/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2010 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

/* General event handling code for SDL */

#include "SDL.h"

#include "SDL_events.h"

#include "SDL_syswm.h"

#include "SDL_thread.h"

#include "SDL_sysevents.h"

#include "SDL_events_c.h"

#include "../timer/SDL_timer_c.h"

#if !SDL_JOYSTICK_DISABLED

#include "../joystick/SDL_joystick_c.h"

#endif

/* Public data -- the event filter */

SDL_EventFilter SDL_EventOK = NULL;

void *SDL_EventOKParam;

typedef struct {

    Uint32 bits[8];

} SDL_DisabledEventBlock;

static SDL_DisabledEventBlock *SDL_disabled_events[256];

static Uint32 SDL_userevents = SDL_USEREVENT;

/* Private data -- event queue */

#define MAXEVENTS	128

static struct

{

    SDL_mutex *lock;

    int active;

    int head;

    int tail;

    SDL_Event event[MAXEVENTS];

    int wmmsg_next;

    struct SDL_SysWMmsg wmmsg[MAXEVENTS];

} SDL_EventQ;

/* Private data -- event locking structure */

static struct

{

    SDL_mutex *lock;

    int safe;

} SDL_EventLock;

/* Thread functions */

static SDL_Thread *SDL_EventThread = NULL;      /* Thread handle */

static SDL_threadID event_thread;     /* The event thread id */

void

SDL_Lock_EventThread(void)

{

    if (SDL_EventThread && (SDL_ThreadID() != event_thread)) {

        /* Grab lock and spin until we're sure event thread stopped */

        SDL_mutexP(SDL_EventLock.lock);

        while (!SDL_EventLock.safe) {

            SDL_Delay(1);

        }

    }

}

void

SDL_Unlock_EventThread(void)

{

    if (SDL_EventThread && (SDL_ThreadID() != event_thread)) {

        SDL_mutexV(SDL_EventLock.lock);

    }

}

static __inline__ SDL_bool

SDL_ShouldPollJoystick()

{

#if !SDL_JOYSTICK_DISABLED

    if (SDL_numjoysticks &&

        (!SDL_disabled_events[SDL_JOYAXISMOTION >> 8] ||

         SDL_JoystickEventState(SDL_QUERY))) {

        return SDL_TRUE;

    }

#endif

    return SDL_FALSE;

}

static int SDLCALL

SDL_GobbleEvents(void *unused)

{

    event_thread = SDL_ThreadID();

    while (SDL_EventQ.active) {

        SDL_VideoDevice *_this = SDL_GetVideoDevice();

        /* Get events from the video subsystem */

        if (_this) {

            _this->PumpEvents(_this);

        }

#if !SDL_JOYSTICK_DISABLED

        /* Check for joystick state change */

        if (SDL_ShouldPollJoystick()) {

            SDL_JoystickUpdate();

        }

#endif

        /* Give up the CPU for the rest of our timeslice */

        SDL_EventLock.safe = 1;

        if (SDL_timer_running) {

            SDL_ThreadedTimerCheck();

        }

        SDL_Delay(1);

        /* Check for event locking.

           On the P of the lock mutex, if the lock is held, this thread

           will wait until the lock is released before continuing.  The

           safe flag will be set, meaning that the other thread can go

           about it's business.  The safe flag is reset before the V,

           so as soon as the mutex is free, other threads can see that

           it's not safe to interfere with the event thread.

         */

        SDL_mutexP(SDL_EventLock.lock);

        SDL_EventLock.safe = 0;

        SDL_mutexV(SDL_EventLock.lock);

    }

    SDL_SetTimerThreaded(0);

    event_thread = 0;

    return (0);

}

static int

SDL_StartEventThread(Uint32 flags)

{

    /* Reset everything to zero */

    SDL_EventThread = NULL;

    SDL_memset(&SDL_EventLock, 0, sizeof(SDL_EventLock));

    /* Create the lock and set ourselves active */

#if !SDL_THREADS_DISABLED

    SDL_EventQ.lock = SDL_CreateMutex();

    if (SDL_EventQ.lock == NULL) {

        return (-1);

    }

#endif /* !SDL_THREADS_DISABLED */

    SDL_EventQ.active = 1;

    if ((flags & SDL_INIT_EVENTTHREAD) == SDL_INIT_EVENTTHREAD) {

        SDL_EventLock.lock = SDL_CreateMutex();

        if (SDL_EventLock.lock == NULL) {

            return (-1);

