<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\rbac;

use Yii;
use yii\base\Object;

/**
 * Item represents an authorization item.
 * An authorization item can be an operation, a task or a role.
 * They form an authorization hierarchy. Items on higher levels of the hierarchy
 * inherit the permissions represented by items on lower levels.
 * A user may be assigned one or several authorization items (called [[Assignment]] assignments).
 * He can perform an operation only when it is among his assigned items.
 *
 * @property Item[] $children All child items of this item. This property is read-only.
 * @property string $name The item name.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Alexander Kochetov <creocoder@gmail.com>
 * @since 2.0
 */
class Item extends Object
{
    const TYPE_OPERATION = 0;
    const TYPE_TASK = 1;
    const TYPE_ROLE = 2;

    /**
     * @var Manager the auth manager of this item
     */
    public $manager;
    /**
     * @var string the item description
     */
    public $description;
    /**
     * @var string the business rule associated with this item
     */
    public $bizRule;
    /**
     * @var mixed the additional data associated with this item
     */
    public $data;
    /**
     * @var integer the authorization item type. This could be 0 (operation), 1 (task) or 2 (role).
     */
    public $type;

    private $_name;
    private $_oldName;

    /**
     * Checks to see if the specified item is within the hierarchy starting from this item.
     * This method is expected to be internally used by the actual implementations
     * of the [[Manager::checkAccess()]].
     * @param  string  $itemName the name of the item to be checked
     * @param  array   $params   the parameters to be passed to business rule evaluation
     * @return boolean whether the specified item is within the hierarchy starting from this item.
     */
    public function checkAccess($itemName, $params = [])
    {
        Yii::trace('Checking permission: ' . $this->_name, __METHOD__);
        if ($this->manager->executeBizRule($this->bizRule, $params, $this->data)) {
            if ($this->_name == $itemName) {
                return true;
            }
            foreach ($this->manager->getItemChildren($this->_name) as $item) {
                if ($item->checkAccess($itemName, $params)) {
                    return true;
                }
            }
        }

        return false;
    }

    /**
     * @return string the item name
     */
    public function getName()
    {
        return $this->_name;
    }

    /**
     * @param string $value the item name
     */
    public function setName($value)
    {
        if ($this->_name !== $value) {
            $this->_oldName = $this->_name;
            $this->_name = $value;
        }
    }

    /**
     * Adds a child item.
     * @param  string              $name the name of the child item
     * @return boolean             whether the item is added successfully
     * @throws \yii\base\Exception if either parent or child doesn't exist or if a loop has been detected.
     * @see Manager::addItemChild
     */
    public function addChild($name)
    {
        return $this->manager->addItemChild($this->_name, $name);
    }

    /**
     * Removes a child item.
     * Note, the child item is not deleted. Only the parent-child relationship is removed.
     * @param  string  $name the child item name
     * @return boolean whether the removal is successful
     * @see Manager::removeItemChild
     */
    public function removeChild($name)
    {
        return $this->manager->removeItemChild($this->_name, $name);
    }

    /**
     * Returns a value indicating whether a child exists
     * @param  string  $name the child item name
     * @return boolean whether the child exists
     * @see Manager::hasItemChild
     */
    public function hasChild($name)
    {
        return $this->manager->hasItemChild($this->_name, $name);
    }

    /**
     * Returns the children of this item.
     * @return Item[] all child items of this item.
     * @see Manager::getItemChildren
     */
    public function getChildren()
    {
        return $this->manager->getItemChildren($this->_name);
    }

    /**
     * Assigns this item to a user.
     * @param  mixed               $userId  the user ID (see [[\yii\web\User::id]])
     * @param  string              $bizRule the business rule to be executed when [[checkAccess()]] is called
     *                                      for this particular authorization item.
     * @param  mixed               $data    additional data associated with this assignment
     * @return Assignment          the authorization assignment information.
     * @throws \yii\base\Exception if the item has already been assigned to the user
     * @see Manager::assign
     */
    public function assign($userId, $bizRule = null, $data = null)
    {
        return $this->manager->assign($userId, $this->_name, $bizRule, $data);
    }

    /**
     * Revokes an authorization assignment from a user.
     * @param  mixed   $userId the user ID (see [[\yii\web\User::id]])
     * @return boolean whether removal is successful
     * @see Manager::revoke
     */
    public function revoke($userId)
    {
        return $this->manager->revoke($userId, $this->_name);
    }

    /**
     * Returns a value indicating whether this item has been assigned to the user.
     * @param  mixed   $userId the user ID (see [[\yii\web\User::id]])
     * @return boolean whether the item has been assigned to the user.
     * @see Manager::isAssigned
     */
    public function isAssigned($userId)
    {
        return $this->manager->isAssigned($userId, $this->_name);
    }

    /**
     * Returns the item assignment information.
     * @param  mixed      $userId the user ID (see [[\yii\web\User::id]])
     * @return Assignment the item assignment information. Null is returned if
     *                           this item is not assigned to the user.
     * @see Manager::getAssignment
     */
    public function getAssignment($userId)
    {
        return $this->manager->getAssignment($userId, $this->_name);
    }

    /**
     * Saves an authorization item to persistent storage.
     */
    public function save()
    {
        $this->manager->saveItem($this, $this->_oldName);
        $this->_oldName = null;
    }
}
