#include "ArduinoCookie.h"
#include "ArduinoComIF.h"

#include <fsfw/globalfunctions/DleEncoder.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <fsfw/globalfunctions/CRC.h>

#include <termios.h>

ArduinoCommInterface::ArduinoCommInterface(object_id_t setObjectId,
        const char *serialDevice) :
		spiMap(MAX_NUMBER_OF_SPI_DEVICES), rxBuffer(
				MAX_PACKET_SIZE * MAX_NUMBER_OF_SPI_DEVICES*10, true), SystemObject(setObjectId) {
	initialized = false;
	serialPort = ::open("/dev/ttyUSB0", O_RDWR);

	if (serialPort < 0) {
		//configuration error
		printf("Error %i from open: %s\n", errno, strerror(errno));
		return;
	}

	struct termios tty;
	memset(&tty, 0, sizeof tty);

	// Read in existing settings, and handle any error
	if (tcgetattr(serialPort, &tty) != 0) {
		printf("Error %i from tcgetattr: %s\n", errno, strerror(errno));
		return;
	}

	tty.c_cflag &= ~PARENB; // Clear parity bit, disabling parity
	tty.c_cflag &= ~CSTOPB; // Clear stop field, only one stop bit used in communication
	tty.c_cflag |= CS8; // 8 bits per byte
	tty.c_cflag &= ~CRTSCTS; // Disable RTS/CTS hardware flow control
	tty.c_lflag &= ~ICANON; //Disable Canonical Mode
	tty.c_oflag &= ~OPOST; // Prevent special interpretation of output bytes (e.g. newline chars)
	tty.c_oflag &= ~ONLCR; // Prevent conversion of newline to carriage return/line feed
	tty.c_cc[VTIME] = 0;    // Non Blocking
	tty.c_cc[VMIN] = 0;

	cfsetispeed(&tty, B9600); //Baudrate

	if (tcsetattr(serialPort, TCSANOW, &tty) != 0) {
		//printf("Error %i from tcsetattr: %s\n", errno, strerror(errno));
		return;
	}

	initialized = true;

}

ArduinoCommInterface::~ArduinoCommInterface() {
	::close(serialPort);
}

ReturnValue_t ArduinoCommInterface::open(Cookie **cookie, uint32_t address,
		uint32_t maxReplyLen) {
	//This is a hack, will be gone with https://egit.irs.uni-stuttgart.de/fsfw/fsfw/issues/19
	switch ((address >> 8) & 0xff) {
	case 0:
		*cookie = new ArduinoCookie(ArduinoCookie::SPI, address, maxReplyLen);
		spiMap.insert(address, (ArduinoCookie*) *cookie); //Yes, I *do* know that it is an ArduinoSpiCookie, I just new'd it
		break;
	default:
		return HasReturnvaluesIF::RETURN_FAILED;
	}
	return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t ArduinoCommInterface::reOpen(Cookie *cookie, uint32_t address,
		uint32_t maxReplyLen) {
	//too lazy right now will be irrelevant with https://egit.irs.uni-stuttgart.de/fsfw/fsfw/issues/19
	return HasReturnvaluesIF::RETURN_FAILED;
}

void ArduinoCommInterface::close(Cookie *cookie) {
	//too lazy as well, find the correct Map, delete it there, then the cookie...
}

ReturnValue_t ArduinoCommInterface::sendMessage(Cookie *cookie, uint8_t *data,
		uint32_t len) {
	ArduinoCookie *arduinoCookie = dynamic_cast<ArduinoCookie*>(cookie);
	if (arduinoCookie == NULL) {
		return INVALID_COOKIE_TYPE;
	}

	return sendMessage(arduinoCookie->command, arduinoCookie->address, data,
			len);
}

ReturnValue_t ArduinoCommInterface::getSendSuccess(Cookie *cookie) {
	return RETURN_OK;
}

ReturnValue_t ArduinoCommInterface::requestReceiveMessage(Cookie *cookie) {
	return RETURN_OK;
}

ReturnValue_t ArduinoCommInterface::readReceivedMessage(Cookie *cookie,
		uint8_t **buffer, uint32_t *size) {

	handleSerialPortRx();

	ArduinoCookie *arduinoCookie = dynamic_cast<ArduinoCookie*>(cookie);
	if (arduinoCookie == NULL) {
		return INVALID_COOKIE_TYPE;
	}

	*buffer = arduinoCookie->replyBuffer;
	*size = arduinoCookie->receivedDataLen;
	return HasReturnvaluesIF::RETURN_OK;
}

ReturnValue_t ArduinoCommInterface::setAddress(Cookie *cookie,
		uint32_t address) {
	//not implemented
	return RETURN_FAILED;
}

uint32_t ArduinoCommInterface::getAddress(Cookie *cookie) {
	//not implemented
	return 0;
}

ReturnValue_t ArduinoCommInterface::setParameter(Cookie *cookie,
		uint32_t parameter) {
	//not implemented
	return RETURN_FAILED;
}

uint32_t ArduinoCommInterface::getParameter(Cookie *cookie) {
	//not implemented
	return 0;
}

ReturnValue_t ArduinoCommInterface::sendMessage(uint8_t command,
		uint8_t address, const uint8_t *data, size_t dataLen) {
	if (dataLen > UINT16_MAX) {
		return TOO_MUCH_DATA;
	}

	//being conservative here
	uint8_t sendBuffer[(dataLen + 6) * 2 + 2];

	sendBuffer[0] = DleEncoder::STX;

	uint8_t *currentPosition = sendBuffer + 1;
	size_t remainingLen = sizeof(sendBuffer) - 1;
	uint32_t encodedLen;