        }

        SDL_EventLock.safe = 0;

        /* The event thread will handle timers too */

        SDL_SetTimerThreaded(2);

#if (defined(__WIN32__) && !defined(_WIN32_WCE)) && !defined(HAVE_LIBC)

#undef SDL_CreateThread

        SDL_EventThread =

            SDL_CreateThread(SDL_GobbleEvents, NULL, NULL, NULL);

#else

        SDL_EventThread = SDL_CreateThread(SDL_GobbleEvents, NULL);

#endif

        if (SDL_EventThread == NULL) {

            return (-1);

        }

    } else {

        event_thread = 0;

    }

    return (0);

}

static void

SDL_StopEventThread(void)

{

    SDL_EventQ.active = 0;

    if (SDL_EventThread) {

        SDL_WaitThread(SDL_EventThread, NULL);

        SDL_EventThread = NULL;

        SDL_DestroyMutex(SDL_EventLock.lock);

        SDL_EventLock.lock = NULL;

    }

    if (SDL_EventQ.lock) {

        SDL_DestroyMutex(SDL_EventQ.lock);

        SDL_EventQ.lock = NULL;

    }

}

SDL_threadID

SDL_EventThreadID(void)

{

    return (event_thread);

}

/* Public functions */

void

SDL_StopEventLoop(void)

{

    int i;

    /* Halt the event thread, if running */

    SDL_StopEventThread();

    /* Shutdown event handlers */

    SDL_KeyboardQuit();

    SDL_MouseQuit();

    SDL_QuitQuit();

    /* Clean out EventQ */

    SDL_EventQ.head = 0;

    SDL_EventQ.tail = 0;

    SDL_EventQ.wmmsg_next = 0;

    /* Clear disabled event state */

    for (i = 0; i < SDL_arraysize(SDL_disabled_events); ++i) {

        if (SDL_disabled_events[i]) {

            SDL_free(SDL_disabled_events[i]);

            SDL_disabled_events[i] = NULL;

        }

    }

}

/* This function (and associated calls) may be called more than once */

int

SDL_StartEventLoop(Uint32 flags)

{

    int retcode;

    /* Clean out the event queue */

    SDL_EventThread = NULL;

    SDL_EventQ.lock = NULL;

    SDL_StopEventLoop();

    /* No filter to start with, process most event types */

    SDL_EventOK = NULL;

    SDL_EventState(SDL_SYSWMEVENT, SDL_DISABLE);

    /* Initialize event handlers */

    retcode = 0;

    retcode += SDL_KeyboardInit();

    retcode += SDL_MouseInit();

    retcode += SDL_QuitInit();

    if (retcode < 0) {

        /* We don't expect them to fail, but... */

        return (-1);

    }

    /* Create the lock and event thread */

    if (SDL_StartEventThread(flags) < 0) {

        SDL_StopEventLoop();

        return (-1);

    }

    return (0);

}

/* Add an event to the event queue -- called with the queue locked */

static int

SDL_AddEvent(SDL_Event * event)

{

    int tail, added;

    tail = (SDL_EventQ.tail + 1) % MAXEVENTS;

    if (tail == SDL_EventQ.head) {

        /* Overflow, drop event */

        added = 0;

    } else {

        SDL_EventQ.event[SDL_EventQ.tail] = *event;

        if (event->type == SDL_SYSWMEVENT) {

            /* Note that it's possible to lose an event */

            int next = SDL_EventQ.wmmsg_next;

            SDL_EventQ.wmmsg[next] = *event->syswm.msg;

            SDL_EventQ.event[SDL_EventQ.tail].syswm.msg =

                &SDL_EventQ.wmmsg[next];

            SDL_EventQ.wmmsg_next = (next + 1) % MAXEVENTS;

        }

        SDL_EventQ.tail = tail;

        added = 1;

    }

    return (added);

}

/* Cut an event, and return the next valid spot, or the tail */

/*                           -- called with the queue locked */

static int

SDL_CutEvent(int spot)

{

    if (spot == SDL_EventQ.head) {

        SDL_EventQ.head = (SDL_EventQ.head + 1) % MAXEVENTS;

        return (SDL_EventQ.head);

