#include "owl.h"

static int dispatch_active = 0;
static int psa_active = 0;

int _owl_select_timer_cmp(const owl_timer *t1, const owl_timer *t2) {
  return t1->time - t2->time;
}

int _owl_select_timer_eq(const owl_timer *t1, const owl_timer *t2) {
  return t1 == t2;
}

owl_timer *owl_select_add_timer(int after, int interval, void (*cb)(owl_timer *, void *), void (*destroy)(owl_timer*), void *data)
{
  owl_timer *t = owl_malloc(sizeof(owl_timer));
  GList **timers = owl_global_get_timerlist(&g);

  t->time = time(NULL) + after;
  t->interval = interval;
  t->callback = cb;
  t->destroy = destroy;
  t->data = data;

  *timers = g_list_insert_sorted(*timers, t,
                                 (GCompareFunc)_owl_select_timer_cmp);
  return t;
}

void owl_select_remove_timer(owl_timer *t)
{
  GList **timers = owl_global_get_timerlist(&g);
  if (t && g_list_find(*timers, t)) {
    *timers = g_list_remove(*timers, t);
    if(t->destroy) {
      t->destroy(t);
    }
    owl_free(t);
  }
}

void owl_select_process_timers(struct timespec *timeout)
{
  time_t now = time(NULL);
  GList **timers = owl_global_get_timerlist(&g);

  while(*timers) {
    owl_timer *t = (*timers)->data;
    int remove = 0;

    if(t->time > now)
      break;

    /* Reschedule if appropriate */
    if(t->interval > 0) {
      t->time = now + t->interval;
      *timers = g_list_remove(*timers, t);
      *timers = g_list_insert_sorted(*timers, t,
                                     (GCompareFunc)_owl_select_timer_cmp);
    } else {
      remove = 1;
    }

    /* Do the callback */
    t->callback(t, t->data);
    if(remove) {
      owl_select_remove_timer(t);
    }
  }

  if(*timers) {
    owl_timer *t = (*timers)->data;
    timeout->tv_sec = t->time - now;
    if (timeout->tv_sec > 60)
      timeout->tv_sec = 60;
  } else {
    timeout->tv_sec = 60;
  }

  timeout->tv_nsec = 0;
}

static const owl_io_dispatch *owl_select_find_io_dispatch_by_fd(const int fd)
{
  int i, len;
  const owl_list *dl;
  owl_io_dispatch *d;
  dl = owl_global_get_io_dispatch_list(&g);
  len = owl_list_get_size(dl);
  for(i = 0; i < len; i++) {
    d = owl_list_get_element(dl, i);
    if (d->fd == fd) return d;
  }
  return NULL;
}

static int owl_select_find_io_dispatch(const owl_io_dispatch *in)
{
  int i, len;
  const owl_list *dl;

  if (in != NULL) {
    dl = owl_global_get_io_dispatch_list(&g);
    len = owl_list_get_size(dl);
    for(i = 0; i < len; i++) {
      const owl_io_dispatch *d = owl_list_get_element(dl, i);
      if (d == in) return i;
    }
  }
  return -1;
}

void owl_select_remove_io_dispatch(const owl_io_dispatch *in)
{
  int elt;
  if (in != NULL) {
    elt = owl_select_find_io_dispatch(in);
    if (elt != -1) {
      owl_list *dl = owl_global_get_io_dispatch_list(&g);
      owl_io_dispatch *d = owl_list_get_element(dl, elt);
      if (dispatch_active)
        d->needs_gc = 1;
      else {
        owl_list_remove_element(dl, elt);
        if (d->destroy)
          d->destroy(d);
        owl_free(d);
      }
    }
  }
}

void owl_select_io_dispatch_gc(void)
{
  int i;
  owl_list *dl;

  dl = owl_global_get_io_dispatch_list(&g);
  /*
   * Count down so we aren't set off by removing items from the list
   * during the iteration.
   */
  for(i = owl_list_get_size(dl) - 1; i >= 0; i--) {
    owl_io_dispatch *d = owl_list_get_element(dl, i);
    if(d->needs_gc) {
      owl_select_remove_io_dispatch(d);
    }
  }
}

