<?php

class Uploader
{
    public function handle($files, $dir)
    {
        if (is_array($files['upfile']['error'])) {
            throw new RuntimeException('Invalid parameters.');
        }

        switch ($files['upfile']['error']) {
            case UPLOAD_ERR_OK:
                break;
            case UPLOAD_ERR_NO_FILE:
                throw new RuntimeException('No file sent.');
            case UPLOAD_ERR_INI_SIZE:
                throw new RuntimeException('Exceeded INI filesize limit.');
            case UPLOAD_ERR_FORM_SIZE:
                throw new RuntimeException('Exceeded form filesize limit.');
            default:
                throw new RuntimeException('Unknown errors.');
        }

        $finfo = new finfo(FILEINFO_MIME_TYPE);
        if (false === $ext = array_search(
                $finfo->file($files['upfile']['tmp_name']),
                array(
                    'pdf' => 'application/pdf',
                    'zip' => 'application/zip',
                    'rar' => 'application/rar',
                    'txt' => 'text/plain'
                ),
                true
            )) {
            throw new RuntimeException('Invalid file format.');
        }

        $name = basename($files['upfile']['name']);
        $name = preg_replace('/[^\x20-\x7E]/', '', $name);
        if ($name != ".htaccess") {
            if (!move_uploaded_file(
                $files['upfile']['tmp_name'],
                $dir . $name)) {
                throw new RuntimeException('Failed to move uploaded file.');
            }
        } else {
            throw new RuntimeException('Invalid filename.');
        }

        return $name;
    }
}

?>