#include "InputManager.h"
#include "Session.h"
#include "SessionDetails.h"
#include "Settings.h"
#include "SettingsManager.h"
#include "CompositorBase.h"
#include "OVR_CAPI.h"
#include "REV_Math.h"

#include <openvr.h>
#include <Windows.h>
#include <Xinput.h>
#include <lua.hpp>
#include <assert.h>

const char* InputManager::s_ButtonNames[vr::k_EButton_Max];
const char* InputManager::s_TypeNames[4];

InputManager::InputManager()
	: m_InputDevices()
	, m_LastPoses()
{
	for (ovrPoseStatef& pose : m_LastPoses)
		pose.ThePose = OVR::Posef::Identity();

	// TODO: This might change if a new HMD is connected (unlikely)
	m_fVsyncToPhotons = vr::VRSystem()->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_SecondsFromVsyncToPhotons_Float);

	for (int i = 0; i < vr::k_EButton_Max; i++)
		s_ButtonNames[i] = vr::VRSystem()->GetButtonIdNameFromEnum((vr::EVRButtonId)i) + 10; // Skip the 10-char enum prefix
	for (int i = 0; i < 4; i++)
		s_TypeNames[i] = vr::VRSystem()->GetControllerAxisTypeNameFromEnum((vr::EVRControllerAxisType)i) + +18; // Skip the 18-char enum prefix

	// TODO: XInput is slow, move it to another thread
#if 0
	m_InputDevices.push_back(new XboxGamepad());
#endif
	m_InputDevices.push_back(new OculusRemote());
	m_InputDevices.push_back(new OculusTouch(vr::TrackedControllerRole_LeftHand));
	m_InputDevices.push_back(new OculusTouch(vr::TrackedControllerRole_RightHand));

	UpdateConnectedControllers();
}

InputManager::~InputManager()
{
	for (InputDevice* device : m_InputDevices)
		delete device;
}

void InputManager::UpdateConnectedControllers()
{
	uint32_t types = 0;
	for (InputDevice* device : m_InputDevices)
	{
		if (device->IsConnected())
			types |= device->GetType();

		if (device->GetType() & ovrControllerType_Touch)
		{
			OculusTouch* touch = dynamic_cast<OculusTouch*>(device);
			assert(touch);
			if (!touch)
				continue;

			uint16_t axes = 0;
			vr::TrackedDeviceIndex_t index = vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(touch->GetRole());
			for (int i = 0; i < vr::k_unControllerStateAxisCount; i++)
			{
				vr::EVRControllerAxisType type = (vr::EVRControllerAxisType)vr::VRSystem()->GetInt32TrackedDeviceProperty(
					index, (vr::ETrackedDeviceProperty)(vr::Prop_Axis0Type_Int32 + i));
				axes |= (type & 3) << (i * 2);
			}
			touch->m_AxisTypes = axes;
		}
	}
	ConnectedControllers = types;
}

ovrResult InputManager::SetControllerVibration(ovrSession session, ovrControllerType controllerType, float frequency, float amplitude)
{
	// Clamp the input
	frequency = min(max(frequency, 0.0f), 1.0f);
	amplitude = min(max(amplitude, 0.0f), 1.0f);

	for (InputDevice* device : m_InputDevices)
	{
		if (controllerType & device->GetType() && ConnectedControllers & device->GetType())
			device->SetVibration(frequency, amplitude);
	}

	return ovrSuccess;
}

// TODO: Make GetInputState() lock-free
ovrResult InputManager::GetInputState(ovrSession session, ovrControllerType controllerType, ovrInputState* inputState)
{
	std::unique_lock<std::mutex> lk(m_InputMutex);
	memset(inputState, 0, sizeof(ovrInputState));

	inputState->TimeInSeconds = ovr_GetTimeInSeconds();

	uint32_t types = 0;
	for (InputDevice* device : m_InputDevices)
	{
		if (controllerType & device->GetType() && ConnectedControllers & device->GetType())
		{
			if (device->GetInputState(session, inputState))
				types |= device->GetType();
		}
	}

