<?php namespace TNEFDecoder;

/**
 * SquirrelMail TNEF Decoder Plugin
 *
 * Copyright (c) 2010- Paul Lesniewski <paul@squirrelmail.org>
 * Copyright (c) 2003  Bernd Wiegmann <bernd@wib-software.de>
 * Copyright (c) 2002  Graham Norburys <gnorbury@bondcar.com>
 *
 * Licensed under the GNU GPL. For full terms see the file COPYING.
 *
 * @package plugins
 * @subpackage tnef_decoder
 *
 */
class TNEFFileRTF extends TNEFFileBase
{
	public string $name = 'EmbeddedRTF.rtf';
	public string $type = 'application/rtf';
	protected int $size = 0;
	const MAX_DICT_SIZE = 4096;
	const INIT_DICT_SIZE = 207;

	public function __construct($debug, $data)
	{
		parent::__construct($debug);
		$this->decode_crtf(new TNEFBuffer($data));
	}

	public function getSize(): int
	{
		return $this->size;
	}

	public function decode_crtf(TNEFBuffer $buffer)
	{
		$size_compressed = $buffer->geti32();
		$this->size = $buffer->geti32();
		$magic = $buffer->geti32();
		$crc32 = $buffer->geti32();

		$this->debug && tnef_log("CRTF: size comp={$size_compressed}, size={$this->size}");

		$data = $buffer->getBytes($buffer->getRemainingBytes());

		switch ($magic) {
			case CRTF_COMPRESSED:
				$this->uncompress($data);
				break;

			case CRTF_UNCOMPRESSED:
				$this->content = $data;
				break;

			default:
				$this->debug && tnef_log("Unknown Compressed RTF Format");
				break;
		}
	}

	public function uncompress($data)
	{
		$preload = "{\\rtf1\\ansi\\mac\\deff0\\deftab720{\\fonttbl;}{\\f0\\fnil \\froman \\fswiss \\fmodern \\fscript \\fdecor MS Sans SerifSymbolArialTimes New RomanCourier{\\colortbl\\red0\\green0\\blue0\n\r\\par \\pard\\plain\\f0\\fs20\\b\\i\\u\\tab\\tx";
		$length_preload = \strlen($preload);
		$init_dict = [];
		for ($cnt = 0; $cnt < $length_preload; ++$cnt) {
			$init_dict[$cnt] = $preload[$cnt];
		}
		$init_dict = \array_merge($init_dict, \array_fill(\count($init_dict), self::MAX_DICT_SIZE - $length_preload, ' '));
		$write_offset = self::INIT_DICT_SIZE;
		$this->content = '';
		$end = false;
		$in = 0;
		$l = \strlen($data);
		while (!$end) {
			if ($in >= $l) {
				break;
			}
			$control = \strrev(\str_pad(\decbin(\ord($data[$in++])), 8, 0, STR_PAD_LEFT));
			for ($i = 0; $i < 8; ++$i) {
				if ($control[$i] == '1') {
					$token = \unpack("n", $data[$in++] . $data[$in++])[1];
					$offset = ($token >> 4) & 0b111111111111;
					$length = $token & 0b1111;
					if ($write_offset == $offset) {
						$end = true;
						break;
					}
					$actual_length = $length + 2;
					for ($step = 0; $step < $actual_length; ++$step) {
						$read_offset = ($offset + $step) % self::MAX_DICT_SIZE;
						$char = $init_dict[$read_offset];
						$this->content .= $char;
						$init_dict[$write_offset] = $char;
						$write_offset = ($write_offset + 1) % self::MAX_DICT_SIZE;
					}
				} else {
					if ($in >= $l) {
						break;
					}
					$val = $data[$in++];
					$this->content .= $val;
					$init_dict[$write_offset] = $val;
					$write_offset = ($write_offset + 1) % self::MAX_DICT_SIZE;
				}
			}
		}
	}

}