<?php

if ( ! function_exists('yaml_parse') ){
	require_once 'lib/yaml/Dumper.php';
	require_once 'lib/yaml/Escaper.php';
	require_once 'lib/yaml/Inline.php';
	require_once 'lib/yaml/Parser.php';
	require_once 'lib/yaml/Unescaper.php';
	require_once 'lib/yaml/Yaml.php';

	function yaml_parse( $string ){
		return Symfony\Component\Yaml\Yaml::parse( $string );
	}
}


if ( ! function_exists('yaml_emit') ){
	require_once 'lib/yaml/Dumper.php';
	require_once 'lib/yaml/Escaper.php';
	require_once 'lib/yaml/Inline.php';
	require_once 'lib/yaml/Parser.php';
	require_once 'lib/yaml/Unescaper.php';
	require_once 'lib/yaml/Yaml.php';

	function yaml_emit( $string ){
		$option = Symfony\Component\Yaml\Yaml::DUMP_MULTI_LINE_LITERAL_BLOCK
			| Symfony\Component\Yaml\Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE;
		return Symfony\Component\Yaml\Yaml::dump( $string, 3, 2, $option );
	}
}


function ptcp_register_message_handler( $classOrObject, $highPrio = FALSE ){
	global $MessageHandlers;
	if ( $highPrio ){
		array_unshift( $MessageHandlers, $classOrObject );
	}
	else {
		array_push( $MessageHandlers, $classOrObject );
	}
}


function ptcp_register_auth_checker( $classOrObject, $highPrio = FALSE ){
	global $AuthCheckers;
	if ( $highPrio ){
		array_unshift( $AuthCheckers, $classOrObject );
	}
	else {
		array_push( $AuthCheckers, $classOrObject );
	}
}


function ptcp_register_id_provider( $classOrObject, $highPrio = FALSE ){
	global $IdProviders;
	if ( $highPrio ){
		array_unshift( $IdProviders, $classOrObject );
	}
	else {
		array_push( $IdProviders, $classOrObject );
	}
}


function ptcp_error( $text ){
	global $PartcpVersion, $ServerData;
	if ( version_compare( $PartcpVersion, '1.0', '<' ) ){
		header( $_SERVER['SERVER_PROTOCOL'] . ' 500 Internal Server Error' );
		die( $text );
	}
	$lines[] = "From: {$ServerData['name']}";
	$lines[] = 'Message-Type: failure-notice';
	$lines[] = "Failure-Description: {$text}";
	die( implode( "\n", $lines ) );
}


function ptcp_get_id_info( $id, $message = NULL ){
	global $IdProviders;
	foreach ( $IdProviders as $provider ){
		$info = $provider->get_info( $id, $message );
		if ( $info ){
			return $info;
		}
	}
	return FALSE;
}


function ptcp_get_pubkey( $id, $message = NULL, $useKeySent = FALSE ){
	if ( $useKeySent && $message && ( $key = $message->get('Public-Key') ) ){
		return $key;
	}
	$info = ptcp_get_id_info( $id, $message );
	return isset( $info['public_key'] ) ? $info['public_key'] : FALSE;
}


function ptcp_is_in_list( $ptcpId, $ptcpList ){
	global $ServerData;
	if ( ! strpos( $ptcpId, '@' ) ){
		$ptcpId .= '@' . $ServerData['name'];
	}
	foreach ( $ptcpList as $key => $id ){
		if ( ! strpos( $id, '@' ) ){
			$ptcpList[ $key ] .= '@' . $ServerData['name'];
		}
	}
	return in_array( $ptcpId, $ptcpList );
}


function ptcp_is_authorized( $ptcpId, $messageType, $object = NULL ){
	global $AuthCheckers;
	foreach ( $AuthCheckers as $classOrObject ){
		$result = call_user_func( [ $classOrObject, 'is_authorized' ],
			$ptcpId, $messageType, $object );
		if ( $result !== NULL ){
			return $result;
		}
	}
	return ptcp_get_id_info( $ptcpId ) != FALSE;
}


function ptcp_handle_message( $message, $receipt ){
	global $MessageHandlers;
	foreach ( $MessageHandlers as $classOrObject ){
		$methodName = 'handle_' . str_replace( '-', '_', $message->get('Message-Type') );
		if ( ! method_exists( $classOrObject, $methodName ) ){
			continue;
		}
		$result = call_user_func( [ $classOrObject, $methodName ], $message, $receipt );
		if ( $result !== FALSE ){
			return $result;
		}
	}
	foreach ( $MessageHandlers as $classOrObject ){
		if ( ! method_exists( $classOrObject, 'router' ) ){
			continue;
		}
		$methodName = call_user_func( [ $classOrObject, 'router' ], $message->get('Message-Type') );
		if ( $methodName !== FALSE && method_exists( $classOrObject, $methodName ) ){
			$result = call_user_func( [ $classOrObject, $methodName ], $message, $receipt );
			if ( $result !== FALSE ){
				return $result;
			}
		}
	}
	return FALSE;
}


