From c8ef298c56b0687df9910d8bd47850139ae791ba Mon Sep 17 00:00:00 2001
From: kichikuou <KichikuouChrome@gmail.com>
Date: Thu, 6 Mar 2025 08:15:46 +0900
Subject: [PATCH] Add quit confirmation dialog

On Android, the back button opens the dialog.
---
 src/sdlmain.cpp        |  1 +
 src/sys/nact.h         |  1 +
 src/sys/nact_input.cpp | 34 +++++++++++++++++++++++++++++++++-
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/sdlmain.cpp b/src/sdlmain.cpp
index 0da0240..9d30558 100644
--- a/src/sdlmain.cpp
+++ b/src/sdlmain.cpp
@@ -44,6 +44,7 @@ SDL_Window* create_window(const GameId& game_id)
 #endif
 
 #ifdef __ANDROID__
+	SDL_SetHint(SDL_HINT_ANDROID_TRAP_BACK_BUTTON, "1");
 	SDL_SetHint(SDL_HINT_ORIENTATIONS, "LandscapeLeft LandscapeRight");
 	Uint32 flags = SDL_WINDOW_FULLSCREEN;
 #else
diff --git a/src/sys/nact.h b/src/sys/nact.h
index de1df53..cf87133 100644
--- a/src/sys/nact.h
+++ b/src/sys/nact.h
@@ -196,6 +196,7 @@ private:
 	void pump_events();
 	void handle_event(SDL_Event e);
 	bool handle_platform_event(const SDL_Event& e);
+	void show_quit_dialog();
 
 	static NACT* create_system1(const Config& config, const GameId& game_id);
 	static NACT* create_system2(const Config& config, const GameId& game_id);
diff --git a/src/sys/nact_input.cpp b/src/sys/nact_input.cpp
index 01e1db5..06843eb 100644
--- a/src/sys/nact_input.cpp
+++ b/src/sys/nact_input.cpp
@@ -33,9 +33,17 @@ void NACT::handle_event(SDL_Event e)
 
 	switch (e.type) {
 	case SDL_QUIT:
-		quit(0);
+		show_quit_dialog();
 		break;
 
+#ifdef __ANDROID__
+	case SDL_KEYUP:
+		if (e.key.keysym.scancode == SDL_SCANCODE_AC_BACK) {
+			show_quit_dialog();
+		}
+		break;
+#endif
+
 	case SDL_MOUSEMOTION:
 		mousex = e.motion.x * ags->screen_width / ags->window_width;
 		mousey = e.motion.y * ags->screen_height / ags->window_height;
@@ -148,6 +156,30 @@ void NACT::set_cursor(int x, int y)
 	SDL_WarpMouseInWindow(g_window, x, y);
 }
 
+void NACT::show_quit_dialog()
+{
+	const SDL_MessageBoxButtonData buttons[] = {
+		{ SDL_MESSAGEBOX_BUTTON_RETURNKEY_DEFAULT, 1, "Quit" },
+		{ SDL_MESSAGEBOX_BUTTON_ESCAPEKEY_DEFAULT, 0, "Cancel" },
+	};
+	const SDL_MessageBoxData messagebox_data = {
+		SDL_MESSAGEBOX_INFORMATION,
+		nullptr,
+		"System3",
+		"Quit game?\nAny unsaved progress will be lost.",
+		SDL_arraysize(buttons),
+		buttons,
+	};
+	int buttonid = 0;
+	if (SDL_ShowMessageBox(&messagebox_data, &buttonid) < 0) {
+		WARNING("error displaying message box");
+		return;
+	}
+	if (buttonid == 1) {
+		quit(0);
+	}
+}
+
 #ifdef __EMSCRIPTEN__
 extern "C" {