	ReturnValue_t result = DleEncoder::encode(&command, 1, currentPosition,
			remainingLen, &encodedLen, false);
	if (result != RETURN_OK) {
		return result;
	}
	currentPosition += encodedLen;
	remainingLen -= encodedLen; //DleEncoder will never return encodedLen > remainingLen

	result = DleEncoder::encode(&address, 1, currentPosition, remainingLen,
			&encodedLen, false);
	if (result != RETURN_OK) {
		return result;
	}
	currentPosition += encodedLen;
	remainingLen -= encodedLen; //DleEncoder will never return encodedLen > remainingLen

	uint8_t temporaryBuffer[2];

	//note to Lukas: yes we _could_ use Serialize here, but for 16 bit it is a bit too much...
	temporaryBuffer[0] = dataLen >> 8; //we checked dataLen above
	temporaryBuffer[1] = dataLen;

	result = DleEncoder::encode(temporaryBuffer, 2, currentPosition,
			remainingLen, &encodedLen, false);
	if (result != RETURN_OK) {
		return result;
	}
	currentPosition += encodedLen;
	remainingLen -= encodedLen; //DleEncoder will never return encodedLen > remainingLen

	//encoding the actual data
	result = DleEncoder::encode(data, dataLen, currentPosition, remainingLen,
			&encodedLen, false);
	if (result != RETURN_OK) {
		return result;
	}
	currentPosition += encodedLen;
	remainingLen -= encodedLen; //DleEncoder will never return encodedLen > remainingLen

	uint16_t crc = CRC::crc16ccitt(&command, 1);
	crc = CRC::crc16ccitt(&address, 1, crc);
	//fortunately the length is still there
	crc = CRC::crc16ccitt(temporaryBuffer, 2, crc);
	crc = CRC::crc16ccitt(data, dataLen, crc);

	temporaryBuffer[0] = crc >> 8;
	temporaryBuffer[1] = crc;

	result = DleEncoder::encode(temporaryBuffer, 2, currentPosition,
			remainingLen, &encodedLen, false);
	if (result != RETURN_OK) {
		return result;
	}
	currentPosition += encodedLen;
	remainingLen -= encodedLen; //DleEncoder will never return encodedLen > remainingLen

	if (remainingLen > 0) {
		*currentPosition = DleEncoder::ETX;
	}
	remainingLen -= 1;

	encodedLen = sizeof(sendBuffer) - remainingLen;

	ssize_t writtenlen = write(serialPort, sendBuffer, encodedLen);
	if (writtenlen < 0) {
		//we could try to find out what happened...
		return RETURN_FAILED;
	}
	if (writtenlen != encodedLen) {
		//the OS failed us, we do not try to block until everything is written, as
		//we can not block the whole system here
		return RETURN_FAILED;
	}
	return RETURN_OK;
}

void ArduinoCommInterface::handleSerialPortRx() {
	uint32_t availableSpace = rxBuffer.availableWriteSpace();

	uint8_t dataFromSerial[availableSpace];

	ssize_t bytesRead = read(serialPort, dataFromSerial,
			sizeof(dataFromSerial));

	if (bytesRead < 0) {
		return;
	}

	rxBuffer.writeData(dataFromSerial, bytesRead);

	uint8_t dataReceivedSoFar[rxBuffer.maxSize()];

	uint32_t dataLenReceivedSoFar = 0;

	rxBuffer.readData(dataReceivedSoFar, sizeof(dataReceivedSoFar), true,
			&dataLenReceivedSoFar);

	//look for STX
	size_t firstSTXinRawData = 0;
	while ((firstSTXinRawData < dataLenReceivedSoFar)
			&& (dataReceivedSoFar[firstSTXinRawData] != DleEncoder::STX)) {
		firstSTXinRawData++;
	}

	if (dataReceivedSoFar[firstSTXinRawData] != DleEncoder::STX) {
		//there is no STX in our data, throw it away...
		rxBuffer.deleteData(dataLenReceivedSoFar);
		return;
	}

	uint8_t packet[MAX_PACKET_SIZE];
	uint32_t packetLen;

	uint32_t readSize;

	ReturnValue_t result = DleEncoder::decode(
			dataReceivedSoFar + firstSTXinRawData,
			dataLenReceivedSoFar - firstSTXinRawData, &readSize, packet,
			sizeof(packet), &packetLen);

	size_t toDelete = firstSTXinRawData;
	if (result == HasReturnvaluesIF::RETURN_OK) {
		handlePacket(packet, packetLen);

		//after handling the packet, we can delete it from the raw stream, it has been copied to packet
		toDelete += readSize;
	}

	//remove Data which was processed
	rxBuffer.deleteData(toDelete);
}

void ArduinoCommInterface::handlePacket(uint8_t *packet, size_t packetLen) {
	uint16_t crc = CRC::crc16ccitt(packet, packetLen);
	if (crc != 0) {
		//CRC error
		return;
	}

	uint8_t command = packet[0];
	uint8_t address = packet[1];

	uint16_t size = (packet[2] << 8) + packet[3];

	if (size != packetLen - 6) {
		//Invalid Length
		return;
	}

	switch (command) {
	case ArduinoCookie::SPI: {
		ArduinoCookie **itsComplicated;
		ReturnValue_t result = spiMap.find(address, &itsComplicated);
		if (result != RETURN_OK) {
			//we do no know this address
			return;
		}
		ArduinoCookie *theActualCookie = *itsComplicated;
		if (packetLen > theActualCookie->maxReplySize + 6) {
			packetLen = theActualCookie->maxReplySize + 6;
		}
		memcpy(theActualCookie->replyBuffer, packet + 4, packetLen - 6);
		theActualCookie->receivedDataLen = packetLen - 6;
	}
		break;
	default:
		return;
	}
}