/*	EQEmu: EQEmulator

	Copyright (C) 2001-2026 EQEmu Development Team

	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, see <http://www.gnu.org/licenses/>.
*/
#include "zone_launch.h"

#include "common/eqemu_config.h"
#include "common/eqemu_logsys.h"
#include "eqlaunch/worldserver.h"

//static const uint32 ZONE_RESTART_DELAY = 10000;
//static const uint32 ZONE_TERMINATE_WAIT = 10000;

int ZoneLaunch::s_running = 0;	//the number of zones running under this launcher
Timer ZoneLaunch::s_startTimer(1);	//I do not trust this things state after static initialization

ZoneLaunch::ZoneLaunch(WorldServer *world, const char *launcher_name,
const char *zone_name, uint16 port, const EQEmuConfig *config)
: m_state(StateStartPending),
	m_world(world),
	m_zone(zone_name),
	m_port(port),
	m_launcherName(launcher_name),
	m_config(config),
	m_timer(config->RestartWait),
	m_ref(ProcLauncher::ProcError),
	m_startCount(0),
	m_killFails(0)
{
	//trigger the startup timer initially so it boots the first time.
	m_timer.Trigger();
}

ZoneLaunch::~ZoneLaunch() {
	if(IsRunning())
		s_running--;
}

void ZoneLaunch::SendStatus() const {
	m_world->SendStatus(m_zone.c_str(), m_startCount, IsRunning());
}

void ZoneLaunch::Start() {
	auto spec = new ProcLauncher::Spec();
	spec->program = m_config->ZoneExe;

	if(m_port) {
		std::string arg = m_zone + std::string(":") + std::to_string(m_port);
		spec->args.push_back(arg);
	} else {
		spec->args.push_back(m_zone);
	}

	spec->args.push_back(m_launcherName);
	spec->handler = this;
	spec->logFile = m_config->LogPrefix + m_zone + m_config->LogSuffix;

	//spec is consumed, even on failure
	m_ref = ProcLauncher::get()->Launch(spec);
	if(m_ref == ProcLauncher::ProcError) {
		Log(Logs::Detail, Logs::Launcher, "Failure to launch '%s %s %s'. ", m_config->ZoneExe.c_str(), m_zone.c_str(), m_launcherName);
		m_timer.Start(m_config->RestartWait);
		return;
	}

	m_startCount++;
	m_state = StateStarted;
	s_running++;
	m_killFails = 0;

	SendStatus();

	Log(Logs::Detail, Logs::Launcher, "Zone %s has been started.", m_zone.c_str());
}

void ZoneLaunch::Restart() {
	switch(m_state) {
	case StateRestartPending:
		Log(Logs::Detail, Logs::Launcher, "Restart of zone %s requested when a restart is already pending.", m_zone.c_str());
		break;
	case StateStartPending:
		//we havent started yet, do nothing
		Log(Logs::Detail, Logs::Launcher, "Restart of %s before it has started. Ignoring.", m_zone.c_str());
		break;
	case StateStarted:
		//process is running along, kill it off..
		if(m_ref == ProcLauncher::ProcError)
			break;	//we have no proc ref... cannot stop..
		if(!ProcLauncher::get()->Terminate(m_ref, true)) {
			//failed to terminate the process, its not likely that it will work if we try again, so give up.
			Log(Logs::Detail, Logs::Launcher, "Failed to terminate zone %s. Giving up and moving to stopped.", m_zone.c_str());
			m_state = StateStopped;
			break;
		}
		Log(Logs::Detail, Logs::Launcher, "Termination signal sent to zone %s.", m_zone.c_str());
		m_timer.Start(m_config->TerminateWait);
		m_state = StateRestartPending;
		break;
	case StateStopPending:
		Log(Logs::Detail, Logs::Launcher, "Restart of zone %s requested when a stop is pending. Ignoring.", m_zone.c_str());
		break;
	case StateStopped:
		//process is already stopped... nothing to do..
		Log(Logs::Detail, Logs::Launcher, "Restart requested when zone %s is already stopped.", m_zone.c_str());
		break;
	}
}

