<?php
/**
 * TAuthorizationRule, TAuthorizationRuleCollection class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Security
 */

namespace Prado\Security;

/**
 * TAuthorizationRule class
 *
 * TAuthorizationRule represents a single authorization rule.
 * A rule is specified by an action (required), a list of users (optional),
 * a list of roles (optional), a verb (optional), and a list of IP rules (optional).
 * Action can be either 'allow' or 'deny'.
 * Guest (anonymous, unauthenticated) users are represented by question mark '?'.
 * All users (including guest users) are represented by asterisk '*'.
 * Authenticated users are represented by '@'.
 * Users/roles are case-insensitive.
 * Different users/roles are separated by comma ','.
 * Verb can be either 'get' or 'post'. If it is absent, it means both.
 * IP rules are separated by comma ',' and can contain wild card in the rules (e.g. '192.132.23.33, 192.122.*.*')
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package Prado\Security
 * @since 3.0
 */
class TAuthorizationRule extends TComponent
{
	/**
	 * @var string action, either 'allow' or 'deny'
	 */
	private $_action;
	/**
	 * @var array list of user IDs
	 */
	private $_users;
	/**
	 * @var array list of roles
	 */
	private $_roles;
	/**
	 * @var string verb, may be empty, 'get', or 'post'.
	 */
	private $_verb;
	/**
	 * @var string IP patterns
	 */
	private $_ipRules;
	/**
	 * @var boolean if this rule applies to everyone
	 */
	private $_everyone;
	/**
	 * @var boolean if this rule applies to guest user
	 */
	private $_guest;
	/**
	 * @var boolean if this rule applies to authenticated users
	 */
	private $_authenticated;

	/**
	 * Constructor.
	 * @param string action, either 'deny' or 'allow'
	 * @param string a comma separated user list
	 * @param string a comma separated role list
	 * @param string verb, can be empty, 'get', or 'post'
	 * @param string IP rules (separated by comma, can contain wild card *)
	 */
	public function __construct($action,$users,$roles,$verb='',$ipRules='')
	{
		$action=strtolower(trim($action));
		if($action==='allow' || $action==='deny')
			$this->_action=$action;
		else
			throw new TInvalidDataValueException('authorizationrule_action_invalid',$action);
		$this->_users=array();
		$this->_roles=array();
		$this->_ipRules=array();
		$this->_everyone=false;
		$this->_guest=false;
		$this->_authenticated=false;

		if(trim($users)==='')
			$users='*';
		foreach(explode(',',$users) as $user)
		{
			if(($user=trim(strtolower($user)))!=='')
			{
				if($user==='*')
				{
					$this->_everyone=true;
					break;
				}
				else if($user==='?')
					$this->_guest=true;
				else if($user==='@')
					$this->_authenticated=true;
				else
					$this->_users[]=$user;
			}
		}

		if(trim($roles)==='')
			$roles='*';
		foreach(explode(',',$roles) as $role)
		{
			if(($role=trim(strtolower($role)))!=='')
				$this->_roles[]=$role;
		}

		if(($verb=trim(strtolower($verb)))==='')
			$verb='*';
		if($verb==='*' || $verb==='get' || $verb==='post')
			$this->_verb=$verb;
		else
			throw new TInvalidDataValueException('authorizationrule_verb_invalid',$verb);

		if(trim($ipRules)==='')
			$ipRules='*';
		foreach(explode(',',$ipRules) as $ipRule)
		{
			if(($ipRule=trim($ipRule))!=='')
				$this->_ipRules[]=$ipRule;
		}
	}

	/**
	 * @return string action, either 'allow' or 'deny'
	 */
	public function getAction()
	{
		return $this->_action;
	}

	/**
	 * @return array list of user IDs
	 */
	public function getUsers()
	{
		return $this->_users;
	}

	/**
	 * @return array list of roles
	 */
	public function getRoles()
	{
		return $this->_roles;
	}

	/**
	 * @return string verb, may be empty, 'get', or 'post'.
	 */
	public function getVerb()
	{
		return $this->_verb;
	}

	/**
	 * @return array list of IP rules.
	 * @since 3.1.1
	 */
	public function getIPRules()
	{
		return $this->_ipRules;
	}

	/**
	 * @return boolean if this rule applies to everyone
	 */
	public function getGuestApplied()
	{
		return $this->_guest || $this->_everyone;
	}

	/**
	 * @return boolean if this rule applies to everyone
	 */
	public function getEveryoneApplied()
	{
		return $this->_everyone;
	}

	/**
	 * @return boolean if this rule applies to authenticated users
	 */
	public function getAuthenticatedApplied()
	{
		return $this->_authenticated || $this->_everyone;
	}

	/**
	 * @param IUser the user object
	 * @param string the request verb (GET, PUT)
	 * @param string the request IP address
	 * @return integer 1 if the user is allowed, -1 if the user is denied, 0 if the rule does not apply to the user
	 */
	public function isUserAllowed(IUser $user,$verb,$ip)
	{
		if($this->isVerbMatched($verb) && $this->isIpMatched($ip) && $this->isUserMatched($user) && $this->isRoleMatched($user))
			return ($this->_action==='allow')?1:-1;
		else
			return 0;
	}

	private function isIpMatched($ip)
	{
		if(empty($this->_ipRules))
			return 1;
		foreach($this->_ipRules as $rule)
		{
			if($rule==='*' || $rule===$ip || (($pos=strpos($rule,'*'))!==false && strncmp($ip,$rule,$pos)===0))
				return 1;
		}
		return 0;
	}

	private function isUserMatched($user)
	{
		return ($this->_everyone || ($this->_guest && $user->getIsGuest()) || ($this->_authenticated && !$user->getIsGuest()) || in_array(strtolower($user->getName()),$this->_users));
	}

	private function isRoleMatched($user)
	{
		foreach($this->_roles as $role)
		{
			if($role==='*' || $user->isInRole($role))
				return true;
		}
		return false;
	}

	private function isVerbMatched($verb)
	{
		return ($this->_verb==='*' || strcasecmp($verb,$this->_verb)===0);
	}
}