HashUtil.php

<?php

/**
 * HashUtils
 * Decode and encode telegram file ids, inline message ids and more
 * This code is under GPLv3 license, see <https://www.gnu.org/licenses/#GPL>.
 *
 * @author    Sys-001 <https://github.com/sys-001>
 * @author    Giuseppe Marino <https://github.com/giuseppeM99/>
 * @copyright 2018 Sys-001
 * @copyright 2018-2021 Giuseppe Marino
 * @license   https://opensource.org/licenses/GPL-3.0 GPLv3
 *
 */
 
class HashUtil
{

    public const WEB_LOCATION_FLAG = 1 << 24;
    public const FILE_REFERENCE_FLAG = 1 << 25;

    public const THUMBNAIL = 0x00;
    public const PROFILE_PHOTO = 0x01;
    public const PHOTO = 0x02;
    public const VOICE = 0x03;
    public const VIDEO = 0x04;
    public const DOCUMENT = 0x05;
    public const ENCRYPTED = 0x06;
    public const TEMP = 0x07;
    public const STICKER = 0x08;
    public const AUDIO = 0x09;
    public const GIF = 0x0A;
    public const ENCRYPTED_THUMBNAIL = 0x0B;
    public const WALLPAPER = 0x0C;
    public const VIDEO_NOTE = 0x0D;
    public const SECURE_RAW = 0x0F;
    public const SECURE = 0x10;
    public const BACKGROUND = 0x11;
    public const SIZE = 0x12;

    /**
     * @param string $type
     * @param int $dc_id
     * @param int $id
     * @param int $access_hash
     * @param int|null $volume_id
     * @param int|null $secret
     * @param int|null $local_id
     * @return string
     * @throws Exception
     */
    public static function encodeFileIdInfo(
        string $type,
        int $dc_id,
        int $id,
        int $access_hash,
        int $volume_id = null,
        int $secret = null,
        int $local_id = null
    ) {
        switch ($type) {
            case 'Thumb':
                $file_type = self::THUMBNAIL;
            case 'Photo':
                if (empty($file_type)) {
                    $file_type = self::PHOTO;
                }
                if (empty($volume_id) or empty($secret) or empty($local_id)) {
                    throw new Exception("Missing required parameters for file type");
                }
                $file_id = pack('VVqqqqV', $file_type, $dc_id, $id, $access_hash, $volume_id, $secret, $local_id);
                break;
            case 'Voice':
                $file_type = self::VOICE;
            case 'Video':
                if (empty($file_type)) {
                    $file_type = self::VIDEO;
                }
            case 'Document':
                if (empty($file_type)) {
                    $file_type = self::DOCUMENT;
                }
            case 'Sticker':
                if (empty($file_type)) {
                    $file_type = self::STICKER;
                }
            case 'Audio':
                if (empty($file_type)) {
                    $file_type = self::AUDIO;
                }
            case 'Animation':
                if (empty($file_type)) {
                    $file_type = self::GIF;
                }
            case 'VideoNote':
                if (empty($file_type)) {
                    $file_type = self::VIDEO_NOTE;
                }
                $file_id = pack('VVqq', $file_type, $dc_id, $id, $access_hash);
                break;
            default:
                $file_id = null;
                break;
        }
        return self::base64UrlEncode(self::rleEncode($file_id . chr(2)));
    }

    /**
     * @param string $string
     * @return string
     */
    protected static function base64UrlEncode(string $string): string
    {
        return str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($string));
    }

    /**
     * @param string $string
     * @return string
     */
    protected static function rleEncode(string $string): string
    {
        $new = '';
        $count = 0;
        $null = chr(0);
        foreach (str_split($string) as $cur) {
            if ($cur === $null) {
                $count++;
            } else {
                if ($count > 0) {
                    $new .= $null . chr($count);
                    $count = 0;
                }
                $new .= $cur;
            }
        }
        return $new;
    }

