From 83bba9954aa2b0b19a938b5061c86b70f3dbe507 Mon Sep 17 00:00:00 2001
From: vv221 <vv221@dotslashplay.it>
Date: Fri, 3 Apr 2020 22:37:30 +0200
Subject: [PATCH] On children pages, show links to other children pages and
 back to the main parent page

---
 MenuItem.php     | 41 ++++++++++++++++++++++++++++++-----------
 action.php       | 34 +++++++++++++++++-----------------
 lang/en/lang.php |  2 ++
 3 files changed, 49 insertions(+), 28 deletions(-)

diff --git a/MenuItem.php b/MenuItem.php
index 1fd401e..b11abd8 100644
--- a/MenuItem.php
+++ b/MenuItem.php
@@ -10,21 +10,28 @@ class MenuItem extends AbstractItem {
 	 *
 	 * @param string $type
 	 * @param string $label
+	 * @param bool   $strip_namespace
 	 */
-	public function __construct(string $type, string $label = '') {
+	public function __construct(
+		string $type,
+		string $label           = '',
+		bool   $strip_namespace = false
+	) {
 		$this->type = $type;
 		if ( empty($label) ) {
 			$label = ucfirst($type);
 		}
 		$this->label = $label;
 		parent::__construct();
-		$this->setTargetFromType();
+		$this->setTargetFromType($strip_namespace);
 	}
 
 	/**
 	 * Set the item target link from its type
+	 *
+	 * @param bool $strip_namespace
 	 */
-	protected function setTargetFromType() : void {
+	protected function setTargetFromType(bool $strip_namespace) : void {
 		global $INFO;
 		global $plugin_controller;
 		$language = null;
@@ -36,16 +43,28 @@ class MenuItem extends AbstractItem {
 			$translation_plugin =& $plugin_controller->load('helper', 'translation');
 			$language = $translation_plugin->getLangPart($INFO['id']);
 		}
+		// Split path to page
+		$page_path = explode(':', $INFO['id']);
 		// If the top level namespace is a language one, the children namespace should be inserted inside it
-		if ( $language !== null && preg_match("/^$language:/", $INFO['id']) ) {
-			$this->id = preg_replace(
-				"/^$language:/",
-				"$language:".$this->type.':',
-				$INFO['id']
-			);
-		} else {
-			$this->id = $this->type.':'.$INFO['id'];
+		$is_in_a_lang_namespace = ( $language !== null && $page_path[0] === $language );
+		if ( $is_in_a_lang_namespace ) {
+			array_shift($page_path);
 		}
+		// Strip the top level namespace if we are already on a child page
+		if ( $strip_namespace ) {
+			array_shift($page_path);
+		}
+		// Build the link target path
+		$target_path = [];
+		if ( $is_in_a_lang_namespace ) {
+			$target_path[] = $language;
+		}
+		// Add namespace of the target child page, unless the special value "_main" has been used
+		// "_main" is used to generate a link back to the main parent page
+		if ( $this->type !== '_main' ) {
+			$target_path[] = $this->type;
+		}
+		$this->id = implode(':', array_merge($target_path, $page_path));
 		$this->params = [];
 	}
 }
diff --git a/action.php b/action.php
index 9062349..96de36e 100644
--- a/action.php
+++ b/action.php
@@ -40,16 +40,20 @@ class action_plugin_childrenpages extends DokuWiki_Action_Plugin {
 		if ( $event->data['view'] !== 'page' ) {
 			return;
 		}
-		// Only add links if the current page is not included in a reserved namespace
+		// If the current page is included in a reserved namespace, add a link back to main page
 		$children_types = $this->getConf('children_list');
 		$top_namespace = $this->getTopLevelNamespace();
-		if ( in_array($top_namespace, $children_types) ) {
-			return;
+		$is_child_page = in_array($top_namespace, $children_types);
+		if ( $is_child_page ) {
+			$main_label = $this->getLang('btn_main');
+			$this->addMenuItem($event, '_main', $main_label, $top_namespace);
 		}
 		// Add menu items for each child page
 		foreach ( $children_types as $child_type ) {
-			$child_label = $this->getLang("btn_$child_type");
-			$this->addMenuItem($event, $child_type, $child_label);
+			if ( $child_type !== $top_namespace ) {
+				$child_label = $this->getLang("btn_$child_type");
+				$this->addMenuItem($event, $child_type, $child_label, $is_child_page);
+			}
 		}
 	}
 
@@ -59,19 +63,15 @@ class action_plugin_childrenpages extends DokuWiki_Action_Plugin {
 	 * @param Doku_Event $event
 	 * @param string     $type
 	 * @param string     $name
+	 * @param bool       $strip_namespace
 	 */
-	protected function addMenuItem(Doku_Event $event, string $type, string $name = '') {
-		$item = $this->generateMenuItem($type, $name);
-		$event->data['items'][] = $item;
-	}
-
-	/**
-	 * Generate a new menu item
-	 *
-	 * @param string $type
-	 */
-	protected function generateMenuItem(string $type, string $name = '') {
-		return new MenuItem($type, $name);
+	protected function addMenuItem(
+		Doku_Event $event,
+		string     $type,
+		string     $name            = '',
+		bool       $strip_namespace = false
+	) {
+		$event->data['items'][] = new MenuItem($type, $name, $strip_namespace);
 	}
 
 	/**
diff --git a/lang/en/lang.php b/lang/en/lang.php
index 7be973b..b737008 100644
--- a/lang/en/lang.php
+++ b/lang/en/lang.php
@@ -1,5 +1,7 @@
 <?php
 
+$lang['btn_main'] = 'Back to main page';
+
 $lang['btn_animation'] = 'Animation';
 $lang['btn_dev']       = 'Dev';
 $lang['btn_gameplay']  = 'Gameplay';