#include "qmacrokeysmanager.h"

#include <codecvt>
#include <locale>


QMacroKeysManager::QMacroKeysManager(QObject *parent)
	: QObject{parent}
{}

void QMacroKeysManager::initDevices()
{
	hid_device_info *deviceInfo = hid_enumerate(MACROKEYS_VID, MACROKEYS_PID);
	if (!deviceInfo) {
		return;
	}

	for (hid_device_info *di = deviceInfo; di != nullptr; di = di->next) {
		QDeviceHandler *deviceHandler = new QDeviceHandler();
		this->mDevices[di->path] = deviceHandler;
		QObject::connect(deviceHandler,
						 &QDeviceHandler::deviceInitialised,
						 this,
						 &QMacroKeysManager::getDeviceInitStatus);
		deviceHandler->initDevice(di);
	}
}

void QMacroKeysManager::getDeviceInitStatus(const HIDDevice &device)
{
	QDeviceHandler *dh = this->mDevices[device.sPath];
	QObject::connect(dh,
					 &QDeviceHandler::buttonStateChanged,
					 this,
					 &QMacroKeysManager::handleNewButtonState);
	QObject::connect(dh,
					 &QDeviceHandler::encoderRotationChanged,
					 this,
					 &QMacroKeysManager::handleNewEncoderRotation);
	emit this->newDeviceFound(device.sPath);
	dh->runDevice();
}

void QMacroKeysManager::handleNewButtonState(const quint8 &row,
											 const quint8 &column,
											 const bool &state)
{
	emit this->newButtonState(row, column, state);
}

void QMacroKeysManager::handleNewEncoderRotation(const quint8 &column,
												 const EncoderRotation &direction)
{
	emit this->newEncoderRotation(column, direction);
}

void QMacroKeysManager::uninitDevices() {}


QDeviceHandler::QDeviceHandler(QObject *parent)
	: QObject{parent}
{
	this->moveToThread(&this->threadButtonReader);
	this->threadButtonReader.start();
}

QDeviceHandler::~QDeviceHandler()
{
	hid_close(this->hidDevice.hidDevice);
	this->threadButtonReader.quit();
	this->threadButtonReader.wait();
}

void QDeviceHandler::initDevice(const hid_device_info *di)
{
	hid_device_info *deviceInfo = hid_enumerate(MACROKEYS_VID, MACROKEYS_PID);
	if (!deviceInfo) {
		return;
	}

	HIDDevice device;

	device.hidInfo = di;

	std::wstring_convert<std::codecvt_utf8<wchar_t>> utf8_conv;
	device.sManufacturer = utf8_conv.to_bytes(di->manufacturer_string).c_str();
	device.sProduct = utf8_conv.to_bytes(di->product_string).c_str();
	device.sPath = di->path;

	hid_device *handle = hid_open(MACROKEYS_VID, MACROKEYS_PID, deviceInfo->serial_number);
	device.hidDevice = handle;
	hid_set_nonblocking(device.hidDevice, 0);

	ButtonStateRow buttonStatesRow;
	buttonStatesRow.fill(false, NUM_BUTTON_COLUMNS);
	QVector<ButtonStateRow> buttonStates;
	buttonStates.fill(buttonStatesRow, NUM_BUTTON_ROWS);
	this->vCurrentButtonStates = buttonStates;

	this->hidDevice = device;

	emit this->deviceInitialised(this->hidDevice);
}

void QDeviceHandler::runDevice()
{
	QMetaObject::invokeMethod(this, "buttonReadLoop");
}
void QDeviceHandler::buttonReadLoop()
{
	while (this->threadButtonReader.isRunning()) {
		const ButtonStateVector &previousState = ButtonStateVector(this->vCurrentButtonStates);

		unsigned char buffer[NUM_HID_BYTES];
		hid_read(this->hidDevice.hidDevice, buffer, NUM_HID_BYTES);
		for (int column = 0; column < NUM_BUTTON_COLUMNS; column++) {
			for (int row = 0; row < NUM_BUTTON_ROWS; row++) {
				// Convert bit position in each byte into a row/column value.
				// Bits are read from left to right, as though they were one
				// little endian value, but with bit order reversed as well.
				// Each successive byte counts down the row number, and then
				// rolls over to the next column for each row.
				//
				// Examples:
				//  - Bit 7 in byte 0 (1000 0000 | 0000 0000) is row 0, column 0
				//  - Bit 6 in byte 0 (0100 0000 | 0000 0000) is row 1, column 0
				//  - Bit 2 in byte 1 (0000 0000 | 0100 0000) is row 2, column 1
				//  - Bit 0 in byte 1 (0000 0000 | 0000 0001) is row 8, column 1
				const quint8 buttonBit = (column * NUM_BUTTON_ROWS) + row;
				const quint8 byte = buttonBit / 8;
				const quint8 byteBit = buttonBit % 8;
				const bool buttonState = (buffer[byte] >> (8 - (byteBit + 1))) & 0b00000001;

				this->vCurrentButtonStates[row][column] = buttonState;
				if (previousState[row][column] != buttonState) {
					emit this->buttonStateChanged(row, column, buttonState);
				}
			}
		}

		const char &encoderDirectionBytes = buffer[NUM_HID_BYTES - 1];
		if (encoderDirectionBytes & ENC1_CCW)	emit encoderRotationChanged(0, EncoderRotation::CCW);
		if (encoderDirectionBytes & ENC1_CW)	emit encoderRotationChanged(0, EncoderRotation::CW);
		if (encoderDirectionBytes & ENC2_CCW)	emit encoderRotationChanged(1, EncoderRotation::CCW);
		if (encoderDirectionBytes & ENC2_CW)	emit encoderRotationChanged(1, EncoderRotation::CW);
		if (encoderDirectionBytes & ENC3_CCW)	emit encoderRotationChanged(2, EncoderRotation::CCW);
		if (encoderDirectionBytes & ENC3_CW)	emit encoderRotationChanged(2, EncoderRotation::CW);
		if (encoderDirectionBytes & ENC4_CCW)	emit encoderRotationChanged(3, EncoderRotation::CCW);
		if (encoderDirectionBytes & ENC4_CW)	emit encoderRotationChanged(3, EncoderRotation::CW);
	}
}