<?php
defined( 'ABSPATH' ) || die;
/**
* Select tree walker for cascading select fields.
*/
class RWMB_Walker_Select_Tree {
/**
* Field settings.
*
* @var array
*/
public $field;
/**
* Field meta value.
*
* @var array
*/
public $meta;
/**
* Constructor.
*
* @param array $field Field parameters.
* @param mixed $meta Meta value.
*/
public function __construct( $field, $meta ) {
$this->field = $field;
$this->meta = (array) $meta;
}
/**
* Display array of elements hierarchically.
*
* @param array $options An array of options.
*
* @return string
*/
public function walk( $options ) {
$children = [];
foreach ( $options as $option ) {
$parent = $option->parent ?? 0;
$children[ $parent ][] = $option;
}
$top_level = isset( $children[0] ) ? 0 : $options[0]->parent;
return $this->display_level( $children, $top_level, true );
}
/**
* Display a hierarchy level.
*
* @param array $options An array of options.
* @param int $parent_id Parent item ID.
* @param bool $active Whether to show or hide.
*
* @return string
*/
public function display_level( $options, $parent_id = 0, $active = false ) {
$field = $this->field;
$walker = new RWMB_Walker_Select( $field, $this->meta );
$attributes = RWMB_Field::call( 'get_attributes', $field, $this->meta );
$children = $options[ $parent_id ];
$output = sprintf(
'<div class="rwmb-select-tree %s" data-parent-id="%s"><select %s>',
$active ? '' : 'hidden',
esc_attr( $parent_id ),
RWMB_Field::render_attributes( $attributes )
);
$output .= $field['placeholder'] ? "<option value=''>{$field['placeholder']}</option>" : '<option></option>';
$output .= $walker->walk( $children, - 1 );
$output .= '</select>';
foreach ( $children as $child ) {
if ( isset( $options[ $child->value ] ) ) {
$output .= $this->display_level( $options, $child->value, in_array( $child->value, $this->meta ) && $active );
}
}
$output .= '</div>';
return $output;
}
}