    /**
     * @param string $file_id
     * @return array
     */
    public static function decodeFileIdInfo(string $file_id)
    {
        $file_info = self::rleDecode(self::base64UrlDecode($file_id));

        $file_type = unpack('C', substr($file_info, 0, 1))[1];
        $file_flags = unpack('V', chr(0) . substr($file_info, 1, 3))[1];

        $version = \ord($file_info[\strlen($file_info) - 1]);
        $subVersion = $version === 4 ? \ord($file_info[\strlen($file_info) - 2]) : 0;

        $file_info = substr($file_info, 4);
        $dc_id = unpack('V', $file_info)[1];
        $file_info = substr($file_info, 4);

        switch ($file_type) {
            case self::THUMBNAIL:
                if (empty($type)) {
                    $type = 'Thumb';
                }
            case self::PROFILE_PHOTO:
                if (empty($type)) {
                    $type = 'profile_photo';
                }
            case self::PHOTO:
                if (empty($type)) {
                    $type = 'Photo';
                }
                $infostring = 'qid/qaccess_hash/qvolume_id/qsecret/Vrobastrana/Vlocal_id';
                //$local_id = unpack('V', substr($file_info, -6))[1];
                break;
            case self::VOICE:
                $type = 'Voice';
            case self::VIDEO:
                if (empty($type)) {
                    $type = 'Video';
                }
            case self::DOCUMENT:
                if (empty($type)) {
                    $type = 'Document';
                }
            case self::ENCRYPTED:
                if (empty($type)) {
                    $type = 'Encrypted';
                }
            case self::TEMP:
                if (empty($type)) {
                    $type = 'Temp';
                }
            case self::STICKER:
                if (empty($type)) {
                    $type = 'Sticker';
                }
            case self::AUDIO:
                if (empty($type)) {
                    $type = 'Audio';
                }
            case self::GIF:
                if (empty($type)) {
                    $type = 'Animation';
                }
            case self::ENCRYPTED_THUMBNAIL:
                if (empty($type)) {
                    $type = 'EncryptedThumbnail';
                }
            case self::WALLPAPER:
                if (empty($type)) {
                    $type = 'Wallpaper';
                }
            case self::VIDEO_NOTE:
                if (empty($type)) {
                    $type = 'VideoNote';
                }
            //case 0x0E:
            //     :shrug:
            case self::SECURE_RAW:
                if (empty($type)) {
                    $type = 'SecureRaw';
                }
            case self::SECURE:
                if (empty($type)) {
                    $type = 'Secure';
                }
            case self::BACKGROUND:
                if (empty($type)) {
                    $type = 'Background';
                }
            case self::SIZE:
                if (empty($type)) {
                    $type = 'Size';
                }
                $infostring = 'qid/qaccess_hash';
                break;
            default:
                $infostring = '';
                $type = $file_type;
                break;
        }

        if ($file_flags & self::FILE_REFERENCE_FLAG) {
            $frlen = ord($file_info[0]);
            $file_info[0] = chr(0);
            if ($frlen == 254) {
                $frlen = unpack('V', $file_info)[1];
                $pad = self::posmod(-$frlen, 4);
            } else {
                $pad = self::posmod(-$frlen, -4);
            }

            $file_reference = substr($file_info, 0, $frlen);
            $file_info = substr($file_info, $frlen+$pad);
        }

        $decrypted_info = unpack($infostring, $file_info);
        $decrypted_info['type'] = $type;
        $decrypted_info['dc_id'] = $dc_id;
        $decrypted_info['version'] = "$version.$subVersion";
        $decrypted_info['flags'] = $file_flags;

        if (isset($file_reference)) {
            $decrypted_info['file_reference'] = self::base64UrlEncode($file_reference);
        }
        if (isset($local_id)) {
            $decrypted_info['local_id'] = $local_id;
        }

        return $decrypted_info;
    }

    /**
     * @param string $string
     * @return string
     */
    protected static function rleDecode(string $string): string
    {
        $new = '';
        $last = '';
        $null = chr(0);
        foreach (str_split($string) as $cur) {
            if ($last === $null) {
                $new .= str_repeat($last, ord($cur));
                $last = '';
            } else {
                $new .= $last;
                $last = $cur;
            }
        }
        return $new . $last;
    }

