<?php

class sspmod_saml_Auth_Source_SP extends SimpleSAML_Auth_Source {

	/**
	 * The entity ID of this SP.
	 *
	 * @var string
	 */
	private $entityId;


	/**
	 * The metadata of this SP.
	 *
	 * @var SimpleSAML_Configuration.
	 */
	private $metadata;


	/**
	 * The IdP the user is allowed to log into.
	 *
	 * @var string|NULL  The IdP the user can log into, or NULL if the user can log into all IdPs.
	 */
	private $idp;


	/**
	 * URL to discovery service.
	 *
	 * @var string|NULL
	 */
	private $discoURL;


	/**
	 * Constructor for SAML SP 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);

		/* For compatibility with code that assumes that $metadata->getString('entityid') gives the entity id. */
		if (array_key_exists('entityID', $config)) {
			$config['entityid'] = $config['entityID'];
		} else {
			$config['entityid'] = $this->getMetadataURL();
		}

		$this->metadata = SimpleSAML_Configuration::loadFromArray($config, 'authsources[' . var_export($this->authId, TRUE) . ']');
		$this->entityId = $this->metadata->getString('entityid');
		$this->idp = $this->metadata->getString('idp', NULL);
		$this->discoURL = $this->metadata->getString('discoURL', NULL);
	}


	/**
	 * Retrieve the URL to the metadata of this SP.
	 *
	 * @return string  The metadata URL.
	 */
	public function getMetadataURL() {

		return SimpleSAML_Module::getModuleURL('saml/sp/metadata.php/' . urlencode($this->authId));
	}


	/**
	 * Retrieve the entity id of this SP.
	 *
	 * @return string  The entity id of this SP.
	 */
	public function getEntityId() {

		return $this->entityId;
	}


	/**
	 * Retrieve the metadata of this SP.
	 *
	 * @return SimpleSAML_Configuration  The metadata of this SP.
	 */
	public function getMetadata() {

		return $this->metadata;

	}


	/**
	 * Retrieve the metadata of an IdP.
	 *
	 * @param string $entityId  The entity id of the IdP.
	 * @return SimpleSAML_Configuration  The metadata of the IdP.
	 */
	public function getIdPMetadata($entityId) {
		assert('is_string($entityId)');

		if ($this->idp !== NULL && $this->idp !== $entityId) {
			throw new SimpleSAML_Error_Exception('Cannot retrieve metadata for IdP ' . var_export($idp, TRUE) .
				' because it isn\'t a valid IdP for this SP.');
		}

		$metadataHandler = SimpleSAML_Metadata_MetaDataStorageHandler::getMetadataHandler();

		/* First, look in saml20-idp-remote. */
		try {
			return $metadataHandler->getMetaDataConfig($entityId, 'saml20-idp-remote');
		} catch (Exception $e) {
			/* Metadata wasn't found. */
		}


		/* Not found in saml20-idp-remote, look in shib13-idp-remote. */
		try {
			return $metadataHandler->getMetaDataConfig($entityId, 'shib13-idp-remote');
		} catch (Exception $e) {
			/* Metadata wasn't found. */
		}

		/* Not found. */
		throw new SimpleSAML_Error_Exception('Could not find the metadata of an IdP with entity ID ' . var_export($entityId, TRUE));
	}


	/**
	 * Send a SAML1 SSO request to an IdP.
	 *
	 * @param SimpleSAML_Configuration $idpMetadata  The metadata of the IdP.
	 * @param array $state  The state array for the current authentication.
	 */
	private function startSSO1(SimpleSAML_Configuration $idpMetadata, array $state) {

		$idpEntityId = $idpMetadata->getString('entityid');

		$state['saml:idp'] = $idpEntityId;

		$ar = new SimpleSAML_XML_Shib13_AuthnRequest();
		$ar->setIssuer($this->entityId);

		$id = SimpleSAML_Auth_State::saveState($state, 'saml:sp:ssosent-saml1');
		$ar->setRelayState($id);

		$useArtifact = $idpMetadata->getBoolean('saml1.useartifact', NULL);
		if ($useArtifact === NULL) {
			$useArtifact = $this->metadata->getBoolean('saml1.useartifact', FALSE);
		}

		if ($useArtifact) {
			$shire = SimpleSAML_Module::getModuleURL('saml/sp/saml1-acs.php/' . $this->authId . '/artifact');
		} else {
			$shire = SimpleSAML_Module::getModuleURL('saml/sp/saml1-acs.php/' . $this->authId);
		}

