<?php
$upload_dir = './pliki/';
$maxfilesize = 102400;

$userfile = $_FILES['userfile'];

if(isset($_POST['send']))
{
    if(is_uploaded_file($userfile['tmp_name']))
    {
        if($userfile['size'] <= $maxfilesize)
        {
            $file_patch = $upload_dir.'/'.$userfile['name'];
            if (file_exists($file_patch))
            {
                $extension = explode('.', $userfile['name']);
                $cnt = count($extension) -2;
                $file_name = '';
                for ($i=0; $i<$cnt; $i++)
                {
                    $file_name .= $extension[$i];
                }
                $i_ext = count($extension) -1;
                $file_patch = $upload_dir.'/'.$file_name.'('.date('YmdGi',time()).').'.$extension[$i_ext];
            }
            if(move_uploaded_file($userfile['tmp_name'], $file_patch))
            {
                echo '<p>Plik został wysłany</p>';
            }
      
        }
    }
}
?>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">
  <input type="hidden" name="MAX_FILE_SIZE" value="<?php echo $maxfilesize; ?>">
  <input type="file" name="userfile">
  <input type="submit" name="send" value="Wyslij plik">
</form>