<?php


/**
 * Authentication processing filter to generate a persistent NameID.
 *
 * @package SimpleSAMLphp
 */
class sspmod_saml_Auth_Process_PersistentNameID extends sspmod_saml_BaseNameIDGenerator
{

    /**
     * Which attribute contains the unique identifier of the user.
     *
     * @var string
     */
    private $attribute;


    /**
     * Initialize this filter, parse configuration.
     *
     * @param array $config Configuration information about this filter.
     * @param mixed $reserved For future use.
     *
     * @throws SimpleSAML_Error_Exception If the required option 'attribute' is missing.
     */
    public function __construct($config, $reserved)
    {
        parent::__construct($config, $reserved);
        assert('is_array($config)');

        $this->format = SAML2_Const::NAMEID_PERSISTENT;

        if (!isset($config['attribute'])) {
            throw new SimpleSAML_Error_Exception("PersistentNameID: Missing required option 'attribute'.");
        }
        $this->attribute = $config['attribute'];
    }


    /**
     * Get the NameID value.
     *
     * @param array $state The state array.
     * @return string|null The NameID value.
     */
    protected function getValue(array &$state)
    {

        if (!isset($state['Destination']['entityid'])) {
            SimpleSAML_Logger::warning('No SP entity ID - not generating persistent NameID.');
            return null;
        }
        $spEntityId = $state['Destination']['entityid'];

        if (!isset($state['Source']['entityid'])) {
            SimpleSAML_Logger::warning('No IdP entity ID - not generating persistent NameID.');
            return null;
        }
        $idpEntityId = $state['Source']['entityid'];

        if (!isset($state['Attributes'][$this->attribute]) || count($state['Attributes'][$this->attribute]) === 0) {
            SimpleSAML_Logger::warning(
                'Missing attribute '.var_export($this->attribute, true).
                ' on user - not generating persistent NameID.'
            );
            return null;
        }
        if (count($state['Attributes'][$this->attribute]) > 1) {
            SimpleSAML_Logger::warning(
                'More than one value in attribute '.var_export($this->attribute, true).
                ' on user - not generating persistent NameID.'
            );
            return null;
        }
        $uid = array_values($state['Attributes'][$this->attribute]); // just in case the first index is no longer 0
        $uid = $uid[0];

        if (empty($uid)) {
            SimpleSAML\Logger::warning(
                'Empty value in attribute '.var_export($this->attribute, true).
                ' on user - not generating persistent NameID.'
            );
            return null;
        }

        $secretSalt = SimpleSAML\Utils\Config::getSecretSalt();

        $uidData = 'uidhashbase'.$secretSalt;
        $uidData .= strlen($idpEntityId).':'.$idpEntityId;
        $uidData .= strlen($spEntityId).':'.$spEntityId;
        $uidData .= strlen($uid).':'.$uid;
        $uidData .= $secretSalt;

        return sha1($uidData);
    }
}