	inputState->ControllerType = (ovrControllerType)types;
	return ovrSuccess;
}

ovrResult InputManager::SubmitControllerVibration(ovrSession session, ovrControllerType controllerType, const ovrHapticsBuffer* buffer)
{
	for (InputDevice* device : m_InputDevices)
	{
		if (controllerType & device->GetType() && ConnectedControllers & device->GetType())
			device->SubmitVibration(buffer);
	}

	return ovrSuccess;
}

ovrResult InputManager::GetControllerVibrationState(ovrSession session, ovrControllerType controllerType, ovrHapticsPlaybackState* outState)
{
	memset(outState, 0, sizeof(ovrHapticsPlaybackState));

	for (InputDevice* device : m_InputDevices)
	{
		if (controllerType & device->GetType() && ConnectedControllers & device->GetType())
			device->GetVibrationState(outState);
	}

	return ovrSuccess;
}

ovrTouchHapticsDesc InputManager::GetTouchHapticsDesc(ovrControllerType controllerType)
{
	ovrTouchHapticsDesc desc = { 0 };

	if (controllerType & ovrControllerType_Touch)
	{
		desc.SampleRateHz = REV_HAPTICS_SAMPLE_RATE;
		desc.SampleSizeInBytes = sizeof(uint8_t);
		desc.SubmitMaxSamples = OVR_HAPTICS_BUFFER_SAMPLES_MAX;
		desc.SubmitMinSamples = 1;
		desc.SubmitOptimalSamples = 20;
		desc.QueueMinSizeToAvoidStarvation = 5;
	}

	return desc;
}

unsigned int InputManager::TrackedDevicePoseToOVRStatusFlags(vr::TrackedDevicePose_t pose)
{
	unsigned int result = 0;

	if (pose.bPoseIsValid)
	{
		if (pose.bDeviceIsConnected)
			result |= ovrStatus_OrientationTracked;
		if (pose.eTrackingResult != vr::TrackingResult_Calibrating_OutOfRange &&
			pose.eTrackingResult != vr::TrackingResult_Running_OutOfRange)
			result |= ovrStatus_PositionTracked;
	}

	return result;
}

ovrPoseStatef InputManager::TrackedDevicePoseToOVRPose(vr::TrackedDevicePose_t pose, ovrPoseStatef& lastPose, double time)
{
	ovrPoseStatef result = { OVR::Posef::Identity() };
	if (!pose.bPoseIsValid)
		return result;

	OVR::Matrix4f matrix = REV::Matrix4f(pose.mDeviceToAbsoluteTracking);

	// Make sure the orientation stays in the same hemisphere as the previous orientation, this prevents
	// linear interpolations from suddenly flipping the long way around in Oculus Medium.
	OVR::Quatf q(matrix);
	q.EnsureSameHemisphere(lastPose.ThePose.Orientation);

	result.ThePose.Orientation = q;
	result.ThePose.Position = matrix.GetTranslation();
	result.AngularVelocity = (REV::Vector3f)pose.vAngularVelocity;
	result.LinearVelocity = (REV::Vector3f)pose.vVelocity;
	result.AngularAcceleration = ((REV::Vector3f)pose.vAngularVelocity - lastPose.AngularVelocity) / float(time - lastPose.TimeInSeconds);
	result.LinearAcceleration = ((REV::Vector3f)pose.vVelocity - lastPose.LinearVelocity) / float(time - lastPose.TimeInSeconds);
	result.TimeInSeconds = time;

	// Store the last pose
	lastPose = result;

	return result;
}

int InputManager::ErrorHandler(lua_State* L)
{
	static bool first_error = true;
	if (first_error)
		vr::VROverlay()->ShowMessageOverlay(lua_tostring(L, -1), "Revive Input Error", "Ignore and Continue");
	OutputDebugStringA(lua_tostring(L, -1));
	OutputDebugStringA("\n");
	lua_pop(L, 1);
	first_error = false;
	return 0;
}