    } else if ((spot + 1) % MAXEVENTS == SDL_EventQ.tail) {

        SDL_EventQ.tail = spot;

        return (SDL_EventQ.tail);

    } else

        /* We cut the middle -- shift everything over */

    {

        int here, next;

        /* This can probably be optimized with SDL_memcpy() -- careful! */

        if (--SDL_EventQ.tail < 0) {

            SDL_EventQ.tail = MAXEVENTS - 1;

        }

        for (here = spot; here != SDL_EventQ.tail; here = next) {

            next = (here + 1) % MAXEVENTS;

            SDL_EventQ.event[here] = SDL_EventQ.event[next];

        }

        return (spot);

    }

    /* NOTREACHED */

}

/* Lock the event queue, take a peep at it, and unlock it */

int

SDL_PeepEvents(SDL_Event * events, int numevents, SDL_eventaction action,

               Uint32 minType, Uint32 maxType)

{

    int i, used;

    /* Don't look after we've quit */

    if (!SDL_EventQ.active) {

        return (-1);

    }

    /* Lock the event queue */

    used = 0;

    if (SDL_mutexP(SDL_EventQ.lock) == 0) {

        if (action == SDL_ADDEVENT) {

            for (i = 0; i < numevents; ++i) {

                used += SDL_AddEvent(&events[i]);

            }

        } else {

            SDL_Event tmpevent;

            int spot;

            /* If 'events' is NULL, just see if they exist */

            if (events == NULL) {

                action = SDL_PEEKEVENT;

                numevents = 1;

                events = &tmpevent;

            }

            spot = SDL_EventQ.head;

            while ((used < numevents) && (spot != SDL_EventQ.tail)) {

                Uint32 type = SDL_EventQ.event[spot].type;

                if (minType <= type && type <= maxType) {

                    events[used++] = SDL_EventQ.event[spot];

                    if (action == SDL_GETEVENT) {

                        spot = SDL_CutEvent(spot);

                    } else {

                        spot = (spot + 1) % MAXEVENTS;

                    }

                } else {

                    spot = (spot + 1) % MAXEVENTS;

                }

            }

        }

        SDL_mutexV(SDL_EventQ.lock);

    } else {

        SDL_SetError("Couldn't lock event queue");

        used = -1;

    }

    return (used);

}

SDL_bool

SDL_HasEvent(Uint32 type)

{

    return (SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, type, type) > 0);

}

SDL_bool

SDL_HasEvents(Uint32 minType, Uint32 maxType)

{

    return (SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, minType, maxType) > 0);

}

void

SDL_FlushEvent(Uint32 type)

{

    SDL_FlushEvents(type, type);

}

void

SDL_FlushEvents(Uint32 minType, Uint32 maxType)

{

    /* Don't look after we've quit */

    if (!SDL_EventQ.active) {

        return;

    }

    /* Make sure the events are current */

    SDL_PumpEvents();

    /* Lock the event queue */

    if (SDL_mutexP(SDL_EventQ.lock) == 0) {

        int spot = SDL_EventQ.head;

        while (spot != SDL_EventQ.tail) {

            Uint32 type = SDL_EventQ.event[spot].type;

            if (minType <= type && type <= maxType) {

                spot = SDL_CutEvent(spot);

            } else {

                spot = (spot + 1) % MAXEVENTS;

            }

        }

        SDL_mutexV(SDL_EventQ.lock);

    }

}

/* Run the system dependent event loops */

void

SDL_PumpEvents(void)

{

    if (!SDL_EventThread) {

        SDL_VideoDevice *_this = SDL_GetVideoDevice();

        /* Get events from the video subsystem */

        if (_this) {

            _this->PumpEvents(_this);

        }

#if !SDL_JOYSTICK_DISABLED

        /* Check for joystick state change */

        if (SDL_ShouldPollJoystick()) {

            SDL_JoystickUpdate();

        }

#endif

    }

}

/* Public functions */

int

SDL_PollEvent(SDL_Event * event)

{

    return SDL_WaitEventTimeout(event, 0);

}

int

SDL_WaitEvent(SDL_Event * event)

{

    return SDL_WaitEventTimeout(event, -1);

}

int

SDL_WaitEventTimeout(SDL_Event * event, int timeout)

