class MenuTreeParameters

class MenuTreeParameters implements \Serializable {
    
    /**
     * A menu link plugin ID that should be used as the root.
     *
     * By default the root ID of empty string '' is used. However, when only the
     * descendants (subtree) of a certain menu link are needed, a custom root can
     * be specified.
     *
     * @var string
     */
    public $root = '';
    
    /**
     * The minimum depth of menu links in the resulting tree relative to the root.
     *
     * @var int|null
     */
    public $minDepth = NULL;
    
    /**
     * The maximum depth of menu links in the resulting tree relative to the root.
     *
     * @var int|null
     */
    public $maxDepth = NULL;
    
    /**
     * An array of parent link IDs.
     *
     * This restricts the tree to only menu links that are at the top level or
     * have a parent ID in this list. If empty, the whole menu tree is built.
     *
     * @var string[]
     */
    public $expandedParents = [];
    
    /**
     * The IDs from the currently active menu link to the root of the whole tree.
     *
     * This is an array of menu link plugin IDs, representing the trail from the
     * currently active menu link to the ("real") root of that menu link's menu.
     * This does not affect the way the tree is built. It is only used to set the
     * value of the inActiveTrail property for each tree element.
     *
     * @var string[]
     */
    public $activeTrail = [];
    
    /**
     * The conditions used to restrict which links are loaded.
     *
     * An associative array of custom query condition key/value pairs.
     *
     * @var array
     */
    public $conditions = [];
    
    /**
     * Sets a root for menu tree loading.
     *
     * @param string $root
     *   A menu link plugin ID, or empty string '' to use the root of the whole
     *   tree.
     *
     * @return $this
     *
     * @codeCoverageIgnore
     */
    public function setRoot($root) {
        $this->root = (string) $root;
        return $this;
    }
    
    /**
     * Sets a minimum depth for menu tree loading.
     *
     * @param int $min_depth
     *   The (root-relative) minimum depth to apply.
     *
     * @return $this
     */
    public function setMinDepth($min_depth) {
        $this->minDepth = max(1, $min_depth);
        return $this;
    }
    
    /**
     * Sets a maximum depth for menu tree loading.
     *
     * @param int $max_depth
     *   The (root-relative) maximum depth to apply.
     *
     * @return $this
     *
     * @codeCoverageIgnore
     */
    public function setMaxDepth($max_depth) {
        $this->maxDepth = $max_depth;
        return $this;
    }
    
    /**
     * Adds parent menu links IDs to restrict the tree.
     *
     * @param string[] $parents
     *   An array containing parent IDs. If supplied, the tree is limited to
     *   links that have these parents.
     *
     * @return $this
     */
    public function addExpandedParents(array $parents) {
        $this->expandedParents = array_merge($this->expandedParents, $parents);
        $this->expandedParents = array_unique($this->expandedParents);
        return $this;
    }
    
    /**
     * Sets the active trail IDs used to set the inActiveTrail property.
     *
     * @param string[] $active_trail
     *   An array containing the active trail: a list of menu link plugin IDs.
     *
     * @return $this
     *
     * @see \Drupal\Core\Menu\MenuActiveTrail::getActiveTrailIds()
     *
     * @codeCoverageIgnore
     */
    public function setActiveTrail(array $active_trail) {
        $this->activeTrail = $active_trail;
        return $this;
    }
    
    /**
     * Adds a custom query condition.
     *
     * @param string $definition_field
     *   Only conditions that are testing menu link definition fields are allowed.
     * @param mixed $value
     *   The value to test the link definition field against. In most cases, this
     *   is a scalar. For more complex options, it is an array. The meaning of
     *   each element in the array is dependent on the $operator.
     * @param string|null $operator
     *   (optional) The comparison operator, such as =, <, or >=. It also accepts
     *   more complex options such as IN, LIKE, or BETWEEN. If NULL, defaults to
     *   the = operator.
     *
     * @return $this
     */
    public function addCondition($definition_field, $value, $operator = NULL) {
        if (!isset($operator)) {
            $this->conditions[$definition_field] = $value;
        }
        else {
            $this->conditions[$definition_field] = [
                $value,
                $operator,
            ];
        }
        return $this;
    }
    
    /**
     * Excludes links that are not enabled.
     *
     * @return $this
     */
    public function onlyEnabledLinks() {
        $this->addCondition('enabled', 1);
        return $this;
    }
    
    /**
     * Ensures only the top level of the tree is loaded.
     *
     * @return $this
     */
    public function setTopLevelOnly() {
        $this->setMaxDepth(1);
        return $this;
    }
    
    /**
     * Excludes the root menu link from the tree.
     *
     * Note that this is only necessary when you specified a custom root, because
     * the normal root ID is the empty string, '', which does not correspond to an
     * actual menu link. Hence when loading a menu link tree without specifying a
     * custom root the tree will start at the children even if this method has not
     * been called.
     *
     * @return $this
     */
    public function excludeRoot() {
        $this->setMinDepth(1);
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function serialize() {
        // Enforce type consistency for all the internal properties of this object.
        $this->root = (string) $this->root;
        $this->minDepth = $this->minDepth !== NULL ? (int) $this->minDepth : NULL;
        $this->maxDepth = $this->maxDepth !== NULL ? (int) $this->maxDepth : NULL;
        $this->activeTrail = array_values(array_filter($this->activeTrail));
        // Sort 'expanded' and 'conditions' to prevent duplicate cache items.
        sort($this->expandedParents);
        asort($this->conditions);
        return serialize([
            'root' => $this->root,
            'minDepth' => $this->minDepth,
            'maxDepth' => $this->maxDepth,
            'expandedParents' => $this->expandedParents,
            'activeTrail' => $this->activeTrail,
            'conditions' => $this->conditions,
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function unserialize($serialized) {
        foreach (unserialize($serialized) as $key => $value) {
            $this->{$key} = $value;
        }
        return $this;
    }

}