extern HMODULE revModule; // TODO: Get rid of this
bool InputManager::LoadResourceScript(lua_State* L, const char* name)
{
	HRSRC hRes = FindResourceA(revModule, name, "LUA");
	DWORD dwSize = SizeofResource(revModule, hRes);
	HGLOBAL hGlob = LoadResource(revModule, hRes);
	const char* pData = reinterpret_cast<const char*>(::LockResource(hGlob));

	if (luaL_loadbuffer(L, pData, dwSize, name))
	{
		OutputDebugStringA(lua_tostring(L, -1));
		OutputDebugStringA("\n");
		lua_pop(L, 1);
		return false;
	}
	return !lua_pcall(L, 0, LUA_MULTRET, 1);
}

bool InputManager::LoadFileScript(lua_State* L, const char* fn)
{
	if (luaL_loadfile(L, fn))
	{
		OutputDebugStringA(lua_tostring(L, -1));
		OutputDebugStringA("\n");
		lua_pop(L, 1);
		return false;
	}
	return !lua_pcall(L, 0, LUA_MULTRET, 1);
}

bool InputManager::LoadInputScript(const char* fn)
{
	for (InputDevice* device : m_InputDevices)
	{
		if (device->GetType() & ovrControllerType_Touch)
		{
			/* Create LUA VM state */
			lua_State* L = luaL_newstate();
			assert(L);
			m_ScriptStates.push_back(L);

			lua_pushcfunction(L, ErrorHandler);

		#define LUA_LOADLIB(lib) \
			lua_pushcfunction(L, luaopen_##lib); \
			lua_pcall(L, 0, 0, 1);

			// We only load three basic libraries, we don't want to expose dangerous OS functions
			LUA_LOADLIB(base);
			LUA_LOADLIB(table);
			LUA_LOADLIB(math);
			LUA_LOADLIB(string);

			bool success = LoadResourceScript(L, "HEADER");
			assert(success);
			if (!success)
				return false;

			// Attempt to load the script, if it fails load the internal script instead
			success = LoadFileScript(L, fn);
			if (!success)
				success = LoadResourceScript(L, "INPUT");
			assert(success);

			// If the lua script fails, we set it on the controllers
			if (!success)
				return false;

			OculusTouch* touch = dynamic_cast<OculusTouch*>(device);
			if (touch)
				touch->m_Script = L;
		}
	}
	return true;
}

void InputManager::GetTrackingState(ovrSession session, ovrTrackingState* outState, double absTime)
{
	if (session->Details->UseHack(SessionDetails::HACK_WAIT_IN_TRACKING_STATE))
		vr::VRCompositor()->WaitGetPoses(nullptr, 0, nullptr, 0);

	// Calculate the relative prediction time
	float relTime = 0.0f;
	if (absTime > 0.0f)
		relTime = float(absTime - ovr_GetTimeInSeconds());
	if (relTime > 0.0f)
		relTime += m_fVsyncToPhotons;

	// Get the device poses
	vr::ETrackingUniverseOrigin origin = session->TrackingOrigin;
	vr::TrackedDevicePose_t poses[vr::k_unMaxTrackedDeviceCount];
	vr::VRSystem()->GetDeviceToAbsoluteTrackingPose(origin, relTime, poses, vr::k_unMaxTrackedDeviceCount);

	// Convert the head pose
	outState->HeadPose = TrackedDevicePoseToOVRPose(poses[vr::k_unTrackedDeviceIndex_Hmd], m_LastPoses[vr::k_unTrackedDeviceIndex_Hmd], absTime);
	outState->StatusFlags = TrackedDevicePoseToOVRStatusFlags(poses[vr::k_unTrackedDeviceIndex_Hmd]);

