/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2015 Attila Molnar <attilamolnar@hush.com>
 *
 * This file is part of InspIRCd.  InspIRCd 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, version 2.
 *
 * 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 "inspircd.h"

#include "pingtimer.h"
#include "treeserver.h"
#include "commandbuilder.h"

PingTimer::PingTimer(TreeServer* ts)
	: Timer(Utils->PingFreq)
	, server(ts)
	, state(PS_SENDPING)
{
}

PingTimer::State PingTimer::TickInternal()
{
	// Timer expired, take next action based on what happened last time
	if (state == PS_SENDPING)
	{
		// Last ping was answered, send next ping
		server->GetSocket()->WriteLine(CmdBuilder("PING").push(server->GetID()));
		LastPingMsec = ServerInstance->Time() * 1000 + (ServerInstance->Time_ns() / 1000000);
		// Warn next unless warnings are disabled. If they are, jump straight to timeout.
		if (Utils->PingWarnTime)
			return PS_WARN;
		else
			return PS_TIMEOUT;
	}
	else if (state == PS_WARN)
	{
		// No pong arrived in PingWarnTime seconds, send a warning to opers
		ServerInstance->SNO->WriteToSnoMask('l', "Server \002%s\002 has not responded to PING for %d seconds, high latency.", server->GetName().c_str(), GetInterval());
		return PS_TIMEOUT;
	}
	else // PS_TIMEOUT
	{
		// They didn't answer the last ping, if they are locally connected, get rid of them
		if (server->IsLocal())
		{
			TreeSocket* sock = server->GetSocket();
			sock->SendError("Ping timeout");
			sock->Close();
		}

		// If the server is non-locally connected, don't do anything until we get a PONG.
		// This is to avoid pinging the server and warning opers more than once.
		// If they do answer eventually, we will move to the PS_SENDPING state and ping them again.
		return PS_IDLE;
	}
}

void PingTimer::SetState(State newstate)
{
	state = newstate;

	// Set when should the next Tick() happen based on the state
	if (state == PS_SENDPING)
		SetInterval(Utils->PingFreq);
	else if (state == PS_WARN)
		SetInterval(Utils->PingWarnTime);
	else if (state == PS_TIMEOUT)
		SetInterval(Utils->PingFreq - Utils->PingWarnTime);

	// If state == PS_IDLE, do not set the timer, see above why
}

bool PingTimer::Tick(time_t currtime)
{
	if (server->IsDead())
		return false;

	SetState(TickInternal());
	return false;
}

void PingTimer::OnPong()
{
	// Calculate RTT
	long ts = ServerInstance->Time() * 1000 + (ServerInstance->Time_ns() / 1000000);
	server->rtt = ts - LastPingMsec;

	// Change state to send ping next, also reschedules the timer appropriately
	SetState(PS_SENDPING);
}