		$url = $ar->createRedirect($idpEntityId, $shire);

		SimpleSAML_Logger::debug('Starting SAML 1 SSO to ' . var_export($idpEntityId, TRUE) .
			' from ' . var_export($this->entityId, TRUE) . '.');
		SimpleSAML_Utilities::redirect($url);
	}


	/**
	 * Send a SAML2 SSO request to an IdP.
	 *
	 * @param SimpleSAML_Configuration $idpMetadata  The metadata of the IdP.
	 * @param array $state  The state array for the current authentication.
	 */
	private function startSSO2(SimpleSAML_Configuration $idpMetadata, array $state) {

		$ar = sspmod_saml2_Message::buildAuthnRequest($this->metadata, $idpMetadata);

		$ar->setAssertionConsumerServiceURL(SimpleSAML_Module::getModuleURL('saml/sp/saml2-acs.php/' . $this->authId));
		$ar->setProtocolBinding(SAML2_Const::BINDING_HTTP_POST);

		if (isset($state['SimpleSAML_Auth_Default.ReturnURL'])) {
			$ar->setRelayState($state['SimpleSAML_Auth_Default.ReturnURL']);
		}

		$id = SimpleSAML_Auth_State::saveState($state, 'saml:sp:ssosent-saml2');
		$ar->setId($id);

		$b = new SAML2_HTTPRedirect();
		$b->setDestination(sspmod_SAML2_Message::getDebugDestination());
		$b->send($ar);

		assert('FALSE');
	}


	/**
	 * Send a SSO request to an IdP.
	 *
	 * @param string $idp  The entity ID of the IdP.
	 * @param array $state  The state array for the current authentication.
	 */
	public function startSSO($idp, array $state) {
		assert('is_string($idp)');

		$idpMetadata = $this->getIdPMetadata($idp);

		$type = $idpMetadata->getString('metadata-set');
		switch ($type) {
		case 'shib13-idp-remote':
			$this->startSSO1($idpMetadata, $state);
			assert('FALSE'); /* Should not return. */
		case 'saml20-idp-remote':
			$this->startSSO2($idpMetadata, $state);
			assert('FALSE'); /* Should not return. */
		default:
			/* Should only be one of the known types. */
			assert('FALSE');
		}
	}


	/**
	 * Start an IdP discovery service operation.
	 *
	 * @param array $state  The state array.
	 */
	private function startDisco(array $state) {

		$id = SimpleSAML_Auth_State::saveState($state, 'saml:disco');

		$config = SimpleSAML_Configuration::getInstance();

		$discoURL = $this->discoURL;
		if ($discoURL === NULL) {
			/* Fallback to internal discovery service. */
			$discoURL = SimpleSAML_Module::getModuleURL('saml/disco.php');
		}

		$returnTo = SimpleSAML_Module::getModuleURL('saml/sp/discoresp.php');
		$returnTo = SimpleSAML_Utilities::addURLparameter($returnTo, array('AuthID' => $id));

		SimpleSAML_Utilities::redirect($discoURL, array(
			'entityID' => $this->entityId,
			'return' => $returnTo,
			'returnIDParam' => 'idpentityid')
			);
	}


	/**
	 * Start login.
	 *
	 * This function saves the information about the login, and redirects to the IdP.
	 *
	 * @param array &$state  Information about the current authentication.
	 */
	public function authenticate(&$state) {
		assert('is_array($state)');

		/* We are going to need the authId in order to retrieve this authentication source later. */
		$state['saml:sp:AuthId'] = $this->authId;

		if ($this->idp === NULL) {
			$this->startDisco($state);
			assert('FALSE');
		}

		$this->startSSO($this->idp, $state);
		assert('FALSE');
	}


	/**
	 * Start a SAML 2 logout operation.
	 *
	 * @param array $state  The logout state.
	 */
	public function startSLO2(&$state) {
		assert('is_array($state)');
		assert('array_key_exists("saml:logout:IdP", $state)');
		assert('array_key_exists("saml:logout:NameID", $state)');
		assert('array_key_exists("saml:logout:SessionIndex", $state)');

