/* Copyright  (C) 2010-2020 The RetroArch team
 *
 * ---------------------------------------------------------------------------------------
 * The following license statement only applies to this file (gx_pthread.h).
 * ---------------------------------------------------------------------------------------
 *
 * Permission is hereby granted, free of charge,
 * to any person obtaining a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef _CTR_PTHREAD_WRAP_CTR_
#define _CTR_PTHREAD_WRAP_CTR_

#include <3ds/thread.h>
#include <3ds/synchronization.h>
#include <3ds/svc.h>
#include <time.h>
#include <errno.h>
#include <retro_inline.h>

#define STACKSIZE (32 * 1024)

#ifndef PTHREAD_SCOPE_PROCESS
/* An earlier version of devkitARM does not define the pthread types. Can remove in r54+. */

typedef Thread     pthread_t;
typedef LightLock  pthread_mutex_t;
typedef void*      pthread_mutexattr_t;
typedef int        pthread_attr_t;
typedef uint32_t   pthread_cond_t;
typedef int        pthread_condattr_t;
#endif

typedef struct {
   uint32_t semaphore;
   LightLock lock;
   uint32_t waiting;
} cond_t;

/* libctru threads return void but pthreads return void pointer */
static bool mutex_inited = false;
static LightLock safe_double_thread_launch;
static void *(*start_routine_jump)(void*);

static void ctr_thread_launcher(void* data)
{
	void *(*start_routine_jump_safe)(void*) = start_routine_jump;
	LightLock_Unlock(&safe_double_thread_launch);
	start_routine_jump_safe(data);
}

static INLINE int pthread_create(pthread_t *thread,
      const pthread_attr_t *attr, void *(*start_routine)(void*), void *arg)
{
   s32 prio = 0;
   Thread new_ctr_thread;
   int procnum = -2; // use default cpu
   bool isNew3DS;

   APT_CheckNew3DS(&isNew3DS);

   if (isNew3DS)
      procnum = 2;

   if (!mutex_inited)
   {
      LightLock_Init(&safe_double_thread_launch);
      mutex_inited = true;
   }

   /*Must wait if attempting to launch 2 threads at once to prevent corruption of function pointer*/
   while (LightLock_TryLock(&safe_double_thread_launch) != 0);

   svcGetThreadPriority(&prio, CUR_THREAD_HANDLE);

   start_routine_jump = start_routine;
   new_ctr_thread     = threadCreate(ctr_thread_launcher, arg, STACKSIZE, prio - 1, procnum, false);

   if (!new_ctr_thread)
   {
      LightLock_Unlock(&safe_double_thread_launch);
      return EAGAIN;
   }

   *thread = (pthread_t)new_ctr_thread;
   return 0;
}

static INLINE pthread_t pthread_self(void)
{
   return (pthread_t)threadGetCurrent();
}

static INLINE int pthread_mutex_init(pthread_mutex_t *mutex,
      const pthread_mutexattr_t *attr)
{
   LightLock_Init((LightLock *)mutex);
   return 0;
}

static INLINE int pthread_mutex_destroy(pthread_mutex_t *mutex)
{
   /*Nothing to destroy*/
   return 0;
}

static INLINE int pthread_mutex_lock(pthread_mutex_t *mutex)
{
   LightLock_Lock((LightLock *)mutex);
   return 0;
}

static INLINE int pthread_mutex_unlock(pthread_mutex_t *mutex)
{
   LightLock_Unlock((LightLock *)mutex);
   return 0;
}

static INLINE void pthread_exit(void *retval)
{
   /*Yes the pointer to int cast is not ideal*/
   /*threadExit((int)retval);*/
   (void)retval;

   threadExit(0);
}

static INLINE int pthread_detach(pthread_t thread)
{
   /* FIXME: pthread_detach equivalent missing? */
   (void)thread;
   return 0;
}

static INLINE int pthread_join(pthread_t thread, void **retval)
{
   /*retval is ignored*/
   if(threadJoin((Thread)thread, INT64_MAX))
      return -1;

