<?php 
require "vendor/autoload.php";
require "config.php";


class LicenseRegistration {
    private $db = null; 
    private $m_request_body = "";
    private $m_input = FALSE;
    
    function __construct() 
    {
        // Takes raw data from the request
        $this->m_request_body = file_get_contents('php://input');
        $this->m_input = json_decode(($this->m_request_body));
        $this->db = new MeekroDB(DB_HOST, DB_USER, DB_PASS,DB_NAME); // from config file
        //enable exception
        $this->db->error_handler  = false;
        $this->db->nonsql_error_handler = false; 
        $this->db->throw_exception_on_error = true;
        $this->db->throw_exception_on_nonsql_error = true;

    }
    
   
    private function is_valid_input() 
    {
        //if it's not a valid json
        if ( $this->m_input != FALSE && 
             property_exists($this->m_input, "license") && 
             property_exists($this->m_input, "mid")
        ){

            if ( strlen($this->m_input->license) >= 10 &&
                 strlen($this->m_input->mid) >=10 
            ){
                return true; 
            }
            
        }
        $this->record_possible_hack();
        return false; 
    }
    
    private function is_legit_code() 
    {
        $code = $this->m_input->license;
        $f = $this->db->query("SELECT * FROM volume WHERE code='$code'");
        return count($f) == 1 ; 
    }
    
    //record possible hack input
    //save ip, date, request header, and invalid inputs
    private function record_possible_hack()
    {
        $dump = new DumpHTTPRequestToString();
        $req = $dump->execute(); 
        $err = $this->db->insert("hack", array(
            "ip" => $this->get_client_ip(),
            "input" => $this->m_request_body,
            "request" => $req
        ));   
    }
    
    private function fresh_registration()
    {
        $config = $this->get_license_config(); 
        //inser it into database
        $license = [
            'code' => $this->m_input->license,
            'mid' => $this->m_input->mid,
            'seat' => 1,
            'quota' => $this->get_license_quota() ,
            'config' => intVal($config["id"]),
            'enabled' => 1,
            'ip' => $this->get_client_ip()
        ];
 
        try {
            $this->db->insert("register", $license);
            $this->send_config($config, $license);
        }catch (MeekroDBException $e){
            $this->send_error("Failed to add registration, please try again later" );
        }
    }
    
    private function get_exact_match()
    {
        $code = $this->m_input->license;
        $mid = $this->m_input->mid;
        $match =  $this->db->query("SELECT * FROM register WHERE code='$code' AND mid='$mid';");
        if (count($match) !=1 ){
            return FALSE;
        }else{
            return $match[0]; 
        }
    }
    
    private function get_license_by_code()
    {
        $code = $this->m_input->license;
        $matches =  $this->db->query("SELECT * FROM register WHERE code='$code';");
        if (count($matches) < 1 ){
            return FALSE;
        }else{
            return $matches;
        }
    }
    
    private function quota_available($matches)
    {
        return count($matches) < $this->get_license_quota(); 
        
    }
    
    private function allocate_seat($matches){
        $seat = $this->find_empty_seat($matches); 
        $config = $this->get_license_config(); 
        
        $license = array(
            'code' => $this->m_input->license,
            'mid' => $this->m_input->mid,
            'seat' => $seat,
            'quota' => $this->get_license_quota() ,
            'config' => intVal($config["id"]),
            'enabled' => 1,
            'ip' => $this->get_client_ip()
        );
        try {
            $this->db->insert("register",$license);
            $this->send_config($config, $license);
        }catch (MeekroDBException $e){
            $this->send_error("Allocate Seats $seat failed");
        }
        
          
    }
    
    private function find_empty_seat($matches)
    {
        for ($i=1; $i <= $this->get_license_quota(); $i++) {
            if ( $this->seats_occupied($matches, $i) ) 
                continue; 
            return $i; 
        }
    }
    
    private function seats_occupied($matches, $seat)
    {
        for ($i=0; $i< count($matches); $i++){
            if ( $matches[$i]["seat"] == $seat )
                return true; 
        }
        return false; 
    }
    
    //main routine
    public function start_registration() 
    {
        if (! $this->is_valid_input() ){
            $this->send_error("Sorry, your input is invalid");
            return; //stop everything 
        }

        if (! $this->is_legit_code()) { 
            $this->send_error("Sorry, Your license is not valid");
            return; 
        }
            
        //check mid see if a matched license code and mid already exist
        $license = $this->get_exact_match(); 
        if ( $license != FALSE ){ //we found the match both license-code and machine-id  
            //get existing config
            if ( $license['enabled'] == 1 ) {
                $existing_config = $this->get_config_by_id($license["config"]);
                $this->send_config($existing_config, $license);
            }else{
                $this->send_error("Sorry, Your license is disabled"); 
            }
        }else{
            $licenses = $this->get_license_by_code(); 
            
            if ( $licenses == FALSE ) {//not found
                $this->fresh_registration(); 
            }else{//we found, existing records
                if ( $this->quota_available($licenses) ){ 
                    $this->allocate_seat($licenses);
                }else{
                    $this->send_error("Sorry, Your license has been fully allocated");
                }
            }
        }
    }
    
    private function get_config_by_id($id)
    {
        $f= $this->db->query("SELECT * FROM servers WHERE id=$id");
        return $f[0];
    }
    
    private function send_config($config, $license) 
    {
        
        $msg = "" ;
        if ($license["quota"] >1){
           $msg = "Seat " . $license["seat"] . "/" . $license["quota"] . " has been allocated to you";
           
        }else{
            $msg = "Single user license registered sucessfully";
        }
        
