<?php

/**

 * Post API: Walker_Page class

 *

 * @package WordPress

 * @subpackage Template

 * @since 4.4.0

 */

/**

 * Core walker class used to create an HTML list of pages.

 *

 * @since 2.1.0

 *

 * @see Walker

 */

class Walker_Page extends Walker {

	/**

	 * What the class handles.

	 *

	 * @since 2.1.0

	 * @var string

	 *

	 * @see Walker::$tree_type

	 */

	public $tree_type = 'page';

	/**

	 * Database fields to use.

	 *

	 * @since 2.1.0

	 * @var array

	 *

	 * @see Walker::$db_fields

	 * @todo Decouple this.

	 */

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

	/**

	 * Outputs the beginning of the current level in the tree before elements are output.

	 *

	 * @since 2.1.0

	 *

	 * @see Walker::start_lvl()

	 *

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

	 * @param int    $depth  Optional. Depth of page. Used for padding. Default 0.

	 * @param array  $args   Optional. Arguments for outputting the next level.

	 *                       Default empty array.

	 */

	public function start_lvl( &$output, $depth = 0, $args = array() ) {

		if ( isset( $args['item_spacing'] ) && 'preserve' === $args['item_spacing'] ) {

			$t = "\t";

			$n = "\n";

		} else {

			$t = '';

			$n = '';

		}

		$indent = str_repeat( $t, $depth );

		$output .= "{$n}{$indent}<ul class='children'>{$n}";

	}

	/**

	 * Outputs the end of the current level in the tree after elements are output.

	 *

	 * @since 2.1.0

	 *

	 * @see Walker::end_lvl()

	 *

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

	 * @param int    $depth  Optional. Depth of page. Used for padding. Default 0.

	 * @param array  $args   Optional. Arguments for outputting the end of the current level.

	 *                       Default empty array.

	 */

	public function end_lvl( &$output, $depth = 0, $args = array() ) {

		if ( isset( $args['item_spacing'] ) && 'preserve' === $args['item_spacing'] ) {

			$t = "\t";

			$n = "\n";

		} else {

			$t = '';

			$n = '';

		}

		$indent = str_repeat( $t, $depth );

		$output .= "{$indent}</ul>{$n}";

	}

	/**

	 * Outputs the beginning of the current element in the tree.

	 *

	 * @see Walker::start_el()

	 * @since 2.1.0

	 *

	 * @param string  $output       Used to append additional content. Passed by reference.

	 * @param WP_Post $page         Page data object.

	 * @param int     $depth        Optional. Depth of page. Used for padding. Default 0.

	 * @param array   $args         Optional. Array of arguments. Default empty array.

	 * @param int     $current_page Optional. Page ID. Default 0.

	 */

	public function start_el( &$output, $page, $depth = 0, $args = array(), $current_page = 0 ) {

		if ( isset( $args['item_spacing'] ) && 'preserve' === $args['item_spacing'] ) {

			$t = "\t";

			$n = "\n";

		} else {

			$t = '';

			$n = '';

		}

		if ( $depth ) {

			$indent = str_repeat( $t, $depth );

		} else {

			$indent = '';

		}

		$css_class = array( 'page_item', 'page-item-' . $page->ID );

		if ( isset( $args['pages_with_children'][ $page->ID ] ) ) {

			$css_class[] = 'page_item_has_children';

		}

		if ( ! empty( $current_page ) ) {

			$_current_page = get_post( $current_page );

			if ( $_current_page && in_array( $page->ID, $_current_page->ancestors ) ) {

				$css_class[] = 'current_page_ancestor';

			}

			if ( $page->ID == $current_page ) {

				$css_class[] = 'current_page_item';

			} elseif ( $_current_page && $page->ID == $_current_page->post_parent ) {

				$css_class[] = 'current_page_parent';

			}

		} elseif ( $page->ID == get_option('page_for_posts') ) {

			$css_class[] = 'current_page_parent';

		}

		/**

		 * Filters the list of CSS classes to include with each page item in the list.

		 *

		 * @since 2.8.0

		 *

		 * @see wp_list_pages()

		 *

		 * @param array   $css_class    An array of CSS classes to be applied

		 *                              to each list item.

		 * @param WP_Post $page         Page data object.

		 * @param int     $depth        Depth of page, used for padding.

		 * @param array   $args         An array of arguments.

		 * @param int     $current_page ID of the current page.

		 */

		$css_classes = implode( ' ', apply_filters( 'page_css_class', $css_class, $page, $depth, $args, $current_page ) );

		if ( '' === $page->post_title ) {

			/* translators: %d: ID of a post */

			$page->post_title = sprintf( __( '#%d (no title)' ), $page->ID );

		}

		$args['link_before'] = empty( $args['link_before'] ) ? '' : $args['link_before'];

		$args['link_after'] = empty( $args['link_after'] ) ? '' : $args['link_after'];

		$atts = array();

		$atts['href'] = get_permalink( $page->ID );

		/**

		 * Filters the HTML attributes applied to a page menu item's anchor element.

		 *

		 * @since 4.8.0

		 *

		 * @param array $atts {

		 *     The HTML attributes applied to the menu item's `<a>` element, empty strings are ignored.

		 *

		 *     @type string $href The href attribute.

		 * }

		 * @param WP_Post $page         Page data object.

		 * @param int     $depth        Depth of page, used for padding.

		 * @param array   $args         An array of arguments.

		 * @param int     $current_page ID of the current page.

		 */

		$atts = apply_filters( 'page_menu_link_attributes', $atts, $page, $depth, $args, $current_page );

		$attributes = '';

		foreach ( $atts as $attr => $value ) {

			if ( ! empty( $value ) ) {

				$value = esc_attr( $value );

				$attributes .= ' ' . $attr . '="' . $value . '"';

			}

		}

		$output .= $indent . sprintf(

			'<li class="%s"><a%s>%s%s%s</a>',

			$css_classes,

			$attributes,

			$args['link_before'],

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

			apply_filters( 'the_title', $page->post_title, $page->ID ),

			$args['link_after']

		);

		if ( ! empty( $args['show_date'] ) ) {

			if ( 'modified' == $args['show_date'] ) {

				$time = $page->post_modified;

			} else {

				$time = $page->post_date;

			}

			$date_format = empty( $args['date_format'] ) ? '' : $args['date_format'];

			$output .= " " . mysql2date( $date_format, $time );

		}

	}

	/**

	 * Outputs the end of the current element in the tree.

	 *

	 * @since 2.1.0

	 *

	 * @see Walker::end_el()

	 *

	 * @param string  $output Used to append additional content. Passed by reference.

	 * @param WP_Post $page   Page data object. Not used.

	 * @param int     $depth  Optional. Depth of page. Default 0 (unused).

	 * @param array   $args   Optional. Array of arguments. Default empty array.

	 */

	public function end_el( &$output, $page, $depth = 0, $args = array() ) {

		if ( isset( $args['item_spacing'] ) && 'preserve' === $args['item_spacing'] ) {

			$t = "\t";

			$n = "\n";

		} else {

			$t = '';

			$n = '';

		}

		$output .= "</li>{$n}";

	}

}