Part-DB.Part-DB-server/src/Entity/StructuralDBElement.php

<?php

declare(strict_types=1);
/**
 * Part-DB Version 0.4+ "nextgen"
 * Copyright (C) 2016 - 2019 Jan Böhmer
 * https://github.com/jbtronics.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

namespace App\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\PersistentCollection;
use App\Validator\Constraints\NoneOfItsChildren;
use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
use Symfony\Component\Serializer\Annotation\DiscriminatorMap;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * All elements with the fields "id", "name" and "parent_id" (at least).
 *
 * This class is for managing all database objects with a structural design.
 * All these sub-objects must have the table columns 'id', 'name' and 'parent_id' (at least)!
 * The root node has always the ID '0'.
 * It's allowed to have instances of root elements, but if you try to change
 * an attribute of a root element, you will get an exception!
 *
 * @ORM\MappedSuperclass(repositoryClass="App\Repository\StructuralDBElementRepository")
 *
 * @UniqueEntity(fields={"name", "parent"}, ignoreNull=false, message="structural.entity.unique_name")
 */
abstract class StructuralDBElement extends AttachmentContainingDBElement
{
    public const ID_ROOT_ELEMENT = 0;

    //This is a not standard character, so build a const, so a dev can easily use it
    public const PATH_DELIMITER_ARROW = ' → ';

    // We can not define the mapping here or we will get an exception. Unfortunatly we have to do the mapping in the
    // subclasses
    /**
     * @var StructuralDBElement[]
     * @Groups({"include_children"})
     */
    protected $children;
    /**
     * @var StructuralDBElement
     * @NoneOfItsChildren()
     * @Groups({"include_parents"})
     */
    protected $parent;

    /**
     * @var string The comment info for this element
     * @ORM\Column(type="string", nullable=true)
     * @Groups({"simple", "extended", "full"})
     */
    protected $comment;

    /**
     * @var int
     * @ORM\Column(type="integer", nullable=true)
     */
    protected $parent_id;

    /**
     * @var int
     */
    protected $level = 0;

    /** @var string[] all names of all parent elements as a array of strings,
     *  the last array element is the name of the element itself
     *
     */
    private $full_path_strings;



    public function __construct()
    {
        $this->children = new ArrayCollection();
    }

    /******************************************************************************
     * StructuralDBElement constructor.
     *****************************************************************************/

    /**
     * Check if this element is a child of another element (recursive).
     *
     * @param StructuralDBElement $another_element the object to compare
     *     IMPORTANT: both objects to compare must be from the same class (for example two "Device" objects)!
     *
     * @return bool True, if this element is child of $another_element.
     *
     * @throws \InvalidArgumentException if there was an error
     */
    public function isChildOf(StructuralDBElement $another_element)
    {
        $class_name = \get_class($this);

        //Check if both elements compared, are from the same type:
        if ($class_name != \get_class($another_element)) {
            throw new \InvalidArgumentException('isChildOf() only works for objects of the same type!');
        }

        if (null == $this->getParent()) { // this is the root node
            return false;
        }

        //If this' parents element, is $another_element, then we are finished
        return ($this->parent->getID() == $another_element->getID())
            || $this->parent->isChildOf($another_element); //Otherwise, check recursivley
    }

    /******************************************************************************
     *
     * Getters
     *
     ******************************************************************************/

    /**
     * Get the parent-ID
     *
     * @return integer          * the ID of the parent element
     *                          * NULL means, the parent is the root node
     *                          * the parent ID of the root node is -1
     */
    protected function getParentID(): int
    {
        return $this->parent_id ?? self::ID_ROOT_ELEMENT; //Null means root element
    }

    /**
     * Get the parent of this element.
     *
     * @return StructuralDBElement|null The parent element. Null if this element, does not have a parent.
     */
    public function getParent(): ?self
    {
        return $this->parent;
    }

    /**
     *  Get the comment of the element.

     * @return string the comment
     */
    public function getComment(): ?string
    {
        return $this->comment;
    }

    /**
     * Get the level.
     *
     * The level of the root node is -1.
     *
     * @return int the level of this element (zero means a most top element
     *             [a subelement of the root node])
     *
     */
    public function getLevel(): int
    {
        /**
         * Only check for nodes that have a parent. In the other cases zero is correct.
         */
        if (0 === $this->level && $this->parent !== null) {
            $element = $this->parent;
            while ($element !== null) {
                /** @var StructuralDBElement $element */
                $element = $element->parent;
                ++$this->level;
            }
        }
        return $this->level;
    }

    /**
     * Get the full path.
     *
     * @param string $delimeter the delimeter of the returned string
     *
     * @return string the full path (incl. the name of this element), delimeted by $delimeter
     *
     */
    public function getFullPath(string $delimeter = self::PATH_DELIMITER_ARROW): string
    {
        if (!\is_array($this->full_path_strings)) {
            $this->full_path_strings = array();
            $this->full_path_strings[] = $this->getName();
            $element = $this;

            $overflow = 20; //We only allow 20 levels depth

            while (null != $element->parent && $overflow >= 0) {
                $element = $element->parent;
                $this->full_path_strings[] = $element->getName();
                //Decrement to prevent mem overflow.
                $overflow--;
            }

            $this->full_path_strings = array_reverse($this->full_path_strings);
        }

        return implode($delimeter, $this->full_path_strings);
    }

    /**
     * Get all subelements of this element.
     *
     * @param bool $recursive if true, the search is recursive
     *
     * @return static[] all subelements as an array of objects (sorted by their full path)
     */
    public function getSubelements(): iterable
    {
        return $this->children;
    }

    public function getChildren(): iterable
    {
        return $this->children;
    }

    /******************************************************************************
     *
     * Setters
     *
     ******************************************************************************/

    /**
     * Sets the new parent object
     * @param self $new_parent The new parent object
     * @return StructuralDBElement
     */
    public function setParent(?self $new_parent) : self
    {
        /*
        if ($new_parent->isChildOf($this)) {
            throw new \InvalidArgumentException('You can not use one of the element childs as parent!');
        } */

        $this->parent = $new_parent;

        return $this;
    }

    /**
     *  Set the comment.
     * @param string $new_comment the new comment
     * @return StructuralDBElement
     */
    public function setComment(?string $new_comment): self
    {
        $this->comment = $new_comment;

        return $this;
    }

    public function setChildren(array $element) : self
    {
        $this->children = $element;

        return $this;
    }

    public function clearChildren() : self
    {
        $this->children = new ArrayCollection();

        return $this;
    }
}