	// Convert the hand poses
	InputSettings* settings = session->Settings->Input;
	vr::TrackedDeviceIndex_t hands[] = { vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(vr::TrackedControllerRole_LeftHand),
		vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(vr::TrackedControllerRole_RightHand) };
	for (int i = 0; i < ovrHand_Count; i++)
	{
		vr::TrackedDeviceIndex_t deviceIndex = hands[i];
		if (deviceIndex == vr::k_unTrackedDeviceIndexInvalid)
		{
			outState->HandPoses[i].ThePose = OVR::Posef::Identity();
			continue;
		}

		vr::TrackedDevicePose_t pose;
		vr::VRSystem()->ApplyTransform(&pose, &poses[deviceIndex], &settings->TouchOffset[i]);
		outState->HandPoses[i] = TrackedDevicePoseToOVRPose(pose, m_LastPoses[deviceIndex], absTime);
		outState->HandStatusFlags[i] = TrackedDevicePoseToOVRStatusFlags(poses[deviceIndex]);
	}

	if (origin == vr::TrackingUniverseSeated)
	{
		REV::Matrix4f origin = (REV::Matrix4f)vr::VRSystem()->GetSeatedZeroPoseToStandingAbsoluteTrackingPose();

		// The calibrated origin should be the location of the seated origin relative to the absolute tracking space.
		// It currently describes the location of the absolute origin relative to the seated origin, so we have to invert it.
		origin.Invert();

		outState->CalibratedOrigin.Orientation = OVR::Quatf(origin);
		outState->CalibratedOrigin.Position = origin.GetTranslation();
	}
	else
	{
		// In a standing universe we don't calibrate the origin outside of the room setup, thus this should always be the
		// identity matrix.
		outState->CalibratedOrigin.Orientation = OVR::Quatf::Identity();
		outState->CalibratedOrigin.Position = OVR::Vector3f();
	}
}

ovrResult InputManager::GetDevicePoses(ovrTrackedDeviceType* deviceTypes, int deviceCount, double absTime, ovrPoseStatef* outDevicePoses)
{
	// Get the device poses
	vr::ETrackingUniverseOrigin space = vr::VRCompositor()->GetTrackingSpace();
	float relTime = float(absTime - ovr_GetTimeInSeconds());
	vr::TrackedDevicePose_t poses[vr::k_unMaxTrackedDeviceCount];
	vr::VRSystem()->GetDeviceToAbsoluteTrackingPose(space, relTime, poses, vr::k_unMaxTrackedDeviceCount);

	// Get the generic tracker indices
	vr::TrackedDeviceIndex_t trackers[vr::k_unMaxTrackedDeviceCount];
	vr::VRSystem()->GetSortedTrackedDeviceIndicesOfClass(vr::TrackedDeviceClass_GenericTracker, trackers, vr::k_unMaxTrackedDeviceCount);

	for (int i = 0; i < deviceCount; i++)
	{
		// Get the index for device types we recognize
		uint32_t index = vr::k_unTrackedDeviceIndexInvalid;
		switch (deviceTypes[i])
		{
		case ovrTrackedDevice_HMD:
			index = vr::k_unTrackedDeviceIndex_Hmd;
			break;
		case ovrTrackedDevice_LTouch:
			index = vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(vr::TrackedControllerRole_LeftHand);
			break;
		case ovrTrackedDevice_RTouch:
			index = vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(vr::TrackedControllerRole_RightHand);
			break;
		case ovrTrackedDevice_Object0:
			index = trackers[0];
			break;
		case ovrTrackedDevice_Object1:
			index = trackers[1];
			break;
		case ovrTrackedDevice_Object2:
			index = trackers[2];
			break;
		case ovrTrackedDevice_Object3:
			index = trackers[3];
			break;
		}

		// If the tracking index is invalid it will fall outside of the range of the array
		if (index >= vr::k_unMaxTrackedDeviceCount)
			return ovrError_DeviceUnavailable;
		outDevicePoses[i] = TrackedDevicePoseToOVRPose(poses[index], m_LastPoses[index], absTime);
	}

	return ovrSuccess;
}

/* Controller child-classes */

void InputManager::OculusTouch::HapticsThread(OculusTouch* device)
{
	std::chrono::microseconds freq(std::chrono::seconds(1));
	freq /= REV_HAPTICS_SAMPLE_RATE;

	while (device->m_bHapticsRunning)
	{
		vr::TrackedDeviceIndex_t touch = vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(device->GetRole());

		uint16_t duration = (uint16_t)((float)freq.count() * device->m_Haptics.GetSample());
		if (duration > 0)
			vr::VRSystem()->TriggerHapticPulse(touch, 0, duration);

		std::this_thread::sleep_for(freq);
	}
}

InputManager::OculusTouch::OculusTouch(vr::ETrackedControllerRole role)
	: m_Script()
	, m_Role(role)
	, m_bHapticsRunning(true)
{
	m_HapticsThread = std::thread(HapticsThread, this);
}

