#ifdef OPENXR

#include "Common/GPU/OpenGL/GLRenderManager.h"
#include "Common/GPU/Vulkan/VulkanContext.h"

#include "Common/VR/PPSSPPVR.h"
#include "Common/VR/VRBase.h"
#include "Common/VR/VRInput.h"
#include "Common/VR/VRMath.h"
#include "Common/VR/VRRenderer.h"

#include "Core/HLE/sceDisplay.h"
#include "Core/Config.h"
#include "Core/KeyMap.h"
#include "Core/System.h"

static long vrCompat[VR_COMPAT_MAX];

/*
================================================================================

VR button mapping

================================================================================
*/

struct ButtonMapping {
	ovrButton ovr;
	int keycode;
	bool pressed;
	int repeat;

	ButtonMapping(int keycode, ovrButton ovr) {
		this->keycode = keycode;
		this->ovr = ovr;
		pressed = false;
		repeat = 0;
	}
};

struct MouseActivator {
	bool activate;
	ovrButton ovr;

	MouseActivator(bool activate, ovrButton ovr) {
		this->activate = activate;
		this->ovr = ovr;
	}
};

static std::vector<ButtonMapping> leftControllerMapping = {
		ButtonMapping(NKCODE_BUTTON_X, ovrButton_X),
		ButtonMapping(NKCODE_BUTTON_Y, ovrButton_Y),
		ButtonMapping(NKCODE_ALT_LEFT, ovrButton_GripTrigger),
		ButtonMapping(NKCODE_DPAD_UP, ovrButton_Up),
		ButtonMapping(NKCODE_DPAD_DOWN, ovrButton_Down),
		ButtonMapping(NKCODE_DPAD_LEFT, ovrButton_Left),
		ButtonMapping(NKCODE_DPAD_RIGHT, ovrButton_Right),
		ButtonMapping(NKCODE_BUTTON_THUMBL, ovrButton_LThumb),
		ButtonMapping(NKCODE_ENTER, ovrButton_Trigger),
		ButtonMapping(NKCODE_BACK, ovrButton_Enter),
};

static std::vector<ButtonMapping> rightControllerMapping = {
		ButtonMapping(NKCODE_BUTTON_A, ovrButton_A),
		ButtonMapping(NKCODE_BUTTON_B, ovrButton_B),
		ButtonMapping(NKCODE_ALT_RIGHT, ovrButton_GripTrigger),
		ButtonMapping(NKCODE_DPAD_UP, ovrButton_Up),
		ButtonMapping(NKCODE_DPAD_DOWN, ovrButton_Down),
		ButtonMapping(NKCODE_DPAD_LEFT, ovrButton_Left),
		ButtonMapping(NKCODE_DPAD_RIGHT, ovrButton_Right),
		ButtonMapping(NKCODE_BUTTON_THUMBR, ovrButton_RThumb),
		ButtonMapping(NKCODE_ENTER, ovrButton_Trigger),
};

static const int controllerIds[] = {DEVICE_ID_XR_CONTROLLER_LEFT, DEVICE_ID_XR_CONTROLLER_RIGHT};
static std::vector<ButtonMapping> controllerMapping[2] = {
		leftControllerMapping,
		rightControllerMapping
};
static int mouseController = -1;
static bool mousePressed[] = {false, false};

static std::vector<MouseActivator> mouseActivators = {
		MouseActivator(true, ovrButton_Trigger),
		MouseActivator(false, ovrButton_Up),
		MouseActivator(false, ovrButton_Down),
		MouseActivator(false, ovrButton_Left),
		MouseActivator(false, ovrButton_Right),
};

/*
================================================================================

VR app flow integration

================================================================================
*/

bool IsVRBuild() {
	return true;
}

#if PPSSPP_PLATFORM(ANDROID)
void InitVROnAndroid(void* vm, void* activity, int version, const char* name) {
	bool useVulkan = (GPUBackend)g_Config.iGPUBackend == GPUBackend::VULKAN;

	ovrJava java;
	java.Vm = (JavaVM*)vm;
	java.ActivityObject = (jobject)activity;
	java.AppVersion = version;
	strcpy(java.AppName, name);
	VR_Init(java, useVulkan);