void ZoneLaunch::Stop(bool graceful) {
	switch(m_state) {
	case StateStartPending:
		//we havent started yet, transition directly to stopped.
		Log(Logs::Detail, Logs::Launcher, "Stopping zone %s before it has started.", m_zone.c_str());
		m_state = StateStopped;
		break;
	case StateStarted:
	case StateRestartPending:
	case StateStopPending:
		if(m_ref == ProcLauncher::ProcError)
			break;	//we have no proc ref... cannot stop..
		if(!ProcLauncher::get()->Terminate(m_ref, graceful)) {
			//failed to terminate the process, its not likely that it will work if we try again, so give up.
			Log(Logs::Detail, Logs::Launcher, "Failed to terminate zone %s. Giving up and moving to stopped.", m_zone.c_str());
			m_state = StateStopped;
			break;
		}
		Log(Logs::Detail, Logs::Launcher, "Termination signal sent to zone %s.", m_zone.c_str());
		m_timer.Start(m_config->TerminateWait);
		m_state = StateStopPending;
		break;
	case StateStopped:
		//process is already stopped... nothing to do..
		Log(Logs::Detail, Logs::Launcher, "Stop requested when zone %s is already stopped.", m_zone.c_str());
		break;
	}
}

bool ZoneLaunch::Process() {
	switch(m_state) {
	case StateStartPending:
		if(m_timer.Check(false)) {
			//our internal timer says its time to start. Check with the shared timer.
			if(!s_startTimer.Check(false)) {
				//we have to wait on the shared timer now..
				break;
			}

			//ok, both timers say we can start.
			//disable our internal timer, will get started again if it is needed.
			m_timer.Disable();

			//actually start up the program
			Log(Logs::Detail, Logs::Launcher, "Starting zone %s", m_zone.c_str());
			Start();

			//now update the shared timer to reflect the proper start interval.
			if(s_running == 1) {
				//we are the first zone started. wait that interval.
				Log(Logs::Detail, Logs::Launcher, "Waiting %d milliseconds before booting the second zone.", m_config->InitialBootWait);
				s_startTimer.Start(m_config->InitialBootWait);
			} else {
				//just some follow on zone, use that interval.
				Log(Logs::Detail, Logs::Launcher, "Waiting %d milliseconds before booting the next zone.", m_config->ZoneBootInterval);
				s_startTimer.Start(m_config->ZoneBootInterval);
			}

		}	//else, timer still ticking, keep waiting
		break;
	case StateStarted:
		//happy state, do nothing..
		break;
	case StateRestartPending:
		//waiting for notification that our child has died..
		if(m_timer.Check()) {
			//we have timed out, try to kill the child again
			Log(Logs::Detail, Logs::Launcher, "Zone %s refused to die, killing again.", m_zone.c_str());
			Restart();
		}
		break;
	case StateStopPending:
		//waiting for notification that our child has died..
		if(m_timer.Check()) {
			//we have timed out, try to kill the child again
			m_killFails++;
			if(m_killFails > 5) {	//should get this number from somewhere..
				Log(Logs::Detail, Logs::Launcher, "Zone %s refused to die, giving up and acting like its dead.", m_zone.c_str());
				m_state = StateStopped;
				s_running--;
				SendStatus();
			} else {
				Log(Logs::Detail, Logs::Launcher, "Zone %s refused to die, killing again.", m_zone.c_str());
				Stop(false);
			}
		}
		break;
	case StateStopped:
		//signal our caller to remove us
		return(false);
		break;
	}
	return(true);
}

//called when the process actually dies off...
void ZoneLaunch::OnTerminate(const ProcLauncher::ProcRef &ref, const ProcLauncher::Spec *spec) {
	s_running--;

	switch(m_state) {
	case StateStartPending:
		Log(Logs::Detail, Logs::Launcher, "Zone %s has gone down before we started it..?? Restart timer started.", m_zone.c_str());
		m_state = StateStartPending;
		m_timer.Start(m_config->RestartWait);
		break;
	case StateStarted:
		//something happened to our happy process...
		Log(Logs::Detail, Logs::Launcher, "Zone %s has gone down. Restart timer started.", m_zone.c_str());
		m_state = StateStartPending;
		m_timer.Start(m_config->RestartWait);
		break;
	case StateRestartPending:
		//it finally died, start it on up again
		Log(Logs::Detail, Logs::Launcher, "Zone %s has terminated. Transitioning to starting state.", m_zone.c_str());
		m_state = StateStartPending;
		break;
	case StateStopPending:
		//it finally died, transition to close.
		Log(Logs::Detail, Logs::Launcher, "Zone %s has terminated. Transitioning to stopped state.", m_zone.c_str());
		m_state = StateStopped;
		break;
	case StateStopped:
		//we already thought it was stopped... dont care...
		Log(Logs::Detail, Logs::Launcher, "Notified of zone %s terminating when we thought it was stopped.", m_zone.c_str());
		break;
	}

	SendStatus();
}