<?php

use dokuwiki\Extension\EventHandler;
use dokuwiki\Extension\Event;

/**
 * Action Component for the Monitor Plugin
 *
 * @license	GPL 3 (http://www.gnu.org/licenses/gpl.html)
 * @author	 Sascha Leib <sascha.leib(at)kolmio.com>
 */

class action_plugin_monitor extends DokuWiki_Action_Plugin {

	/**
     * Registers a callback functions
     *
     * @param EventHandler $controller DokuWiki's event controller object
     * @return void
     */
    public function register(EventHandler $controller) {
        $controller->register_hook('TPL_METAHEADER_OUTPUT', 'BEFORE', $this, 'insertHeader');
    }

    /**
     * Inserts tracking code to the page header
     *
     * @param Event $event event object by reference
     * @return void
     */
	public function insertHeader(Event $event, $param) {

		global $INFO;

		// is there a user logged in?
        $username = ( !empty($INFO['userinfo']) && !empty($INFO['userinfo']['name'])
        ?  $INFO['userinfo']['name'] : null);

		// build the tracker code:
		$code = NL . DOKU_TAB . "document._monitor = {'t0': Date.now()};" . NL;
        if ($username) {
			$code .= DOKU_TAB . 'document._monitor.user = "' . $username . '";'. NL;
		}
		$code .= DOKU_TAB . "addEventListener('load',function(){" . NL;

		$code .= DOKU_TAB . DOKU_TAB . "const e=document.createElement('script');" . NL;
        $code .= DOKU_TAB . DOKU_TAB . "e.async=true;e.defer=true;" . NL;
        $code .= DOKU_TAB . DOKU_TAB . "e.src='".DOKU_BASE."lib/plugins/monitor/client.js';" . NL;
        $code .= DOKU_TAB . DOKU_TAB . "document.getElementsByTagName('head')[0].appendChild(e);" . NL;
		$code .= DOKU_TAB . "});" . NL;

        $event->data['script'][] = [
			'_data'   => $code
        ];
    }
}