        $result= array(
            "success" => true,
            "type" => $config["type"], 
            "host" => $config["host"],
            "port" => $config["port"],
            "username" => $config["user"],
            "password" => $config["pass"], 
            "license" => $license["code"],
            "mid" => $license["mid"],
            "proxyDNS" => true,
            "enable" => true,
            "errMsg" => $msg,
            "link" => "https://hk-01.biukop.com/",
            "linkText" => "Check My IP",
        );
        $myJSON = json_encode($result);
        echo $myJSON; 
    }
    
    private function send_error($msg){
        echo $msg; 
        die(); 
    }
    
    private function decode_pass($encrypt)
    {
        $buf = base64_decode($encrypt);
        if ( substr($buf, -3, 2) != "#!" )
            return "invalid-encrypt";
        
        $magic_digit = intVal(substr($buf, 2 , 1)); 
        $pass = substr($buf,5, -$magic_digit);
        return $pass; 
    }
    
    private function encode_pass($pass) {
        // prefix: "xxyxx";  Y is digit
        $magic_digit = $this->rand_digit();
        $prefix = $this->build_prefix($magic_digit);
        $suffix = $this->build_suffix($magic_digit);     
        //surffix  yyyyy#!xx , max 9  
        return base64_encode($prefix . $pass . $suffix);  
    }
        
    private function rand_char() {
        $pool="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789~!@#$%^&*()_+:{}|<>?[]\;,./";
        $idx = rand(0, strlen($pool) -1 ); 
        return substr($pool, $idx, 1);  
    }
    
    private function rand_digit() {
        return rand(3,9); 
    }
    
    private function build_prefix($magic_digit) 
    {
        return $this->rand_char() . $this->rand_char() . 
                   "$magic_digit" . 
               $this->rand_char() . $this->rand_char();
    }
    
    private function build_suffix($magic_digit)
    {   //$magic_digit >=3
        $suffix = "";
        for ($i=1; $i<= $magic_digit-3; $i++) {
            $suffix .= $this->rand_char();
        }
        $suffix .= "#!";
        $suffix .= $this->rand_char(); 
        return $suffix; 
    }
    
    private function get_client_ip ()
    {
        //whether ip is from share internet
        if (!empty($_SERVER['HTTP_CLIENT_IP']))
        {
            $ip_address = $_SERVER['HTTP_CLIENT_IP'];
        }
        //whether ip is from proxy
        elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
        {
            $ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
        }
        //whether ip is from remote address
        else
        {
            $ip_address = $_SERVER['REMOTE_ADDR'];
        }
        return $ip_address;
    }
    
    private function get_license_quota()
    {
        $code = $this->m_input->license;
        $f = $this->db->query("SELECT * FROM volume WHERE code='$code'");
        return intVal($f[0]["max"]);
    }
    
    private function get_license_config()
    {
        $code = $this->m_input->license;
        $f = $this->db->query("SELECT * FROM servers WHERE code='$code'");
        return $f[0];
    }
    
    public function test_password() {
        $encrypt = $this->encode_pass("superforex");
        $pass1 = $this->decode_pass($encrypt);
        $pass = $this->decode_pass("Y2Q1ZDFzdXBlcmZvcmV4MTIjITU=");
        if ($pass != $pass1){
            echo "wrong"; 
        }
    }
    
    public function test_license_quota() {
        $this->m_input = new stdClass();
        $this->m_input->license = "VOL-XDTG-ADQE-DQERG-QERFDA"; 
        $six = $this->get_license_quota();
        if ($six != 6)
            echo "wrong: license quota"; 
    }
    
    public function test_get_config() {
        $this->m_input = new stdClass();
        $this->m_input->license = "VOL-XDTG-ADQE-DQERG-QERFDA";
        $config = $this->get_license_config(); 
    }
    
    public function test_fresh_registration() {
        $this->m_input = new stdClass();
        $this->m_input->license = "VOL-XDTG-ADQE-DQERG-QERFDA";
        $this->m_input->mid = "AFDAFDSAFDSAFSDAFSAFSDA";
        $this->fresh_registration(); 
        
    }
    
    public function test_licenses() {
        $this->m_input = new stdClass();
        $this->m_input->license = "VOL-XDTG-ADQE-DQERG-QERFDA";
        $this->m_input->mid = "2-AFDAFDSAFDSAFSDAFSAFSDA";
        $this->start_registration(); 
    }
    
    public function test() {
        $this->m_input = new stdClass();
        $this->m_input->license = "VOL";
        $this->m_input->mid = "2-AFD";
        $this->start_registration();
    }
    
}

class DumpHTTPRequestToString {
    public function execute() {
        $data = sprintf(
            "%s %s %s %s\n\nHTTP headers:\n",
            $_SERVER['REQUEST_METHOD'],
            $_SERVER['REQUEST_URI'],
            $_SERVER['SERVER_PROTOCOL'],
            $_SERVER['REMOTE_ADDR']
            );
        foreach ($this->getHeaderList() as $name => $value) {
            $data .= $name . ': ' . $value . "\n";
        }
        $data .= "\nRequest body:\n" . file_get_contents('php://input');
        return $data; 
    }
    private function getHeaderList() {
        $headerList = [];
        foreach ($_SERVER as $name => $value) {
            if (preg_match('/^HTTP_/',$name)) {
                // convert HTTP_HEADER_NAME to Header-Name
                $name = strtr(substr($name,5),'_',' ');
                $name = ucwords(strtolower($name));
                $name = strtr($name,' ','-');
                // add to list
                $headerList[$name] = $value;
            }
        }
        return $headerList;
    }
}

$bb = new LicenseRegistration();
$bb->start_registration();
//$bb->test(); 

?>