<?php

/**

 * Taxonomy API: Walker_CategoryDropdown class

 *

 * @package WordPress

 * @subpackage Template

 * @since 4.4.0

 */

/**

 * Core class used to create an HTML dropdown list of Categories.

 *

 * @since 2.1.0

 *

 * @see Walker

 */

class Walker_CategoryDropdown extends Walker {

	/**

	 * What the class handles.

	 *

	 * @since 2.1.0

	 * @var string

	 *

	 * @see Walker::$tree_type

	 */

	public $tree_type = 'category';

	/**

	 * Database fields to use.

	 *

	 * @since 2.1.0

	 * @todo Decouple this

	 * @var array

	 *

	 * @see Walker::$db_fields

	 */

	public $db_fields = array ('parent' => 'parent', 'id' => 'term_id');

	/**

	 * Starts the element output.

	 *

	 * @since 2.1.0

	 *

	 * @see Walker::start_el()

	 *

	 * @param string $output   Used to append additional content (passed by reference).

	 * @param object $category Category data object.

	 * @param int    $depth    Depth of category. Used for padding.

	 * @param array  $args     Uses 'selected', 'show_count', and 'value_field' keys, if they exist.

	 *                         See wp_dropdown_categories().

	 * @param int    $id       Optional. ID of the current category. Default 0 (unused).

	 */

	public function start_el( &$output, $category, $depth = 0, $args = array(), $id = 0 ) {

		$pad = str_repeat(' ', $depth * 3);

		/** This filter is documented in wp-includes/category-template.php */

		$cat_name = apply_filters( 'list_cats', $category->name, $category );

		if ( isset( $args['value_field'] ) && isset( $category->{$args['value_field']} ) ) {

			$value_field = $args['value_field'];

		} else {

			$value_field = 'term_id';

		}

		$output .= "\t<option class=\"level-$depth\" value=\"" . esc_attr( $category->{$value_field} ) . "\"";

		// Type-juggling causes false matches, so we force everything to a string.

		if ( (string) $category->{$value_field} === (string) $args['selected'] )

			$output .= ' selected="selected"';

		$output .= '>';

		$output .= $pad.$cat_name;

		if ( $args['show_count'] )

			$output .= '  ('. number_format_i18n( $category->count ) .')';

		$output .= "</option>\n";

	}

}