[applet] ReconfigureControllers fallback unconditional disconnect fix

src/core/frontend/applets/controller.cpp

@@ -12,6 +12,7 @@
 #include "hid_core/frontend/emulated_controller.h"
 #include "hid_core/hid_core.h"
 #include "hid_core/hid_types.h"
+#include <array>
 
 namespace Core::Frontend {
 
@@ -29,23 +30,39 @@ void DefaultControllerApplet::ReconfigureControllers(ReconfigureCallback callbac
 
     const std::size_t min_supported_players =
         parameters.enable_single_mode ? 1 : parameters.min_players;
+    using Core::HID::NpadStyleIndex;
+    const std::size_t max_supported_players = parameters.enable_single_mode ? 1 : parameters.max_players;
+    std::size_t num_selected_players = 0;
+    std::array<bool, HID::HIDCore::available_controllers> keep_connected{};
 
-    // Disconnect Handheld first.
+    // reserve existing AND valid players before filling slots. include Handheld, but not other
+    for (std::size_t index = 0; index < hid_core.available_controllers - 1; ++index) {
+        const auto* controller = hid_core.GetEmulatedControllerByIndex(index);
+        if (!parameters.keep_controllers_connected || !controller->IsConnected() || num_selected_players >= max_supported_players) continue;
+
+        const auto style = controller->GetNpadStyleIndex();
+        keep_connected[index] =
+            (style == NpadStyleIndex::Fullkey && parameters.allow_pro_controller) ||
+            (style == NpadStyleIndex::JoyconDual && parameters.allow_dual_joycons) ||
+            (style == NpadStyleIndex::JoyconLeft && parameters.allow_left_joycon) ||
+            (style == NpadStyleIndex::JoyconRight && parameters.allow_right_joycon) ||
+            (style == NpadStyleIndex::Handheld && parameters.enable_single_mode && parameters.allow_handheld && !Settings::IsDockedMode()) ||
+            (style == NpadStyleIndex::GameCube && parameters.allow_gamecube_controller);
+        num_selected_players += keep_connected[index];
+    }
     auto* handheld = hid_core.GetEmulatedController(Core::HID::NpadIdType::Handheld);
-    handheld->Disconnect();
+    if (!keep_connected[hid_core.available_controllers - 2]) handheld->Disconnect();
 
     // Deduce the best configuration based on the input parameters.
     for (std::size_t index = 0; index < hid_core.available_controllers - 2; ++index) {
         auto* controller = hid_core.GetEmulatedControllerByIndex(index);
 
-        // First, disconnect all controllers regardless of the value of keep_controllers_connected.
-        // This makes it easy to connect the desired controllers.
+        if (keep_connected[index]) continue;
         controller->Disconnect();
 
-        // Only connect the minimum number of required players.
-        if (index >= min_supported_players) {
-            continue;
-        }
+        // only add players still needed to reach the minimum
+        if (num_selected_players >= min_supported_players) continue;
+        ++num_selected_players;
 
         // Connect controllers based on the following priority list from highest to lowest priority:
         // Pro Controller -> Dual Joycons -> Left Joycon/Right Joycon -> Handheld