<?php
/**
 * Tabpage plugin: Shows links to children pages in the page menu
 *
 * @license    BSD 2-Clause
 * @author     Antoine Le Gonidec <vv221.dokuwiki@dotslashplay.it>
 */

// must be run within Dokuwiki
if ( ! defined('DOKU_INC') ) {
	die();
}

class action_plugin_childrenpages extends DokuWiki_Action_Plugin {
	/**
	 * Registers a callback function for a given event
	 *
	 * @param Doku_Event_Handler $controller
	 */
	public function register(Doku_Event_Handler $controller) : void {
		$controller->register_hook('MENU_ITEMS_ASSEMBLY', 'AFTER', $this, 'addMenuItem');
	}

	/**
	 * Add new items to the page menu
	 *
	 * @param Doku_Event $event
	 */
	public function addMenuItem(Doku_Event $event) : void {
		global $INFO;
		// Check that this method has been called in the expected context
		if ( $event->name !== 'MENU_ITEMS_ASSEMBLY' ) {
			$message = "Tabpage plugin error:";
			$message .= "addMenuItem method should only be called by \"MENU_ITEMS_ASSEMBLY\" event";
			$message .= ", but it has been called by \"$event->name\".";
			throw new Exception($message);
		}
		// Only add content to the page menu
		if ( $event->data['view'] !== 'page' ) {
			return;
		}
		// Only add links if the current page is not included in a namespace
		if ( ! empty($INFO['namespace']) ) {
			return;
		}
		trigger_error('addMenuItem() not implemented in '.get_class($this), E_USER_WARNING);
	}
}