Your IP : 216.73.216.171
<?php
/**
* LearnDash Step Walker class.
*
* @since 4.6.0
*
* @package LearnDash\Core
*/
/** NOTICE: This code is currently under development and may not be stable.
* Its functionality, behavior, and interfaces may change at any time without notice.
* Please refrain from using it in production or other critical systems.
* By using this code, you assume all risks and liabilities associated with its use.
* Thank you for your understanding and cooperation.
**/
namespace LearnDash\Core\Template\Steps;
use LearnDash\Core\Template\Template;
// TODO: Write tests for it.
// TODO: Start using the $depth modificator.
/**
* LearnDash Steps walker class.
*
* @since 4.6.0
*/
class Walker extends \Walker {
/**
* ID field names.
*
* @since 4.6.0
*
* @var array{
* parent: string,
* id: string
* }
*/
public $db_fields = [
'parent' => 'parent_id',
'id' => 'id',
];
/**
* Depth modificator. Used to calculate the depth of the current step.
*
* @since 4.6.0
*
* @var int
*/
protected $depth_modificator = 0;
/**
* Sets the depth modificator.
*
* @since 4.6.0
*
* @param int $depth_modificator The depth modificator.
*
* @return self
*/
public function set_depth_modificator( int $depth_modificator ): self {
$this->depth_modificator = $depth_modificator;
return $this;
}
/**
* Starts the list before the elements are added.
*
* The $args parameter holds additional values that may be used with the child
* class methods. This method is called at the start of the output list.
*
* @since 4.6.0
*
* @param string $output Used to append additional content (passed by reference).
* @param int $depth Depth of the item.
* @param array<mixed> $args An array of additional arguments.
*
* @return void
*/
public function start_lvl( &$output, $depth = 0, $args = array() ): void {
$output .= Template::get_template( 'components/steps/list/start', $args );
$output .= Template::get_template( 'components/steps/step/link', $args );
}
/**
* Ends the list of after the elements are added.
*
* The $args parameter holds additional values that may be used with the child
* class methods. This method finishes the list at the end of output of the elements.
*
* @since 4.6.0
*
* @param string $output Used to append additional content (passed by reference).
* @param int $depth Depth of the item.
* @param array<mixed> $args An array of additional arguments.
*
* @return void
*/
public function end_lvl( &$output, $depth = 0, $args = array() ): void {
$output .= Template::get_template( 'components/steps/step/loader', $args );
$output .= Template::get_template( 'components/steps/list/end', $args );
}
/**
* Starts the element output.
*
* The $args parameter holds additional values that may be used with the child
* class methods. Also includes the element output.
*
* @since 4.6.0
*
* @param string $output Used to append additional content (passed by reference).
* @param Step $data_object The step object.
* @param int $depth Depth of the item.
* @param array<mixed> $args An array of additional arguments.
* @param int $current_object_id Optional. ID of the current item. Default 0.
*
* @return void
*/
public function start_el( &$output, $data_object, $depth = 0, $args = [], $current_object_id = 0 ): void {
$output .= Template::get_template( 'components/steps/list/item/start', $args );
$output .= Template::get_template(
'components/steps/' . ( $data_object->is_section() ? 'section' : 'step' ),
$args
);
}
/**
* Ends the element output, if needed.
*
* The $args parameter holds additional values that may be used with the child class methods.
*
* @since 4.6.0
*
* @param string $output Used to append additional content (passed by reference).
* @param Step $data_object The data object.
* @param int $depth Depth of the item.
* @param array<mixed> $args An array of additional arguments.
*
* @return void
*/
public function end_el( &$output, $data_object, $depth = 0, $args = array() ): void {
$output .= Template::get_template( 'components/steps/list/item/end', $args );
}
/**
* Traverses elements to create list from elements.
*
* Display one element if the element doesn't have any children otherwise,
* display the element and its children. Will only traverse up to the max
* depth and no ignore elements under that depth. It is possible to set the
* max depth to include all depths, see walk() method.
*
* This method should not be called directly, use the walk() method instead.
*
* @since 4.6.0
*
* @param Step|null $element Data object.
* @param array<string,array<mixed>> $children_elements List of elements to continue traversing (passed by reference).
