/*
Copyright (C) 2009 Andrey Nazarov

This program 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; either version 2
of the License, or (at your option) any later version.

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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "common.h"
#include "sys_public.h"
#include "io_sleep.h"
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#else
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#endif

static ioentry_t    entries[FD_SETSIZE];
static int          numfds;

ioentry_t *IO_Add(int fd)
{
    ioentry_t *e;
#ifdef _WIN32
    int i;

    for (i = 0, e = entries; i < numfds; i++, e++) {
        if (!e->inuse) {
            break;
        }
    }

    if (i == numfds) {
        if (++numfds > FD_SETSIZE) {
            Com_Error(ERR_FATAL, "%s: no more space for fd: %d", __func__, fd);
        }
    }

    e->fd = fd;
#else

#define CHECK_FD \
    if( fd < 0 || fd >= FD_SETSIZE ) { \
        Com_Error( ERR_FATAL, "%s: fd out of range: %d", __func__, fd ); \
    }

    CHECK_FD

    if (fd >= numfds) {
        numfds = fd + 1;
    }

    e = &entries[fd];
#endif
    e->inuse = qtrue;
    return e;
}

void IO_Remove(int fd)
{
    ioentry_t *e;
    int i;

    e = IO_Get(fd);
    memset(e, 0, sizeof(*e));

    for (i = numfds - 1; i >= 0; i--) {
        e = &entries[i];
        if (e->inuse) {
            break;
        }
    }

    numfds = i + 1;
}

ioentry_t *IO_Get(int fd)
{
    ioentry_t *e;
#ifdef _WIN32
    int i;

    for (i = 0, e = entries; i < numfds; i++, e++) {
        if (!e->inuse) {
            continue;
        }
        if (e->fd == fd) {
            return e;
        }
    }

    Com_Error(ERR_FATAL, "%s: fd not found: %d", __func__, fd);
#else
    CHECK_FD

    e = &entries[fd];
    return e;
#endif
}

//void IO_Mask( int fd ) {
//}

/*
====================
IO_Sleep

Sleeps msec or until some file descriptor is ready
====================
*/
int IO_Sleep(int msec)
{
    struct timeval timeout;
    fd_set rfd, wfd;
#ifdef _WIN32
    fd_set efd;
#endif
    ioentry_t *e;
    int i, ret;

    if (!numfds) {
        // don't bother with select()
        Sys_Sleep(msec);
        return 0;
    }

    FD_ZERO(&rfd);
    FD_ZERO(&wfd);
#ifdef _WIN32
    FD_ZERO(&efd);
#endif

#ifdef _WIN32
#define FD e->fd
#else
#define FD i
#endif

    for (i = 0, e = entries; i < numfds; i++, e++) {
        if (!e->inuse) {
            continue;
        }
        e->canread = qfalse;
        if (e->wantread) {
            FD_SET(FD, &rfd);
        }
        e->canwrite = qfalse;
        if (e->wantwrite) {
            FD_SET(FD, &wfd);
        }
#ifdef _WIN32
        e->canexcept = qfalse;
        if (e->wantexcept) {
            FD_SET(FD, &efd);
        }
#endif
    }

    timeout.tv_sec = msec / 1000;
    timeout.tv_usec = (msec % 1000) * 1000;

    ret = select(numfds, &rfd, &wfd,
#ifdef _WIN32
                 & efd,
#else
                 NULL,
#endif
                 & timeout);
    if (ret == -1) {
#ifdef _WIN32
        // TODO: report WSA error
#else
        if (errno != EINTR) {
            Com_EPrintf("%s: %s\n", __func__, strerror(errno));
        }
#endif
        return ret;
    }

    if (!ret) {
        return ret;
    }

    for (i = 0; i < numfds; i++) {
        e = &entries[i];
        if (!e->inuse) {
            continue;
        }
        if (e->wantread && FD_ISSET(FD, &rfd)) {
            e->canread = qtrue;
        }
        if (e->wantwrite && FD_ISSET(FD, &wfd)) {
            e->canwrite = qtrue;
        }
#ifdef _WIN32
        if (e->wantexcept && FD_ISSET(FD, &efd)) {
            e->canexcept = qtrue;
        }
#endif
    }

    return ret;
}

#if USE_AC_SERVER

/*
====================
IO_Sleep

Sleeps msec or until some file descriptor from a given subset is ready
====================
*/
int IO_Sleepv(int msec, ...)
{
    va_list argptr;
    struct timeval timeout;
    fd_set rfd, wfd;
#ifdef _WIN32
    fd_set efd;
#endif
    ioentry_t *e;
    int i, ret;

    if (!numfds) {
        // don't bother with select()
        Sys_Sleep(msec);
        return 0;
    }

    FD_ZERO(&rfd);
    FD_ZERO(&wfd);
#ifdef _WIN32
    FD_ZERO(&efd);
#endif

    va_start(argptr, msec);
    while (1) {
        i = va_arg(argptr, int);
        if (i == -1) {
            break;
        }
        e = &entries[i];
        if (!e->inuse) {
            continue;
        }
        e->canread = qfalse;
        if (e->wantread) {
            FD_SET(FD, &rfd);
        }
        e->canwrite = qfalse;
        if (e->wantwrite) {
            FD_SET(FD, &wfd);
        }
#ifdef _WIN32
        e->canexcept = qfalse;
        if (e->wantexcept) {
            FD_SET(FD, &efd);
        }
#endif
    }
    va_end(argptr);

    timeout.tv_sec = msec / 1000;
    timeout.tv_usec = (msec % 1000) * 1000;

    ret = select(numfds, &rfd, &wfd,
#ifdef _WIN32
                 & efd,
#else
                 NULL,
#endif
                 & timeout);
    if (ret == -1) {
#ifdef _WIN32
        // TODO: report WSA error
#else
        if (errno != EINTR) {
            Com_EPrintf("%s: %s\n", __func__, strerror(errno));
        }
#endif
        return ret;
    }

    if (!ret) {
        return ret;
    }

    va_start(argptr, msec);
    while (1) {
        i = va_arg(argptr, int);
        if (i == -1) {
            break;
        }
        e = &entries[i];
        if (!e->inuse) {
            continue;
        }
        if (e->wantread && FD_ISSET(FD, &rfd)) {
            e->canread = qtrue;
        }
        if (e->wantwrite && FD_ISSET(FD, &wfd)) {
            e->canwrite = qtrue;
        }
#ifdef _WIN32
        if (e->wantexcept && FD_ISSET(FD, &efd)) {
            e->canexcept = qtrue;
        }
#endif
    }
    va_end(argptr);

    return ret;
}

#endif // USE_AC_SERVER