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

  def input
    label_from_options = options[:label]

    l = if label_from_options == false
          ""
        else
          label_from_options || object.class.human_attribute_name(attribute_name)
        end

    field_set_tag(l, class: (input_html_classes + ["uc-form-fieldset-datetime", "inline-inputs", "legend-as-label"]).map(&:to_s).join(" ")) do
      (date_field + time_field + timezone_label)
    end
  end

  def label
    ""
  end

  private

  def date_value
    value = @builder.object.public_send("#{attribute_name}_date_part")
    value.blank? ? value : format_date(value)
  end

  def time_value
    @builder.object.public_send("#{attribute_name}_time_part")
  end

  def format_date(date)
    user_agent.mobile? ? Date.parse(date).iso8601 : date
  end

  def date_aria_label
    aria_label = "Date (format: MM/DD/YYYY)"
    if options[:input_html] && options[:input_html]["disable-future-dates"]
      aria_label += ". You cannot select a future date."
    end
    aria_label
  end

  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.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 date_field
    input_html_options.merge!(date_name_and_id)
    input_html_options.merge!(
      placeholder: "MM/DD/YYYY",
      class: "#{input_html_classes.join(' ')} date_part",
      value: date_value,
      label: false,
      "aria-label" => date_aria_label
    )

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

  def time_field
    content_tag :div, class: 'uc-form-field-datetime-time uc-form-field-time' do
      @builder.text_field(attribute_name, input_html_options.merge(time_name_and_id).merge(
        "data-presents" => "timepicker",
        placeholder: "HH:MM AM",
        class: "#{input_html_classes.join(' ')} time_part",
        value: time_value,
        label: false,
        "aria-label" => "Time (format: HH:MM AM)"
      ))
    end
  end

  def timezone_label
    content_tag :div, "", class: "js-timezone uc-form-field-datetime-timezone"
  end

  def date_name_and_id
    {
      name: input_name_from_type("date_part"),
      id: input_id_from_type("date_part")
    }
  end

  def time_name_and_id
    {
      name: input_name_from_type("time_part"),
      id: input_id_from_type("time_part")
    }
  end

  def index
    @builder.instance_variable_get('@default_options')[:index]
  end

  def prefix
    @builder.instance_variable_get('@object_name')
  end

  def field_name
    attribute_name.to_s
  end

  # Returns the name attribute for the input tag
  #  => post[written_on_date_part]
  def input_name_from_type(suffix)
    "#{prefix}#{"[#{index}]" if index}[#{field_name}_#{suffix}]"
  end

  # Returns the id attribute for the input tag
  #  => "post_written_on_date_part"
  def input_id_from_type(suffix)
    remove_brackets("#{prefix}#{"[#{index}]" if index}_#{field_name}_#{suffix}")
  end

  def remove_brackets(input_string)
    input_string.tr('[]', '_').gsub(/_+/, "_")
  end
end