	__DisplaySetFramerate(72);
}
#endif

void EnterVR(bool firstStart, void* vulkanContext) {
	if (firstStart) {
		engine_t* engine = VR_GetEngine();
		bool useVulkan = (GPUBackend)g_Config.iGPUBackend == GPUBackend::VULKAN;
		if (useVulkan) {
			auto* context = (VulkanContext*)vulkanContext;
			engine->graphicsBindingVulkan = {};
			engine->graphicsBindingVulkan.type = XR_TYPE_GRAPHICS_BINDING_VULKAN_KHR;
			engine->graphicsBindingVulkan.next = NULL;
			engine->graphicsBindingVulkan.device = context->GetDevice();
			engine->graphicsBindingVulkan.instance = context->GetInstance();
			engine->graphicsBindingVulkan.physicalDevice = context->GetCurrentPhysicalDevice();
			engine->graphicsBindingVulkan.queueFamilyIndex = context->GetGraphicsQueueFamilyIndex();
			engine->graphicsBindingVulkan.queueIndex = 0;
			VR_EnterVR(engine, &engine->graphicsBindingVulkan);
		} else {
			VR_EnterVR(engine, nullptr);
		}
		IN_VRInit(engine);
	}
	VR_SetConfig(VR_CONFIG_VIEWPORT_VALID, false);
}

void GetVRResolutionPerEye(int* width, int* height) {
	if (VR_GetEngine()->appState.Instance) {
		VR_GetResolution(VR_GetEngine(), width, height);
	}
}

void UpdateVRInput(bool(*NativeKey)(const KeyInput &key), bool(*NativeTouch)(const TouchInput &touch), bool haptics, float dp_xscale, float dp_yscale) {
	//buttons
	KeyInput keyInput = {};
	for (int j = 0; j < 2; j++) {
		int status = IN_VRGetButtonState(j);
		bool cameraControl = VR_GetConfig(VR_CONFIG_CAMERA_CONTROL);
		for (ButtonMapping& m : controllerMapping[j]) {

			//check if camera key was pressed
			bool cameraKey = false;
			std::vector<int> nativeKeys;
			if (KeyMap::KeyToPspButton(controllerIds[j], m.keycode, &nativeKeys)) {
				for (int& nativeKey : nativeKeys) {
					if (nativeKey == VIRTKEY_VR_CAMERA_ADJUST) {
						cameraKey = true;
						break;
					}
				}
			}

			//fill KeyInput structure
			bool pressed = status & m.ovr;
			keyInput.flags = pressed ? KEY_DOWN : KEY_UP;
			keyInput.keyCode = m.keycode;
			keyInput.deviceId = controllerIds[j];

			//process the key action
			if (m.pressed != pressed) {
				if (pressed && haptics) {
					INVR_Vibrate(100, j, 1000);
				}
				if (!cameraControl || cameraKey) {
					NativeKey(keyInput);
				}
				m.pressed = pressed;
				m.repeat = 0;
			} else if (pressed && (m.repeat > 30)) {
				keyInput.flags |= KEY_IS_REPEAT;
				if (!cameraControl || cameraKey) {
					NativeKey(keyInput);
				}
				m.repeat = 0;
			} else {
				m.repeat++;
			}
		}
	}

	//enable or disable mouse
	for (int j = 0; j < 2; j++) {
		int status = IN_VRGetButtonState(j);
		for (MouseActivator& m : mouseActivators) {
			if (status & m.ovr) {
				mouseController = m.activate ? j : -1;
			}
		}
	}

	//mouse cursor
	if (mouseController >= 0) {
		//get position on screen
		XrPosef pose = IN_VRGetPose(mouseController);
		XrVector3f angles = XrQuaternionf_ToEulerAngles(pose.orientation);
		float width = (float)VR_GetConfig(VR_CONFIG_VIEWPORT_WIDTH);
		float height = (float)VR_GetConfig(VR_CONFIG_VIEWPORT_HEIGHT);
		float cx = width / 2;
		float cy = height / 2;
		float speed = (cx + cy) / 2;
		float x = cx - tan(ToRadians(angles.y - (float)VR_GetConfig(VR_CONFIG_MENU_YAW))) * speed;
		float y = cy - tan(ToRadians(angles.x)) * speed;

		//set renderer
		VR_SetConfig(VR_CONFIG_MOUSE_X, (int)x);
		VR_SetConfig(VR_CONFIG_MOUSE_Y, (int)y);
		VR_SetConfig(VR_CONFIG_MOUSE_SIZE, 6 * (int)pow(VR_GetConfig(VR_CONFIG_CANVAS_DISTANCE), 0.25f));

