/*
 *
 * (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 "config.h"

#include <errno.h>

#ifndef _WIN32
# include <sys/poll.h>
# include <poll.h>
# include <sys/types.h>
# include <sys/time.h>
# include <sys/resource.h>
# ifndef POLLRDHUP
#  define POLLRDHUP 0
# endif
#else
# define poll WSAPoll
# define POLLRDHUP POLLHUP
#endif

static std::vector<pollfd> events;
static std::map<int, unsigned> socket_positions;

void SocketEngine::Init()
{
	events.resize(DefaultSize);
}

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)
	{
		pollfd ev;
		memset(&ev, 0, sizeof(ev));

		ev.fd = s->GetFD();
		ev.events = (s->flags[SF_READABLE] ? POLLIN : 0) | (s->flags[SF_WRITABLE] ? POLLOUT : 0);

		socket_positions[ev.fd] = events.size();
		events.push_back(ev);
	}
	else if (before_registered && !now_registered)
	{
		std::map<int, unsigned>::iterator pos = socket_positions.find(s->GetFD());
		if (pos == socket_positions.end())
			throw SocketException("Unable to remove fd " + stringify(s->GetFD()) + " from poll, it does not exist?");

		if (pos->second != events.size() - 1)
		{
			pollfd &ev = events[pos->second],
				&last_ev = events[events.size() - 1];

			ev = last_ev;

			socket_positions[ev.fd] = pos->second;
		}

		socket_positions.erase(pos);
		events.pop_back();
	}
	else if (before_registered && now_registered)
	{
		std::map<int, unsigned>::iterator pos = socket_positions.find(s->GetFD());
		if (pos == socket_positions.end())
			throw SocketException("Unable to modify fd " + stringify(s->GetFD()) + " in poll, it does not exist?");

		pollfd &ev = events[pos->second];
		ev.events = (s->flags[SF_READABLE] ? POLLIN : 0) | (s->flags[SF_WRITABLE] ? POLLOUT : 0);
	}
}

void SocketEngine::Process()
{
	int total = poll(&events.front(), events.size(), Config->ReadTimeout * 1000);
	Anope::CurTime = time(NULL);

	/* EINTR can be given if the read timeout expires */
	if (total < 0)
	{
		if (errno != EINTR)
			Log() << "SockEngine::Process(): error: " << Anope::LastError();
		return;
	}

	for (unsigned i = 0, processed = 0; i < events.size() && processed != static_cast<unsigned>(total); ++i)
	{
		pollfd *ev = &events[i];

		if (ev->revents != 0)
			++processed;

		std::map<int, Socket *>::iterator it = Sockets.find(ev->fd);
		if (it == Sockets.end())
			continue;
		Socket *s = it->second;

		if (ev->revents & (POLLERR | POLLRDHUP))
		{
			s->ProcessError();
			delete s;
			continue;
		}

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

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

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

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