/*
 * Remote Laboratory FPGA Server
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * (c) 2012-2013 Timothy Pearson
 * Raptor Engineering
 * http://www.raptorengineeringinc.com
 */

#include <stdio.h>                /* perror() */
#include <stdlib.h>               /* atoi() */
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>               /* read() */
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <fcntl.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <sys/signal.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <math.h>

#include <tqtimer.h>

#include <tdelocale.h>

#include "fpga_conn.h"

#include "bbb-gpmc-init.h"

#define FLUSH_IN	0
#define FLUSH_OUT	1
#define FLUSH_BOTH	2

#define ABORT_SOCKET(s) 		s->close();						\
					s->disconnect();					\
					delete s;						\
					s = NULL;

/* exception handling */
struct exit_exception {
	int c;
	exit_exception(int c):c(c) { }
};

/*
  The FPGASocket class provides a socket that is connected with a client.
  For every client that connects to the server, the server creates a new
  instance of this class.
*/
FPGASocket::FPGASocket(int sock, TQObject *parent, const char *name) :
	TDEKerberosServerSocket(parent, name), m_criticalSection(0), m_pollInterval(10), enableDebug(false), m_loopTimer(NULL), m_config(static_cast<FPGAServer*>(parent)->m_config) {

	// Read settings
        m_config->setGroup("Tuning");
        m_pollInterval = m_config->readNumEntry("pollInterval", m_pollInterval);
	enableDebug = m_config->readBoolEntry("enableDebug", enableDebug);

	// Initialize timers
	m_kerberosInitTimer = new TQTimer();
	connect(m_kerberosInitTimer, SIGNAL(timeout()), this, SLOT(finishKerberosHandshake()));

	setServiceName("ulab");

	line = 0;
	connect(this, SIGNAL(connectionClosed()), SLOT(connectionClosedHandler()));
	connect(this, SIGNAL(connectionClosed()), parent, SLOT(remoteConnectionClosed()));
	setSocket(sock);
}

FPGASocket::~FPGASocket() {
	if (m_kerberosInitTimer) {
		m_kerberosInitTimer->stop();
		delete m_kerberosInitTimer;
		m_kerberosInitTimer = NULL;
	}
	if (m_loopTimer) {
		m_loopTimer->stop();
		delete m_loopTimer;
		m_loopTimer = NULL;
	}
}

void FPGASocket::close() {
	if (state() == TQSocket::Connected) {
		TDEKerberosServerSocket::close();
		connectionClosedHandler();
		TQTimer::singleShot(0, parent(), SLOT(remoteConnectionClosed()));
	}
}

void FPGASocket::connectionClosedHandler() {
	if (enableDebug) {
		printf("[DEBUG] Connection from %s closed\n\r", m_remoteHost.ascii()); fflush(stdout);
	}

	if (m_criticalSection > 0) {
		throw exit_exception(-1);
	}
}

void FPGASocket::initiateKerberosHandshake() {
	setUsingKerberos(true);
	m_kerberosInitTimer->start(100, TRUE);
}

