/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

#ifdef WIN32
#include "winport.h"
#include <stdlib.h>
#include <stdint.h> /* for int64_t */
#include <winsock2.h> /* must always be included before ws2tcpip.h */
#include <ws2tcpip.h> /* for SOCKET */

int pthread_mutex_lock(pthread_mutex_t* _mutex ){      
       int rc = WaitForSingleObject( *_mutex,    // handle to mutex
            INFINITE);  // no time-out interval
       return ((rc == WAIT_OBJECT_0) ? 0: rc); 
}

int pthread_mutex_unlock( pthread_mutex_t* _mutex ){   
       int rc = ReleaseMutex(*_mutex);
       return ((rc != 0)? 0: GetLastError());  
}

int pthread_mutex_init(pthread_mutex_t* _mutex, void* ignoredAttr){
       //use CreateMutex as we are using the HANDLES in pthread_cond
       *_mutex = CreateMutex( 
        NULL,              // default security attributes
        FALSE,             // initially not owned
        NULL);             // unnamed mutex    
       return ((*_mutex == NULL) ? GetLastError() : 0);
}

int pthread_mutex_destroy(pthread_mutex_t* _mutex)
{
       int rc = CloseHandle(*_mutex);
       return ((rc != 0)? 0: GetLastError());  
}

int pthread_create(pthread_t *thread, const pthread_attr_t *attr, unsigned  (__stdcall* start_routine)(void* a), void *arg)
{
   int _intThreadId; 
   (*thread).thread_handle = (HANDLE)_beginthreadex( NULL, 0, start_routine , arg, 0, (unsigned int*)&_intThreadId );
   (*thread).thread_id = _intThreadId;
   return (((*thread).thread_handle == 0 ) ? errno : 0 );         
}


int pthread_equal(pthread_t t1, pthread_t t2){
//Is there a better way to do this? GetThreadId(handle) is only supported Windows 2003 n above.
       return ((t1.thread_id == t2.thread_id) ? 1:0);              
}

pthread_t pthread_self(){
    pthread_t thread_self;
    thread_self.thread_handle = GetCurrentThread();
    thread_self.thread_id     = GetCurrentThreadId();
    return thread_self;
}

int pthread_join(pthread_t _thread, void** ignore)
{
       int rc = WaitForSingleObject( _thread.thread_handle, INFINITE );
       return ((rc == WAIT_OBJECT_0) ? 0: rc); 
}

int pthread_detach(pthread_t _thread)
{
       int rc = CloseHandle(_thread.thread_handle) ;
       return  (rc != 0) ? 0: GetLastError();
}

void pthread_mutexattr_init(pthread_mutexattr_t* ignore){}
void pthread_mutexattr_settype(pthread_mutexattr_t* ingore_attr, int ignore){}
void pthread_mutexattr_destroy(pthread_mutexattr_t* ignore_attr){}
       
int 
pthread_cond_init (pthread_cond_t *cv,
                   const pthread_condattr_t * ignore)
{
  cv->waiters_count_ = 0;
  cv->was_broadcast_ = 0;
  cv->sema_ = CreateSemaphore (NULL,       // no security
                                0,          // initially 0
                                0x7fffffff, // max count
                                NULL);      // unnamed 
  if (cv->sema_ == NULL ) 
               return GetLastError();
  InitializeCriticalSection (&cv->waiters_count_lock_);
  cv->waiters_done_ = CreateEvent (NULL,  // no security
                                   FALSE, // auto-reset
                                   FALSE, // non-signaled initially
                                   NULL); // unnamed
  return (cv->waiters_done_ == NULL) ? GetLastError() : 0;
       
}


int pthread_cond_destroy(pthread_cond_t *cond)
{
       CloseHandle( cond->sema_);
       DeleteCriticalSection(&cond->waiters_count_lock_);
       return (CloseHandle( cond->waiters_done_ ) == 0)? GetLastError(): 0 ;
}


int
pthread_cond_signal (pthread_cond_t *cv)
{
  int have_waiters;
  EnterCriticalSection (& (cv->waiters_count_lock_));
  have_waiters = cv->waiters_count_ > 0;
  LeaveCriticalSection (&cv->waiters_count_lock_);

  // If there aren't any waiters, then this is a no-op.  
  if (have_waiters){
         return (ReleaseSemaphore (cv->sema_, 1, 0) == 0 )  ? GetLastError() : 0 ;
  }else
         return 0;
}


int
pthread_cond_broadcast (pthread_cond_t *cv)
{
  // This is needed to ensure that <waiters_count_> and <was_broadcast_> are
  // consistent relative to each other.
  int have_waiters = 0;
  EnterCriticalSection (&cv->waiters_count_lock_);
  
  if (cv->waiters_count_ > 0) {
    // We are broadcasting, even if there is just one waiter...
    // Record that we are broadcasting, which helps optimize
    // <pthread_cond_wait> for the non-broadcast case.
    cv->was_broadcast_ = 1;
    have_waiters = 1;
  }

  if (have_waiters) {
    // Wake up all the waiters atomically.
    ReleaseSemaphore (cv->sema_, cv->waiters_count_, 0);