		//inform engine about the status
		TouchInput touch;
		touch.id = mouseController;
		touch.x = x * dp_xscale;
		touch.y = (height - y - 1) * dp_yscale;
		bool pressed = IN_VRGetButtonState(mouseController) & ovrButton_Trigger;
		if (mousePressed[mouseController] != pressed) {
			if (!pressed) {
				touch.flags = TOUCH_DOWN;
				NativeTouch(touch);
				touch.flags = TOUCH_UP;
				NativeTouch(touch);
			}
			mousePressed[mouseController] = pressed;
		}
	} else {
		VR_SetConfig(VR_CONFIG_MOUSE_SIZE, 0);
	}
}

void UpdateVRSpecialKeys(const KeyInput &key) {
	std::vector<int> nativeKeys;
	if (KeyMap::KeyToPspButton(key.deviceId, key.keyCode, &nativeKeys)) {
		for (int& nativeKey : nativeKeys) {
			// adjust camera parameters
			if (nativeKey == VIRTKEY_VR_CAMERA_ADJUST) {
				VR_SetConfig(VR_CONFIG_CAMERA_CONTROL, key.flags & KEY_DOWN);
			}
			// force 2D rendering
			else if (nativeKey == CTRL_SCREEN) {
				VR_SetConfig(VR_CONFIG_FORCE_2D, key.flags & KEY_DOWN);
			}
		}
	}
}

/*
================================================================================

// VR games compatibility

================================================================================
*/

void PreprocessSkyplane(GLRStep* step) {

	// Do not do anything if the scene is not in VR.
	if (IsFlatVRScene()) {
		return;
	}

	// Check if it is the step we need to modify.
	for (auto& cmd : step->commands) {
		if (cmd.cmd == GLRRenderCommand::BIND_FB_TEXTURE) {
			return;
		}
	}

	// Clear sky with the fog color.
	if (!vrCompat[VR_COMPAT_FBO_CLEAR]) {
		GLRRenderData skyClear {};
		skyClear.cmd = GLRRenderCommand::CLEAR;
		skyClear.clear.colorMask = 0xF;
		skyClear.clear.clearMask = GL_COLOR_BUFFER_BIT;
		skyClear.clear.clearColor = vrCompat[VR_COMPAT_FOG_COLOR];
		step->commands.insert(step->commands.begin(), skyClear);
		vrCompat[VR_COMPAT_FBO_CLEAR] = true;
	}

	// Remove original sky plane.
	bool depthEnabled = false;
	for (auto& command : step->commands) {
		if (command.cmd == GLRRenderCommand::DEPTH) {
			depthEnabled = command.depth.enabled;
		} else if ((command.cmd == GLRRenderCommand::DRAW_INDEXED) && !depthEnabled) {
			command.drawIndexed.count = 0;
		}
	}
}

void PreprocessStepVR(void* step) {
	auto* glrStep = (GLRStep*)step;
	if (vrCompat[VR_COMPAT_SKYPLANE]) PreprocessSkyplane(glrStep);
}

void SetVRCompat(VRCompatFlag flag, long value) {
	vrCompat[flag] = value;
}

/*
================================================================================

VR rendering integration

================================================================================
*/

void* BindVRFramebuffer() {
	return VR_BindFramebuffer(VR_GetEngine());
}

bool StartVRRender() {
	if (!VR_GetConfig(VR_CONFIG_VIEWPORT_VALID)) {
		VR_InitRenderer(VR_GetEngine(), IsMultiviewSupported());
		VR_SetConfig(VR_CONFIG_VIEWPORT_VALID, true);
	}

	if (VR_InitFrame(VR_GetEngine())) {

		// Decide if the scene is 3D or not
		if (g_Config.bEnableVR && !VR_GetConfig(VR_CONFIG_FORCE_2D) && (VR_GetConfig(VR_CONFIG_3D_GEOMETRY_COUNT) > 15)) {
			bool stereo = VR_GetConfig(VR_CONFIG_6DOF_PRECISE) && g_Config.bEnableStereo;
			VR_SetConfig(VR_CONFIG_MODE, stereo ? VR_MODE_STEREO_6DOF : VR_MODE_MONO_6DOF);
		} else {
			VR_SetConfig(VR_CONFIG_MODE, g_Config.bEnableStereo ? VR_MODE_STEREO_SCREEN : VR_MODE_MONO_SCREEN);
		}
		VR_SetConfig(VR_CONFIG_3D_GEOMETRY_COUNT, VR_GetConfig(VR_CONFIG_3D_GEOMETRY_COUNT) / 2);

