/*
 *
 * (C) 2003-2022 Anope Team
 * Contact us at team@anope.org
 *
 * Please read COPYING and README for further details.
 *
 * Based on the original code of Epona by Lara.
 * Based on the original code of Services by Andy Church.
 */

#include "services.h"
#include "anope.h"
#include "sockets.h"
#include "socketengine.h"
#include "logger.h"
#include "config.h"

#ifdef _AIX
# undef FD_ZERO
# define FD_ZERO(p) memset((p), 0, sizeof(*(p)))
#endif /* _AIX */

static int MaxFD;
static unsigned FDCount;
static fd_set ReadFDs;
static fd_set WriteFDs;

void SocketEngine::Init()
{
	FD_ZERO(&ReadFDs);
	FD_ZERO(&WriteFDs);
}

void SocketEngine::Shutdown()
{
	while (!Sockets.empty())
		delete Sockets.begin()->second;
}

void SocketEngine::Change(Socket *s, bool set, SocketFlag flag)
{
	if (set == s->flags[flag])
		return;

	bool before_registered = s->flags[SF_READABLE] || s->flags[SF_WRITABLE];

	s->flags[flag] = set;

	bool now_registered = s->flags[SF_READABLE] || s->flags[SF_WRITABLE];

	if (!before_registered && now_registered)
	{
		if (s->GetFD() > MaxFD)
			MaxFD = s->GetFD();
		if (s->flags[SF_READABLE])
			FD_SET(s->GetFD(), &ReadFDs);
		if (s->flags[SF_WRITABLE])
			FD_SET(s->GetFD(), &WriteFDs);
		++FDCount;
	}
	else if (before_registered && !now_registered)
	{
		if (s->GetFD() == MaxFD)
			--MaxFD;
		FD_CLR(s->GetFD(), &ReadFDs);
		FD_CLR(s->GetFD(), &WriteFDs);
		--FDCount;
	}
	else if (before_registered && now_registered)
	{
		if (s->flags[SF_READABLE])
			FD_SET(s->GetFD(), &ReadFDs);
		else
			FD_CLR(s->GetFD(), &ReadFDs);

		if (s->flags[SF_WRITABLE])
			FD_SET(s->GetFD(), &WriteFDs);
		else
			FD_CLR(s->GetFD(), &WriteFDs);
	}
}

void SocketEngine::Process()
{
	fd_set rfdset = ReadFDs, wfdset = WriteFDs, efdset = ReadFDs;
	timeval tval;
	tval.tv_sec = Config->ReadTimeout;
	tval.tv_usec = 0;

#ifdef _WIN32
	/* We can use the socket engine to "sleep" services for a period of
	 * time between connections to the uplink, which allows modules,
	 * timers, etc to function properly. Windows, being as useful as it is,
	 * does not allow to select() on 0 sockets and will immediately return error.
	 * Thus:
	 */
	if (FDCount == 0)
	{
		sleep(tval.tv_sec);
		return;
	}
#endif

	int sresult = select(MaxFD + 1, &rfdset, &wfdset, &efdset, &tval);
	Anope::CurTime = time(NULL);

	if (sresult == -1)
	{
		Log() << "SockEngine::Process(): error: " << Anope::LastError();
	}
	else if (sresult)
	{
		int processed = 0;
		for (std::map<int, Socket *>::const_iterator it = Sockets.begin(), it_end = Sockets.end(); it != it_end && processed != sresult;)
		{
			Socket *s = it->second;
			++it;

			bool has_read = FD_ISSET(s->GetFD(), &rfdset), has_write = FD_ISSET(s->GetFD(), &wfdset), has_error = FD_ISSET(s->GetFD(), &efdset);
			if (has_read || has_write || has_error)
				++processed;

			if (has_error)
			{
				s->ProcessError();
				delete s;
				continue;
			}

			if (!s->Process())
			{
				if (s->flags[SF_DEAD])
					delete s;
				continue;
			}

			if (has_read && !s->ProcessRead())
				s->flags[SF_DEAD] = true;

			if (has_write && !s->ProcessWrite())
				s->flags[SF_DEAD] = true;

			if (s->flags[SF_DEAD])
				delete s;
		}
	}
}