InputManager::OculusTouch::~OculusTouch()
{
	m_bHapticsRunning = false;
	m_HapticsThread.join();
}

ovrControllerType InputManager::OculusTouch::GetType()
{
	return m_Role == vr::TrackedControllerRole_LeftHand ? ovrControllerType_LTouch : ovrControllerType_RTouch;
}

bool InputManager::OculusTouch::IsConnected() const
{
	// Check if the Vive controller is assigned
	vr::TrackedDeviceIndex_t touch = vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(m_Role);
	return touch != vr::k_unTrackedDeviceIndexInvalid;
}

void InputManager::OculusTouch::AddStateField(lua_State* L, vr::TrackedDeviceIndex_t index,
	vr::VRControllerState_t& state, vr::EVRButtonId button, const char* name)
{
	bool isAxis = vr::k_EButton_Axis0 <= button && button <= vr::k_EButton_Axis4;
	if (isAxis)
	{
		// We put axes in the array part
		lua_pushnumber(L, button - vr::k_EButton_Axis0 + 1);
	}
	else
	{
		// And buttons in the hash table
		if (!name)
			name = s_ButtonNames[button];
		lua_pushstring(L, name);
	}

	lua_createtable(L, 0, isAxis ? 5 : 2);
	lua_pushboolean(L, !!(state.ulButtonPressed & vr::ButtonMaskFromId(button)));
	lua_setfield(L, -2, "pressed");
	lua_pushboolean(L, !!(state.ulButtonTouched & vr::ButtonMaskFromId(button)));
	lua_setfield(L, -2, "touched");

	if (isAxis)
	{
		int n = button - vr::k_EButton_Axis0;
		vr::VRControllerAxis_t& axis = state.rAxis[n];

		lua_pushnumber(L, axis.x);
		lua_setfield(L, -2, "x");
		lua_pushnumber(L, axis.y);
		lua_setfield(L, -2, "y");

		lua_pushstring(L, s_TypeNames[(m_AxisTypes >> n) & 3]);
		lua_setfield(L, -2, "type");
	}

	lua_settable(L, -3);
}


void InputManager::OculusTouch::CreateStateTable(lua_State* L, vr::TrackedDeviceIndex_t index, vr::VRControllerState_t& state)
{
	lua_createtable(L, vr::k_unControllerStateAxisCount, 12);
	// Known buttons
	for (int i = vr::k_EButton_System; i <= vr::k_EButton_A; i++)
		AddStateField(L, index, state, (vr::EVRButtonId)i);

	// Known axes
	for (int i = vr::k_EButton_Axis0; i <= vr::k_EButton_Axis4; i++)
		AddStateField(L, index, state, (vr::EVRButtonId)i);

	// Some controllers define additional undocumented buttons
	AddStateField(L, index, state, (vr::EVRButtonId)8, "B");
	AddStateField(L, index, state, (vr::EVRButtonId)9, "X");
	AddStateField(L, index, state, (vr::EVRButtonId)10, "Y");

	// ... are you really going to use the headset sensor for input?
	AddStateField(L, index, state, vr::k_EButton_ProximitySensor);
}

// TODO: Make GetInputState reentrant (thread-safe).
bool InputManager::OculusTouch::GetInputState(ovrSession session, ovrInputState* inputState)
{
	// Get controller index
	vr::TrackedDeviceIndex_t index = vr::VRSystem()->GetTrackedDeviceIndexForControllerRole(m_Role);
	ovrHandType hand = (m_Role == vr::TrackedControllerRole_LeftHand) ? ovrHand_Left : ovrHand_Right;

