<?php
    if (session_id() == "")
    {
       session_start();
    }
    if (!isset($_SESSION['username']))
    {
       $accessdenied_page = '';
       header('Location: '.$accessdenied_page);
       exit;
    }
    $mysql_server = 'localhost';
    $mysql_username = 'bceus_user';
    $mysql_password = 'password';
    $mysql_database = 'bceus_data';
    $mysql_table = 'details2';
    $success_page = '/League.php';
    $username = 'username';
    $_SESSION['username'] = $username;
    $db = mysql_connect($mysql_server, $mysql_username, $mysql_password);
          if (!$db)
          {
             die('Failed to connect to database server!<br>'.mysql_error());
          }
          mysql_select_db($mysql_database, $db) or die('Failed to select database<br>'.mysql_error());

    $sql = "UPDATE `".$mysql_table."` SET `Credit` = IF(Credit > 0, Credit - 20, 0) WHERE `username` = `".$username."`";

    $Result = mysql_query($sql, $db);

    if ($Result < 1) {
    echo "Your Credit is not Enough , Please Buy a Credit";
    }
    header('Location: '.$success_page);
    exit;
    ?>