/*
 *
 *    Copyright (c) 2014-2017 Nest Labs, Inc.
 *    All rights reserved.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

/*
 * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/*
 * Wed Apr 17 16:05:29 EDT 2002 (James Roth)
 *
 *  - Fixed an unlikely sys_thread_new() race condition.
 *
 *  - Made current_thread() work with threads which where
 *    not created with sys_thread_new().  This includes
 *    the main thread and threads made with pthread_create().
 *
 *  - Catch overflows where more than SYS_MBOX_SIZE messages
 *    are waiting to be read.  The sys_mbox_post() routine
 *    will block until there is more room instead of just
 *    leaking messages.
 */
#include "lwip/debug.h"

#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

#include "lwip/sys.h"
#include "lwip/opt.h"
#include "lwip/stats.h"

#define UMAX(a, b)      ((a) > (b) ? (a) : (b))

static struct timeval starttime;

#if !NO_SYS

static struct sys_thread *threads = NULL;
static pthread_mutex_t threads_mutex = PTHREAD_MUTEX_INITIALIZER;

struct sys_mbox_msg {
  struct sys_mbox_msg *next;
  void *msg;
};

#define SYS_MBOX_SIZE 128

struct sys_mbox {
  int first, last;
  void *msgs[SYS_MBOX_SIZE];
  struct sys_sem *not_empty;
  struct sys_sem *not_full;
  struct sys_sem *mutex;
  int wait_send;
};

struct sys_sem {
  unsigned int c;
  pthread_cond_t cond;
  pthread_mutex_t mutex;
};

struct sys_thread {
  struct sys_thread *next;
  pthread_t pthread;
};

#if SYS_LIGHTWEIGHT_PROT
static pthread_mutex_t lwprot_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_t lwprot_thread = (pthread_t)0xDEAD;
static int lwprot_count = 0;
#endif /* SYS_LIGHTWEIGHT_PROT */

static struct sys_sem *sys_sem_new_internal(u8_t count);
static void sys_sem_free_internal(struct sys_sem *sem);

static u32_t cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex,
                       u32_t timeout);

/*-----------------------------------------------------------------------------------*/
static struct sys_thread * 
introduce_thread(pthread_t id)
{
  struct sys_thread *thread;

  thread = (struct sys_thread *)malloc(sizeof(struct sys_thread));

  if (thread != NULL) {
    pthread_mutex_lock(&threads_mutex);
    thread->next = threads;
    thread->pthread = id;
    threads = thread;
    pthread_mutex_unlock(&threads_mutex);
  }

  return thread;
}
/*-----------------------------------------------------------------------------------*/
static void 
finish_thread(struct sys_thread *thread)
{
  struct sys_thread *cursor;
  struct sys_thread *previous;

  if (thread != NULL) {
    pthread_mutex_lock(&threads_mutex);

    previous = NULL;
    cursor = threads;
    while (cursor != NULL) {
      if (cursor == thread) {
        if (previous != NULL) {
          previous->next = cursor->next;
        } else {
          threads = cursor->next;
        }
        cursor->next = NULL;
        cursor->pthread = 0;
        break;
      }
      previous = cursor;
      cursor = cursor->next;
    }

    pthread_mutex_unlock(&threads_mutex);
    free(thread);
  }
}
/*-----------------------------------------------------------------------------------*/
sys_thread_t
sys_thread_new(const char *name, lwip_thread_fn function, void *arg, int stacksize, int prio)
{
  int code;
  pthread_t tmp;
  struct sys_thread *st = NULL;
  LWIP_UNUSED_ARG(name);
  LWIP_UNUSED_ARG(stacksize);
  LWIP_UNUSED_ARG(prio);

  code = pthread_create(&tmp,
                        NULL, 
                        (void *(*)(void *)) 
                        function, 
                        arg);
  
  if (0 == code) {
    st = introduce_thread(tmp);
  }
  
  if (NULL == st) {
    LWIP_DEBUGF(SYS_DEBUG, ("sys_thread_new: pthread_create %d, st = 0x%lx",
                       code, (unsigned long)st));
    abort();
  }
  return st;
}
/*-----------------------------------------------------------------------------------*/
err_t sys_thread_finish(sys_thread_t t)
{
    int code;

    code = pthread_join(t->pthread, NULL);
    if (0 == code) {
      finish_thread(t);
      return ERR_OK;
    }
    else {
      return ERR_VAL;
    }
}
/*-----------------------------------------------------------------------------------*/
err_t sys_mbox_new_extra(void *pool, struct sys_mbox **mb, int size) {
    return sys_mbox_new(mb, size);
}

err_t
sys_mbox_new(struct sys_mbox **mb, int size)
{
  struct sys_mbox *mbox;
  LWIP_UNUSED_ARG(size);

  mbox = (struct sys_mbox *)malloc(sizeof(struct sys_mbox));
  if (mbox == NULL) {
    return ERR_MEM;
  }
  mbox->first = mbox->last = 0;
  mbox->not_empty = sys_sem_new_internal(0);
  mbox->not_full = sys_sem_new_internal(0);
  mbox->mutex = sys_sem_new_internal(1);
  mbox->wait_send = 0;

