/*
 * Remote Laboratory Logic Analyzer 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) 2012-2019 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 "logic_analyzer_server.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) { }
};

void gpmc_clear_channel_traces();

/*
  The LogicAnalyzerSocket 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.
*/
LogicAnalyzerSocket::LogicAnalyzerSocket(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<LogicAnalyzerServer*>(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);
}

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

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

void LogicAnalyzerSocket::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;
		}
		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;
		}

		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 LogicAnalyzerSocket::setupGPMC() {
	int ret;

	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);
		gpmc_clear_channel_traces();
	}

	return 0;
}

int gpmc_channel_count() {
	return 64;
}

int gpmc_sample_count() {
	return 2048;
}

double gpmc_timestep() {
	return ((read_gpmc_uint16_t(0x0e/2))*1e-9);
}

int gpmc_get_running() {
	return read_gpmc(0x0d) & 0x1;
}

void gpmc_set_running(bool running) {
	if (running) {
		write_gpmc(0x0d, read_gpmc(0x0d) | 0x1);
	}
	else {
		write_gpmc(0x0d, read_gpmc(0x0d) & ~0x1);
	}
}

int gpmc_get_channel_name(TQString &name, unsigned int traceNumber) {
	int offset;
	char rawName[32];
	memcpy_from_gpmc(rawName, 0x800 + (traceNumber * 32), 32);
	for (offset=0; offset<32; offset++) {
		if (rawName[offset] != 0) {
			break;
		}
	}

	name = TQString(rawName + offset);
	name.replace("<", "&lt;");
	name.replace(">", "&gt;");

	return 0;
}

void gpmc_clear_channel_traces() {
	unsigned int i;
	int traceLength;

	traceLength = gpmc_sample_count();
	for (i=0; i<traceLength; i++) {
		write_gpmc_uint64_t(0x800 + i, 0x0);
	}
}

int gpmc_get_channel_traces(TQDoubleArray& traceData, TQDoubleArray& positionData, unsigned int traceNumber) {
	unsigned int i;
	int traceLength;
	double timestep;
	double position;

	traceLength = gpmc_sample_count();
	timestep = gpmc_timestep();
	traceData.resize(traceLength);
	positionData.resize(traceLength);
	position = 0;
	for (i=0; i<traceLength; i++) {
		traceData[i] = ((read_gpmc_uint64_t(0x800 + i) & ((uint64_t)1 << traceNumber)) >> traceNumber);
		positionData[i] = position;
		position = position + timestep;
	}

	return traceLength;
}

void LogicAnalyzerSocket::commandLoop() {
	bool transferred_data;
	TQString instrumentCommand;

	m_criticalSection++;
	try {
		transferred_data = false;
		if (state() == TQSocket::Connected) {
			if (canReadFrame()) {
				TQDataStream ds(this);
				ds.setPrintableData(true);
				ds >> instrumentCommand;

				if (instrumentCommand != "") {
					if ((instrumentCommand == "LOGICANALYZER")) {			// requesting logic analyzer access
						ds << TQString("ACK");
						writeEndOfFrame();
					}
					else if ((instrumentCommand == "RESET")) {			// requesting reset
						// Nothing to reset...
						ds << TQString("ACK");
						writeEndOfFrame();
					}
					else if ((instrumentCommand == "GETLOGICTRACES")) {		// Want all channel traces
						ds << TQString("ACK");
						int i;
						int channels = gpmc_channel_count();
						for (i=0; i<channels; i++) {
							TQDoubleArray traceData;
							TQDoubleArray positionData;
							gpmc_get_channel_traces(traceData, positionData, i);
							ds << traceData;
							ds << positionData;
						}
						writeEndOfFrame();
					}
					else if (instrumentCommand == "GETHORIZONTALDIVCOUNT") {	// Want the number of horizontal divisions available
						// One horizontal division per sample
						TQ_INT16 divisions = gpmc_sample_count();
						if (divisions >= 0) {
							ds << TQString("ACK");
							ds << divisions;
							writeEndOfFrame();
						}
						else {
							ds << TQString("NCK");
							writeEndOfFrame();
						}
					}
					else if (instrumentCommand == "GETTRACESAMPLECOUNT") {		// Want to get number of samples in a trace
						int i;
						int channels = gpmc_channel_count();
						TQ_INT32 samples = gpmc_sample_count();
						ds << TQString("ACK");
						for (i=0; i<channels; i++) {
							ds << samples;
						}
						writeEndOfFrame();
					}
					else if (instrumentCommand == "GETNUMBEROFCHANNELS") {		// Want the number of channels available
						TQ_INT32 channels = gpmc_channel_count();
						if (channels > 0) {
							ds << TQString("ACK");
							ds << channels;
							writeEndOfFrame();
						}
						else {
							ds << TQString("NCK");
							writeEndOfFrame();
						}
					}
					else if (instrumentCommand == "GETCHANNELNAME") {		// Want to get channel name
						TQString name;
						int i;
						int channels = gpmc_channel_count();
						ds << TQString("ACK");
						for (i=0; i<channels; i++) {
							gpmc_get_channel_name(name, i);
							ds << name;
						}
						writeEndOfFrame();
					}
					else if (instrumentCommand == "GETCHANNELACTIVE") {		// Want to get channel activity
						TQ_INT16 state;
						int i;
						int channels = gpmc_channel_count();
						ds << TQString("ACK");
						for (i=0; i<channels; i++) {
							// All channels are always active
							state = 1;
							ds << state;
						}
						writeEndOfFrame();
					}
					else if (instrumentCommand == "GETSECONDSSDIV") {		// Want to get seconds per division
						double secondsdiv;
						int i;
						int channels = gpmc_channel_count();
						ds << TQString("ACK");
						for (i=0; i<channels; i++) {
							secondsdiv = gpmc_timestep();
							ds << secondsdiv;
						}
						writeEndOfFrame();
					}
					else if (instrumentCommand == "GETRUNNING") {			// Want to get run status
						TQ_INT16 running = gpmc_get_running();
						ds << TQString("ACK");
						ds << running;
						writeEndOfFrame();
					}
					else if (instrumentCommand == "SETRUNNING") {			// Want to change run status
						TQ_INT16 value;
						ds >> value;
						gpmc_set_running(value);
						ds << TQString("ACK");
						writeEndOfFrame();
					}
					else {
						printf("[WARNING] Received unknown command %s from host %s\n\r", instrumentCommand.ascii(), m_remoteHost.ascii()); fflush(stdout);
						ds << TQString("NCK");
						writeEndOfFrame();
					}
				}

				transferred_data = true;
			}
		}
		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 LogicAnalyzerSocket::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 LogicAnalyzerServer class handles new connections to the server. For every
  client that connects, it creates a new LogicAnalyzerSocket -- that instance is now
  responsible for the communication with that client.
*/
LogicAnalyzerServer::LogicAnalyzerServer(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);
}

LogicAnalyzerServer::~LogicAnalyzerServer() {
	//
}

void LogicAnalyzerServer::newConnection(int socket) {
	LogicAnalyzerSocket *s = new LogicAnalyzerSocket(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 LogicAnalyzerServer::remoteConnectionClosed() {
	m_numberOfConnections--;
}