* @param int $max_depth Max depth to traverse.
* @param int $depth Depth of current element.
* @param array<mixed> $args An array of arguments.
* @param string $output Used to append additional content (passed by reference).
*
* @return void
*/
public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ): void {
if ( ! $element ) {
return;
}
$depth = $depth + $this->depth_modificator;
$id_field = $this->db_fields['id'];
$id = $element->$id_field;
// Display this element.
$this->has_children = ! empty( $children_elements[ $id ] );
if ( isset( $args[0] ) && is_array( $args[0] ) ) {
$args[0]['has_children'] = $this->has_children; // Back-compat.
}
$args[0]['depth'] = $depth;
$args[0]['children_count'] = isset( $children_elements[ $id ] ) ? count( $children_elements[ $id ] ) : 0;
$args[0]['step'] = $element;
$this->start_el( $output, $element, $depth, ...array_values( $args ) );
// Descend only when the depth is right and there are children for this element.
if ( ( 0 === $max_depth || $max_depth > $depth + 1 ) && isset( $children_elements[ $id ] ) ) {
foreach ( $children_elements[ $id ] as $child ) {
if ( ! isset( $new_level ) ) {
$new_level = true;
// Start the child delimiter.
$this->start_lvl( $output, $depth, ...array_values( $args ) );
}
$this->display_element( $child, $children_elements, $max_depth, $depth + 1, $args, $output );
}
unset( $children_elements[ $id ] );
}
if ( isset( $new_level ) ) {
// End the child delimiter.
$this->end_lvl( $output, $depth, ...array_values( $args ) );
}
// End this element.
$this->end_el( $output, $element, $depth, ...array_values( $args ) );
}
/**
* Displays array of elements hierarchically.
*
* Does not assume any existing order of elements.
*
* $max_depth = -1 means flatly display every element.
* $max_depth = 0 means display all levels.
* $max_depth > 0 specifies the number of display levels.
*
* @since 4.6.0
*
* @param Step[] $elements An array of elements.
* @param int $max_depth The maximum hierarchical depth.
* @param mixed ...$args Optional additional arguments.
*
* @return string The hierarchical item output.
*/
public function walk( $elements, $max_depth, ...$args ): string {
$output = '';
// Invalid parameter or nothing to walk.
if ( $max_depth < -1 || empty( $elements ) ) {
return $output;
}
$parent_field = $this->db_fields['parent'];
// Flat display.
if ( -1 == $max_depth ) {
$empty_array = array();
foreach ( $elements as $e ) {
$this->display_element( $e, $empty_array, 1, 0, $args, $output );
}
return $output;
}
/*
* Need to display in hierarchical order.
* Separate elements into two buckets: top level and children elements.
* Children_elements is two dimensional array. Example:
* Children_elements[10][] contains all sub-elements whose parent is 10.
*/
$top_level_elements = array();
$children_elements = array();
foreach ( $elements as $e ) {
if ( empty( $e->$parent_field ) || ! isset( $elements[ $e->get_parent_id() ] ) ) {
$top_level_elements[] = $e;
} else {
$children_elements[ $e->$parent_field ][] = $e;
}
}
/*
* When none of the elements is top level.
* Assume the first one must be root of the sub elements.
*/
if ( empty( $top_level_elements ) ) {
$first = array_slice( $elements, 0, 1 );
$root = $first[0];
$top_level_elements = array();
$children_elements = array();
foreach ( $elements as $e ) {
if ( $root->$parent_field == $e->$parent_field ) {
$top_level_elements[] = $e;
} else {
$children_elements[ $e->$parent_field ][] = $e;
}
}
}
foreach ( $top_level_elements as $e ) {
$this->display_element( $e, $children_elements, $max_depth, 0, $args, $output );
}
/*
* If we are displaying all levels, and remaining children_elements is not empty,
* then we got orphans, which should be displayed regardless.
*/
if ( ( 0 == $max_depth ) && count( $children_elements ) > 0 ) {
$empty_array = array();
foreach ( $children_elements as $orphans ) {
foreach ( $orphans as $op ) {
$this->display_element( $op, $empty_array, 1, 0, $args, $output );
}
}
}
return $output;
}
}