   threadFree((Thread)thread);

   return 0;
}

static INLINE int pthread_mutex_trylock(pthread_mutex_t *mutex)
{
   return LightLock_TryLock((LightLock *)mutex);
}

static INLINE int pthread_cond_wait(pthread_cond_t *cond,
      pthread_mutex_t *mutex)
{
   cond_t *cond_data = (cond_t *)*cond;
   LightLock_Lock(&cond_data->lock);
   cond_data->waiting++;
   LightLock_Unlock(mutex);
   LightLock_Unlock(&cond_data->lock);
   svcWaitSynchronization(cond_data->semaphore, INT64_MAX);
   LightLock_Lock(mutex);
   return 0;
}

static INLINE int pthread_cond_timedwait(pthread_cond_t *cond,
      pthread_mutex_t *mutex, const struct timespec *abstime)
{
   struct timespec now = {0};
   /* Missing clock_gettime*/
   struct timeval tm;
   int retval = 0;

   cond_t *cond_data = (cond_t *)*cond;
   LightLock_Lock(&cond_data->lock);
   cond_data->waiting++;

   gettimeofday(&tm, NULL);
   now.tv_sec = tm.tv_sec;
   now.tv_nsec = tm.tv_usec * 1000;
   s64 timeout = (abstime->tv_sec - now.tv_sec) * 1000000000 + (abstime->tv_nsec - now.tv_nsec);

   if (timeout >= 0) {
      LightLock_Unlock(mutex);
      LightLock_Unlock(&cond_data->lock);
      if (svcWaitSynchronization(cond_data->semaphore, timeout))
         retval = ETIMEDOUT;

      LightLock_Lock(mutex);
   } else {
      retval = ETIMEDOUT;
   }

   return retval;
}

static INLINE int pthread_cond_init(pthread_cond_t *cond,
      const pthread_condattr_t *attr)
{
   cond_t *cond_data = calloc(1, sizeof(cond_t));
   if (!cond_data)
      goto error;

   if (svcCreateSemaphore(&cond_data->semaphore, 0, 1))
      goto error;

   LightLock_Init(&cond_data->lock);
   cond_data->waiting = 0;
   *cond = (pthread_cond_t)cond_data;
   return 0;

 error:
   svcCloseHandle(cond_data->semaphore);
   if (cond_data)
      free(cond_data);
   return -1;
}

static INLINE int pthread_cond_signal(pthread_cond_t *cond)
{
   int32_t count;
   cond_t *cond_data = (cond_t *)*cond;
   LightLock_Lock(&cond_data->lock);
   if (cond_data->waiting) {
      cond_data->waiting--;
      LightLock_Unlock(&cond_data->lock);
      svcReleaseSemaphore(&count, cond_data->semaphore, 1);
   } else {
      LightLock_Unlock(&cond_data->lock);
   }
   return 0;
}

static INLINE int pthread_cond_broadcast(pthread_cond_t *cond)
{
   int32_t count;
   cond_t *cond_data = (cond_t *)*cond;
   LightLock_Lock(&cond_data->lock);
   while (cond_data->waiting) {
      cond_data->waiting--;
      LightLock_Unlock(&cond_data->lock);
      svcReleaseSemaphore(&count, cond_data->semaphore, 1);
      LightLock_Lock(&cond_data->lock);
   }
   LightLock_Unlock(&cond_data->lock);

   return 0;
}

static INLINE int pthread_cond_destroy(pthread_cond_t *cond)
{
   if (*cond) {
      cond_t *cond_data = (cond_t *)*cond;

      svcCloseHandle(cond_data->semaphore);
      free(cond_data);
   }
   *cond = 0;
   return 0;
}

static INLINE int pthread_equal(pthread_t t1, pthread_t t2)
{
	if (threadGetHandle((Thread)t1) == threadGetHandle((Thread)t2))
		return 1;
	return 0;
}

#endif