/*
 * Copyright (C) 2002 Igor Sysoev, http://sysoev.ru
 */

/*
    NEED ? : unify change_list and event_list:
       event_list = change_list;
*/

#include <ngx_config.h>
#include <ngx_types.h>
#include <ngx_log.h>
#include <ngx_connection.h>
#include <ngx_event.h>
#include <ngx_kqueue_module.h>

#if (USE_KQUEUE) && !(HAVE_KQUEUE)
#error "kqueue is not supported on this platform"
#endif

static void ngx_add_timer(ngx_event_t *ev, u_int timer);
static void ngx_inline ngx_del_timer(ngx_event_t *ev);


static int              kq;
static struct kevent   *change_list, *event_list;
static int              nchanges, nevents;

static ngx_event_t      timer_queue;

void ngx_kqueue_init(int max_connections, ngx_log_t *log)
{
    int size = sizeof(struct kevent) * 512;

    nchanges = 0;
    nevents = 512;

    if ((kq = kqueue()) == -1)
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "ngx_kqueue_init: kqueue failed");

    change_list = ngx_alloc(size, log);
    event_list = ngx_alloc(size, log);

    timer_queue.timer_prev = &timer_queue;
    timer_queue.timer_next = &timer_queue;

#if !(USE_KQUEUE)
    ngx_event_actions.add = ngx_kqueue_add_event;
    ngx_event_actions.del = ngx_kqueue_del_event;
    ngx_event_actions.process = ngx_kqueue_process_events;
#endif

}

int ngx_kqueue_add_event(ngx_event_t *ev, int event, u_int flags)
{
    if (event == NGX_TIMER_EVENT) {
        ngx_add_timer(ev, flags);
        return 0;
    }

    return ngx_kqueue_set_event(ev, event, EV_ADD | flags);
}

int ngx_kqueue_del_event(ngx_event_t *ev, int event)
{
    if (event == NGX_TIMER_EVENT) {
        ngx_del_timer(ev);
        return 0;
    }

    return ngx_kqueue_set_event(ev, event, EV_DELETE);
}

int ngx_kqueue_set_event(ngx_event_t *ev, int filter, u_int flags)
{
    struct timespec  ts = { 0, 0 };
    ngx_connection_t *cn = (ngx_connection_t *) ev->data;

    ngx_log_debug(ev->log, "ngx_kqueue_set_event: %d: ft:%d f:%08x" _
                  cn->fd _ filter _ flags);

    if (nchanges >= nevents) {
        ngx_log_error(NGX_LOG_WARN, ev->log, 0,
                      "ngx_kqueue_set_event: change list is filled up");

        if (kevent(kq, change_list, nchanges, NULL, 0, &ts) == -1) {
            ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_errno,
                          "ngx_kqueue_set_event: kevent failed");
            return -1;
        }
        nchanges = 0;
    }

    change_list[nchanges].ident = cn->fd;
    change_list[nchanges].filter = filter;
    change_list[nchanges].flags = flags;
    change_list[nchanges].fflags = 0;
    change_list[nchanges].data = 0;
    change_list[nchanges].udata = ev;
    nchanges++;

    return 0;
}

int ngx_kqueue_process_events(ngx_log_t *log)
{
    int              events, i;
    u_int            timer = 0, delta = 0;
    ngx_event_t      *ev, *nx;
    struct timeval   tv;
    struct timespec  ts, *tp = NULL;

    if (timer_queue.timer_next != &timer_queue) {
        timer = timer_queue.timer_next->timer_delta;
        ts.tv_sec = timer / 1000;
        ts.tv_nsec = (timer % 1000) * 1000000;
        tp = &ts;
        gettimeofday(&tv, NULL);
        delta = tv.tv_sec * 1000 + tv.tv_usec / 1000;
    }

    ngx_log_debug(log, "ngx_kqueue_process_events: timer: %d" _ timer);

    if ((events = kevent(kq, change_list, nchanges, event_list, nevents, tp))
                == -1) {
        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                      "ngx_kqueue_process_events: kevent failed");
        return -1;
    }

    nchanges = 0;

    if (timer) {
        gettimeofday(&tv, NULL);
        delta = tv.tv_sec * 1000 + tv.tv_usec / 1000 - delta;

    } else {
        ngx_assert((events != 0), return -1, log,
                   "ngx_kqueue_process_events: "
                   "kevent returns no events without timeout");
    }

    ngx_log_debug(log, "ngx_kqueue_process_events: "
                       "timer: %d, delta: %d" _ timer _ delta);

    if (timer) {
        if (delta >= timer) {
            for (ev = timer_queue.timer_next;
                 ev != &timer_queue && delta >= ev->timer_delta;
                 /* void */)
            {
                delta -= ev->timer_delta;
                nx = ev->timer_next;
                ngx_del_timer(ev);
                if (ev->timer_handler(ev) == -1)
                    ev->close_handler(ev);
                ev = nx;
            }

        } else {
           timer_queue.timer_next->timer_delta -= delta;
        }
    }

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

        ngx_log_debug(log, "ngx_kqueue_process_events: kevent: "
                      "%d: ft:%d f:%08x ff:%08x d:%d ud:%08x" _
                      event_list[i].ident _ event_list[i].filter _
                      event_list[i].flags _ event_list[i].fflags _
                      event_list[i].data _ event_list[i].udata);

        if (event_list[i].flags & EV_ERROR) {
            ngx_log_error(NGX_LOG_ALERT, log, event_list[i].data,
                          "ngx_kqueue_process_events: kevent error");
            continue;
        }

        ev = (ngx_event_t *) event_list[i].udata;

        switch (event_list[i].filter) {

        case EVFILT_READ:
        case EVFILT_WRITE:
            ev->ready = 1;
            ev->available = event_list[i].data;

            if (event_list[i].flags & EV_EOF) {
                ev->eof = 1;
                ev->error = event_list[i].fflags;
            }

            if (ev->event_handler(ev) == -1)
                ev->close_handler(ev);

            break;

        default:
            ngx_assert(0, /* void */, log,
                       "ngx_kqueue_process_events: unknown filter %d" _
                       event_list[i].filter);
        }
    }

    return 0;
}

static void ngx_add_timer(ngx_event_t *ev, u_int timer)
{
    ngx_event_t *e;

    for (e = timer_queue.timer_next;
         e != &timer_queue && timer > e->timer_delta;
         e = e->timer_next)
        timer -= e->timer_delta;

    ev->timer_delta = timer;

    ev->timer_next = e;
    ev->timer_prev = e->timer_prev;

    e->timer_prev->timer_next = ev;
    e->timer_prev = ev;
}

static void ngx_inline ngx_del_timer(ngx_event_t *ev)
{
    if (ev->timer_prev)
        ev->timer_prev->timer_next = ev->timer_next;

    if (ev->timer_next) {
        ev->timer_next->timer_prev = ev->timer_prev;
        ev->timer_prev = NULL;
    }

    if (ev->timer_prev)
        ev->timer_next = NULL;
}