<?php

/*
	This file is part of the ParTCP Server project
	Copyright (C) 2024 Martin Wandelt

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>
*/


function ptcp_get_id_data( $ptcpId, $message = NULL ){
	global $IdProviders;
	foreach ( $IdProviders as $provider ){
		$idData = $provider->get_info( $ptcpId, $message );
		if ( $idData ){
			break;
		}
	}
	return $idData ?? 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_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 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_local_decrypt( $string ){
	global $ServerData;
	static $secret;
	if ( empty( $secret ) ){
		$keyPair = ParTCP_Server_Key_Storage::get_keypair( $ServerData['name'] );
		$secret = hash( 'sha256', $keyPair[1], TRUE );
	}
	list( $iv, $encrypted ) = explode( ':', $string ) + [ '', '' ];
	$iv = base64_decode( $iv );
	if ( ! $iv || strlen( $iv ) != 16 ){
		return $string;
	}
	return openssl_decrypt( $encrypted, 'aes-256-cbc', $secret, 0, $iv );
}


function ptcp_local_encrypt( $value ){
	global $ServerData;
	static $secret;
	if ( empty( $secret ) ){
		$keyPair = ParTCP_Server_Key_Storage::get_keypair( $ServerData['name'] );
		$secret = hash( 'sha256', $keyPair[1], TRUE );
	}
	if ( is_array( $value ) ){
		$value = json_encode( $value );
	}
	$iv = openssl_random_pseudo_bytes( 16 );
	$encrypted = openssl_encrypt( $value, 'aes-256-cbc', $secret, 0, $iv );
	return base64_encode( $iv ) . ':' . $encrypted;
}


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


function ptcp_subdir_rules( $estimatedTotal ){
	global $Config;
	$itemsPerDirectory = $Config['max_items_per_dir']
		?? $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 ptcp_update_object( &$object, $newData ){
	$hasChanged = FALSE;
	foreach ( $newData as $key => $value ){
		if ( is_null( $value ) && isset( $object[ $key ] ) ){
			unset( $object[ $key ] );
			$hasChanged = TRUE;
		}
		elseif ( is_array( $value ) && is_string( array_keys( $value )[0] )
			&& isset( $object[ $key ] ) && is_array( $object[ $key ] )
		){
			if ( ptcp_update_object( $object[ $key ], $value ) ){
				$hasChanged = TRUE;
			}
		}
		elseif ( ! isset( $object[ $key ] ) || $object[ $key ] != $value ){
			$object[ $key ] = $value;
			$hasChanged = TRUE;
		}
	}
	return $hasChanged;
}


function ptcp_yaml_emit( $data ){
	$yaml = trim( yaml_emit( $data, YAML_UTF8_ENCODING ) );
	if ( substr( $yaml, 0, 4 ) == "---\n" ){
		$yaml = substr( $yaml, 4 );
	}
	if ( substr( $yaml, -4 ) == "\n..." ){
		$yaml = substr( $yaml, 0, -4 );
	}
	return $yaml;
}


// Main script

header( 'Access-Control-Allow-Origin: *' );
header( 'Access-Control-Allow-Methods: GET, POST, OPTIONS' );
header( 'Access-Control-Allow-Headers: Accept, Authorization, '
	. 'Access-Control-Allow-Origin, Content-Type, Content-Length, Cookie, Origin, '
	. 'User-Agent, X-Partcp-Version, X-Partcp-Kx-Method' );

include 'config.php';

$Timestamp = time();
$BaseDir = __DIR__;
$RequestHeaders = function_exists('apache_request_headers') ?
	array_change_key_case( apache_request_headers() ) : [];
$PartcpVersion = $RequestHeaders['x-partcp-version'] ?? '0.8';
$MessageHandlers = [];
$AuthCheckers = [];
$IdProviders = [];
$Counter = NULL;
$Shortcoder = NULL;
$ServerData = $Config['server_data'] ?? $Config['Server-Data'] ?? [];
if ( empty( $ServerData['name'] ) ){
	$ServerData['name'] = $_SERVER['SERVER_NAME'];
}
$BaseUrl = $Config['base_url'] ??  "https://{$ServerData['name']}";

require_once 'lib/partcp-php/crypto.class.php';
ParTCP_Crypto::$useLegacyKx = empty( $RequestHeaders['x-partcp-kx-method'] );
require_once 'lib/partcp-php/key_storage_fs.class.php';
require_once 'lib/partcp-php/identity.class.php';
require_once 'lib/partcp-php/incoming_message.class.php';
require_once 'lib/partcp-php/outgoing_message.class.php';
require_once 'lib/partcp-php/partcp.class.php';
require_once 'lib/server_key_storage.class.php';


// Initialize file system

$WormDir = $Config['path_to_worm'] ?? $Config['Worm-Directory'] ?? "{$BaseDir}/worm";
$DataDir = $Config['path_to_data'] ?? $Config['Data-Directory'] ?? "{$BaseDir}/data";

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

require_once "{$BaseDir}/lib/file_system.class.php";
$FileSystem = new ParTCP_File_System( $rootDirs );


// Initialize Partcp module

$dir = $Config['path_to_keys'] ?? $Config['Key-Directory'] ?? NULL;
if ( ! $dir	){
	ptcp_error( _('Key directory not specified') );
}
$Partcp = new ParTCP( 'ParTCP_Server_Key_Storage', [ 'storageDir' => $dir ] );
$localId = $Partcp->set_local_id( $ServerData['name'], TRUE, TRUE );


// Load modules

require_once 'lib/mtd_manager.class.php';
$MtdManager = new Mtd_Manager( [ __DIR__ . '/mtd' ] );

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


// Initialize localisation

if ( ! empty( $ServerData['locale'] ) ){
	putenv( "LANG={$ServerData['locale']}" );
	setlocale( LC_ALL, $ServerData['locale'] );
	bindtextdomain( 'messages', "{$BaseDir}/locale" );
	textdomain('messages');
}


// end of file initialize.php