<?php

/*
	This file is part of the ParTCP PHP Library project
	Copyright (C) 2023 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/>
*/

class ParTCP_Outgoing_Message {

	public $remoteId;
	public $localId;
	public $data = [];


	public function __construct( $remoteId = NULL, $localId = NULL, $data = NULL ){
		if ( $remoteId ){
			$this->set_remote_id( $remoteId );
		}
		if ( $localId ){
			$this->set_local_id( $localId );
		}
		if ( is_array( $data ) ){
			$this->multiset( $data );
		}
		elseif ( is_string( $data ) ){
			$this->set( 'Message-Type', $data );
		}
	}


	public function set_remote_id( $remoteId ){
		if ( ! is_object( $remoteId ) ){
			$remoteId = new ParTCP_Public_Identity( $remoteId );
		}
		$this->remoteId = $remoteId;
		if ( empty( $this->data['To'] ) ){
			$this->set( 'To', $this->remoteId->id );
		}
	}


	public function set_local_id( $localId ){
		if ( ! is_object( $localId ) ){
			$localId = new ParTCP_Private_Identity( $localId );
		}
		$this->localId = $localId;
		if ( empty( $this->data['From'] ) ){
			$this->set( 'From', $this->localId->id );
		}
	}


	public function set( $name, $value = NULL, $encrypted = FALSE ){
		if ( is_null( $value ) ){
			unset( $this->data[ $name ] );
			return;
		}
		if ( substr( $name, -1 ) == '~' ){
			$encrypted = TRUE;
			$name = rtrim( $name, '~' );
		}
		if ( $encrypted ){
			unset( $this->data[ $name ] );
			$name .= '~';
			if ( is_array( $value ) ){
				$value = json_encode( $value );
			}
			$value = trim( chunk_split( $this->encrypt( $value ), 300, "\n" ) );
		}
		if ( is_string( $value ) ){
			 // remove non-UTF8 characters
			$value = mb_convert_encoding( $value, 'UTF-8', 'UTF-8' );
		}
		$this->data[ $name ] = $value;
	}


	public function multiset( $namesAndValues ){
		foreach ( $namesAndValues as $name => $value ){
			$this->set( $name, $value );
		}
	}


	public function set_date( $date = 'now' ){
		$this->set( 'Date', date_create( $date ) );
	}


	public function set_public_key(){
		if ( empty( $this->localId->pubKey ) ){
			throw new Exception('Missing public key');
		}
		$this->set( 'Public-Key', $this->localId->pubKey );
	}


	public function set_failure( $description ){
		$this->set( 'Message-Type', 'failure-notice' );
		$this->set( 'Failure-Description', $description );
	}


	public function set_rejection( $code, $reason ){
		$this->set( 'Message-Type', 'rejection-notice' );
		$this->set( 'Rejection-Code', $code );
		$this->set( 'Rejection-Reason', $reason );
	}


	public function dump( $withSignature = NULL ){
		$data = array_filter( array_replace( [
			'Message-Type' => null,
			'To' => null,
			'From' => null,
			'Date' => null
			], $this->data ), function( $v ){ return ! is_null( $v ); } );
		$message = trim( yaml_emit( $data ) );
		if ( substr( $message, 0, 4 ) == "---\n" ){
			$message = substr( $message, 4 );
		}
		if ( substr( $message, -4 ) == "\n..." ){
			$message = substr( $message, 0, -4 );
		}
		if ( $withSignature && empty( $this->localId->privKey ) ){
			throw new Exception('Missing key for signing');
		}
		elseif ( $withSignature || ( is_null( $withSignature )
			&& ! empty( $this->localId->privKey ) )
		){
			ParTCP_Crypto::set_local_privkey( $this->localId->privKey );
			$signature = ParTCP_Crypto::generate_signature( $message );
			$message = "Signature: {$signature}\n{$message}";
		}
		return $message;
	}


	public function send( $withSignature = NULL, $useSsl = NULL, $port = NULL ){
		$message = $this->dump( $withSignature );
		$host = $this->data['Via'] ?? $this->data['To'] ?? NULL;
		if ( ! $host ){
			return FALSE;
		}
		if ( is_null( $useSsl ) ){
			$useSsl = ! preg_match( '/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/', $host )
				&& $host != 'localhost';
		}
		if ( is_null( $port ) ){
			$port = $useSsl ? 443 : 80;
		}
		return $this->post_message( $message, $host, $useSsl, $port );
	}


	private function post_message( $content, $host, $useSsl, $port ){
		try {
			$connection = @fsockopen( ( $useSsl ? 'ssl://' : '' ) . $host, $port );
		}
		catch ( Exception $e ) {
			return [ 'status' => -1 ];
		}
		if ( ! $connection ){
			return [ 'status' => -1 ];
		}
		$request = 'POST / HTTP/1.1' . "\r\n"
			. 'Host: ' . $host . ( $port != 80 ? ':' . $port : '' ) . "\r\n"
			. 'Connection: close' . "\r\n"
			. 'Content-Type: text/plain; charset=utf-8' . "\r\n"
			. 'Content-Length: ' . strlen( $content ) . "\r\n"
			. 'X-Partcp-Version: 1.0' . "\r\n"
			. ( ParTCP_Crypto::$useLegacyKx ? '' : 'X-Partcp-Kx-Method: 1' . "\r\n" )
			. "\r\n"
			. $content;
		fwrite( $connection, $request );
		$response = '';
		while ( $data = fgets( $connection ) ) {
			$response .= $data;
		}
		fclose( $connection );
		if ( empty( $response ) ){
			return [ 'status' => '', 'message' => 'Empty response from server',
				'head' => '', 'body' => '' ];
		}
		$headEnd = strpos( $response, "\r\n\r\n" );
		$head = substr( $response, 0, $headEnd );
		$body = substr( $response, $headEnd + 2 );
		list ( $firstLine, $remainder ) = explode( "\r\n", $head, 2 );
		list ( $dummy, $status, $message ) = explode( ' ', $firstLine, 3 );
		if ( strpos( $remainder, "\r\nTransfer-Encoding: chunked\r\n" ) ) {
			$body = '';
			$markerPos = $headEnd + 4;
			$markerLength = strpos( $response, "\r\n", $markerPos ) - $markerPos;
			$dataSize = hexdec( trim( substr( $response, $markerPos, $markerLength ) ) );
			while ( $dataSize > 0 ) {
				$body .= substr( $response, $markerPos + $markerLength + 2, $dataSize );
				$markerPos =  $markerPos + $markerLength + 2 + $dataSize + 2;
				$markerLength = strpos( $response, "\r\n", $markerPos ) - $markerPos;
				$dataSize = hexdec( trim( substr( $response, $markerPos, $markerLength ) ) );
			}
		}
		return compact( 'status', 'message', 'head', 'body' );
	}


	private function encrypt( $value ){
		static $initialized = FALSE;
		if ( ! $initialized ){
			if ( empty( $this->localId->privKey )
				|| empty( $this->remoteId->pubKey )
			){
				throw new Exception('Missing key for encryption');
			}
			ParTCP_Crypto::set_remote_pubkey( $this->remoteId->pubKey );
			ParTCP_Crypto::set_local_privkey( $this->localId->privKey );
			$initialized = TRUE;
		}
		return ParTCP_Crypto::encrypt( $value );
	}
}

// end of file outgoing_message.class.php