/* Each FD may have at most one dispatcher.
 * If a new dispatch is added for an FD, the old one is removed.
 * mode determines what types of events are watched for, and may be any combination of:
 * OWL_IO_READ, OWL_IO_WRITE, OWL_IO_EXCEPT
 */
const owl_io_dispatch *owl_select_add_io_dispatch(int fd, int mode, void (*cb)(const owl_io_dispatch *, void *), void (*destroy)(const owl_io_dispatch *), void *data)
{
  owl_io_dispatch *d = owl_malloc(sizeof(owl_io_dispatch));
  owl_list *dl = owl_global_get_io_dispatch_list(&g);

  d->fd = fd;
  d->needs_gc = 0;
  d->mode = mode;
  d->callback = cb;
  d->destroy = destroy;
  d->data = data;

  owl_select_remove_io_dispatch(owl_select_find_io_dispatch_by_fd(fd));
  owl_list_append_element(dl, d);

  return d;
}

int owl_select_prepare_io_dispatch_fd_sets(fd_set *rfds, fd_set *wfds, fd_set *efds) {
  int i, len, max_fd;
  owl_io_dispatch *d;
  owl_list *dl = owl_global_get_io_dispatch_list(&g);

  max_fd = 0;
  len = owl_list_get_size(dl);
  for (i = 0; i < len; i++) {
    d = owl_list_get_element(dl, i);
    if (d->mode & (OWL_IO_READ | OWL_IO_WRITE | OWL_IO_EXCEPT)) {
      if (max_fd < d->fd) max_fd = d->fd;
      if (d->mode & OWL_IO_READ) FD_SET(d->fd, rfds);
      if (d->mode & OWL_IO_WRITE) FD_SET(d->fd, wfds);
      if (d->mode & OWL_IO_EXCEPT) FD_SET(d->fd, efds);
    }
  }
  return max_fd + 1;
}

void owl_select_io_dispatch(const fd_set *rfds, const fd_set *wfds, const fd_set *efds, const int max_fd)
{
  int i, len;
  owl_io_dispatch *d;
  owl_list *dl = owl_global_get_io_dispatch_list(&g);

  dispatch_active = 1;
  len = owl_list_get_size(dl);
  for (i = 0; i < len; i++) {
    d = owl_list_get_element(dl, i);
    if (d->fd < max_fd && d->callback != NULL &&
        ((d->mode & OWL_IO_READ && FD_ISSET(d->fd, rfds)) ||
         (d->mode & OWL_IO_WRITE && FD_ISSET(d->fd, wfds)) ||
         (d->mode & OWL_IO_EXCEPT && FD_ISSET(d->fd, efds)))) {
      d->callback(d, d->data);
    }
  }
  dispatch_active = 0;
  owl_select_io_dispatch_gc();
}

int owl_select_add_perl_io_dispatch(int fd, int mode, SV *cb)
{
  const owl_io_dispatch *d = owl_select_find_io_dispatch_by_fd(fd);
  if (d != NULL && d->callback != owl_perlconfig_io_dispatch) {
    /* Don't mess with non-perl dispatch functions from here. */
    return 1;
  }
  owl_select_add_io_dispatch(fd, mode, owl_perlconfig_io_dispatch, owl_perlconfig_io_dispatch_destroy, cb);
  return 0;
}

int owl_select_remove_perl_io_dispatch(int fd)
{
  const owl_io_dispatch *d = owl_select_find_io_dispatch_by_fd(fd);
  if (d != NULL && d->callback == owl_perlconfig_io_dispatch) {
    /* Only remove perl io dispatchers from here. */
    owl_select_remove_io_dispatch(d);
    return 0;
  }
  return 1;
}

int owl_select_aim_hack(fd_set *rfds, fd_set *wfds)
{
  aim_conn_t *cur;
  aim_session_t *sess;
  int max_fd;

  max_fd = 0;
  sess = owl_global_get_aimsess(&g);
  for (cur = sess->connlist, max_fd = 0; cur; cur = cur->next) {
    if (cur->fd != -1) {
      FD_SET(cur->fd, rfds);
      if (cur->status & AIM_CONN_STATUS_INPROGRESS) {
        /* Yes, we're checking writable sockets here. Without it, AIM
           login is really slow. */
        FD_SET(cur->fd, wfds);
      }
      
      if (cur->fd > max_fd)
        max_fd = cur->fd;
    }
  }
  return max_fd;
}

void owl_process_input_char(owl_input j)
{
  int ret;

  owl_global_set_lastinputtime(&g, time(NULL));
  ret = owl_keyhandler_process(owl_global_get_keyhandler(&g), j);
  if (ret!=0 && ret!=1) {
    owl_function_makemsg("Unable to handle keypress");
  }
}

void owl_select_mask_signals(sigset_t *oldmask) {
  sigset_t set;

  sigemptyset(&set);
  sigaddset(&set, SIGINT);
  sigprocmask(SIG_BLOCK, &set, oldmask);
}

void owl_select_handle_intr(sigset_t *restore)
{
  owl_input in;

  owl_global_unset_interrupted(&g);

  sigprocmask(SIG_SETMASK, restore, NULL);

