5 files changed, 55 insertions, 4 deletions
diff --git a/lib/nes/app/input/input-device-controller.hh b/lib/nes/app/input/input-device-controller.hh
index 69dd2a8..93147cd 100644
--- a/lib/nes/app/input/input-device-controller.hh
+++ b/lib/nes/app/input/input-device-controller.hh
@@ -2,7 +2,6 @@
 
 #include "nes/app/input/input-device.hh"
 #include "nes/common/containers/list.hh"
-#include <string_view>
 
 namespace nes::app
 {
@@ -23,9 +22,6 @@ namespace nes::app
 		/// controller already selected.
 		virtual auto is_reliable() const -> bool = 0;
 
-		/// Human-readable name for the controller.
-		virtual auto get_name() const -> std::string_view = 0;
-
 		/// Get the (persistent) player index for the controller, if already set before.
 		virtual auto get_index() const -> index = 0;
 
diff --git a/lib/nes/app/input/input-device-keyboard.hh b/lib/nes/app/input/input-device-keyboard.hh
index 23ee65c..ef89c59 100644
--- a/lib/nes/app/input/input-device-keyboard.hh
+++ b/lib/nes/app/input/input-device-keyboard.hh
@@ -43,6 +43,8 @@ namespace nes::app
 			return res;
 		}
 
+		auto get_name() const -> std::string_view final { return "Keyboard"; }
+
 	protected:
 		explicit input_device_keyboard() = default;
 	};
diff --git a/lib/nes/app/input/input-device.hh b/lib/nes/app/input/input-device.hh
index cc03057..008825d 100644
--- a/lib/nes/app/input/input-device.hh
+++ b/lib/nes/app/input/input-device.hh
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "nes/sys/types/button-mask.hh"
+#include <string_view>
 
 namespace nes::app
 {
@@ -15,8 +16,12 @@ namespace nes::app
 		auto operator=(input_device const&) -> input_device& = delete;
 		auto operator=(input_device&&) -> input_device& = delete;
 
+		/// Read the controller button state.
 		virtual auto read_buttons() -> sys::button_mask = 0;
 
+		/// Human-readable name for the device.
+		virtual auto get_name() const -> std::string_view = 0;
+
 	protected:
 		explicit input_device() = default;
 	};
diff --git a/lib/nes/app/input/input-manager.cc b/lib/nes/app/input/input-manager.cc
index ceb6690..e88ac84 100644
--- a/lib/nes/app/input/input-manager.cc
+++ b/lib/nes/app/input/input-manager.cc
@@ -15,6 +15,7 @@ namespace nes::app
 				return res;
 			}
 
+			auto get_name() const -> std::string_view override { return "(None)"; }
 			auto read_buttons() -> sys::button_mask override { return sys::button_mask{}; }
 		};
 	} // namespace
@@ -36,6 +37,10 @@ namespace nes::app
 				// This controller was previously used and assigned an index -> replace the current device with this
 				// (known) controller.
 				auto const i = static_cast<u32>(index);
+				if (keyboard_index_ == index)
+				{
+					keyboard_index_ = input_device_controller::index::unused;
+				}
 				if (inputs_[i].controller)
 				{
 					inputs_[i].controller->set_index(input_device_controller::index::unused);
@@ -56,6 +61,43 @@ namespace nes::app
 		fill_unassigned_inputs();
 	}
 
+	auto input_manager::toggle_input(u32 const i) -> void
+	{
+		// If currently none/keyboard, use the first available controller.
+		auto curr_was_prev = inputs_[i].controller == nullptr;
+		if (curr_was_prev && keyboard_index_ == input_device_controller::index::unused)
+		{
+			// If currently none and keyboard is available, switch to keyboard.
+			keyboard_index_ = static_cast<input_device_controller::index>(i);
+			inputs_[i].controller = nullptr;
+			inputs_[i].device = keyboard_;
+			return;
+		}
+
+		// Reset old controller index
+		if (inputs_[i].controller) { inputs_[i].controller->set_index(input_device_controller::index::unused); }
+		if (keyboard_index_ == static_cast<input_device_controller::index>(i)) { keyboard_index_ = input_device_controller::index::unused; }
+
+		for (auto& controller : controllers_)
+		{
+			if (&controller == inputs_[i].controller)
+			{
+				curr_was_prev = true;
+			}
+			else if (curr_was_prev && controller.get_index() == input_device_controller::index::unused)
+			{
+				inputs_[i].controller = &controller;
+				inputs_[i].controller->set_index(static_cast<input_device_controller::index>(i));
+				inputs_[i].device = &controller;
+				return;
+			}
+		}
+
+		// No successor found, switch to none.
+		inputs_[i].controller = nullptr;
+		inputs_[i].device = &input_device_dummy::get_instance();
+	}
+
 	auto input_manager::fill_unassigned_inputs() -> void
 	{
 		auto it = controllers_.begin();
@@ -87,6 +129,7 @@ namespace nes::app
 				// We're all out of controllers -> fall back to the keyboard (if this is the first missing controller)
 				// or nothing.
 				inputs_[i].device = fallback;
+				if (fallback == keyboard_) { keyboard_index_ = static_cast<input_device_controller::index>(i); }
 				fallback = &input_device_dummy::get_instance(); // Only use the keyboard as a fallback once.
 			}
 		}
diff --git a/lib/nes/app/input/input-manager.hh b/lib/nes/app/input/input-manager.hh
index b0b60e8..7a63326 100644
--- a/lib/nes/app/input/input-manager.hh
+++ b/lib/nes/app/input/input-manager.hh
@@ -16,6 +16,7 @@ namespace nes::app
 		static constexpr auto input_count = u32{ 2 };
 
 		input_device_keyboard* keyboard_;
+		input_device_controller::index keyboard_index_{ input_device_controller::index::unused };
 		list<input_device_controller> controllers_;
 		struct
 		{
@@ -34,6 +35,9 @@ namespace nes::app
 		auto get_input_1() const -> input_device& { return *inputs_[0].device; }
 		auto get_input_2() const -> input_device& { return *inputs_[1].device; }
 
+		auto toggle_input_1() -> void { toggle_input(0); }
+		auto toggle_input_2() -> void { toggle_input(1); }
+
 		auto get_keyboard() const -> input_device_keyboard& { return *keyboard_; }
 		auto get_controllers() const -> list<input_device_controller> const& { return controllers_; }
 
@@ -41,6 +45,7 @@ namespace nes::app
 		auto remove_controller(input_device_controller&) -> void;
 
 	private:
+		auto toggle_input(u32) -> void;
 		auto fill_unassigned_inputs() -> void;
 	};
 } // namespace nes::app
 \ No newline at end of file