void FPGASocket::finishKerberosHandshake() {
	if (kerberosStatus() == TDEKerberosServerSocket::KerberosInitializing) {
		m_kerberosInitTimer->start(100, TRUE);
		return;
	}
	if (kerberosStatus() == TDEKerberosServerSocket::KerberosInUse) {
		m_config->setGroup("Security");
		TQString masterUser = m_config->readEntry("masteruser");
		TQString masterRealm = m_config->readEntry("masterrealm");
		if (masterRealm == "") {
			masterRealm = "(NULL)";
		}
		if ((m_authenticatedUserName != masterUser) || (m_authenticatedRealmName != masterRealm)) {
			if (enableDebug) {
				printf("[DEBUG] Connection from %s closed due to authentication failure (attempted connection as user %s@%s)\n\r", m_remoteHost.ascii(), m_authenticatedUserName.ascii(), m_authenticatedRealmName.ascii()); fflush(stdout);
			}
			close();
			return;
		}
		m_config->setGroup("FPGA");
		m_interfaceType = m_config->readEntry("interface", "serial");
		if (m_interfaceType == "serial") {
			if (setupSerial() != 0) {
				if (enableDebug) {
					printf("[DEBUG] Connection from %s closed due to serial port initialization failure\n\r", m_remoteHost.ascii()); fflush(stdout);
				}
				close();
				return;
			}
		}
		else if (m_interfaceType == "gpmc") {
			if (setupGPMC() != 0) {
				if (enableDebug) {
					printf("[DEBUG] Connection from %s closed due to GPMC initialization failure\n\r", m_remoteHost.ascii()); fflush(stdout);
				}
				close();
				return;
			}
		}
		else {
			if (enableDebug) {
				printf("[DEBUG] Connection from %s closed due to incorrect interface type specification in configuration file\n\r", m_remoteHost.ascii()); fflush(stdout);
			}
			close();
			return;
		}

		TQDataStream ds(this);
		ds.setPrintableData(true);
		ds << TQString("OK");
		writeEndOfFrame();

		enterCommandLoop();
		return;
	}
	else {
		if (enableDebug) {
			printf("[DEBUG] Connection from %s closed due to Kerberos failure\n\r", m_remoteHost.ascii()); fflush(stdout);
		}
		close();
		return;
	}
}

int FPGASocket::setupSerial() {
	struct termios oldtio, newtio;

	m_config->setGroup("FPGA");
	TQString serialDevice = m_config->readEntry("serialdevice", "/dev/ttyS0");
	TQString desiredBaudRate = m_config->readEntry("baudrate", "9600");

	m_fd_tty = ::open(serialDevice.ascii(), O_RDWR | O_NOCTTY | O_NONBLOCK | O_APPEND);
	if (m_fd_tty < 0) {
		printf("[FAIL] Unable to open serial device %s\n\r", serialDevice.ascii()); fflush(stdout);
		return 1;
	}

	tcgetattr(m_fd_tty, &oldtio);	// Save current port settings

	long serialBaud;
	if (desiredBaudRate == "1200") {
		serialBaud = B1200;
	}
	else if (desiredBaudRate == "9600") {
		serialBaud = B9600;
	}
	else if (desiredBaudRate == "19200") {
		serialBaud = B19200;
	}
	else if (desiredBaudRate == "115200") {
		serialBaud = B115200;
	}
	else {
		printf("[WARNING] Invalid baudrate %s specified, selecting 9600 instead\n\r", desiredBaudRate.ascii()); fflush(stdout);
		serialBaud = B9600;
	}

	bzero(&newtio, sizeof(newtio));
	newtio.c_cflag = serialBaud | CS8 | CLOCAL | CREAD;
	newtio.c_iflag = IGNPAR;
	newtio.c_oflag = 0;

	// Set input mode (non-canonical, no echo,...)
	newtio.c_lflag = 0;

	newtio.c_cc[VTIME] = 0;	// Inter-character timer unused
	newtio.c_cc[VMIN]  = 0;	// Blocking read unused
	
	tcflush(m_fd_tty, TCIFLUSH);
	tcsetattr(m_fd_tty, TCSANOW, &newtio);

	return 0;
}

int FPGASocket::setupGPMC() {
	int i;
	int ret;

	m_stateTXRequested = false;
	m_stateImageRXRequested = false;
	m_stateImageTXRequested = false;

	ret = setup_gpmc_bbb();
	if (ret == 0) {
		// Verify attached uLab hardware model and version
		unsigned char model = read_gpmc(0x00);
		unsigned char version = read_gpmc(0x01);
		if ((model != 0x42) || (version < 1)) {
			printf("A compatible uLab hardware debug interface was not detected!  Please verify your configuration.\n"); 
			return -1;
		}
		printf("[DEBUG] Detected a compatible uLab hardware debug interface (model number 0x%02x, firmware version 0x%02x)\n", model, version); 

