#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include <stddef.h>

#include "EVAPI.h"
#include "xthread.h"

/* our userdata */
typedef struct {
  mutex_t lock; /* global loop lock */
  void (*signal_func) (void *signal_arg, int value);
  void *signal_arg;
  ev_async async_w;
  thread_t tid;

  cond_t invoke_cv;
  mutex_t invoke_mutex;

  SV *interrupt;
} udat;

static void
c_func (pTHX_ void *loop_, int value)
{
  struct ev_loop *loop = (struct ev_loop *)loop_;
  udat *u = ev_userdata (EV_A);
  X_LOCK (u->lock);
  ev_invoke_pending (loop);
  X_UNLOCK (u->lock);
  X_COND_SIGNAL (u->invoke_cv);
}

static void
async_cb (EV_P_ ev_async *w, int revents)
{
  /* just used for the side effects */
}

static void
l_release (EV_P)
{
  udat *u = ev_userdata (EV_A);
  X_UNLOCK (u->lock);
}

static void
l_acquire (EV_P)
{
  udat *u = ev_userdata (EV_A);
  X_LOCK (u->lock);
}

static void
l_invoke (EV_P)
{
  udat *u = ev_userdata (EV_A);
  X_UNLOCK (u->lock);
  u->signal_func (u->signal_arg, 1);
  X_COND_WAIT (u->invoke_cv, u->invoke_mutex);
  X_LOCK (u->lock);
}

X_THREAD_PROC(l_run)
{
  struct ev_loop *loop = (struct ev_loop *)thr_arg;
  udat *u = ev_userdata (loop);

  X_LOCK (u->invoke_mutex);
  X_LOCK (u->lock);
  ev_ref (loop); /* really? */
  for (;;) /* really? */
    ev_loop (loop, 0);
  X_UNLOCK (u->lock);
}

static void
scope_lock_cb (pTHX_ void *loop_)
{
  struct ev_loop *loop = (struct ev_loop *)SvIVX ((SV *)loop_);
  udat *u = ev_userdata (loop);

  X_UNLOCK (u->lock);
  SvREFCNT_dec ((SV *)loop_);
}

MODULE = EV::Loop::Async                PACKAGE = EV::Loop::Async

PROTOTYPES: ENABLE

BOOT:
{
	I_EV_API ("EV::Loop::Async");
        CvNODEBUG_on (get_cv ("EV::Loop::Async::scope_lock", 0)); /* otherwise calling scope can be the debugger */
}

void
_c_func (SV *loop)
	PPCODE:
        EXTEND (SP, 2);
        PUSHs (sv_2mortal (newSViv (PTR2IV (c_func))));
        PUSHs (sv_2mortal (newSViv (SvIVX (SvRV (loop)))));

void
_attach (SV *loop_, SV *interrupt, IV sig_func, void *sig_arg)
	CODE:
{
  	pthread_mutexattr_t ma;
	struct ev_loop *loop = (struct ev_loop *)SvIVX (SvRV (loop_));
  	udat *u;

        Newz (0, u, 1, udat);
        u->interrupt   = newSVsv (interrupt);
        u->signal_func = (void (*)(void *, int))sig_func;
        u->signal_arg  = sig_arg;

        ev_async_init (&u->async_w, async_cb);
        ev_async_start (loop, &u->async_w);

        pthread_mutexattr_init (&ma);
        pthread_mutexattr_settype (&ma, PTHREAD_MUTEX_RECURSIVE);
        pthread_mutex_init (&u->lock, &ma);
        pthread_mutex_init (&u->invoke_mutex, &ma);
        pthread_mutexattr_destroy (&ma);

        pthread_cond_init (&u->invoke_cv, 0);

        ev_set_userdata (loop, u);
        ev_set_invoke_pending_cb (loop, l_invoke);
        ev_set_loop_release_cb (loop, l_release, l_acquire);

        pthread_create (&u->tid, 0, l_run, loop);
}

SV *
interrupt (SV *loop_)
	CODE:
{
	struct ev_loop *loop = (struct ev_loop *)SvIVX (SvRV (loop_));
  	udat *u = ev_userdata (loop);

        RETVAL = newSVsv (u->interrupt);
}
	OUTPUT:
        RETVAL

void
lock (SV *loop_)
	ALIAS:
        lock   = 0
        unlock = 1
        notify = 2
	CODE:
{
	struct ev_loop *loop = (struct ev_loop *)SvIVX (SvRV (loop_));
  	udat *u = ev_userdata (loop);

        switch (ix)
          {
            case 0: X_LOCK   (u->lock); break;
            case 1: X_UNLOCK (u->lock); break;
            case 2: ev_async_send (loop, &u->async_w); break;
          }
}

void
scope_lock (SV *loop_)
	CODE:
{
	struct ev_loop *loop = (struct ev_loop *)SvIVX (SvRV (loop_));
  	udat *u = ev_userdata (loop);

        X_LOCK (u->lock);

        LEAVE; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
        SAVEDESTRUCTOR_X (scope_lock_cb, (void *)SvREFCNT_inc (SvRV (loop_)));
        ENTER; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
}

void
DESTROY (SV *loop_)
	CODE:
{
	struct ev_loop *loop = (struct ev_loop *)SvIVX (SvRV (loop_));
  	udat *u = ev_userdata (loop);

        if (u)
          {
            pthread_cancel (u->tid);
            ev_async_send (loop, &u->async_w);
            pthread_join (u->tid, 0);
            X_LOCK (u->lock);
            ev_async_stop (loop, &u->async_w);
            pthread_mutex_destroy (&u->lock);
            pthread_cond_destroy (&u->invoke_cv);
            pthread_mutex_destroy (&u->invoke_mutex); /* TODO: locked by another thread... */
            SvREFCNT_dec (u->interrupt);
            Safefree (u);
          }
}