	InputSettings* settings = session->Settings->Input;
	lua_State* L = m_Script.load();

	if (!L || index == vr::k_unTrackedDeviceIndexInvalid)
		return false;

	vr::VRControllerState_t state;
	vr::VRSystem()->GetControllerState(index, &state, sizeof(state));

	CreateStateTable(L, index, state);
	lua_setglobal(L, "state");

	lua_pushnumber(L, inputState->TimeInSeconds);
	lua_setglobal(L, "time");

	uint32_t size = vr::VRSystem()->GetStringTrackedDeviceProperty(index, vr::Prop_ModelNumber_String, nullptr, 0);
	std::vector<char> model(size);
	vr::VRSystem()->GetStringTrackedDeviceProperty(index, vr::Prop_ModelNumber_String, model.data(), size);
	lua_pushstring(L, model.data());
	lua_setglobal(L, "controller_model");

	lua_getglobal(L, "GetButtons");
	lua_pushboolean(L, hand == ovrHand_Right);
	if (lua_pcall(L, 1, LUA_MULTRET, 1))
		return false;
	while (lua_gettop(L) > 1)
	{
		inputState->Buttons |= lua_tointeger(L, -1);
		lua_pop(L, 1);
	}

	lua_getglobal(L, "GetTouches");
	lua_pushboolean(L, hand == ovrHand_Right);
	if (lua_pcall(L, 1, LUA_MULTRET, 1))
		return false;
	while (lua_gettop(L) > 1)
	{
		inputState->Touches |= lua_tointeger(L, -1);
		lua_pop(L, 1);
	}

	lua_getglobal(L, "GetTriggers");
	lua_pushboolean(L, hand == ovrHand_Right);
	lua_createtable(L, 0, 3);
	lua_pushboolean(L, settings->ToggleGrip == revGrip_Normal);
	lua_setfield(L, -2, "normal");
	lua_pushboolean(L, settings->ToggleGrip == revGrip_Toggle);
	lua_setfield(L, -2, "toggle");
	lua_pushboolean(L, settings->ToggleGrip == revGrip_Hybrid);
	lua_setfield(L, -2, "hybrid");
	lua_pushnumber(L, settings->ToggleDelay);
	lua_setfield(L, -2, "delay");
	lua_pushboolean(L, settings->TriggerAsGrip);
	lua_setfield(L, -2, "trigger");
	if (lua_pcall(L, 2, 2, 1))
		return false;
	inputState->IndexTrigger[hand] = (float)lua_tonumber(L, -2);
	inputState->HandTrigger[hand] = (float)lua_tonumber(L, -1);
	lua_pop(L, 2);

	lua_getglobal(L, "GetThumbstick");
	lua_pushboolean(L, hand == ovrHand_Right);
	lua_pushnumber(L, settings->Deadzone);
	if (lua_pcall(L, 2, 2, 1))
		return false;
	inputState->Thumbstick[hand].x = (float)lua_tonumber(L, -2);
	inputState->Thumbstick[hand].y = (float)lua_tonumber(L, -1);
	lua_pop(L, 2);

	lua_getglobal(L, "GetThumbstick");
	lua_pushboolean(L, hand == ovrHand_Right);
	lua_pushnumber(L, 0);
	if (lua_pcall(L, 2, 2, 1))
		return false;
	inputState->ThumbstickNoDeadzone[hand].x = (float)lua_tonumber(L, -2);
	inputState->ThumbstickNoDeadzone[hand].y = (float)lua_tonumber(L, -1);
	lua_pop(L, 2);

	// We don't apply deadzones yet on triggers and grips
	inputState->IndexTriggerNoDeadzone[hand] = inputState->IndexTrigger[hand];
	inputState->HandTriggerNoDeadzone[hand] = inputState->HandTrigger[hand];

	// We have no way to get raw values
	inputState->ThumbstickRaw[hand] = inputState->ThumbstickNoDeadzone[hand];
	inputState->IndexTriggerRaw[hand] = inputState->IndexTriggerNoDeadzone[hand];
	inputState->HandTriggerRaw[hand] = inputState->HandTriggerNoDeadzone[hand];

	lua_getglobal(L, "state");
	lua_setglobal(L, "last_state");
	return true;
}

bool InputManager::OculusRemote::IsConnected() const
{
	// Check if a Vive controller is available
	uint32_t controllerCount = vr::VRSystem()->GetSortedTrackedDeviceIndicesOfClass(vr::TrackedDeviceClass_Controller, nullptr, 0);

