module ActionView::Helpers::DateHelperInstanceTag

def datetime_selector(options, html_options)
  datetime = value(object) || default_datetime(options)
  @auto_index ||= nil
  options = options.dup
  options[:field_name]           = @method_name
  options[:include_position]     = true
  options[:prefix]             ||= @object_name
  options[:index]                = @auto_index if @auto_index && !options.has_key?(:index)
  DateTimeSelector.new(datetime, options, html_options)
end

def default_datetime(options)
  return if options[:include_blank] || options[:prompt]
  case options[:default]
    when nil
      Time.current
    when Date, Time
      options[:default]
    else
      default = options[:default].dup
      # Rename :minute and :second to :min and :sec
      default[:min] ||= default[:minute]
      default[:sec] ||= default[:second]
      time = Time.current
      [:year, :month, :day, :hour, :min, :sec].each do |key|
        default[key] ||= time.send(key)
      end
      Time.utc_time(
        default[:year], default[:month], default[:day],
        default[:hour], default[:min], default[:sec]
      )
  end
end

def to_date_select_tag(options = {}, html_options = {})
  datetime_selector(options, html_options).select_date.html_safe
end

def to_datetime_select_tag(options = {}, html_options = {})
  datetime_selector(options, html_options).select_datetime.html_safe
end

def to_time_select_tag(options = {}, html_options = {})
  datetime_selector(options, html_options).select_time.html_safe
end