  in.ch = in.uch = owl_global_get_startup_tio(&g)->c_cc[VINTR];
  owl_process_input_char(in);
}

owl_ps_action *owl_select_add_pre_select_action(int (*cb)(owl_ps_action *, void *), void (*destroy)(owl_ps_action *), void *data)
{
  owl_ps_action *a = owl_malloc(sizeof(owl_ps_action));
  owl_list *psa_list = owl_global_get_psa_list(&g);
  a->needs_gc = 0;
  a->callback = cb;
  a->destroy = destroy;
  a->data = data;
  owl_list_append_element(psa_list, a);
  return a;
}

void owl_select_psa_gc(void)
{
  int i;
  owl_list *psa_list;
  owl_ps_action *a;

  psa_list = owl_global_get_psa_list(&g);
  for (i = owl_list_get_size(psa_list) - 1; i >= 0; i--) {
    a = owl_list_get_element(psa_list, i);
    if (a->needs_gc) {
      owl_list_remove_element(psa_list, i);
      if (a->destroy) {
        a->destroy(a);
      }
      owl_free(a);
    }
  }
}

void owl_select_remove_pre_select_action(owl_ps_action *a)
{
  a->needs_gc = 1;
  if (!psa_active)
    owl_select_psa_gc();
}

int owl_select_do_pre_select_actions(void)
{
  int i, len, ret;
  owl_list *psa_list;

  psa_active = 1;
  ret = 0;
  psa_list = owl_global_get_psa_list(&g);
  len = owl_list_get_size(psa_list);
  for (i = 0; i < len; i++) {
    owl_ps_action *a = owl_list_get_element(psa_list, i);
    if (a->callback != NULL && a->callback(a, a->data)) {
      ret = 1;
    }
  }
  psa_active = 0;
  owl_select_psa_gc();
  return ret;
}

void owl_select(void)
{
  int i, max_fd, max_fd2, aim_done, ret;
  fd_set r;
  fd_set w;
  fd_set e;
  fd_set aim_rfds, aim_wfds;
  struct timespec timeout;
  sigset_t mask;

  owl_select_process_timers(&timeout);

  owl_select_mask_signals(&mask);

  if(owl_global_is_interrupted(&g)) {
    owl_select_handle_intr(&mask);
    return;
  }
  FD_ZERO(&r);
  FD_ZERO(&w);
  FD_ZERO(&e);

  max_fd = owl_select_prepare_io_dispatch_fd_sets(&r, &w, &e);

  /* AIM HACK: 
   *
   *  The problem - I'm not sure where to hook into the owl/faim
   *  interface to keep track of when the AIM socket(s) open and
   *  close. In particular, the bosconn thing throws me off. So,
   *  rather than register particular dispatchers for AIM, I look up
   *  the relevant FDs and add them to select's watch lists, then
   *  check for them individually before moving on to the other
   *  dispatchers. --asedeno
   */
  aim_done = 1;
  FD_ZERO(&aim_rfds);
  FD_ZERO(&aim_wfds);
  if (owl_global_is_doaimevents(&g)) {
    aim_done = 0;
    max_fd2 = owl_select_aim_hack(&aim_rfds, &aim_wfds);
    if (max_fd < max_fd2) max_fd = max_fd2;
    for(i = 0; i <= max_fd2; i++) {
      if (FD_ISSET(i, &aim_rfds)) {
        FD_SET(i, &r);
        FD_SET(i, &e);
      }
      if (FD_ISSET(i, &aim_wfds)) {
        FD_SET(i, &w);
        FD_SET(i, &e);
      }
    }
  }
  /* END AIM HACK */

  if (owl_select_do_pre_select_actions()) {
    timeout.tv_sec = 0;
    timeout.tv_nsec = 0;
  }

  ret = pselect(max_fd+1, &r, &w, &e, &timeout, &mask);

  if(ret < 0 && errno == EINTR) {
    if(owl_global_is_interrupted(&g)) {
      owl_select_handle_intr(NULL);
    }
    sigprocmask(SIG_SETMASK, &mask, NULL);
    return;
  }

  sigprocmask(SIG_SETMASK, &mask, NULL);

  if(ret > 0) {
    /* AIM HACK: process all AIM events at once. */
    for(i = 0; !aim_done && i <= max_fd; i++) {
      if (FD_ISSET(i, &r) || FD_ISSET(i, &w) || FD_ISSET(i, &e)) {
        if (FD_ISSET(i, &aim_rfds) || FD_ISSET(i, &aim_wfds)) {
          owl_process_aim();
          aim_done = 1;
        }
      }
    }
    owl_select_io_dispatch(&r, &w, &e, max_fd);
  }
}