		// Set compatibility
		vrCompat[VR_COMPAT_SKYPLANE] = PSP_CoreParameter().compat.vrCompat().Skyplane;

		// Camera control
		if (VR_GetConfig(VR_CONFIG_CAMERA_CONTROL)) {
			//left joystick controls height and side
			float height = g_Config.fCameraHeight;
			float side = g_Config.fCameraSide;
			int status = IN_VRGetButtonState(0);
			if (status & ovrButton_Left) side -= 0.05f;
			if (status & ovrButton_Right) side += 0.05f;
			if (status & ovrButton_Down) height -= 0.05f;
			if (status & ovrButton_Up) height += 0.05f;
			if (status & ovrButton_LThumb) {
				height = 0;
				side = 0;
			}
			g_Config.fCameraHeight = std::clamp(height, -10.0f, 10.0f);
			g_Config.fCameraSide = std::clamp(side, -10.0f, 10.0f);

			//right joystick controls distance and fov
			float dst = g_Config.fCameraDistance;
			float fov = g_Config.fFieldOfViewPercentage;
			status = IN_VRGetButtonState(1);
			if (status & ovrButton_Left) fov -= 1.0f;
			if (status & ovrButton_Right) fov += 1.0f;
			if (status & ovrButton_Down) dst -= 0.1f;
			if (status & ovrButton_Up) dst += 0.1f;
			if (status & ovrButton_RThumb) {
				fov = 100;
				dst = 0;
			}
			g_Config.fCameraDistance = std::clamp(dst, -10.0f, 10.0f);
			g_Config.fFieldOfViewPercentage = std::clamp(fov, 100.0f, 200.0f);
		}

		// Set customizations
		VR_SetConfig(VR_CONFIG_6DOF_ENABLED, g_Config.bEnable6DoF);
		VR_SetConfig(VR_CONFIG_CAMERA_DISTANCE, g_Config.fCameraDistance * 1000);
		VR_SetConfig(VR_CONFIG_CAMERA_HEIGHT, g_Config.fCameraHeight * 1000);
		VR_SetConfig(VR_CONFIG_CAMERA_SIDE, g_Config.fCameraSide * 1000);
		VR_SetConfig(VR_CONFIG_CANVAS_DISTANCE, g_Config.fCanvasDistance);
		VR_SetConfig(VR_CONFIG_FOV_SCALE, g_Config.fFieldOfViewPercentage);
		VR_SetConfig(VR_CONFIG_MIRROR_UPDATED, false);
		return true;
	}
	return false;
}

void FinishVRRender() {
	VR_FinishFrame(VR_GetEngine());
}

void PreVRFrameRender(int fboIndex) {
	VR_BeginFrame(VR_GetEngine(), fboIndex);
	vrCompat[VR_COMPAT_FBO_CLEAR] = false;
}

void PostVRFrameRender() {
	VR_EndFrame(VR_GetEngine());
}

int GetVRFBOIndex() {
	return VR_GetConfig(VR_CONFIG_CURRENT_FBO);
}

int GetVRPassesCount() {
	if (!IsMultiviewSupported() && g_Config.bEnableStereo) {
		return 2;
	} else {
		return 1;
	}
}

bool IsMultiviewSupported() {
	return false;
}

bool IsFlatVRScene() {
	int vrMode = VR_GetConfig(VR_CONFIG_MODE);
	return (vrMode == VR_MODE_MONO_SCREEN) || (vrMode == VR_MODE_STEREO_SCREEN);
}

bool Is2DVRObject(float* projMatrix, bool ortho) {

	// Quick analyze if the object is in 2D
	if ((fabs(fabs(projMatrix[12]) - 1.0f) < EPSILON) && (fabs(fabs(projMatrix[13]) - 1.0f) < EPSILON) && (fabs(fabs(projMatrix[14]) - 1.0f) < EPSILON)) {
		return true;
	} else if ((fabs(projMatrix[0]) > 10.0f) && (fabs(projMatrix[5]) > 10.0f)) {
		return true;
	} else if (fabs(projMatrix[15] - 1) < EPSILON) {
		return true;
	}

	// Chceck if the projection matrix is identity
	bool identity = true;
	for (int i = 0; i < 4; i++) {
		for (int j = 0; j < 4; j++) {
			float value = projMatrix[i * 4 + j];