		$id = SimpleSAML_Auth_State::saveState($state, 'saml:slosent');

		$idp = $state['saml:logout:IdP'];
		$nameId = $state['saml:logout:NameID'];
		$sessionIndex = $state['saml:logout:SessionIndex'];

		$idpMetadata = $this->getIdPMetadata($idp);

		$lr = sspmod_saml2_Message::buildLogoutRequest($this->metadata, $idpMetadata);
		$lr->setNameId($nameId);
		$lr->setSessionIndex($sessionIndex);
		$lr->setRelayState($id);

		$b = new SAML2_HTTPRedirect();
		$b->setDestination(sspmod_SAML2_Message::getDebugDestination());
		$b->send($lr);

		assert('FALSE');
	}


	/**
	 * Start logout operation.
	 *
	 * @param array $state  The logout state.
	 */
	public function logout(&$state) {
		assert('is_array($state)');
		assert('array_key_exists("saml:logout:Type", $state)');

		$logoutType = $state['saml:logout:Type'];
		switch ($logoutType) {
		case 'saml1':
			/* Nothing to do. */
			return;
		case 'saml2':
			$this->startSLO2($state);
			assert('FALSE');
		default:
			/* Should never happen. */
			assert('FALSE');
		}
	}


	/**
	 * Handle a response from a SSO operation.
	 *
	 * @param array $state  The authentication state.
	 * @param string $idp  The entity id of the IdP.
	 * @param array $attributes  The attributes.
	 */
	public function handleResponse(array $state, $idp, array $attributes) {
		assert('is_string($idp)');
		assert('array_key_exists("LogoutState", $state)');
		assert('array_key_exists("saml:logout:Type", $state["LogoutState"])');

		$idpMetadata = $this->getIdpMetadata($idp);

		$spMetadataArray = $this->metadata->toArray();
		$idpMetadataArray = $idpMetadata->toArray();

		$authProcState = array(
			'saml:sp:IdP' => $idp,
			'saml:sp:State' => $state,
			'ReturnCall' => array('sspmod_saml_Auth_Source_SP', 'onProcessingCompleted'),

			'Attributes' => $attributes,
			'Destination' => $spMetadataArray,
			'Source' => $idpMetadataArray,
		);

		$pc = new SimpleSAML_Auth_ProcessingChain($idpMetadataArray, $spMetadataArray, 'sp');
		$pc->processState($authProcState);

		self::onProcessingCompleted($authProcState);
	}


	/**
	 * Handle a logout request from an IdP.
	 *
	 * @param string $idpEntityId  The entity ID of the IdP.
	 */
	public function handleLogout($idpEntityId) {
		assert('is_string($idpEntityId)');

		/* Call the logout callback we registered in onProcessingCompleted(). */
		$this->callLogoutCallback($idpEntityId);
	}


	/**
	 * Called when we have completed the procssing chain.
	 *
	 * @param array $authProcState  The processing chain state.
	 */
	public static function onProcessingCompleted(array $authProcState) {
		assert('array_key_exists("saml:sp:IdP", $authProcState)');
		assert('array_key_exists("saml:sp:State", $authProcState)');
		assert('array_key_exists("Attributes", $authProcState)');

		$idp = $authProcState['saml:sp:IdP'];
		$state = $authProcState['saml:sp:State'];

		$sourceId = $state['saml:sp:AuthId'];
		$source = SimpleSAML_Auth_Source::getById($sourceId);
		if ($source === NULL) {
			throw new Exception('Could not find authentication source with id ' . $sourceId);
		}

		/* Register a callback that we can call if we receive a logout request from the IdP. */
		$source->addLogoutCallback($idp, $state);

		$state['Attributes'] = $authProcState['Attributes'];

		if (isset($state['saml:sp:isUnsoliced']) && (bool)$state['saml:sp:isUnsoliced']) {
			if (isset($state['saml:sp:RelayState'])) {
				$redirectTo = $state['saml:sp:RelayState'];
			} else {
				$redirectTo = $source->getMetadata()->getString('RelayState', '/');
			}
			SimpleSAML_Auth_Default::handleUnsolicedAuth($sourceId, $state, $redirectTo);
		}

		SimpleSAML_Auth_Source::completeAuth($state);
	}

}