class DatePickerInput < SimpleForm::Inputs::StringInput
  include ActionView::Helpers::FormTagHelper
  include ActionView::Context

  def input
    input_html_options[:id] ||= date_id
    input_html_options.reverse_merge!(
      placeholder: "MM/DD/YYYY",
      value: date_value,
      :"aria-describedby" => hint_id
    )

    content_tag(:div, class: 'uc-form-field-date') do
      user_agent.mobile? ? input_for_mobile : input_for_desktop
    end
  end

  def hint
    options[:hint_html] ||= {}
    options[:hint_html].merge!(id: hint_id, class: 'hidden')
    hint_text = 'Date (format: MM/DD/YYYY)'
    if options[:input_html]["disable-future-dates"]
      hint_text << '. You cannot select a future date.'
    end
    hint_text
  end

  def label_html_options
    options[:input_html] ||= {}
    options[:input_html][:id] ||= date_id
    super
  end

  private

  def user_agent
    @user_agent ||= UserAgent.parse(@builder.template.controller.request.user_agent)
  end

  def input_for_mobile
    @builder.text_field(attribute_name, input_html_options.reverse_merge(
      type: 'date'
    ))
  end

  def input_for_desktop
    data_presents = ['datepicker']
    if input_html_options['data-presents']
      data_presents << input_html_options['data-presents']
    end

    @builder.text_field(attribute_name, input_html_options.merge(
      'type' => 'text',
      'data-presents' => data_presents.join(' '),
    ))
  end

  def hint_id
    "#{object.class.name.underscore}_#{object_id}_datepicker_hint"
  end

  def date_id
    "#{object.class.name.underscore}_#{object_id}_datepicker"
  end

  def date_value
    value = input_html_options.fetch(:value, @builder.object.public_send(attribute_name))
    value.blank? ? value : format_date(value)
  end

  def format_date(date)
    value = date.is_a?(String) ? Date.parse(date) : date
    user_agent.mobile? ? value.iso8601 : value.to_s(:default)
  rescue ArgumentError
    date
  end
end