  SYS_STATS_INC_USED(mbox);
  *mb = mbox;
  return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/
void
sys_mbox_free(struct sys_mbox **mb)
{
  if ((mb != NULL) && (*mb != SYS_MBOX_NULL)) {
    struct sys_mbox *mbox = *mb;
    SYS_STATS_DEC(mbox.used);
    sys_arch_sem_wait(&mbox->mutex, 0);
    
    sys_sem_free_internal(mbox->not_empty);
    sys_sem_free_internal(mbox->not_full);
    sys_sem_free_internal(mbox->mutex);
    mbox->not_empty = mbox->not_full = mbox->mutex = NULL;
    /*  LWIP_DEBUGF("sys_mbox_free: mbox 0x%lx\n", mbox); */
    free(mbox);
  }
}
/*-----------------------------------------------------------------------------------*/
err_t
sys_mbox_trypost(struct sys_mbox **mb, void *msg)
{
  u8_t first;
  struct sys_mbox *mbox;
  LWIP_ASSERT("invalid mbox", (mb != NULL) && (*mb != NULL));
  mbox = *mb;

  sys_arch_sem_wait(&mbox->mutex, 0);

  LWIP_DEBUGF(SYS_DEBUG, ("sys_mbox_trypost: mbox %p msg %p\n",
                          (void *)mbox, (void *)msg));

  if ((mbox->last + 1) >= (mbox->first + SYS_MBOX_SIZE)) {
    sys_sem_signal(&mbox->mutex);
    return ERR_MEM;
  }

  mbox->msgs[mbox->last % SYS_MBOX_SIZE] = msg;

  if (mbox->last == mbox->first) {
    first = 1;
  } else {
    first = 0;
  }

  mbox->last++;

  if (first) {
    sys_sem_signal(&mbox->not_empty);
  }

  sys_sem_signal(&mbox->mutex);

  return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/
void
sys_mbox_post(struct sys_mbox **mb, void *msg)
{
  u8_t first;
  struct sys_mbox *mbox;
  LWIP_ASSERT("invalid mbox", (mb != NULL) && (*mb != NULL));
  mbox = *mb;

  sys_arch_sem_wait(&mbox->mutex, 0);

  LWIP_DEBUGF(SYS_DEBUG, ("sys_mbox_post: mbox %p msg %p\n", (void *)mbox, (void *)msg));

  while ((mbox->last + 1) >= (mbox->first + SYS_MBOX_SIZE)) {
    mbox->wait_send++;
    sys_sem_signal(&mbox->mutex);
    sys_arch_sem_wait(&mbox->not_full, 0);
    sys_arch_sem_wait(&mbox->mutex, 0);
    mbox->wait_send--;
  }

  mbox->msgs[mbox->last % SYS_MBOX_SIZE] = msg;

  if (mbox->last == mbox->first) {
    first = 1;
  } else {
    first = 0;
  }

  mbox->last++;

  if (first) {
    sys_sem_signal(&mbox->not_empty);
  }

  sys_sem_signal(&mbox->mutex);
}
/*-----------------------------------------------------------------------------------*/
u32_t
sys_arch_mbox_tryfetch(struct sys_mbox **mb, void **msg)
{
  struct sys_mbox *mbox;
  LWIP_ASSERT("invalid mbox", (mb != NULL) && (*mb != NULL));
  mbox = *mb;

  sys_arch_sem_wait(&mbox->mutex, 0);

  if (mbox->first == mbox->last) {
    sys_sem_signal(&mbox->mutex);
    return SYS_MBOX_EMPTY;
  }

  if (msg != NULL) {
    LWIP_DEBUGF(SYS_DEBUG, ("sys_mbox_tryfetch: mbox %p msg %p\n", (void *)mbox, *msg));
    *msg = mbox->msgs[mbox->first % SYS_MBOX_SIZE];
  }
  else{
    LWIP_DEBUGF(SYS_DEBUG, ("sys_mbox_tryfetch: mbox %p, null msg\n", (void *)mbox));
  }

  mbox->first++;

  if (mbox->wait_send) {
    sys_sem_signal(&mbox->not_full);
  }

  sys_sem_signal(&mbox->mutex);

  return 0;
}
/*-----------------------------------------------------------------------------------*/
u32_t
sys_arch_mbox_fetch(struct sys_mbox **mb, void **msg, u32_t timeout)
{
  u32_t time_needed = 0;
  struct sys_mbox *mbox;
  LWIP_ASSERT("invalid mbox", (mb != NULL) && (*mb != NULL));
  mbox = *mb;

