2 files changed, 129 insertions, 0 deletions

diff --git a/src/core/frontend/applets/controller.cpp b/src/core/frontend/applets/controller.cpp
new file mode 100644
index 000000000..4505da758
--- /dev/null
+++ b/src/core/frontend/applets/controller.cpp
@@ -0,0 +1,81 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+#include "common/logging/log.h"
+#include "core/core.h"
+#include "core/frontend/applets/controller.h"
+#include "core/hle/service/hid/controllers/npad.h"
+#include "core/hle/service/hid/hid.h"
+#include "core/hle/service/sm/sm.h"
+
+namespace Core::Frontend {
+
+ControllerApplet::~ControllerApplet() = default;
+
+DefaultControllerApplet::~DefaultControllerApplet() = default;
+
+void DefaultControllerApplet::ReconfigureControllers(std::function<void()> callback,
+                                                     ControllerParameters parameters) const {
+    LOG_INFO(Service_HID, "called, deducing the best configuration based on the given parameters!");
+
+    auto& npad =
+        Core::System::GetInstance()
+            .ServiceManager()
+            .GetService<Service::HID::Hid>("hid")
+            ->GetAppletResource()
+            ->GetController<Service::HID::Controller_NPad>(Service::HID::HidController::NPad);
+
+    auto& players = Settings::values.players;
+
+    const std::size_t min_supported_players =
+        parameters.enable_single_mode ? 1 : parameters.min_players;
+
+    // Disconnect Handheld first.
+    npad.DisconnectNPadAtIndex(8);
+
+    // Deduce the best configuration based on the input parameters.
+    for (std::size_t index = 0; index < players.size() - 2; ++index) {
+        // First, disconnect all controllers regardless of the value of keep_controllers_connected.
+        // This makes it easy to connect the desired controllers.
+        npad.DisconnectNPadAtIndex(index);
+
+        // Only connect the minimum number of required players.
+        if (index >= min_supported_players) {
+            continue;
+        }
+
+        // Connect controllers based on the following priority list from highest to lowest priority:
+        // Pro Controller -> Dual Joycons -> Left Joycon/Right Joycon -> Handheld
+        if (parameters.allow_pro_controller) {
+            npad.AddNewControllerAt(
+                npad.MapSettingsTypeToNPad(Settings::ControllerType::ProController), index);
+        } else if (parameters.allow_dual_joycons) {
+            npad.AddNewControllerAt(
+                npad.MapSettingsTypeToNPad(Settings::ControllerType::DualJoyconDetached), index);
+        } else if (parameters.allow_left_joycon && parameters.allow_right_joycon) {
+            // Assign left joycons to even player indices and right joycons to odd player indices.
+            // We do this since Captain Toad Treasure Tracker expects a left joycon for Player 1 and
+            // a right Joycon for Player 2 in 2 Player Assist mode.
+            if (index % 2 == 0) {
+                npad.AddNewControllerAt(
+                    npad.MapSettingsTypeToNPad(Settings::ControllerType::LeftJoycon), index);
+            } else {
+                npad.AddNewControllerAt(
+                    npad.MapSettingsTypeToNPad(Settings::ControllerType::RightJoycon), index);
+            }
+        } else if (index == 0 && parameters.enable_single_mode && parameters.allow_handheld &&
+                   !Settings::values.use_docked_mode) {
+            // We should *never* reach here under any normal circumstances.
+            npad.AddNewControllerAt(npad.MapSettingsTypeToNPad(Settings::ControllerType::Handheld),
+                                    index);
+        } else {
+            UNREACHABLE_MSG("Unable to add a new controller based on the given parameters!");
+        }
+    }
+
+    callback();
+}
+
+} // namespace Core::Frontend
diff --git a/src/core/frontend/applets/controller.h b/src/core/frontend/applets/controller.h
new file mode 100644
index 000000000..a227f15cd
--- /dev/null
+++ b/src/core/frontend/applets/controller.h
@@ -0,0 +1,48 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <functional>
+
+#include "common/common_types.h"
+
+namespace Core::Frontend {
+
+using BorderColor = std::array<u8, 4>;
+using ExplainText = std::array<char, 0x81>;
+
+struct ControllerParameters {
+    s8 min_players{};
+    s8 max_players{};
+    bool keep_controllers_connected{};
+    bool enable_single_mode{};
+    bool enable_border_color{};
+    std::vector<BorderColor> border_colors{};
+    bool enable_explain_text{};
+    std::vector<ExplainText> explain_text{};
+    bool allow_pro_controller{};
+    bool allow_handheld{};
+    bool allow_dual_joycons{};
+    bool allow_left_joycon{};
+    bool allow_right_joycon{};
+};
+
+class ControllerApplet {
+public:
+    virtual ~ControllerApplet();
+
+    virtual void ReconfigureControllers(std::function<void()> callback,
+                                        ControllerParameters parameters) const = 0;
+};
+
+class DefaultControllerApplet final : public ControllerApplet {
+public:
+    ~DefaultControllerApplet() override;
+
+    void ReconfigureControllers(std::function<void()> callback,
+                                ControllerParameters parameters) const override;
+};
+
+} // namespace Core::Frontend