/*
 *
 * (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 <sys/epoll.h>
#include <ulimit.h>
#include <errno.h>

static int EngineHandle;
static std::vector<epoll_event> events;

void SocketEngine::Init()
{
	EngineHandle = epoll_create(4);

	if (EngineHandle == -1)
		throw SocketException("Could not initialize epoll socket engine: " + Anope::LastError());

	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];

	epoll_event ev;

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

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

	int mod;
	if (!before_registered && now_registered)
		mod = EPOLL_CTL_ADD;
	else if (before_registered && !now_registered)
		mod = EPOLL_CTL_DEL;
	else if (before_registered && now_registered)
		mod = EPOLL_CTL_MOD;
	else
		return;

	if (epoll_ctl(EngineHandle, mod, ev.data.fd, &ev) == -1)
		 throw SocketException("Unable to epoll_ctl() fd " + stringify(ev.data.fd) + " to epoll: " + Anope::LastError());
}

void SocketEngine::Process()
{
	if (Sockets.size() > events.size())
		events.resize(events.size() * 2);

	int total = epoll_wait(EngineHandle, &events.front(), events.size(), Config->ReadTimeout * 1000);
	Anope::CurTime = time(NULL);

	/* EINTR can be given if the read timeout expires */
	if (total == -1)
	{
		if (errno != EINTR)
			Log() << "SockEngine::Process(): error: " << Anope::LastError();
		return;
	}

	for (int i = 0; i < total; ++i)
	{
		epoll_event &ev = events[i];

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

		if (ev.events & (EPOLLHUP | EPOLLERR))
		{
			s->ProcessError();
			delete s;
			continue;
		}

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

		if ((ev.events & EPOLLIN) && !s->ProcessRead())
			s->flags[SF_DEAD] = true;

		if ((ev.events & EPOLLOUT) && !s->ProcessWrite())
			s->flags[SF_DEAD] = true;

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