{

    Uint32 expiration = 0;

    if (timeout > 0)

        expiration = SDL_GetTicks() + timeout;

    for (;;) {

        SDL_PumpEvents();

        switch (SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_FIRSTEVENT, SDL_LASTEVENT)) {

        case -1:

            return 0;

        case 1:

            return 1;

        case 0:

            if (timeout == 0) {

                /* Polling and no events, just return */

                return 0;

            }

            if (timeout > 0 && ((int) (SDL_GetTicks() - expiration) >= 0)) {

                /* Timeout expired and no events */

                return 0;

            }

            SDL_Delay(10);

            break;

        }

    }

}

int

SDL_PushEvent(SDL_Event * event)

{

    if (SDL_EventOK && !SDL_EventOK(SDL_EventOKParam, event)) {

        return 0;

    }

    if (SDL_PeepEvents(event, 1, SDL_ADDEVENT, 0, 0) <= 0) {

        return -1;

    }

    return 1;

}

void

SDL_SetEventFilter(SDL_EventFilter filter, void *userdata)

{

    SDL_Event bitbucket;

    /* Set filter and discard pending events */

    SDL_EventOK = filter;

    SDL_EventOKParam = userdata;

    while (SDL_PollEvent(&bitbucket) > 0);

}

SDL_bool

SDL_GetEventFilter(SDL_EventFilter * filter, void **userdata)

{

    if (filter) {

        *filter = SDL_EventOK;

    }

    if (userdata) {

        *userdata = SDL_EventOKParam;

    }

    return SDL_EventOK ? SDL_TRUE : SDL_FALSE;

}

void

SDL_FilterEvents(SDL_EventFilter filter, void *userdata)

{

    if (SDL_mutexP(SDL_EventQ.lock) == 0) {

        int spot;

        spot = SDL_EventQ.head;

        while (spot != SDL_EventQ.tail) {

            if (filter(userdata, &SDL_EventQ.event[spot])) {

                spot = (spot + 1) % MAXEVENTS;

            } else {

                spot = SDL_CutEvent(spot);

            }

        }

    }

    SDL_mutexV(SDL_EventQ.lock);

}

Uint8

SDL_EventState(Uint32 type, int state)

{

    Uint8 current_state;

    Uint8 hi = ((type >> 8) & 0xff);

    Uint8 lo = (type & 0xff);

    if (SDL_disabled_events[hi] &&

        (SDL_disabled_events[hi]->bits[lo/32] & (1 << (lo&31)))) {

        current_state = SDL_DISABLE;

    } else {

        current_state = SDL_ENABLE;

    }

    if (state != current_state)

    {

        switch (state) {

        case SDL_DISABLE:

            /* Disable this event type and discard pending events */

            if (!SDL_disabled_events[hi]) {

                SDL_disabled_events[hi] = (SDL_DisabledEventBlock*) SDL_calloc(1, sizeof(SDL_DisabledEventBlock));

                if (!SDL_disabled_events[hi]) {

                    /* Out of memory, nothing we can do... */

                    break;

                }

            }

            SDL_disabled_events[hi]->bits[lo/32] |= (1 << (lo&31));

            SDL_FlushEvent(type);

            break;

        case SDL_ENABLE:

            SDL_disabled_events[hi]->bits[lo/32] &= ~(1 << (lo&31));

            break;

        default:

            /* Querying state... */

            break;

        }

    }

    return current_state;

}

Uint32

SDL_RegisterEvents(int numevents)

{

    Uint32 event_base;

    if (SDL_userevents+numevents <= SDL_LASTEVENT) {

        event_base = SDL_userevents;

        SDL_userevents += numevents;

    } else {

        event_base = (Uint32)-1;

    }

    return event_base;

}

/* This is a generic event handler.

 */

int

SDL_SendSysWMEvent(SDL_SysWMmsg * message)

{

    int posted;

    posted = 0;

    if (SDL_GetEventState(SDL_SYSWMEVENT) == SDL_ENABLE) {

        SDL_Event event;

        SDL_memset(&event, 0, sizeof(event));

        event.type = SDL_SYSWMEVENT;

        event.syswm.msg = message;

        posted = (SDL_PushEvent(&event) > 0);

    }

    /* Update internal event state */

    return (posted);

}

/* vi: set ts=4 sw=4 expandtab: */