/*
The stellarium telescope library helps building
telescope server programs, that can communicate with stellarium
by means of the stellarium TCP telescope protocol.
It also contains smaple server classes (dummy, Meade LX200).

Author and Copyright of this file and of the stellarium telescope library:
Johannes Gajdosik, 2006

This library 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 2
of the License, or (at your option) any later version.

This library 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 library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "Lx200Connection.hpp"
#include "Lx200Command.hpp"
#include "TelescopeClientDirectLx200.hpp"
#include "LogFile.hpp"

using namespace std;

#include <math.h>


Lx200Connection::Lx200Connection(Server &server, const char *serial_device) : SerialPort(server, serial_device)
{
	time_between_commands = 0;
	next_send_time = GetNow();
	read_timeout_endtime = 0x7FFFFFFFFFFFFFFFLL;
	goto_commands_queued = 0;
}

//! Resets the connection.
//! Removes all commands in the queue without executing them and
//! cleans both the read and the write buffers.
void Lx200Connection::resetCommunication(void)
{
	while (!command_list.empty())
	{
		delete command_list.front();
		command_list.pop_front();
	}
	
	read_buff_end = read_buff;
	write_buff_end = write_buff;
	#ifdef DEBUG4
	*log_file << Now() << "Lx200Connection::resetCommunication" << endl;
	#endif
	// wait 10 seconds before sending the next command in order to read
	// and ignore data coming from the telescope:
	next_send_time = GetNow() + 10000000;
	read_timeout_endtime = 0x7FFFFFFFFFFFFFFFLL;
	goto_commands_queued = 0;
	static_cast<TelescopeClientDirectLx200&>(server).communicationResetReceived();
}

//! Commands the telescope to slew to the given right ascension and declination.
//! Converts the coordinates and queues the necessary sequence of Lx200Command
//! objects to perform the slew.
void Lx200Connection::sendGoto(unsigned int ra_int, int dec_int)
{
	if (goto_commands_queued <= 1)
	{
		int dec = (int)floor(0.5 + dec_int * (360*3600/4294967296.0));
		if (dec < -90*3600)
		{
			dec = -180*3600 - dec;
			ra_int += 0x80000000;
		}
		else if (dec > 90*3600)
		{
			dec = 180*3600 - dec;
			ra_int += 0x80000000;
		}
		int ra = (int)floor(0.5 + ra_int * (86400.0/4294967296.0));
		if (ra >= 86400)
			ra -= 86400;
		sendCommand(new Lx200CommandStopSlew(server));
		sendCommand(new Lx200CommandSetSelectedRa(server, ra));
		sendCommand(new Lx200CommandSetSelectedDec(server, dec));
		sendCommand(new Lx200CommandGotoSelected(server));
		goto_commands_queued++;
	}
	else
	{
		#ifdef DEBUG4
		*log_file << Now() << "Lx200Connection::sendGoto: ignoring command" << endl;
		#endif
	}
}

bool Lx200Connection::writeFrontCommandToBuffer(void)
{
	if(command_list.empty())
	{
		return false;
	}
	
	const long long int now = GetNow();
	if (now < next_send_time) 
	{
#ifdef DEBUG4
		/*
		*log_file << Now() << "Lx200Connection::writeFrontCommandToBuffer("
		                   << (*command_list.front()) << "): delayed for "
		                   << (next_send_time-now) << endl;
		*/
#endif
		return false;
	}
	
	const bool rval = command_list.front()->writeCommandToBuffer(write_buff_end, write_buff+sizeof(write_buff));
	if (rval)
	{
		next_send_time = now;
		if (command_list.front()->needsNoAnswer())
		{
			next_send_time += time_between_commands;
			read_timeout_endtime = 0x7FFFFFFFFFFFFFFFLL;
		}
		else
		{
			if (command_list.front()->isCommandGotoSelected())
			{
				// shorter timeout for AutoStar 494 slew:
				read_timeout_endtime = now + 3000000;
			}
			else
			{
				// extra long timeout for AutoStar 494:
				read_timeout_endtime = now + 5000000;
			}
		}
		#ifdef DEBUG4
		*log_file << Now()
		          << "Lx200Connection::writeFrontCommandToBuffer("
		          << (*command_list.front())
		          << "): queued"
		          << endl;
		#endif
	}
	
