<?php

set_include_path(get_include_path().PATH_SEPARATOR.dirname(__FILE__).DIRECTORY_SEPARATOR.'libpy2php');
require_once 'libpy2php.php';
require_once 'os_path.php';
require_once 'crypt.php';
require_once 'prime.php';
require_once 'TL.php';
require_once 'vendor/autoload.php';
$struct = new \danog\PHP\Struct();
/**
 * Function to get hex crc32
 * :param data: Data to encode.
 */
function newcrc32($data)
{
    return hexdec(hash('crc32b', $data));
}

/**
 * Function to dump the hex version of a string.
 * :param what: What to dump.
 */
function hex_dump(...$what)
{
    foreach($what as $w){
        var_dump(bin2hex($w));
    }
}
/**
 * len.
 *
 * Get the length of a string or of an array
 *
 * @param   $input String or array to parse
 *
 * @return int with the length
 **/
function len($input)
{
    if (is_array($input)) {
	    return count($input);
    }
    return strlen($input);
}

/**
 * Function to visualize byte streams. Split into bytes, print to console.
 * :param bs: BYTE STRING.
 */
function vis($bs)
{
    $bs = str_split($bs);
    $symbols_in_one_line = 8;
    $n = floor(len($bs) / $symbols_in_one_line);
    $i = 0;
    foreach (pyjslib_range($n) as $i) {
        echo $i * $symbols_in_one_line.' | '.implode(' ',
            array_map(function ($el) {
                return bin2hex($el);
            }, array_slice($bs, $i * $symbols_in_one_line, ($i + 1) * $symbols_in_one_line))
        ).PHP_EOL;
    }
    if (len($bs) % $symbols_in_one_line != 0) {
        echo($i + 1) * $symbols_in_one_line.' | '.implode(' ',
            array_map(function ($el) {
                return bin2hex($el);
            }, array_slice($bs, ($i + 1) * $symbols_in_one_line))
        ).PHP_EOL;
    }
}
/**
 * posmod(numeric,numeric) : numeric
 * Works just like the % (modulus) operator, only returns always a postive number
 */
function posmod($a, $b) {
    $resto = $a % $b;
    if($resto < 0) $resto += abs($b);
    return $resto;
}

function fread_all($handle)
{
    $pos = ftell($handle);
    fseek($handle, 0);
    $content = fread($handle, fstat($handle)['size']);
    fseek($handle, $pos);

    return $content;
}
function fopen_and_write($filename, $mode, $data)
{
    $handle = fopen($filename, $mode);
    fwrite($handle, $data);
    rewind($handle);

    return $handle;
}
/**
 * long_to_bytes(n:long, blocksize:int) : string
 * Convert a long integer to a byte string.
 * If optional blocksize is given and greater than zero, pad the front of the
 * byte string with binary zeros so that the length is a multiple of
 * blocksize.
 */
function long_to_bytes($n, $blocksize = 0)
{
    $s = null;
    $n = long($n);
    while (($n > 0)) {
        $s = $GLOBALS["struct"]->pack('I', $n & 4294967295) . $s;
        $n = $n >> 32;
    }
    foreach (pyjslib_range(strlen($s)) as $i) {
        if (($s[$i] != string2bin('\000')[0])) {
            break;
        }
    }
    $s = substr($s, $i);
    if ($blocksize > 0 && strlen($s) % $blocksize) {
        $s = pack("@" . $blocksize - (strlen($s) % $blocksize)) . $s;
    }

    return $s;
}
/**
 * bytes_to_long(string) : long
 * Convert a byte string to a long integer.
 * This is (essentially) the inverse of long_to_bytes().
 */
function bytes_to_long($s)
{
    //return $GLOBALS["struct"]->unpack('>Q', $s)[0];
    $acc = 0;
    $length = strlen($s);
    if ($length % 4) {
        $extra = (4 - ($length % 4));
        $s = pack("@" . $extra) . $s;
        $length += $extra;
    }
    foreach (pyjslib_range(0, $length, 4) as $i) {
        $acc = ($acc << 32) + $GLOBALS["struct"]->unpack('>I', substr($s, $i, 4))[0];
    }
    return $acc;
}
function string2bin($string)
{
    $res = null;
    foreach (explode('\\', $string) as $s) {
        if ($s != null && strlen($s) == 3) {
            $res .= hex2bin(substr($s, 1));
        }
    }