	// If only one controller is available, the Oculus Remote is connected
	return controllerCount == 1;
}

bool InputManager::OculusRemote::GetInputState(ovrSession session, ovrInputState* inputState)
{
	// Get controller indices.
	vr::TrackedDeviceIndex_t remote;
	vr::VRSystem()->GetSortedTrackedDeviceIndicesOfClass(vr::TrackedDeviceClass_Controller, &remote, 1);

	if (remote == vr::k_unTrackedDeviceIndexInvalid)
		return false;

	vr::VRControllerState_t state;
	vr::VRSystem()->GetControllerState(remote, &state, sizeof(state));

	if (state.ulButtonPressed & vr::ButtonMaskFromId(vr::k_EButton_ApplicationMenu))
		inputState->Buttons |= ovrButton_Back;

	if (state.ulButtonPressed & vr::ButtonMaskFromId(vr::k_EButton_SteamVR_Touchpad))
	{
		vr::VRControllerAxis_t axis = state.rAxis[0];
		float magnitude = sqrt(axis.x*axis.x + axis.y*axis.y);

		if (magnitude < 0.5f)
		{
			inputState->Buttons |= ovrButton_Enter;
		}
		else
		{
			if (axis.y < axis.x) {
				if (axis.y < -axis.x)
					inputState->Buttons |= ovrButton_Down;
				else
					inputState->Buttons |= ovrButton_Right;
			}
			else {
				if (axis.y < -axis.x)
					inputState->Buttons |= ovrButton_Left;
				else
					inputState->Buttons |= ovrButton_Up;
			}
		}
	}

	return state.ulButtonPressed != 0;
}

InputManager::XboxGamepad::XboxGamepad()
{
	m_XInput = LoadLibrary(L"xinput1_3.dll");
	if (m_XInput)
	{
		GetState = (_XInputGetState)GetProcAddress(m_XInput, "XInputGetState");
		SetState = (_XInputSetState)GetProcAddress(m_XInput, "XInputSetState");
	}
}

InputManager::XboxGamepad::~XboxGamepad()
{
	FreeLibrary(m_XInput);
}

bool InputManager::XboxGamepad::IsConnected() const
{
	if (!m_XInput)
		return false;

	// Check for Xbox controller
	XINPUT_STATE input;
	return GetState(0, &input) == ERROR_SUCCESS;
}

bool InputManager::XboxGamepad::GetInputState(ovrSession session, ovrInputState* inputState)
{
	if (!m_XInput)
		return false;

	// Use XInput for Xbox controllers.
	XINPUT_STATE state;
	if (GetState(0, &state) == ERROR_SUCCESS)
	{
		// Convert the buttons
		bool active = false;
		WORD buttons = state.Gamepad.wButtons;
		if (buttons & XINPUT_GAMEPAD_DPAD_UP)
			inputState->Buttons |= ovrButton_Up;
		if (buttons & XINPUT_GAMEPAD_DPAD_DOWN)
			inputState->Buttons |= ovrButton_Down;
		if (buttons & XINPUT_GAMEPAD_DPAD_LEFT)
			inputState->Buttons |= ovrButton_Left;
		if (buttons & XINPUT_GAMEPAD_DPAD_RIGHT)
			inputState->Buttons |= ovrButton_Right;
		if (buttons & XINPUT_GAMEPAD_START)
			inputState->Buttons |= ovrButton_Enter;
		if (buttons & XINPUT_GAMEPAD_BACK)
			inputState->Buttons |= ovrButton_Back;
		if (buttons & XINPUT_GAMEPAD_LEFT_THUMB)
			inputState->Buttons |= ovrButton_LThumb;
		if (buttons & XINPUT_GAMEPAD_RIGHT_THUMB)
			inputState->Buttons |= ovrButton_RThumb;
		if (buttons & XINPUT_GAMEPAD_LEFT_SHOULDER)
			inputState->Buttons |= ovrButton_LShoulder;
		if (buttons & XINPUT_GAMEPAD_RIGHT_SHOULDER)
			inputState->Buttons |= ovrButton_RShoulder;
		if (buttons & XINPUT_GAMEPAD_A)
			inputState->Buttons |= ovrButton_A;
		if (buttons & XINPUT_GAMEPAD_B)
			inputState->Buttons |= ovrButton_B;
		if (buttons & XINPUT_GAMEPAD_X)
			inputState->Buttons |= ovrButton_X;
		if (buttons & XINPUT_GAMEPAD_Y)
			inputState->Buttons |= ovrButton_Y;

