/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2008 InspIRCd Development Team
 * See: http://www.inspircd.org/wiki/index.php/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#include "inspircd.h"
#ifndef WINDOWS
#include <sys/select.h>
#endif // WINDOWS
#include "socketengines/socketengine_select.h"


SelectEngine::SelectEngine(InspIRCd* Instance) : SocketEngine(Instance)
{
	EngineHandle = 0;
	CurrentSetSize = 0;
	memset(writeable, 0, sizeof(writeable));
}

SelectEngine::~SelectEngine()
{
}

bool SelectEngine::AddFd(EventHandler* eh)
{
	int fd = eh->GetFd();
	if ((fd < 0) || (fd > MAX_DESCRIPTORS))
		return false;

	if (GetRemainingFds() <= 1)
		return false;

	if (ref[fd])
		return false;

	fds[fd] = fd;
	ref[fd] = eh;
	CurrentSetSize++;

	ServerInstance->Log(DEBUG,"New file descriptor: %d", fd);
	return true;
}

void SelectEngine::WantWrite(EventHandler* eh)
{
	writeable[eh->GetFd()] = true;
}

bool SelectEngine::DelFd(EventHandler* eh, bool force)
{
	int fd = eh->GetFd();

	if ((fd < 0) || (fd > MAX_DESCRIPTORS))
		return false;

	std::map<int,int>::iterator t = fds.find(fd);
	if (t != fds.end())
		fds.erase(t);

	CurrentSetSize--;
	ref[fd] = NULL;
	fds[fd] = 0;

	ServerInstance->Log(DEBUG,"Remove file descriptor: %d", fd);
	return true;
}

int SelectEngine::GetMaxFds()
{
	return FD_SETSIZE;
}

int SelectEngine::GetRemainingFds()
{
	return FD_SETSIZE - CurrentSetSize;
}

int SelectEngine::DispatchEvents()
{
	int result = 0;
	timeval tval;
	int sresult = 0;
	EventHandler* ev[MAX_DESCRIPTORS];
	socklen_t codesize;
	int errcode;

	FD_ZERO(&wfdset);
	FD_ZERO(&rfdset);
	FD_ZERO(&errfdset);

	for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++)
	{
		if (ref[a->second]->Readable())
			FD_SET (a->second, &rfdset);
		else
			FD_SET (a->second, &wfdset);
		if (writeable[a->second])
			FD_SET (a->second, &wfdset);

		FD_SET (a->second, &errfdset);
	}
	tval.tv_sec = 1;
	tval.tv_usec = 0;
	sresult = select(FD_SETSIZE, &rfdset, &wfdset, &errfdset, &tval);
	if (sresult > 0)
	{
		for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++)
		{
			if ((FD_ISSET (a->second, &rfdset)) || (FD_ISSET (a->second, &wfdset)) || FD_ISSET (a->second, &errfdset))
			{
				ev[result++] = ref[a->second];
			}
		}
	}

	/** An event handler may remove its own descriptor from the list, therefore it is not
	 * safe to directly iterate over the list and dispatch events there with STL iterators.
	 * Thats a shame because it makes this code slower and more resource intensive, but maybe
	 * the user should stop using select(), as select() smells anyway.
	 */
	for (int i = 0; i < result; i++)
	{
		if (ev[i])
		{
			if (FD_ISSET (ev[i]->GetFd(), &errfdset))
			{
				ErrorEvents++;

				if (getsockopt(ev[i]->GetFd(), SOL_SOCKET, SO_ERROR, (char*)&errcode, &codesize) < 0)
					errcode = errno;

				ev[i]->HandleEvent(EVENT_ERROR, errcode);

				continue;
			}
			else
			{
				if (writeable[ev[i]->GetFd()])
				{
					WriteEvents++;
					writeable[ev[i]->GetFd()] = false;
					ev[i]->HandleEvent(EVENT_WRITE);
				}
				else
				{
					if (ev[i]->Readable())
					{
						ReadEvents++;
						ev[i]->HandleEvent(EVENT_READ);
					}
					else
					{
						WriteEvents++;
						ev[i]->HandleEvent(EVENT_WRITE);
					}
				}
			}
		}
	}

	return result;
}

std::string SelectEngine::GetName()
{
	return "select";
}