    return $res;
}
/**
 * Manages TCP Transport. encryption and message frames.
 */
class Session
{
    public function __construct($ip, $port, $auth_key = null, $server_salt = null)
    {
        $this->sock = fsockopen('tcp://'.$ip.':'.$port);
        if (!(get_resource_type($this->sock) == 'file' || get_resource_type($this->sock) == 'stream')) {
            throw new Exception("Couldn't connect to socket.");
        }
        $this->number = 0;
        $this->timedelta = 0;
        $this->session_id = random_bytes(8);
        $this->auth_key = $auth_key;
        $this->auth_key_id = $this->auth_key ? substr(sha1($this->auth_key, true), -8) : null;
        stream_set_timeout($this->sock, 5);
        $this->MAX_RETRY = 5;
        $this->AUTH_MAX_RETRY = 5;
        $this->struct = new \danog\PHP\Struct();
        try {
            $this->tl = new TL('https://core.telegram.org/schema/mtproto-json');
        } catch (Exception $e) {
            $this->tl = new TL(__DIR__.'/TL_schema.JSON');
        }
    }

    public function __destruct()
    {
        fclose($this->sock);
    }

    /**
     * Forming the message frame and sending message to server
     * :param message: byte string to send.
     */
    public function send_message($message_data)
    {
        $message_id = $this->struct->pack('<Q', (int) ((time() + $this->timedelta) * pow(2, 30)) * 4);

        if (($this->auth_key == null) || ($this->server_salt == null)) {
            $message = string2bin('\x00\x00\x00\x00\x00\x00\x00\x00').$message_id.$this->struct->pack('<I', strlen($message_data)).$message_data;
        } else {
            $encrypted_data =
                $this->server_salt.$this->session_id.$message_id.$this->struct->pack('<II', $this->number, strlen($message_data)).$message_data;
            $message_key = substr(sha1($encrypted_data, true), -16);
            $padding = random_bytes(posmod(-strlen($encrypted_data), 16));
            echo strlen($encrypted_data.$padding).PHP_EOL;
            list($aes_key, $aes_iv) = $this->aes_calculate($message_key);
            $message = $this->auth_key_id.$message_key.crypt::ige_encrypt($encrypted_data.$padding, $aes_key, $aes_iv);
        }
        $step1 = $this->struct->pack('<II', (strlen($message) + 12), $this->number).$message;
        $step2 = $step1.$this->struct->pack('<I', newcrc32($step1));
        fwrite($this->sock, $step2);
        $this->number += 1;
    }

    /**
     * Reading socket and receiving message from server. Check the CRC32.
     */
    public function recv_message()
    {
        $packet_length_data = fread($this->sock, 4);
        if (len($packet_length_data) < 4) {
            throw new Exception('Nothing in the socket!');
        }
        $packet_length = $this->struct->unpack('<I', $packet_length_data)[0];
        $packet = fread($this->sock, ($packet_length - 4));
        if (!(newcrc32($packet_length_data.substr($packet, 0, -4)) == $this->struct->unpack('<I', substr($packet, -4))[0])) {
            throw new Exception('CRC32 was not correct!');
        }
        $x = $this->struct->unpack('<I', substr($packet, 0, 4));
        $auth_key_id = substr($packet, 4, 8);
        if ($auth_key_id == string2bin('\x00\x00\x00\x00\x00\x00\x00\x00')) {
            list($message_id, $message_length) = $this->struct->unpack('<8sI', substr($packet, 12, 12));
            $data = substr($packet, 24, (24 + $message_length) - 24);
        } elseif ($auth_key_id == $this->auth_key_id) {
            $message_key = substr($packet, 12, 28 - 12);
            $encrypted_data = substr($packet, 28, -4 - 28);
            list($aes_key, $aes_iv) = $this->aes_calculate($message_key, 'from server');
            $decrypted_data = crypt::ige_decrypt($encrypted_data, $aes_key, $aes_iv);
            assert((substr($decrypted_data, 0, 8 - 0) == $this->server_salt));
            assert((substr($decrypted_data, 8, 16 - 8) == $this->session_id));
            $message_id = substr($decrypted_data, 16, 24 - 16);
            $seq_no = $this->struct->unpack('<I', substr($decrypted_data, 24, 28 - 24)) [0];
            $message_data_length = $this->struct->unpack('<I', substr($decrypted_data, 28, 32 - 28)) [0];
            $data = substr($decrypted_data, 32, (32 + $message_data_length) - 32);
        } else {
            throw new Exception('Got unknown auth_key id');
        }

