deep-web-solutions/wordpress-framework-foundations

<?php

namespace DeepWebSolutions\Framework\Foundations\Hierarchy;

\defined( 'ABSPATH' ) || exit;

/**
 * Basic implementation of the parent interface.
 *
 * @since   1.0.0
 * @version 1.0.0
 * @author  Antonius Hegyes <a.hegyes@deep-web-solutions.com>
 * @package DeepWebSolutions\WP-Framework\Foundations\Hierarchy
 */
trait ParentTrait {
    // region FIELDS AND CONSTANTS

    /**
     * The children of the using instance.
     *
     * @since   1.0.0
     * @version 1.0.0
     *
     * @access  protected
     * @var     ChildInterface[]
     */
    protected array $children = array();

    // endregion

    // region GETTERS

    /**
     * Method for determining whether the instance has any children or not.
     *
     * @since   1.0.0
     * @version 1.0.0
     *
     * @return  bool
     */
    public function has_children(): bool {
        return ! empty( $this->get_children() );
    }

    /**
     * Method for retrieving the instance's children.
     *
     * @since   1.0.0
     * @version 1.0.0
     *
     * @return  ChildInterface[]
     */
    public function get_children(): array {
        return \array_filter(
            $this->children,
            fn( $child ) => \is_a( $child, ChildInterface::class )
        );
    }

    // endregion

    // region SETTERS

    /**
     * Sets the children on the instance.
     *
     * @since   1.0.0
     * @version 1.0.0
     *
     * @param   object[]    $children   Children to set.
     */
    public function set_children( array $children ) {
        $this->children = \array_filter(
            $children,
            fn( $child ) => \is_object( $child ) && \is_a( $child, ChildInterface::class )
        );
    }

    // endregion

    // region METHODS

    /**
     * Method for adding a new child to the instance.
     *
     * @param   string|object       $child      Object or class name to instantiate and add as a child.
     *
     * @noinspection PhpMissingReturnTypeInspection
     * @return  bool
     */
    public function add_child( $child ) {
        if ( ! \is_a( $this, ParentInterface::class ) || ! \is_a( $child, ChildInterface::class, true ) ) {
            return false;
        }

        if ( ! \is_object( $child ) ) {
            $child = new $child();
        } elseif ( $child->has_parent() || $child === $this ) {
            return false;
        }

        $child->set_parent( $this );
        $this->children[] = $child;

        return true;
    }

    // endregion
}