  /* The mutex lock is quick so we don't bother with the timeout
     stuff here. */
  sys_arch_sem_wait(&mbox->mutex, 0);

  while (mbox->first == mbox->last) {
    sys_sem_signal(&mbox->mutex);

    /* We block while waiting for a mail to arrive in the mailbox. We
       must be prepared to timeout. */
    if (timeout != 0) {
      time_needed = sys_arch_sem_wait(&mbox->not_empty, timeout);

      if (time_needed == SYS_ARCH_TIMEOUT) {
        return SYS_ARCH_TIMEOUT;
      }
    } else {
      sys_arch_sem_wait(&mbox->not_empty, 0);
    }

    sys_arch_sem_wait(&mbox->mutex, 0);
  }

  if (msg != NULL) {
    LWIP_DEBUGF(SYS_DEBUG, ("sys_mbox_fetch: mbox %p msg %p\n", (void *)mbox, *msg));
    *msg = mbox->msgs[mbox->first % SYS_MBOX_SIZE];
  }
  else{
    LWIP_DEBUGF(SYS_DEBUG, ("sys_mbox_fetch: mbox %p, null msg\n", (void *)mbox));
  }

  mbox->first++;

  if (mbox->wait_send) {
    sys_sem_signal(&mbox->not_full);
  }

  sys_sem_signal(&mbox->mutex);

  return time_needed;
}
/*-----------------------------------------------------------------------------------*/
static struct sys_sem *
sys_sem_new_internal(u8_t count)
{
  struct sys_sem *sem;

  sem = (struct sys_sem *)malloc(sizeof(struct sys_sem));
  if (sem != NULL) {
    sem->c = count;
    pthread_cond_init(&(sem->cond), NULL);
    pthread_mutex_init(&(sem->mutex), NULL);
  }
  return sem;
}
/*-----------------------------------------------------------------------------------*/
err_t
sys_sem_new(struct sys_sem **sem, u8_t count)
{
  SYS_STATS_INC_USED(sem);
  *sem = sys_sem_new_internal(count);
  if (*sem == NULL) {
    return ERR_MEM;
  }
  return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/
static u32_t
cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex, u32_t timeout)
{
  time_t tdiff;
  time_t sec, usec;
  struct timeval rtime1, rtime2;
  struct timespec ts;
  int retval;

  if (timeout > 0) {
    /* Get a timestamp and add the timeout value. */
    gettimeofday(&rtime1, NULL);
    sec = rtime1.tv_sec;
    usec = rtime1.tv_usec;
    usec += timeout % 1000 * 1000;
    sec += (int)(timeout / 1000) + (int)(usec / 1000000);
    usec = usec % 1000000;
    ts.tv_nsec = usec * 1000;
    ts.tv_sec = sec;

    retval = pthread_cond_timedwait(cond, mutex, &ts);

    if (retval == ETIMEDOUT) {
      return SYS_ARCH_TIMEOUT;
    } else {
      /* Calculate for how long we waited for the cond. */
      gettimeofday(&rtime2, NULL);
      tdiff = (rtime2.tv_sec - rtime1.tv_sec) * 1000 +
        (rtime2.tv_usec - rtime1.tv_usec) / 1000;

      if (tdiff <= 0) {
        return 0;
      }
      return (u32_t)tdiff;
    }
  } else {
    pthread_cond_wait(cond, mutex);
    return 0;
  }
}
/*-----------------------------------------------------------------------------------*/
u32_t
sys_arch_sem_wait(struct sys_sem **s, u32_t timeout)
{
  u32_t time_needed = 0;
  struct sys_sem *sem;
  LWIP_ASSERT("invalid sem", (s != NULL) && (*s != NULL));
  sem = *s;

  pthread_mutex_lock(&(sem->mutex));
  while (sem->c <= 0) {
    if (timeout > 0) {
      time_needed = cond_wait(&(sem->cond), &(sem->mutex), timeout);

      if (time_needed == SYS_ARCH_TIMEOUT) {
        pthread_mutex_unlock(&(sem->mutex));
        return SYS_ARCH_TIMEOUT;
      }
      /*      pthread_mutex_unlock(&(sem->mutex));
              return time_needed; */
    } else {
      cond_wait(&(sem->cond), &(sem->mutex), 0);
    }
  }
  sem->c--;
  pthread_mutex_unlock(&(sem->mutex));
  return (u32_t)time_needed;
}
/*-----------------------------------------------------------------------------------*/
void
sys_sem_signal(struct sys_sem **s)
{
  struct sys_sem *sem;
  LWIP_ASSERT("invalid sem", (s != NULL) && (*s != NULL));
  sem = *s;

