Help Browser: Actually show the correct topics with the correct icons

This also fixes the lag when opening help and makes the topic text appear.
(The topic text is not parsed at the moment, though.)

data/gui/window/help_browser.cfg

@@ -33,7 +33,6 @@
 
 										[image]
 											id = "topic_icon"
-											label = "help/topic.png"
 											linked_group = "images"
 										[/image]
 									[/column]

src/gui/dialogs/help_browser.cpp

@@ -53,54 +53,81 @@ help_browser::help_browser()
 void help_browser::pre_show(window& window)
 {
 	tree_view& topic_tree = find_widget<tree_view>(&window, "topic_tree", false);
-	multi_page& topic_pages = find_widget<multi_page>(&window, "topic_text_pages", false);
 
 	topic_tree.set_selection_change_callback(std::bind(&help_browser::on_topic_select, this, std::ref(window)));
 
 	window.keyboard_capture(&topic_tree);
 
-	unsigned id = 0;
-
-	for(const auto& topic : help_cfg_.child_range("topic")) {
-		std::map<std::string, string_map> data;
-		string_map item;
+	const config toc = help_cfg_.child("toplevel");
 
-		item["label"] = topic["title"];
-		data.emplace("topic_name", item);
+	for(const std::string& section : utils::split(toc["sections"])) {
+		add_topic(window, help_cfg_.find_child("section", "id", section), true);
+	}
 
-		topic_tree.add_node("topic", data).set_id(std::to_string(id));
+	for(const std::string& topic : utils::split(toc["topics"])) {
+		add_topic(window, help_cfg_.find_child("topic", "id", topic), false);
+	}
 
-		// FIXME: maybe using a multi page isn't a good idea here... :| it causes massive lag when opening.
-		item.clear();
-		data.clear();
+	on_topic_select(window);
+}
 
-		item["label"] = topic["text"].empty() ? "" : topic["text"].str();
-		data.emplace("topic_text", item);
+void help_browser::add_topic(window& window, const config& topic, bool expands, tree_view_node*) {
+	tree_view& topic_tree = find_widget<tree_view>(&window, "topic_tree", false);
+	std::map<std::string, string_map> data;
+	string_map item;
 
-		topic_pages.add_page(data);
+	item["label"] = topic["title"];
+	data.emplace("topic_name", item);
 
-		++id;
-	}
+	item.clear();
+	item["label"] = expands ? "help/closed_section.png" : "help/topic.png";
+	data.emplace("topic_icon", item);
 
-	on_topic_select(window);
+	topic_tree.add_node("topic", data).set_id(std::string(expands ? "+" : "-") + topic["id"]);
 }
 
 void help_browser::on_topic_select(window& window)
 {
-	tree_view& tree = find_widget<tree_view>(&window, "topic_tree", false);
+	multi_page& topic_pages = find_widget<multi_page>(&window, "topic_text_pages", false);
+	tree_view& topic_tree = find_widget<tree_view>(&window, "topic_tree", false);
 
-	if(tree.empty()) {
+	if(topic_tree.empty()) {
 		return;
 	}
 
-	assert(tree.selected_item());
+	assert(topic_tree.selected_item());
+	std::string topic_id = topic_tree.selected_item()->id();
 
-	if(tree.selected_item()->id() == "") {
+	if(topic_id == "") {
 		return;
 	}
 
-	const unsigned topic_i = lexical_cast<unsigned>(tree.selected_item()->id());
-	find_widget<multi_page>(&window, "topic_text_pages", false).select_page(topic_i);
+	if(topic_id[0] == '+') {
+		topic_id.replace(topic_id.begin(), topic_id.begin() + 1, 2, '.');
+	} else {
+		topic_id.erase(topic_id.begin());
+	}
+
+	auto iter = parsed_pages_.find(topic_id);
+	if(iter == parsed_pages_.end()) {
+		const config& topic = help_cfg_.find_child("topic", "id", topic_id);
+		if(!topic) {
+			return;
+		}
+
+		std::map<std::string, string_map> data;
+		string_map item;
+
+		item["label"] = topic["text"];
+		data.emplace("topic_text", item);
+
+		parsed_pages_.emplace(topic_id, topic_pages.get_page_count());
+		topic_pages.add_page(data);
+		window.invalidate_layout();
+	}
+
+	const unsigned topic_i = parsed_pages_.at(topic_id);
+	topic_pages.select_page(topic_i);
 
 }
 

src/gui/dialogs/help_browser.hpp

@@ -17,6 +17,8 @@
 
 #include "gui/dialogs/modal_dialog.hpp"
 
+#include <map>
+
 class config;
 class CVideo;
 
@@ -41,13 +43,17 @@ class help_browser : public modal_dialog
 
 	const config& help_cfg_;
 
+	std::map<std::string, int> parsed_pages_;
+
 	/** Inherited from modal_dialog, implemented by REGISTER_DIALOG. */
 	virtual const std::string& window_id() const;
 
 	/** Inherited from modal_dialog. */
 	void pre_show(window& window);
 
 	void on_topic_select(window& window);
+
+	void add_topic(window& window, const config& topic, bool expands, class tree_view_node* parent = nullptr);
 };
 
 } // namespace dialogs

src/gui/dialogs/title_screen.cpp

@@ -298,11 +298,12 @@ void title_screen::pre_show(window& win)
 	// Help
 	//
 	register_button(win, "help", hotkey::HOTKEY_HELP, [](window& w) {
+		help::help_manager help_manager(&game_config_manager::get()->game_config());
+
 		if(gui2::new_widgets) {
 			gui2::dialogs::help_browser::display(w.video());
 		}
 
-		help::help_manager help_manager(&game_config_manager::get()->game_config());
 		help::show_help(w.video());
 	});