(attr_get).change(hour: value&.hour, min: value&.min))
        end
      end
    end
  end
end