  pthread_mutex_lock(&(sem->mutex));
  sem->c++;

  if (sem->c > 1) {
    sem->c = 1;
  }

  pthread_cond_broadcast(&(sem->cond));
  pthread_mutex_unlock(&(sem->mutex));
}
/*-----------------------------------------------------------------------------------*/
static void
sys_sem_free_internal(struct sys_sem *sem)
{
  pthread_cond_destroy(&(sem->cond));
  pthread_mutex_destroy(&(sem->mutex));
  free(sem);
}
/*-----------------------------------------------------------------------------------*/
void
sys_sem_free(struct sys_sem **sem)
{
  if ((sem != NULL) && (*sem != SYS_SEM_NULL)) {
    SYS_STATS_DEC(sem.used);
    sys_sem_free_internal(*sem);
  }
}
#endif /* !NO_SYS */
/*-----------------------------------------------------------------------------------*/
u32_t
sys_now(void)
{
  struct timeval tv;
  u32_t msec;
  gettimeofday(&tv, NULL);

  msec = (u32_t)((tv.tv_sec - starttime.tv_sec) * 1000 + (tv.tv_usec - starttime.tv_usec) / 1000);

  return msec;
}
/*-----------------------------------------------------------------------------------*/
void
sys_init(void)
{
  gettimeofday(&starttime, NULL);
}
/*-----------------------------------------------------------------------------------*/
#if SYS_LIGHTWEIGHT_PROT
/** sys_prot_t sys_arch_protect(void)

This optional function does a "fast" critical region protection and returns
the previous protection level. This function is only called during very short
critical regions. An embedded system which supports ISR-based drivers might
want to implement this function by disabling interrupts. Task-based systems
might want to implement this by using a mutex or disabling tasking. This
function should support recursive calls from the same task or interrupt. In
other words, sys_arch_protect() could be called while already protected. In
that case the return value indicates that it is already protected.

sys_arch_protect() is only required if your port is supporting an operating
system.
*/
sys_prot_t
sys_arch_protect(void)
{
    /* Note that for the UNIX port, we are using a lightweight mutex, and our
     * own counter (which is locked by the mutex). The return code is not actually
     * used. */
    if (lwprot_thread != pthread_self())
    {
        /* We are locking the mutex where it has not been locked before *
        * or is being locked by another thread */
        pthread_mutex_lock(&lwprot_mutex);
        lwprot_thread = pthread_self();
        lwprot_count = 1;
    }
    else
        /* It is already locked by THIS thread */
        lwprot_count++;
    return 0;
}
/*-----------------------------------------------------------------------------------*/

/** void sys_arch_unprotect(sys_prot_t pval)

This optional function does a "fast" set of critical region protection to the
value specified by pval. See the documentation for sys_arch_protect() for
more information. This function is only required if your port is supporting
an operating system.
*/
void
sys_arch_unprotect(sys_prot_t pval)
{
    LWIP_UNUSED_ARG(pval);
    if (lwprot_thread == pthread_self())
    {
        if (--lwprot_count == 0)
        {
            lwprot_thread = (pthread_t) 0xDEAD;
            pthread_mutex_unlock(&lwprot_mutex);
        }
    }
}
#endif /* SYS_LIGHTWEIGHT_PROT */

/*-----------------------------------------------------------------------------------*/

#ifndef MAX_JIFFY_OFFSET
#define MAX_JIFFY_OFFSET ((~0U >> 1)-1)
#endif

#ifndef HZ
#define HZ 100
#endif

u32_t
sys_jiffies(void)
{
    struct timeval tv;
    unsigned long sec;
    long usec;

    gettimeofday(&tv,NULL);
    sec = tv.tv_sec - starttime.tv_sec;
    usec = tv.tv_usec;

    if (sec >= (MAX_JIFFY_OFFSET / HZ))
      return MAX_JIFFY_OFFSET;
    usec += 1000000L / HZ - 1;
    usec /= 1000000L / HZ;
    return HZ * sec + usec;
}

#if PPP_DEBUG

#include <stdarg.h>

void ppp_trace(int level, const char *format, ...)
{
    va_list args;

    (void)level;
    va_start(args, format);
    vprintf(format, args);
    va_end(args);
}
#endif

#if LWIP_DEBUG

unsigned char gLwIP_DebugFlags = 0;


#endif