    /**
     * @param string $string
     * @return string
     */
    protected static function base64UrlDecode(string $string): string
    {
        return base64_decode(str_pad(strtr($string, '-_', '+/'), strlen($string) % 4, '=', STR_PAD_RIGHT));
    }

    /**
     * @param int $chat_creator
     * @param int $chat_id
     * @param int $access_hash
     * @return string
     */
    public static function encodeChatInviteHashInfo(int $chat_creator, int $chat_id, int $access_hash): string
    {
        $inverted_hash = pack('q', $access_hash);
        $inverted_hash = unpack('q', strrev($inverted_hash))[1];
        if (strpos((string)$chat_id, '-100') === 0) {
            $chat_id = substr($chat_id, 4);
            $chat_id = (int)$chat_id;
        } else {
            $chat_id = substr($chat_id, 1);
        }
        $chat_id = (int)$chat_id;
        $chat_invite_hash = pack('NNq', $chat_creator, $chat_id, $inverted_hash);
        return self::base64UrlEncode($chat_invite_hash);
    }

    /**
     * @param string $chat_invite_hash
     * @return array
     */
    public static function decodeChatInviteHashInfo(string $chat_invite_hash): array
    {
        $chat_invite_info = self::base64UrlDecode($chat_invite_hash);
        $decrypted_info = unpack('Nchat_creator/Nchat_id/qaccess_hash', $chat_invite_info);
        if (strlen($decrypted_info['chat_id']) < 10) {
            $chat_id = '-' . $decrypted_info['chat_id'];
            $decrypted_info['chat_id'] = (int)$chat_id;
            return $decrypted_info;
        }
        $chat_id = '-100' . $decrypted_info['chat_id'];
        $decrypted_info['chat_id'] = (int)$chat_id;
        $real_hash = pack('q', $decrypted_info['access_hash']);
        $decrypted_info['access_hash'] = unpack('q', strrev($real_hash))[1];
        return $decrypted_info;
    }

    /**
     * @param int $dc_id
     * @param int $message_id
     * @param int $chat_id
     * @param int $access_hash
     * @return string
     */
    public static function encodeInlineMessageIdInfo(
        int $dc_id,
        int $message_id,
        int $chat_id,
        int $access_hash
    ): string {
        if ($chat_id < 0) {
            $chat_id = substr($chat_id, 4);
            $chat_id = (int)$chat_id * -1;
        }
        $inline_message_id = pack('VVlq', $dc_id, $message_id, $chat_id, $access_hash);
        return self::base64UrlEncode($inline_message_id);
    }

    /**
     * @param string $inline_message_id
     * @return array
     */
    public static function decodeInlineMessageIdInfo(string $inline_message_id): array
    {
        $inline_message_info = self::base64UrlDecode($inline_message_id);
        $decrypted_info = unpack('Vdc_id/Vmessage_id/lchat_id/qaccess_hash', $inline_message_info);
        if ($decrypted_info['chat_id'] < 0) {
            $chat_id = '-100' . ($decrypted_info['chat_id'] * -1);
            $decrypted_info['chat_id'] = (int)$chat_id;
            return $decrypted_info;
        }
        $decrypted_info['user_id'] = $decrypted_info['chat_id'];
        unset($decrypted_info['chat_id']);
        return $decrypted_info;
    }


    /**
     * @param int $a
     * @param int $b
     * @return int
     */
    public static function posmod(int $a, int $b): int
    {
        $resto = $a % $b;

        return $resto < 0 ? $resto + \abs($b) : $resto;
    }
}