			// Other number than zero on non-diagonale
			if ((i != j) && (fabs(value) > EPSILON)) identity = false;
			// Other number than one on diagonale
			if ((i == j) && (fabs(value - 1.0f) > EPSILON)) identity = false;
		}
	}

	// Update 3D geometry count
	if (!identity && !ortho) {
		VR_SetConfig(VR_CONFIG_3D_GEOMETRY_COUNT, VR_GetConfig(VR_CONFIG_3D_GEOMETRY_COUNT) + 1);
	}
	return identity;
}

void UpdateVRProjection(float* projMatrix, float* leftEye, float* rightEye) {

	// Update project matrices
	float* dst[] = {leftEye, rightEye};
	VRMatrix enums[] = {VR_PROJECTION_MATRIX_LEFT_EYE, VR_PROJECTION_MATRIX_RIGHT_EYE};
	for (int index = 0; index < 2; index++) {
		ovrMatrix4f hmdProjection = VR_GetMatrix(enums[index]);
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				if ((hmdProjection.M[i][j] > 0) != (projMatrix[i * 4 + j] > 0)) {
					hmdProjection.M[i][j] *= -1.0f;
				}
			}
		}
		memcpy(dst[index], hmdProjection.M, 16 * sizeof(float));
	}

	// Set mirroring of axes
	if (!VR_GetConfig(VR_CONFIG_MIRROR_UPDATED)) {
		VR_SetConfig(VR_CONFIG_MIRROR_UPDATED, true);
		VR_SetConfig(VR_CONFIG_MIRROR_AXIS_X, projMatrix[0] < 0);
		VR_SetConfig(VR_CONFIG_MIRROR_AXIS_Y, projMatrix[5] < 0);
		VR_SetConfig(VR_CONFIG_MIRROR_AXIS_Z, projMatrix[10] > 0);
		if ((projMatrix[0] < 0) && (projMatrix[10] < 0)) { //e.g. Dante's inferno
			VR_SetConfig(VR_CONFIG_MIRROR_PITCH, true);
			VR_SetConfig(VR_CONFIG_MIRROR_YAW, true);
			VR_SetConfig(VR_CONFIG_MIRROR_ROLL, false);
		} else if (projMatrix[10] < 0) { //e.g. GTA - Liberty city
			VR_SetConfig(VR_CONFIG_MIRROR_PITCH, false);
			VR_SetConfig(VR_CONFIG_MIRROR_YAW, false);
			VR_SetConfig(VR_CONFIG_MIRROR_ROLL, false);
		} else if (projMatrix[5] < 0) { //e.g. PES 2014
			VR_SetConfig(VR_CONFIG_MIRROR_PITCH, true);
			VR_SetConfig(VR_CONFIG_MIRROR_YAW, true);
			VR_SetConfig(VR_CONFIG_MIRROR_ROLL, false);
		} else { //e.g. Lego Pirates
			VR_SetConfig(VR_CONFIG_MIRROR_PITCH, false);
			VR_SetConfig(VR_CONFIG_MIRROR_YAW, true);
			VR_SetConfig(VR_CONFIG_MIRROR_ROLL, true);
		}
	}

	// Set 6DoF scale
	float scale = pow(fabs(projMatrix[14]), 1.15f);
	if (PSP_CoreParameter().compat.vrCompat().UnitsPerMeter > 0) {
		scale = PSP_CoreParameter().compat.vrCompat().UnitsPerMeter;
		VR_SetConfig(VR_CONFIG_6DOF_PRECISE, true);
	} else {
		VR_SetConfig(VR_CONFIG_6DOF_PRECISE, false);
	}
	VR_SetConfig(VR_CONFIG_6DOF_SCALE, (int)(scale * 1000000));
}

void UpdateVRView(float* leftEye, float* rightEye) {
	float* dst[] = {leftEye, rightEye};
	VRMatrix enums[] = {VR_VIEW_MATRIX_LEFT_EYE, VR_VIEW_MATRIX_RIGHT_EYE};
	for (int index = 0; index < 2; index++) {

		// Get view matrix from the game
		ovrMatrix4f gameView;
		memcpy(gameView.M, dst[index], 16 * sizeof(float));

		// Get view matrix from the headset
		ovrMatrix4f hmdView = VR_GetMatrix(enums[index]);

		// Combine the matrices
		ovrMatrix4f renderView = ovrMatrix4f_Multiply(&hmdView, &gameView);
		memcpy(dst[index], renderView.M, 16 * sizeof(float));
	}
}

#endif