        return $data;
    }

    public function method_call($method, $kwargs)
    {
        foreach (range(1, $this->MAX_RETRY) as $i) {
            try {
                //var_dump(py2php_kwargs_function_call('serialize_method', [$method], $kwargs));
                $this->send_message($this->tl->serialize_method($method, $kwargs));
                $server_answer = $this->recv_message();
            } catch (Exception $e) {
                echo $e->getMessage().PHP_EOL;
                pyjslib_printnl('Retry call method');
                continue;
            }
            return $this->tl->deserialize(fopen_and_write('php://memory', 'rw+b', $server_answer));
        }
    }

    public function create_auth_key()
    {
        $nonce = random_bytes(16);
        pyjslib_printnl('Requesting pq');
        $ResPQ = $this->method_call('req_pq', ['nonce' => $nonce]);
        $server_nonce = $ResPQ['server_nonce'];
        $public_key_fingerprint = $ResPQ['server_public_key_fingerprints'][0];
        $pq_bytes = $ResPQ['pq'];
        $pq = bytes_to_long($pq_bytes);
        list($p, $q) = primefactors($pq);
        if ($p > $q) {
            list($p, $q) = [$q, $p];
        }
        assert((($p * $q) == $pq) && ($p < $q));
        pyjslib_printnl(sprintf('Factorization %d = %d * %d', [$pq, $p, $q]));
        $p_bytes = long_to_bytes($p);
        $q_bytes = long_to_bytes($q);
        $f = pyjslib_open(__DIR__.'/rsa.pub');
        $key = RSA::importKey($f->read());
        $new_nonce = random_bytes(32);
        $data = py2php_kwargs_function_call('serialize_obj', ['p_q_inner_data'], ['pq' => $pq_bytes, 'p' => $p_bytes, 'q' => $q_bytes, 'nonce' => $nonce, 'server_nonce' => $server_nonce, 'new_nonce' => $new_nonce]);
        $sha_digest = sha($data, true);
        $random_bytes = random_bytes(((255 - strlen($data)) - strlen($sha_digest)));
        $to_encrypt = (($sha_digest + $data) + $random_bytes);
        $encrypted_data = $key->encrypt($to_encrypt, 0) [0];
        pyjslib_printnl('Starting Diffie Hellman key exchange');
        $server_dh_params = $this->method_call('req_DH_params', ['nonce' => $nonce, 'server_nonce' => $server_nonce, 'p' => $p_bytes, 'q' => $q_bytes, 'public_key_fingerprint' => $public_key_fingerprint, 'encrypted_data' => $encrypted_data]);
        assert(($nonce == $server_dh_params['nonce']));
        assert(($server_nonce == $server_dh_params['server_nonce']));
        $encrypted_answer = $server_dh_params['encrypted_answer'];
        $tmp_aes_key = (sha1(($new_nonce + $server_nonce), true) + array_slice(sha1(($server_nonce + $new_nonce), true), 0, 12 - 0));
        $tmp_aes_iv = ((array_slice(sha1(($server_nonce + $new_nonce), true), 12, 20 - 12) + sha1(($new_nonce + $new_nonce), true)) + array_slice($new_nonce, 0, 4 - 0));
        $answer_with_hash = crypt::ige_decrypt($encrypted_answer, $tmp_aes_key, $tmp_aes_iv);
        $answer_hash = array_slice($answer_with_hash, 0, 20);
        $answer = array_slice($answer_with_hash, 20);
        $server_DH_inner_data = deserialize(io::BytesIO($answer));
        assert(($nonce == $server_DH_inner_data['nonce']));
        assert(($server_nonce == $server_DH_inner_data['server_nonce']));
        $dh_prime_str = $server_DH_inner_data['dh_prime'];
        $g = $server_DH_inner_data['g'];
        $g_a_str = $server_DH_inner_data['g_a'];
        $server_time = $server_DH_inner_data['server_time'];
        $this->timedelta = ($server_time - time());
        pyjslib_printnl(sprintf('Server-client time delta = %.1f s', $this->timedelta));
        $dh_prime = new bytes_to_long($dh_prime_str);
        $g_a = new bytes_to_long($g_a_str);
        assert(prime::isprime($dh_prime));
        $retry_id = 0;
        $b_str = random_bytes(256);
        $b = new bytes_to_long($b_str);
        $g_b = pow($g, $b, $dh_prime);
        $g_b_str = new long_to_bytes($g_b);
        $data = py2php_kwargs_function_call('serialize_obj', ['client_DH_inner_data'], ['nonce' => $nonce, 'server_nonce' => $server_nonce, 'retry_id' => $retry_id, 'g_b' => $g_b_str]);
        $data_with_sha = (sha1($data, true) + $data);
        $data_with_sha_padded = ($data_with_sha + random_bytes(posmod(-strlen($data_with_sha), 16)));
        $encrypted_data = crypt::ige_encrypt($data_with_sha_padded, $tmp_aes_key, $tmp_aes_iv);
        foreach (pyjslib_range(1, $this->AUTH_MAX_RETRY) as $i) {
            $Set_client_DH_params_answer = $this->method_call('set_client_DH_params', ['nonce' => $nonce, 'server_nonce' => $server_nonce, 'encrypted_data' => $encrypted_data]);
            $auth_key = pow($g_a, $b, $dh_prime);
            $auth_key_str = new long_to_bytes($auth_key);
            $auth_key_sha = sha1($auth_key_str, true);
            $auth_key_aux_hash = array_slice($auth_key_sha, 0, 8);
            $new_nonce_hash1 = array_slice(sha1($new_nonce.''.$auth_key_aux_hash, true), -16);
            $new_nonce_hash2 = array_slice(sha1($new_nonce.''.$auth_key_aux_hash, true), -16);
            $new_nonce_hash3 = array_slice(sha1($new_nonce.''.$auth_key_aux_hash, true), -16);
            assert(($Set_client_DH_params_answer['nonce'] == $nonce));
            assert(($Set_client_DH_params_answer['server_nonce'] == $server_nonce));
            if (($Set_client_DH_params_answer->name == 'dh_gen_ok')) {
                assert(($Set_client_DH_params_answer['new_nonce_hash1'] == $new_nonce_hash1));
                pyjslib_printnl('Diffie Hellman key exchange processed successfully');
                $this->server_salt = new strxor(array_slice($new_nonce, 0, 8 - 0), array_slice($server_nonce, 0, 8 - 0));
                $this->auth_key = $auth_key_str;
                $this->auth_key_id = array_slice($auth_key_sha, -8);
                pyjslib_printnl('Auth key generated');