		// Clear out DSP and LCD RAM
		unsigned char dsp_ram_bits = read_gpmc(0x0b);
		unsigned int dsp_ram_offset = (1 << dsp_ram_bits);
		unsigned int dsp_ram_size = (1 << dsp_ram_bits);
		for (i=0; i<dsp_ram_size; i++) {
			write_gpmc(dsp_ram_offset + i, 0x00);
		}
		for (i=0; i<32; i++) {
			write_gpmc(0x20 + i, 0x00);
		}
	}

	return 0;
}

void FPGASocket::commandLoop() {
	int cc;
	int ret;
	char buffer[1024];
	bool transferred_data;

	m_criticalSection++;
	try {
		transferred_data = false;
		if (state() == TQSocket::Connected) {
			if (m_interfaceType == "serial") {
				cc = read(m_fd_tty, buffer, 1024);
				if (cc > 0) {
					writeBlock(buffer, cc);
					flush();
					transferred_data = true;
					if (enableDebug) {
						printf("[DEBUG] Got %d bytes from the serial port\n\r", cc); fflush(stdout);
					}
				}
				if (canReadData()) {
					cc = readBlock(buffer, 1024);
					if (cc > 0) {
						ret = write(m_fd_tty, buffer, cc);
	
						// HACK
						// This works around a buffer overflow on FTDI serial devices
						// It may not be sufficient for baudrates less than 115200!
						if (cc > 128) {
							usleep(100000);
						}
	
						while ((ret < 0) && (errno == EAGAIN)) {
							usleep(1000);
							ret = write(m_fd_tty, buffer, cc);
						}
						if (ret < 0) {
							// ERROR
							printf("[ERROR] Failed to transmit data to serial port (%s, code %d)!  Continuing, but data was likely lost\n\r", strerror(errno), errno); fflush(stdout);
						}
						ioctl(m_fd_tty, TCFLSH, FLUSH_OUT);
						transferred_data = true;
						if (enableDebug) {
							printf("[DEBUG] Got %d bytes from the network interface\n\r", cc); fflush(stdout);
						}
					}
				}
			}
			else if (m_interfaceType == "gpmc") {
				if (m_stateImageTXRequested) {
					if (read_gpmc(0x0a) & 0x02) {
						m_stateImageTXRequested = false;

						// Transmit image back to client
						unsigned char dsp_ram_bits = read_gpmc(0x0b);
						unsigned int dsp_ram_size = (1 << dsp_ram_bits);
						unsigned int dsp_ram_offset = (1 << dsp_ram_bits);
						TQByteArray dataToSend(dsp_ram_size);
						memcpy_from_gpmc(dataToSend.data(), dsp_ram_offset, dsp_ram_size);
						int offset = 0;
						while (offset <= dsp_ram_size) {
							writeBlock(dataToSend.data()+offset, 1024);
							writeBufferedData();
							offset = offset + 1024;
						}
					}
				}
				else if (m_stateTXRequested) {
					m_stateTXRequested = false;

					char data[42];

					// Read state data from memory map and assemble a reply
					memcpy_from_gpmc(data+0, 0x20, 0x1f);	// LCD display
					data[32] = 1;				// Input mode (locked to Remote)
					data[33] = read_gpmc(0x0b);		// Number of address bits of DSP RAM
					data[34] = read_gpmc(0x02);		// 4-bit LEDs
					data[35] = read_gpmc(0x03);		// 8-bit LEDs
					data[36] = read_gpmc(0x04);		// 16-bit LEDs (upper byte)
					data[37] = read_gpmc(0x05);		// 16-bit LEDs (lower byte)
					memcpy_from_gpmc(data+38, 0x06, 0x04);	// 7-segment LED display

					writeBlock(data, 42);
					writeBufferedData();
				}
				if (canReadData()) {
					int read_offset = 0;
					cc = readBlock(buffer, 1024);
					if (cc > 0) {
						if (m_stateImageRXRequested) {
							unsigned char dsp_ram_bits = read_gpmc(0x0b);
							unsigned int dsp_ram_offset = (1 << dsp_ram_bits);
							unsigned int dsp_ram_size = (1 << dsp_ram_bits);

