FlappyBug: Persist high score to disk

Previously, the high score was only in-memory, so only persisted for as
long as the FlappyBug window was open.

Userland/Games/FlappyBug/Game.cpp

@@ -27,9 +27,9 @@ void Game::reset()
 
 void Game::game_over()
 {
-    if (m_highscore.value_or(0) < m_difficulty) {
+    if (on_game_end)
-        m_highscore = m_difficulty;
+        m_highscore = on_game_end(static_cast<u32>(m_difficulty));
-    }
+
     reset();
 }
 

Userland/Games/FlappyBug/Game.h

@@ -25,6 +25,8 @@ public:
     static const int game_width = 560;
     static const int game_height = 480;
 
+    Function<u32(u32)> on_game_end;
+
 private:
     Game();
 

Userland/Games/FlappyBug/main.cpp

@@ -5,10 +5,12 @@
  */
 
 #include "Game.h"
+#include <LibCore/ConfigFile.h>
 #include <LibGUI/Application.h>
 #include <LibGUI/Icon.h>
 #include <LibGUI/Menu.h>
 #include <LibGUI/Menubar.h>
+#include <LibGUI/MessageBox.h>
 #include <LibGUI/Window.h>
 #include <unistd.h>
 
@@ -20,6 +22,7 @@ int main(int argc, char** argv)
     }
 
     auto app = GUI::Application::construct(argc, argv);
+    auto config = Core::ConfigFile::get_for_app("FlappyBug");
 
     if (pledge("stdio rpath wpath cpath recvfd sendfd", nullptr) < 0) {
         perror("pledge");
@@ -31,11 +34,18 @@ int main(int argc, char** argv)
         return 1;
     }
 
+    if (unveil(config->filename().characters(), "crw") < 0) {
+        perror("unveil");
+        return 1;
+    }
+
     if (unveil(nullptr, nullptr) < 0) {
         perror("unveil");
         return 1;
     }
 
+    u32 high_score = static_cast<u32>(config->read_num_entry("Game", "HighScore", 0));
+
     auto window = GUI::Window::construct();
     window->resize(FlappyBug::Game::game_width, FlappyBug::Game::game_height);
     auto app_icon = GUI::Icon::default_icon("app-flappybug");
@@ -43,8 +53,20 @@ int main(int argc, char** argv)
     window->set_title("Flappy Bug");
     window->set_double_buffering_enabled(false);
     window->set_resizable(false);
-    window->set_main_widget<FlappyBug::Game>();
+    auto& widget = window->set_main_widget<FlappyBug::Game>();
-    window->show();
+
+    widget.on_game_end = [&](u32 score) {
+        if (score <= high_score)
+            return high_score;
+
+        config->write_num_entry("Game", "HighScore", static_cast<int>(score));
+        high_score = score;
+
+        if (!config->sync())
+            GUI::MessageBox::show(window, "Configuration could not be saved", "Error", GUI::MessageBox::Type::Error);
+
+        return high_score;
+    };
 
     auto menubar = GUI::Menubar::construct();
 
@@ -57,6 +79,7 @@ int main(int argc, char** argv)
     help_menu.add_action(GUI::CommonActions::make_about_action("Flappy Bug", app_icon, window));
 
     window->set_menubar(move(menubar));
+    window->show();
 
     return app->exec();
 }