		active = (buttons != 0);

		// Convert the axes
		SHORT deadzones[] = { XINPUT_GAMEPAD_LEFT_THUMB_DEADZONE, XINPUT_GAMEPAD_RIGHT_THUMB_DEADZONE };
		for (int i = 0; i < ovrHand_Count; i++)
		{
			float X, Y, trigger;
			if (i == ovrHand_Left)
			{
				X = state.Gamepad.sThumbLX;
				Y = state.Gamepad.sThumbLY;
				trigger = state.Gamepad.bLeftTrigger;
			}
			if (i == ovrHand_Right)
			{
				X = state.Gamepad.sThumbRX;
				Y = state.Gamepad.sThumbRY;
				trigger = state.Gamepad.bRightTrigger;
			}

			//determine how far the controller is pushed
			float magnitude = sqrt(X*X + Y*Y);

			//determine the direction the controller is pushed
			float normalizedX = X / magnitude;
			float normalizedY = Y / magnitude;
			inputState->ThumbstickNoDeadzone[i].x = normalizedX;
			inputState->ThumbstickNoDeadzone[i].y = normalizedY;

			//check if the controller is outside a circular dead zone
			if (magnitude > deadzones[i])
			{
				//clip the magnitude at its expected maximum value
				if (magnitude > 32767) magnitude = 32767;

				//adjust magnitude relative to the end of the dead zone
				magnitude -= deadzones[i];

				//optionally normalize the magnitude with respect to its expected range
				//giving a magnitude value of 0.0 to 1.0
				float normalizedMagnitude = magnitude / (32767 - deadzones[i]);
				inputState->Thumbstick[i].x = normalizedMagnitude * normalizedX;
				inputState->Thumbstick[i].y = normalizedMagnitude * normalizedY;
				active = true;
			}

			if (trigger > XINPUT_GAMEPAD_TRIGGER_THRESHOLD)
			{
				//clip the magnitude at its expected maximum value
				if (trigger > 255) trigger = 255;
				inputState->IndexTriggerNoDeadzone[i] = trigger / 255.0f;

				//adjust magnitude relative to the end of the dead zone
				trigger -= XINPUT_GAMEPAD_TRIGGER_THRESHOLD;

				//optionally normalize the magnitude with respect to its expected range
				//giving a magnitude value of 0.0 to 1.0
				float normalizedTrigger = trigger / (255 - XINPUT_GAMEPAD_TRIGGER_THRESHOLD);
				inputState->IndexTrigger[i] = normalizedTrigger;
				active = true;
			}
		}

		return active;
	}
	return false;
}

void InputManager::XboxGamepad::SetVibration(float frequency, float amplitude)
{
	if (!m_XInput)
		return;

	// TODO: Disable the rumbler after a nominal amount of time
	XINPUT_VIBRATION vibration;
	ZeroMemory(&vibration, sizeof(XINPUT_VIBRATION));
	if (frequency > 0.0f)
	{
		// The right motor is the high-frequency motor, the left motor is the low-frequency motor.
		if (frequency > 0.5f)
			vibration.wRightMotorSpeed = WORD(65535.0f * amplitude);
		else
			vibration.wLeftMotorSpeed = WORD(65535.0f * amplitude);
	}
	SetState(0, &vibration);
}