<?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\Component;
use yii\base\Exception;

/**
 * Manager is the base class for authorization manager classes.
 *
 * Manager extends [[Component]] and implements some methods
 * that are common among authorization manager classes.
 *
 * Manager together with its concrete child classes implement the Role-Based
 * Access Control (RBAC).
 *
 * The main idea is that permissions are organized as a hierarchy of
 * [[Item]] authorization items. Items on higer level inherit the permissions
 * represented by items on lower level. And roles are simply top-level authorization items
 * that may be assigned to individual users. A user is said to have a permission
 * to do something if the corresponding authorization item is inherited by one of his roles.
 *
 * Using authorization manager consists of two aspects. First, the authorization hierarchy
 * and assignments have to be established. Manager and its child classes
 * provides APIs to accomplish this task. Developers may need to develop some GUI
 * so that it is more intuitive to end-users. Second, developers call [[IManager::checkAccess()]]
 * at appropriate places in the application code to check if the current user
 * has the needed permission for an operation.
 *
 * @property array $roles Roles (name=>Item).
 * @property array $tasks Tasks (name=>Item).
 * @property array $operations Operations (name=>Item).
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Alexander Kochetov <creocoder@gmail.com>
 * @since 2.0
 */
abstract class Manager extends Component implements IManager
{
	/**
	 * @var boolean Enable error reporting for bizRules.
	 */
	public $showErrors = false;

	/**
	 * @var array list of role names that are assigned to all users implicitly.
	 * These roles do not need to be explicitly assigned to any user.
	 * When calling [[checkAccess()]], these roles will be checked first.
	 * For performance reason, you should minimize the number of such roles.
	 * A typical usage of such roles is to define an 'authenticated' role and associate
	 * it with a biz rule which checks if the current user is authenticated.
	 * And then declare 'authenticated' in this property so that it can be applied to
	 * every authenticated user.
	 */
	public $defaultRoles = array();

	/**
	 * Creates a role.
	 * This is a shortcut method to [[IManager::createItem()]].
	 * @param string $name the item name
	 * @param string $description the item description.
	 * @param string $bizRule the business rule associated with this item
	 * @param mixed $data additional data to be passed when evaluating the business rule
	 * @return Item the authorization item
	 */
	public function createRole($name, $description = '', $bizRule = null, $data = null)
	{
		return $this->createItem($name, Item::TYPE_ROLE, $description, $bizRule, $data);
	}

	/**
	 * Creates a task.
	 * This is a shortcut method to [[IManager::createItem()]].
	 * @param string $name the item name
	 * @param string $description the item description.
	 * @param string $bizRule the business rule associated with this item
	 * @param mixed $data additional data to be passed when evaluating the business rule
	 * @return Item the authorization item
	 */
	public function createTask($name, $description = '', $bizRule = null, $data = null)
	{
		return $this->createItem($name, Item::TYPE_TASK, $description, $bizRule, $data);
	}

	/**
	 * Creates an operation.
	 * This is a shortcut method to [[IManager::createItem()]].
	 * @param string $name the item name
	 * @param string $description the item description.
	 * @param string $bizRule the business rule associated with this item
	 * @param mixed $data additional data to be passed when evaluating the business rule
	 * @return Item the authorization item
	 */
	public function createOperation($name, $description = '', $bizRule = null, $data = null)
	{
		return $this->createItem($name, Item::TYPE_OPERATION, $description, $bizRule, $data);
	}

	/**
	 * Returns roles.
	 * This is a shortcut method to [[IManager::getItems()]].
	 * @param mixed $userId the user ID. If not null, only the roles directly assigned to the user
	 * will be returned. Otherwise, all roles will be returned.
	 * @return Item[] roles (name=>AuthItem)
	 */
	public function getRoles($userId = null)
	{
		return $this->getItems($userId, Item::TYPE_ROLE);
	}

	/**
	 * Returns tasks.
	 * This is a shortcut method to [[IManager::getItems()]].
	 * @param mixed $userId the user ID. If not null, only the tasks directly assigned to the user
	 * will be returned. Otherwise, all tasks will be returned.
	 * @return Item[] tasks (name=>AuthItem)
	 */
	public function getTasks($userId = null)
	{
		return $this->getItems($userId, Item::TYPE_TASK);
	}

	/**
	 * Returns operations.
	 * This is a shortcut method to [[IManager::getItems()]].
	 * @param mixed $userId the user ID. If not null, only the operations directly assigned to the user
	 * will be returned. Otherwise, all operations will be returned.
	 * @return Item[] operations (name=>AuthItem)
	 */
	public function getOperations($userId = null)
	{
		return $this->getItems($userId, Item::TYPE_OPERATION);
	}

	/**
	 * Executes the specified business rule.
	 * @param string $bizRule the business rule to be executed.
	 * @param array $params parameters passed to [[IManager::checkAccess()]].
	 * @param mixed $data additional data associated with the authorization item or assignment.
	 * @return boolean whether the business rule returns true.
	 * If the business rule is empty, it will still return true.
	 */
	public function executeBizRule($bizRule, $params, $data)
	{
		return $bizRule === '' || $bizRule === null || ($this->showErrors ? eval($bizRule) != 0 : @eval($bizRule) != 0);
	}

	/**
	 * Checks the item types to make sure a child can be added to a parent.
	 * @param integer $parentType parent item type
	 * @param integer $childType child item type
	 * @throws Exception if the item cannot be added as a child due to its incompatible type.
	 */
	protected function checkItemChildType($parentType, $childType)
	{
		static $types = array('operation', 'task', 'role');
		if ($parentType < $childType) {
			throw new Exception("Cannot add an item of type '$types[$childType]' to an item of type '$types[$parentType]'.");
		}
	}
}