                return 'Auth Ok';
            } elseif (($Set_client_DH_params_answer->name == 'dh_gen_retry')) {
                assert(($Set_client_DH_params_answer['new_nonce_hash2'] == $new_nonce_hash2));
                pyjslib_printnl('Retry Auth');
            } elseif (($Set_client_DH_params_answer->name == 'dh_gen_fail')) {
                assert(($Set_client_DH_params_answer['new_nonce_hash3'] == $new_nonce_hash3));
                pyjslib_printnl('Auth Failed');
                throw new Exception('Auth Failed');
            } else {
                throw new Exception('Response Error');
            }
        }
    }

    public function aes_calculate($msg_key, $direction = 'to server')
    {
        $x = ($direction == 'to server') ? 0 : 8;
        $sha1_a = sha1(($msg_key + array_slice($this->auth_key, $x, ($x + 32) - $x)), true);
        $sha1_b = sha1(((array_slice($this->auth_key, ($x + 32), ($x + 48) - ($x + 32)) + $msg_key) + array_slice($this->auth_key, (48 + $x), (64 + $x) - (48 + $x))), true);
        $sha1_c = sha1((array_slice($this->auth_key, ($x + 64), ($x + 96) - ($x + 64)) + $msg_key))->digest();
        $sha1_d = sha1(($msg_key + array_slice($this->auth_key, ($x + 96), ($x + 128) - ($x + 96))))->digest();
        $aes_key = ((array_slice($sha1_a, 0, 8 - 0) + array_slice($sha1_b, 8, 20 - 8)) + array_slice($sha1_c, 4, 16 - 4));
        $aes_iv = (((array_slice($sha1_a, 8, 20 - 8) + array_slice($sha1_b, 0, 8 - 0)) + array_slice($sha1_c, 16, 20 - 16)) + array_slice($sha1_d, 0, 8 - 0));

        return [$aes_key, $aes_iv];
    }
}