<?php

// Mini-TinyURL script
// v0.5
// By BohwaZ 2006-2013 <http://bohwaz.net/>
// GNU/GPL License

define('CONFIG_FILE', dirname(__FILE__) . '/' . basename(__FILE__, '.php') . '.config.php');

if (file_exists(CONFIG_FILE))
{
    require CONFIG_FILE;
}

if (!defined('DB_FILE'))
    define('DB_FILE', dirname(__FILE__) . '/urls.sqlite');

if (!defined('BASE_URL'))
    define('BASE_URL', 'http://'. $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']);

if (!defined('REDIR_URL'))
    define('REDIR_URL', BASE_URL . '?');

if (!defined('ENABLE_API'))
    define('ENABLE_API', true);

if (!defined('ENABLE_EXPORT'))
    define('ENABLE_EXPORT', true);

// TinyURL class
class TinyURL
{
    private $db;

    static private $base_index = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$-_+!*\'(),';

    static private function baseConv($num, $base=null)
    {
        if (is_null($base))
            $base = strlen(self::$base_index);

        $index = substr(self::$base_index, 0, $base);

        $out = "";
        for ($t = floor(log10($num) / log10($base)); $t >= 0; $t--)
        {
            $a = floor($num / pow($base, $t));
            $out = $out . substr($index, $a, 1);
            $num = $num - ($a * pow($base, $t));
        }

        return $out;
    }

    static private function baseConvReverse($num, $base=null)
    {
        if (is_null($base))
            $base = strlen(self::$base_index);

        $index = substr(self::$base_index, 0, $base);

        $out = 0;
        $len = strlen($num) - 1;

        for ($t = 0; $t <= $len; $t++)
        {
            $out = $out + strpos($index, substr($num, $t, 1)) * pow($base, $len - $t);
        }

        return $out;
    }

    public function __construct()
    {
        $init = file_exists(DB_FILE) ? false : true;

        $this->db = new SQLite3(DB_FILE);

        if ($init)
        {
            $this->db->exec('CREATE TABLE urls (id VARCHAR(255) NOT NULL PRIMARY KEY, url VARCHAR(255) NOT NULL);');
        }
    }

    public function checkID($id)
    {
        return preg_match('!^['.preg_quote(self::$base_index, '!') . ']{1,254}$!', $id) ? true : false;
    }

    public function add($url, $id=null)
    {
        if (trim($id))
        {
            if (!$this->checkID($id))
            {
                return false;
            }

            $res = $this->db->querySingle('SELECT 1 FROM urls WHERE id = \''.$this->db->escapeString($id).'\';');

            if (!empty($res))
            {
                return false;
            }
        }
        else
        {
            $id = false;
            $length = 1;

            while (!$id)
            {
                $id = substr(sha1(mt_rand() . uniqid()), 0, $length++);
                $id = self::baseConv(hexdec($id));

                $res = $this->db->querySingle('SELECT 1 FROM urls WHERE id = \''.$this->db->escapeString($id).'\';');

                if (!empty($res))
                {
                    $id = false;
                }
            }
        }

        $this->db->exec('INSERT INTO urls (id, url) VALUES (\''.$this->db->escapeString($id).'\', "'.$this->db->escapeString($url).'");');

        return $id;
    }

    public function getUrl($id)
    {
        $res = $this->db->querySingle('SELECT url FROM urls WHERE id="'.$this->db->escapeString($id).'";');
        return $res;
    }

    public function checkUrl($url)
    {
        $url = parse_url($url);

        if (empty($url['host']) || empty($url['scheme']))
            return false;

        return true;
    }

    public function listAll()
    {
        $res = $this->db->query('SELECT * FROM urls;');
        $out = array();

        while ($row = $res->fetchArray(SQLITE3_ASSOC))
        {
            $out[$row['id']] = $row['url'];
        }

        return $out;
    }
}

$tiny = new TinyURL;

if (isset($_GET['export']))
{
    header('Content-Type: text/csv');
    foreach ($tiny->listAll() as $key=>$value)
    {
        echo $key . "\t" . $value . "\n";
    }
    exit;
}

$html = '';
$msg = false;

if(!empty($_SERVER['QUERY_STRING']) && !isset($_GET['msg']) && !isset($_GET['api']) && !isset($_GET['togglePreview']))
{
    $params = explode('&', $_SERVER['QUERY_STRING']);

    $url = $tiny->getUrl($params[0]);

    if(empty($url))
    {
        header('HTTP/1.1 404 Not Found', true, 404);
        echo '<h1>404 Not Found</h1>';
        exit;
    }
    elseif ((empty($params[1]) || $params[1] != 'preview') && empty($_REQUEST['preview']))
    {
        header('Location: '.$url);
    }

    echo '<p>Click on the link to get redirected:</p>';
    echo '<pre><a href="'.htmlspecialchars($url).'">'.htmlspecialchars(wordwrap($url, 80, '<br />', true)).'</a></pre>';

    exit;
}
elseif (isset($_GET['api']) || !empty($_POST['create']))
{
    $msg = false;

    if (isset($_GET['api']))
        $src =& $_GET;
    else
        $src =& $_POST;

    if (empty($src['url']) || !trim($src['url']))
        $msg = 'Empty URL.';
    elseif (!$tiny->checkUrl($src['url']))
        $msg = 'URL is not valid.';
    elseif (!empty($src['id']))
    {
        if (!$tiny->checkID($src['id']))
            $msg = 'ID is not valid.';
        elseif ($tiny->getUrl($src['id']))
            $msg = 'ID already exists, choose another.';
    }

    if (!$msg)
    {
        $id = $tiny->add($src['url'], $src['id']);
        $url = REDIR_URL . $id;
    }

    if (isset($_GET['api']))
    {
        if (!ENABLE_API)
        {
            header('HTTP/1.1 404 Not Found', true, 404);
            echo "API is disabled.";
            exit;
        }