function ptcp_subdir_rules( $estimatedTotal ){
	global $Config;
	$itemsPerDirectory = $Config['Max-Items-Per-Directory'] ?? 9999;
	$directoriesNeeded = ceil( $estimatedTotal / $itemsPerDirectory );
	$totalPathLength = ceil( log( $directoriesNeeded, 16 ) );
	$maxDirNameLength = floor( log( $itemsPerDirectory, 16 ) );
	$subdirDepth = ceil( $totalPathLength / $maxDirNameLength );
	$subdirNameLength = $subdirDepth ? ceil( $totalPathLength / $subdirDepth ) : 0;
	return [ (int) $subdirDepth, (int) $subdirNameLength ];
}


function pxtc_update_object( &$object, $newData ){
	foreach ( $newData as $key => $value ){
		if ( is_null( $value ) ){
			unset( $object[ $key ] );
		}
		elseif ( is_array( $value )
			&& isset( $object[ $key ] ) && is_array( $object[ $key ] )
			&& count( array_filter( array_keys( $value ), 'is_string' ) ) > 0
		){
			pxtc_update_object( $object[ $key ], $value );
		}
		else {
			$object[ $key ] = $value;
		}
	}
}


// Main script

error_reporting( E_ALL );
ini_set( 'display_errors', 1 );
$Timestamp = time();
$startTime = microtime( TRUE );
$BaseDir = __DIR__;
$RequestHeaders = apache_request_headers();
$PartcpVersion = $RequestHeaders['X-Partcp-Version'] ?? '0.8';
$MessageHandlers = [];
$AuthCheckers = [];
$IdProviders = [];
$Counter = NULL;
$Crypto = NULL;
$FsWriter = NULL;
header('Content-Type: text/plain');

require_once 'lib/file_system.class.php';
require_once 'lib/incoming_message.class.php';
require_once 'lib/outgoing_message.class.php';
require_once 'config.php';
$DataDir = $Config['Data-Directory'] ?? "{$BaseDir}/data";
$TempDir = $Config['Temp-Directory'] ?? "{$BaseDir}/tmp";

$rootDirs[] = $DataDir;
if ( file_exists( "{$DataDir}/_continuations" ) ){
	$listing = glob( "{$DataDir}/_continuations/[0-9]*" );
	foreach ( $listing as $file ){
		$dir = file_get_contents( $file );
		if ( $dir && file_exists( $dir ) ){
			array_unshift( $rootDirs, $point );
		}
	}
}
$FileSystem = new ParTCP_File_System( $rootDirs );

$ServerData = $Config['Server-Data'];
if ( empty( $ServerData['name'] ) ){
	$ServerData['name'] = $_SERVER['SERVER_NAME'];
}


// If there is nothing to process, show contents of this script file

if ( empty( $_POST['message'] ) ){
	$_POST['message'] = file_get_contents('php://input');
	if ( empty( $_POST['message'] ) ){
		readfile( __FILE__ );
		exit;
	}
}


// Load modules

if ( ! empty( $ServerData['modules'] ) ){
	foreach ( $ServerData['modules'] as $module ){
		$path = "{$BaseDir}/modules/{$module}/init.php";
		if ( file_exists( $path ) ){
			include $path;
		}
		else {
			ptcp_error( "Module {$module} could not be initialized" );
		}
	}
}


// Prepare processing

$Message = new ParTCP_Incoming_Message( $_POST['message'], $Crypto, 'ptcp_get_pubkey' );
$Receipt = new ParTCP_Outgoing_Message( $Crypto, 'ptcp_get_pubkey' );
$Receipt->set( 'From', $ServerData['name'] );
if ( $id = $Message->get('From') ){
	$pubKey = ptcp_get_pubkey( $id, $Message, TRUE );
	$Receipt->set_recipient( $Message->get('From'), $pubKey );
}
else {
	$Receipt->set_recipient('<anonymous>');
}
if ( empty( $pubKey ) && ( $pubKey = $Message->get('Public-Key') ) ){
	$Receipt->recipientPubKey = $pubKey;
}
$Receipt->set_date();
$Receipt->set( 'Message-Type', 'receipt' );
$Receipt->set( 'Original-Message', $_POST['message'] );


// Process message and deliver receipt

if ( ! $Message->get('Message-Type') ){
	$Receipt->set( 'Message-Type', 'rejection-notice' );
	$Receipt->set( 'Rejection-Reason', 'Message-Type header is missing' );
	die( $Receipt->dump_signed() );
}

$result = ptcp_handle_message( $Message, $Receipt );

if ( $result === FALSE ){
	$Receipt->set( 'Message-Type', 'rejection-notice' );
	$Receipt->set( 'Rejection-Reason', "Unknown message type '{$Message->get('Message-Type')}'" );
	die( $Receipt->dump_signed() );
}

if ( version_compare( $PartcpVersion, '1.0', '<' ) ){
	$tmpMsg = new ParTCP_Incoming_Message( $result, $Crypto );
	$type = $tmpMsg->get('Message-Type');
	if ( $type == 'rejection-notice' ){
		header( $_SERVER['SERVER_PROTOCOL'] . ' 400 Bad Request' );
	}
	elseif ( $type == 'failure-notice' ){
		header( $_SERVER['SERVER_PROTOCOL'] . ' 500 Internal Server Error' );
	}
	die( $result );
}

header( 'X-Elapsed-Time: ' . sprintf( '%.3f ms', 1000 * ( microtime( TRUE ) - $startTime ) ) );
echo $result;


// end of file process.php