<?php

/**
 * Authenticate using PAPI protocol.
 *
 * @author Jaime Perez, RedIRIS
 * @package simpleSAMLphp
 */
include("poa2/PoA.php");

class sspmod_papi_Auth_Source_PAPI extends SimpleSAML_Auth_Source {

    /**
     * The string used to identify our states.
     */
    const STAGE_INIT = 'sspmod_papi_Auth_Source_PAPI.state';
    
    /**
     * The key of the AuthId field in the state.
     */
    const AUTHID = 'sspmod_papi_Auth_Source_PAPI.AuthId';

	/**
	 * @var the PoA to use.
	 */
	private $_poa;

	/**
	 * @var the home locator interface to use.
	 */
	private $_hli;

	/**
	 * @var the PAPIOPOA to use.
	 */
	private $_papiopoa;

	/**
	 * @var the attributes of the user.
	 */
	private $_attrs;

	/**
	 * @var the state ID to retrieve the original request later.
	 */
	private $_stateId;

    /**
     * Constructor for this authentication source.
     *
     * @param array $info  Information about this authentication source.
     * @param array $config  Configuration.
     */
    public function __construct($info, $config) {
        assert('is_array($info)');
        assert('is_array($config)');

        /* Call the parent constructor first, as required by the interface. */
        parent::__construct($info, $config);

        if (!array_key_exists('site', $config)) {
                throw new Exception('PAPI authentication source is not properly configured: missing [site]');
        }
		$this->_poa = new PoA($config['site']);

		if (array_key_exists('hli', $config)) {
			$this->_hli = $config['hli'];
		}

	}

	/**
	 * Hook that will set Home Locator Identifier, PAPIOPOA and/or State ID.
	 *
	 * @param The PAPI request parameters that will be modified/extended.
	 */
	public function modifyParams(&$params) {
		if (!empty($this->_hli)) {
			$params['PAPIHLI'] = $this->_hli;
		}
		if (!empty($this->_papiopoa)) {
			$params['PAPIOPOA'] = $this->_papiopoa;
		}
		$params['URL'] = $params['URL'].urlencode("&SSPStateID=".$this->_stateId);
		return false;
	}

	/**
	 * Parse the attribute array in a format suitable for SSP.
	 *
 	 * @param the original attribute array.
	*/
	protected function parseAttributes($attrs) {
		assert('is_array($attrs)');

		foreach ($attrs as $name => $value) {
			if (!is_array($value)) {
				$attrs[$name] = array($value);
			}
		}
		return $attrs;
	}

    /**
     * Log-in using PAPI
     *
     * @param array &$state  Information about the current authentication.
     */
    public function authenticate(&$state) {
		assert('is_array($state)');
		$this->_papiopoa = $state['SPMetadata']['entityid'];

		// check if we are returning back from PAPI authentication
        if (isset($_REQUEST['SSPStateID'])) {
			// yes! restore original request
           	$this->_stateId = (string)$_REQUEST['SSPStateID'];
           	
			// sanitize the input
			$sid = SimpleSAML_Utilities::parseStateID($this->_stateId);
			if (!is_null($sid['url'])) {
				SimpleSAML_Utilities::checkURLAllowed($sid['url']);
			}

           	$state = SimpleSAML_Auth_State::loadState($this->_stateId, self::STAGE_INIT);
		} else if (!$this->_poa->isAuthenticated()) { 
			// no! we have to save the request

        	/* We are will need the authId in order to retrieve this authentication source later. */
        	$state[self::AUTHID] = $this->authId;
        	$this->_stateId = SimpleSAML_Auth_State::saveState($state, self::STAGE_INIT);

			$this->_poa->addHook("PAPI_REDIRECT_URL_FINISH", new Hook(array($this, "modifyParams")));
		}

		$this->_poa->authenticate();
		$this->_attrs = $this->_poa->getAttributes();
		$state['Attributes'] = $this->parseAttributes($this->_attrs);
		self::completeAuth($state);
	}

    /**
     * Log out from this authentication source.
     *
     * This function should be overridden if the authentication source requires special
     * steps to complete a logout operation.
     *
     * If the logout process requires a redirect, the state should be saved. Once the
     * logout operation is completed, the state should be restored, and completeLogout
     * should be called with the state. If this operation can be completed without
     * showing the user a page, or redirecting, this function should return.
     *
     * @param array &$state  Information about the current logout operation.
     */
    public function logout(&$state) {
    	assert('is_array($state)');

    	// check first if we have a valid session
    	if ($this->_poa->isAuthenticated()) {
    		/* We are will need the authId in order to retrieve this authentication source later. */
        	$state[self::AUTHID] = $this->authId;
        	$this->_stateId = SimpleSAML_Auth_State::saveState($state, self::STAGE_INIT);

        	// TODO: pending on phpPoA adding PAPI_SLO_REDIRECT_URL_FINISH hook
        	$this->_poa->addHook("PAPI_SLO_REDIRECT_URL_FINISH", new Hook(array($this, "modifyParams")));

        	// perform single logout, this won't return
    		$this->_poa->logout(true);
    	} else if (isset($_REQUEST['SSPStateID'])) {
    		$this->_stateId = (string)$_REQUEST['SSPStateID'];

			// sanitize the input
			$sid = SimpleSAML_Utilities::parseStateID($this->_stateId);
			if (!is_null($sid['url'])) {
				SimpleSAML_Utilities::checkURLAllowed($sid['url']);
			}

    		$state = SimpleSAML_Auth_State::loadState($this->_stateId, self::STAGE_INIT);
    	} else {
    		return;
    	}

    	self::completeLogout($state);
	}

}