							memcpy_to_gpmc(buffer, (dsp_ram_offset + m_stateImageRXCounter), cc);

							m_stateImageRXCounter = m_stateImageRXCounter + cc;
							if (m_stateImageRXCounter >= dsp_ram_size) {
								m_stateImageRXRequested = false;
								m_stateImageTXRequested = true;
							}
						}
						else {
							// Parse and write state data to the memory map
							while (read_offset < cc) {
								if (buffer[read_offset+0] == 'M') {
									// Receive image data and store in FPGA memory
									m_stateImageRXRequested = true;
									m_stateImageTXRequested = false;
									m_stateImageRXCounter = 0;
									read_offset = read_offset + 2;
								}
								else if (buffer[read_offset+0] == 'L') {
									m_stateTXRequested = true;
									read_offset = read_offset + 2;
								}
								else if (buffer[read_offset+0] == 'I') {
									write_gpmc(0x02, buffer[read_offset+2]);
									read_offset = read_offset + 4;
								}
								else if (buffer[read_offset+0] == 'B') {
									write_gpmc(0x03, buffer[read_offset+2]);
									read_offset = read_offset + 4;
								}
								else if (buffer[read_offset+0] == 'C') {
									write_gpmc(0x04, buffer[read_offset+2]);
									write_gpmc(0x05, buffer[read_offset+4]);
									read_offset = read_offset + 6;
								}
							}
							if (m_stateImageTXRequested) {
								m_stateImageTXRequested = false;
							}
						}

						transferred_data = true;
						if (enableDebug) {
							printf("[DEBUG] Got %d bytes from the network interface\n\r", cc); fflush(stdout);
						}
					}
				}
			}
		}
		m_criticalSection--;
		if (transferred_data) {
			if (m_loopTimer) m_loopTimer->start(0, TRUE);
		}
		else {
			if (m_loopTimer) m_loopTimer->start(m_pollInterval, TRUE);
		}
		return;
	}
	catch (...) {
		m_criticalSection--;
		return;
	}
}

int FPGASocket::enterCommandLoop() {
	if (!m_loopTimer) {
		m_loopTimer = new TQTimer();
		connect(m_loopTimer, SIGNAL(timeout()), this, SLOT(commandLoop()));
	}
	if (m_loopTimer) m_loopTimer->start(0, TRUE);
	return 0;
}

/*
  The FPGAServer class handles new connections to the server. For every
  client that connects, it creates a new FPGASocket -- that instance is now
  responsible for the communication with that client.
*/
FPGAServer::FPGAServer(TQObject* parent, int port, KSimpleConfig* config) :
	TQServerSocket( port, 1, parent ), m_config(config), m_numberOfConnections(0) {

	if ( !ok() ) {
		printf("[ERROR] Failed to bind to port %d\n\r", port);
		exit(1);
	}

	printf("[INFO] Server started on port %d\n\r", port); fflush(stdout);
}

FPGAServer::~FPGAServer() {
	//
}

void FPGAServer::newConnection(int socket) {
	FPGASocket *s = new FPGASocket(socket, this);
	s->m_remoteHost = s->peerAddress().toString();
	printf("[DEBUG] New connection from %s\n\r", s->m_remoteHost.ascii()); fflush(stdout);
	if (m_numberOfConnections > 0) {
		printf("[DEBUG] Connection from %s closed due to multiple access attempt\n\r", s->m_remoteHost.ascii()); fflush(stdout);
		ABORT_SOCKET(s)
		return;
	}
	connect(s, SIGNAL(connectionClosed()), s, SLOT(deleteLater()));
	s->initiateKerberosHandshake();
	emit newConnect(s);
}

void FPGAServer::remoteConnectionClosed() {
	m_numberOfConnections--;
}