<?php

/**
 * Receive component of the DokuWiki Linkback action plugin.
 *
 * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
 * @author     Gina Haeussge <osd@foosel.net>
 * @link       http://wiki.foosel.net/snippets/dokuwiki/linkback
 */

class action_plugin_linkback_receive extends DokuWiki_Action_Plugin {

    /**
     * Register the eventhandlers.
     */
    function register(Doku_Event_Handler $controller) {
        $controller->register_hook('TPL_ACT_RENDER', 'BEFORE', $this, 'addTrackbackLink', array ());
        $controller->register_hook('TPL_METAHEADER_OUTPUT', 'BEFORE', $this, 'addPingbackLinkToMetaheader', array ());
        $controller->register_hook('ACTION_HEADERS_SEND', 'BEFORE', $this, 'addPingbackLinkToHTTPHeader', array ());
    }

    /**
     * Handler for the TPL_ACT_RENDER event
     */
    function addTrackbackLink(Doku_Event $event, $params) {
        global $ID;

        // Action not 'show'? Quit
        if ($event->data != 'show')
            return;

        // Trackbacks disabled? Quit
        if (!$this->getConf('enable_trackback'))
            return;

        // Get linkback metadata
        $file = metaFN($ID, '.linkbacks');
        $data = array (
            'send' => false,
            'receive' => false,
            'display' => false,
            'sentpings' => array (),
            'receivedpings' => array (),
            'number' => 0,

        );
        if (@ file_exists($file))
            $data = unserialize(io_readFile($file, false));

        // Does not accept linkbacks? Quit
        if (!$data['receive'])
            return;

        // if trackbacks are enabled, insert RDF definition of trackback into output
        if ($this->getConf('enable_trackback')) {
            echo '<!--<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"' . NL .
            'xmlns:dc="https://purl.org/dc/elements/1.1/"' . NL .
            'xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/">' . NL .
            '<rdf:Description' . NL .
            'rdf:about="' . wl($ID, '', true) . '"' . NL .
            'dc:identifier="' . wl($ID, '', true) . '"' . NL .
            'dc:title="' . tpl_pagetitle($ID, true) . '"' . NL .
            'trackback:ping="' . DOKU_URL . 'lib/plugins/linkback/exe/trackback.php/' . $ID . '" />' . NL .
            '</rdf:RDF>-->';
        }
    }

    /**
     * Handler for the TPL_METAHEADER_OUTPUT event
     * @param Doku_Event $event
     * @param $params
     * @return bool|void
     */
    function addPingbackLinkToMetaheader(Doku_Event $event, $params) {
        global $ID;

        // Pingbacks disabled? Quit
        if (!$this->getConf('enable_pingback'))
            return;

        // Get linkback metadata
        $file = metaFN($ID, '.linkbacks');
        $data = array (
            'send' => false,
            'receive' => false,
            'display' => false,
            'sentpings' => array (),
            'receivedpings' => array (),
            'number' => 0,

        );
        if (@ file_exists($file))
            $data = unserialize(io_readFile($file, false));

        // Does not accept linkbacks? Quit
        if (!$data['receive'])
            return;

        // Add pingback metaheader
        $event->data['link'][] = array (
            'rel' => 'pingback',
            'href' => DOKU_URL . 'lib/plugins/linkback/exe/pingback.php/' . $ID
        );
        return true;
    }

    /**
     * Handler for the ACTION_HEADERS_SEND event
     *
     * @param Doku_Event $event
     * @param $params
     * @return bool|void
     */
    function addPingbackLinkToHTTPHeader(Doku_Event $event, $params) {
        global $ID;

        // Pingbacks disabled? Quit
        if (!$this->getConf('enable_pingback'))
            return;

        // Get linkback metadata
        $file = metaFN($ID, '.linkbacks');
        $data = array (
            'send' => false,
            'receive' => false,
            'display' => false,
            'sentpings' => array (),
            'receivedpings' => array (),
            'number' => 0,

        );
        if (@ file_exists($file))
            $data = unserialize(io_readFile($file, false));

        // Does not accept linkbacks? Quit
        if (!$data['receive'])
            return;

        // Add pingback header
        $event->data[] = 'X-Pingback: ' . DOKU_URL . 'lib/plugins/linkback/exe/pingback.php/' . $ID;
        return true;
    }
}