        $return = array('success' => $msg ? '0' : '1', 'message' => $msg ? $msg : $url);

        switch ($_GET['api'])
        {
            case 'js':
                header('Content-Type: text/javascript');
                echo 'var tiny_response = '.json_encode($return).';';
                exit;
            case 'json':
                header('Content-Type: application/json');
                echo json_encode($return);
                exit;
            case 'xml':
                header('Content-Type: text/xml');
                echo '<?xml version="1.0" encoding="UTF-8"?>';
                echo "\n";
                echo "<response>\n";

                foreach ($return as $key=>$value)
                    echo '  <'.$key.'>'.$value.'</'.$key.">\n";

                echo "</response>";
                exit;
            default:
                header('Content-Type: text/plain');
                echo $msg ? 'FAIL' : 'OK';
                echo "\n";
                echo $msg ? $msg : $url;
                exit;
        }
    }
    else
    {
        if ($msg)
        {
            $html = '<p class="err">'.htmlspecialchars($msg).'</p>';
        }
        else
        {
            $html = '<p>URL successfully created!</p>
                <p><tt><strong><a href="'.htmlspecialchars($url).'">'.htmlspecialchars($url).'</a></strong></tt></p>
                <p><input type="text" class="preview" onclick="this.select();" value="'.htmlspecialchars($url).'" /></p>';
        }
    }
}
else
{
    if (isset($_GET['togglePreview']))
    {
        $expire = time() + (3600 * 24 * 355.25 * 5);
        $url = parse_url(BASE_URL);
        $path = isset($url['path']) ? $url['path'] : '/';

        if (!empty($_COOKIE['preview']))
        {
            setcookie('preview', '', $expire, $path);
            unset($_COOKIE['preview']);
        }
        else
        {
            setcookie('preview', '1', $expire, $path);
            $_COOKIE['preview'] = 1;
        }
    }

    $html = '
    <form method="post" action="'.BASE_URL.'">
    <fieldset>
        <legend>Create your mini-URL</legend>
        <dl>
            <dt><label for="furl">Long URL:</label></dt>
            <dd><input type="text" name="url" id="furl" maxlength="255" /></dd>
            <dt><label for="fid">Mini-URL identifier (optional):</label></dt>
            <dd><input type="text" id="fid" name="id" maxlength="255" /></dd>
        </dl>
    </fieldset>
    <p class="submit"><input type="submit" name="create" value="Create Mini-URL" /></p>
    </form>
    <div class="help">
    <h2>How to use this service?</h2>
    <p>Just copy/paste the long URL you want to make shorter in the Long URL field.
        The click <q>Create Mini-URL</q> and you will get a new short URL you can copy/paste in services that don\'t accept long URLs
        (like Twitter).
    </p>
    <h3>Can I preview the URLs before being redirected?</h3>
    <p>Yes if you like you can add <tt>&preview</tt> at the end of each short URL.
        Or if you want to have a preview for all URLs of this service, just click here:
        <a href="?togglePreview='.rand().'">'.(empty($_COOKIE['preview']) ? 'Enable preview' : 'Disable preview').'</a>.
    </p>';

    if (ENABLE_API)
    {
        $html .= '
            <h2>API</h2>
            <p>There is a simple and easy to use API for this service to create new URLs.
                Just make a GET request to '.BASE_URL.' with those parameters:</p>
            <dl>
                <dt>api</dt>
                <dd>Return type. Possible values: json, js, text, xml.</dd>
                <dt>url</dt>
                <dd>URL to make shorter.</dd>
                <dt>id (optional)</dt>
                <dd>Desired ID for short URL.</dd>
            </dl>
            <p>You will get in return two different data, the first will be the success of the query,
                either 0 or 1 (FAIL or OK for text return) and the second one will be either the error message or
                the created URL depending if the query succeed or not.</p>
        ';
    }

    if (ENABLE_EXPORT)
    {
        $html .= '
            <h2>Database export</h2>
            <p>You can make a simple export of the entire database of this service simply by requesting this URL:<br />
                <a href="'.BASE_URL.'?export">'.BASE_URL.'?export</a>.</p>
            <p>The output format is a classic CSV.</p>
        ';
    }

    $html .= '
    </div>';
}


echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
    <title>Tiny-Mini-URL</title>
    <style type="text/css">

    body {
        font-family: Arial, Helvetica, sans-serif;
        font-size: 12px;
    }

    input#fid, input#furl { width: 100%; }

    h1 { font-size: 2em; border-bottom: 2px solid #ccc; }
    h1 a { text-decoration: none; color: #099; }

    #page { width: 50em; }

    .err { color: red; font-weight: bold; }

    fieldset { border: 1px solid #999; }

    dt { font-weight: bold; }
    dd { margin: 1em; }

    input.preview {
        padding: 0.5em;
        width: 30em;
        background: #ccc;
        border: solid 1px #000;
        color: #000;
    }

    .help {
        margin-top: 1em;
        border-top: 2px solid #ccc;
    }
    .help dd {
        margin-top: 0;
    }
    </style>
</head>

<body>
<h1><a href="'.BASE_URL.'">Tiny-Mini-URL service</a></h1>
<div id="page">
    '.$html.'
    <hr />
</div>
</body>
</html>';


?>