    LeaveCriticalSection (&cv->waiters_count_lock_);

    // Wait for all the awakened threads to acquire the counting
    // semaphore. 
    WaitForSingleObject (cv->waiters_done_, INFINITE);
    // This assignment is okay, even without the <waiters_count_lock_> held 
    // because no other waiter threads can wake up to access it.
    cv->was_broadcast_ = 0;
  }
  else
    LeaveCriticalSection (&cv->waiters_count_lock_);
}


int
pthread_cond_wait (pthread_cond_t *cv, 
                   pthread_mutex_t *external_mutex)
{
  int last_waiter;
  // Avoid race conditions.
  EnterCriticalSection (&cv->waiters_count_lock_);
  cv->waiters_count_++;
  LeaveCriticalSection (&cv->waiters_count_lock_);

  // This call atomically releases the mutex and waits on the
  // semaphore until <pthread_cond_signal> or <pthread_cond_broadcast>
  // are called by another thread.
  SignalObjectAndWait (*external_mutex, cv->sema_, INFINITE, FALSE);

  // Reacquire lock to avoid race conditions.
  EnterCriticalSection (&cv->waiters_count_lock_);

  // We're no longer waiting...
  cv->waiters_count_--;

  // Check to see if we're the last waiter after <pthread_cond_broadcast>.
  last_waiter = cv->was_broadcast_ && cv->waiters_count_ == 0;

  LeaveCriticalSection (&cv->waiters_count_lock_);

  // If we're the last waiter thread during this particular broadcast
  // then let all the other threads proceed.
  if (last_waiter)
    // This call atomically signals the <waiters_done_> event and waits until
    // it can acquire the <external_mutex>.  This is required to ensure fairness. 
    SignalObjectAndWait (cv->waiters_done_, *external_mutex, INFINITE, FALSE);
  else
    // Always regain the external mutex since that's the guarantee we
    // give to our callers. 
    WaitForSingleObject (*external_mutex, INFINITE);
}

int pthread_key_create(pthread_key_t *key, void (*destructor)(void *) )
{
  int result = 0;
  pthread_key_t* newkey;

  if ((newkey = (pthread_key_t*) calloc (1, sizeof (pthread_key_t))) == NULL)
    {
      result = ENOMEM;
    }
  else if ((newkey->key = TlsAlloc ()) == TLS_OUT_OF_INDEXES)
    {
      result = EAGAIN;
      free (newkey);
      newkey = NULL;
    }
  else if (destructor != NULL)
    {
      //--we have to store the function pointer for destructor, so that we can call it 
         //--to free up the user allocated storage--       
      newkey->destructor = destructor;
    }
  key = newkey;  
  return (result);     
}

int pthread_key_delete(pthread_key_t key)
{
  int rc = 0;
  LPVOID lpvData =  TlsGetValue(key.key);
  rc = TlsFree (key.key);
  rc = (rc != 0 ) ? 0 : GetLastError();
  if (key.destructor != NULL && lpvData != 0){
       key.destructor(lpvData);         //we take control of calling destructor, instead of calling it on thread exit.
  }
  free (&key);
  return (rc);
}

void *pthread_getspecific(pthread_key_t key)
{
       LPVOID lpvData =  TlsGetValue(key.key);
       if ((lpvData == 0) && (GetLastError() != ERROR_SUCCESS)) 
               return NULL;
       else 
               return lpvData;
}

int pthread_setspecific(pthread_key_t key, const void *value)
{
       int rc = TlsSetValue (key.key, value);
       return ((rc != 0 ) ? 0 : GetLastError());
}

int gettimeofday(struct timeval *tp, void *tzp) {
        int64_t now = 0;
        if (tzp != 0) { errno = EINVAL; return -1; }
        GetSystemTimeAsFileTime( (LPFILETIME)&now );
        tp->tv_sec = (long)(now / 10000000 - 11644473600LL);
        tp->tv_usec = (now / 10) % 1000000;
        return 0;
}

int close(SOCKET fd) {
        return closesocket(fd);
}

int Win32WSAStartup()
{
       WORD    wVersionRq;
       WSADATA wsaData;
       int             err;

       wVersionRq = MAKEWORD(2,0);
       err = WSAStartup(wVersionRq, &wsaData);
       if (err != 0)
               return 1;
       
       // confirm the version information
       if ((LOBYTE(wsaData.wVersion) != 2) ||
           (HIBYTE(wsaData.wVersion) != 0))
       {
               Win32WSACleanup();              
               return 1;
       }
       return 0;
}

void Win32WSACleanup()
{
       WSACleanup();
}

double drand48(void)
{
    return (double)(rand()) / RAND_MAX;
}

#endif //WIN32