	return rval;
}

void Lx200Connection::dataReceived(const char *&p, const char *read_buff_end)
{
	if (isClosed())
	{
		*log_file << Now() << "Lx200Connection::dataReceived: strange: fd is closed" << endl;
	}
	else if (command_list.empty())
	{
		if (GetNow() < next_send_time)
		{
			// just ignore
			p = read_buff_end;
		}
		else
		{
			#ifdef DEBUG4
			*log_file << Now()
			          << "Lx200Connection::dataReceived: error: command_list is empty"
			          << endl;
			#endif
			resetCommunication();
		}
	}
	else if (command_list.front()->needsNoAnswer())
	{
		*log_file << Now() << "Lx200Connection::dataReceived: "
		                      "strange: command("
		                   << *command_list.front()
		                   << ") needs no answer"
		                   << endl;
		p = read_buff_end;
	}
	else
	{
		while(true)
		{
			if (!command_list.front()->hasBeenWrittenToBuffer())
			{
				*log_file << Now()
				          << "Lx200Connection::dataReceived: "
				             "strange: no answer expected"
				          << endl;
				p = read_buff_end;
				break;
			}
			const int rc=command_list.front()->readAnswerFromBuffer(p, read_buff_end);
			/*
			*log_file << Now()
			          << "Lx200Connection::dataReceived: "
			          << *command_list.front()
			          << "->readAnswerFromBuffer returned "
			          << rc
			          << endl;
			*/
			if (rc <= 0)
			{
				if (rc < 0)
				{
					resetCommunication();
				}
				break;
			}
			if (command_list.front()->isCommandGotoSelected())
			{
				goto_commands_queued--;
			}
			delete command_list.front();
			command_list.pop_front();
			read_timeout_endtime = 0x7FFFFFFFFFFFFFFFLL;
			if (!writeFrontCommandToBuffer())
				break;
		}
	}
}

void Lx200Connection::prepareSelectFds(fd_set &read_fds,
                                       fd_set &write_fds,
                                       int &fd_max)
{
	// if some telegram is delayed try to queue it now:
	flushCommandList();
	if (!command_list.empty() && GetNow() > read_timeout_endtime)
	{
		if (command_list.front()->shortAnswerReceived())
		{
			// the lazy telescope, propably AutoStar 494
			// has not sent the full answer
			#ifdef DEBUG4
			*log_file << Now() << "Lx200Connection::prepareSelectFds: "
			                      "dequeueing command("
			                   << *command_list.front()
			                   << ") because of timeout"
			                   << endl;
			#endif
			if (command_list.front()->isCommandGotoSelected())
			{
				goto_commands_queued--;
			}
			delete command_list.front();
			command_list.pop_front();
			read_timeout_endtime = 0x7FFFFFFFFFFFFFFFLL;
		}
		else
		{
			resetCommunication();
		}
	}
	SerialPort::prepareSelectFds(read_fds, write_fds, fd_max);
}

void Lx200Connection::flushCommandList(void)
{
	if (!command_list.empty())
	{
		while (!command_list.front()->hasBeenWrittenToBuffer())
		{
			if (writeFrontCommandToBuffer())
			{
				//*log_file << Now()
				//          << "Lx200Connection::flushCommandList: "
				//          << (*command_list.front())
				//          << "::writeFrontCommandToBuffer ok"
				//          << endl;
				if (command_list.front()->needsNoAnswer())
				{
					delete command_list.front();
					command_list.pop_front();
					read_timeout_endtime = 0x7FFFFFFFFFFFFFFFLL;
					if (command_list.empty())
						break;
				}
				else
				{
					break;
				}
			}
			else
			{
				//*log_file << Now() << "Lx200Connection::flushCommandList: "
				//                   << (*command_list.front())
				//                   << "::writeFrontCommandToBuffer failed/delayed" << endl;
				break;
			}
		}
	}
}

void Lx200Connection::sendCommand(Lx200Command *command)
{
	if (command)
	{
		#ifdef DEBUG4
		*log_file << Now()
		          << "Lx200Connection::sendCommand("
		          << *command
		          << ")"
		          << endl;
		#endif
		command_list.push_back(command);
		flushCommandList();
		//*log_file << Now() << "Lx200Connection::sendCommand(" << *command << ") end"
		//          << endl;
	}
}