confirm dialog when opening rom if emulator already running

gui/src/macos/cacao_window_manager.rs

@@ -14,6 +14,8 @@ use cacao::{
         Event, EventMask, EventMonitor,
     },
     core_foundation::base::TCFTypeRef,
+    filesystem::ModalResponse,
+    foundation::{NSInteger, NSString},
 };
 use cpal::Stream;
 use frontend_common::{
@@ -24,6 +26,11 @@ use gb_emu_lib::{
     connect::{EmulatorMessage, JoypadButtons, JoypadState, RendererMessage, ResolutionData},
     renderer::{RendererBackend, RendererBackendManager, WindowOptions},
 };
+use objc::{
+    class, msg_send, msg_send_id,
+    rc::{Id, Owned},
+    runtime::Object,
+};
 use raw_window_handle::{
     AppKitDisplayHandle, AppKitWindowHandle, HasRawDisplayHandle, HasRawWindowHandle,
     RawDisplayHandle, RawWindowHandle,
@@ -184,6 +191,43 @@ impl CacaoWindowManager {
         }
     }
 
+    pub fn can_open_new_rom(&mut self) -> bool {
+        if if let Some(handles) = &self.handles {
+            handles.sender.send(EmulatorMessage::Pause).unwrap();
+            let title = NSString::new("Emulator running!");
+            let message = NSString::new("Stopping may result in lost data");
+            let close = NSString::new("Continue");
+            let continue_ = NSString::new("Stop");
+            let escape_keycode = NSString::new("\x1b");
+
+            let out: ModalResponse = unsafe {
+                let mut alert: Id<Object, Owned> = msg_send_id![class!(NSAlert), new];
+                let _: () = msg_send![&mut alert, setMessageText: &*title];
+                let _: () = msg_send![&mut alert, setInformativeText: &*message];
+                let _: () = msg_send![&mut alert, addButtonWithTitle: &*continue_];
+                let close_button: cacao::foundation::id =
+                    msg_send![&mut alert, addButtonWithTitle: &*close];
+                let _: () = msg_send![&mut *close_button, setKeyEquivalent: &*escape_keycode];
+
+                let out: NSInteger = msg_send![&*alert, runModal];
+                out.into()
+            };
+
+            handles.sender.send(EmulatorMessage::Start).unwrap();
+            matches!(out, ModalResponse::FirstButtonReturned)
+        } else {
+            true
+        } {
+            let _ = self.handles.take();
+            for (_, w) in self.windows.drain() {
+                w.close();
+            }
+            true
+        } else {
+            false
+        }
+    }
+
     pub fn message(&mut self, message: EmuWindowMessage) {
         match message {
             EmuWindowMessage::Closing { window_type } => {

gui/src/macos/mod.rs

@@ -56,7 +56,7 @@ pub(crate) struct TwincUiApp {
 
 impl TwincUiApp {
     fn open_dialog(&self) {
-        if self.current_game.read().unwrap().is_emulator_running() {
+        if !self.current_game.write().unwrap().can_open_new_rom() {
             return;
         }
 
@@ -110,7 +110,9 @@ impl AppDelegate for TwincUiApp {
         if let Some(url) = urls.first() {
             if url.scheme() == "file" {
                 if let Ok(path) = url.to_file_path() {
-                    dispatch(AppMessage::Core(CoreMessage::OpenRom(path)));
+                    if self.current_game.write().unwrap().can_open_new_rom() {
+                        dispatch(AppMessage::Core(CoreMessage::OpenRom(path)));
+                    }
                 }
             }
         }