Plugin allowing to integrate Flattr

<?php

// Wiki plugin for the integration of Flattr
// By Daniel Kasmeroglu, Copyright (C) 2011. All rights reserved.
// Licensed under the GNU LESSER GENERAL PUBLIC LICENSE (LGPL).

function wikiplugin_flattr_help() {
    return tra("Create a Flattr link").":<br />   {flattr(url=*, button=large|compact|static)}".tra("text")."{flattr}   ";
}

function wikiplugin_flattr_info() {
    return array(
        'name' => tra('Flattr'),
        'description' => tra('Create a Flattr link in the wiki page.'),
        'validate' => 'all',
        'params' => array(
            'url' => array(
                'required' => true,
                'name' => tra('The location of the resource for the contribution'),
                'description' => tra('The URL is used to identify the resource (project) which will be used for the contribution.'),
            ),
            'button' => array(
                'required' => false,
                'name' => tra('Type of the Flattr button to be displayed.'),
                'description' => tra('Just select the button type. Default is *large*. Allowed: large, compact, static.'),
            ),
        ),
    );
}

$wikiplugin_flattr_gotscript = 0;

function wikiplugin_flattr($data, $params) {

    // Always include this line to read the data and parameters.
    extract ($params,EXTR_SKIP);

    $quote ='';

    // Check for color
    if (!isset($url)) {
        $msg = 'Please specify a valid URL.';
        return $msg;
    } else {
        $u = $url;
    }

    // Check for the button type
    if (!isset($button)) {
        $b = "large";
    } else {
        if ((strcmp("large", $button) == 0) || (strcmp("compact", $button) == 0) || (strcmp("static", $button) == 0)) {
            $b = $button;
        } else {
            $msg = 'The button type is only allowed to have one of the following values: large, compact, static.';
            return $msg;
        }
    }

    // @todo [24-Mar-2011:KASI]   Check how to alter the head-element of a page, so the script part could go there.
    if ($wikiplugin_flattr_gotscript == 0) {
        $quote .= "<script type='text/javascript'>";
        $quote .= "/* <![CDATA[ */";
        $quote .= "    (function() {";
        $quote .= "        var s = document.createElement('script'), t = document.getElementsByTagName('script')[0];";
        $quote .= "        s.type = 'text/javascript';";
        $quote .= "        s.async = true;";
        $quote .= "        s.src = 'http://api.flattr.com/js/0.6/load.js?mode=auto';";
        $quote .= "        t.parentNode.insertBefore(s, t);";
        $quote .= "    })();";
        $quote .= "/* ]]> */";
        $quote .= "</script>";
        $wikiplugin_flattr_gotscript = 1;
    }

    // Build the output
    if (strcmp("large", $b) == 0) {
        $quote .= "<a class='FlattrButton' style='display:none;' href='".$u."'></a>";
    } else if (strcmp("compact", $b) == 0) {
        $quote .= "<a class='FlattrButton' style='display:none;' href='".$u."' rev='flattr;button:compact;'></a>";
    } else /* if (strcmp("static", $b) == 0) */ {
        $quote .= "<a href='".$u."' target='_blank'>";
        $quote .= "<img src='http://api.flattr.com/button/flattr-badge-large.png' alt='Flattr this' title='Flattr this' border='0'/></a>";
    }
    return $quote;
}

?>