#include "toisegment.h"

/*******************************/
/******* BufferSegment *********/
/*******************************/

TOISegmented::BufferSegment::BufferSegment(int sz) {
  status     = NEW;
  bufferSize = sz;
  sn0        = -1;

  refcount   = 0;

  data       = new double[sz];
  flags     = new uint_8[sz];

  pthread_mutex_init(&refcount_mutex, NULL);
}

TOISegmented::BufferSegment::~BufferSegment() {
  if (refcount > 0) {
    throw(ForbiddenError("TOISegment : delete Buffer with refcount>0"));
  }
  delete[] data;
  delete[] flags;
  pthread_mutex_destroy(&refcount_mutex);
}

void TOISegmented::BufferSegment::putData(int sn, double d, uint_8 f) {
  if (status == NEW) {
    status = WRITE;
    sn0 = sn;
  }
  if (status == COMMITTED) {
    throw(ForbiddenError("TOISegment : putData in committed buffer"));
  }
  checkInRange(sn);
  data[sn-sn0] = d;
  flags[sn-sn0] = f;
}

void TOISegmented::BufferSegment::incRefCount() {
  pthread_mutex_lock(&refcount_mutex);
  refcount++;
  pthread_mutex_unlock(&refcount_mutex);
}

void TOISegmented::BufferSegment::decRefCount() {
  pthread_mutex_lock(&refcount_mutex);
  int nrc = --refcount;
  pthread_mutex_unlock(&refcount_mutex);
  if (nrc<0)
    throw(ForbiddenError("TOISegment : buffer refcount < 0"));
}

int TOISegmented::BufferSegment::getRefCount() {
  pthread_mutex_lock(&refcount_mutex);
  int rc = refcount;
  pthread_mutex_unlock(&refcount_mutex);
  return rc;
}


/*******************************/
/********** BufferView *********/
/*******************************/

TOISegmented::BufferView::BufferView(MasterView* m) {
  master = m;
  sn0 = -1;
  segmentSize = m->segmentSize;
  pthread_mutex_init(&mutex, NULL);
  pthread_cond_init(&condv, NULL);
}

TOISegmented::BufferView::~BufferView() {
  pthread_mutex_destroy(&mutex);
  pthread_cond_destroy(&condv);
}

double TOISegmented::BufferView::getData(int sn) { /* Single-thread */
  ensure(sn);
  int seg = (sn-sn0)/segmentSize;
  return segments[seg]->getData(sn);
}

uint_8 TOISegmented::BufferView::getFlag(int sn) { /* Single-thread */
  ensure(sn);
  int seg = (sn-sn0)/segmentSize;
  return segments[seg]->getFlag(sn);
}

void  TOISegmented::BufferView::ensure(int sn) { /* Single-thread */
  if (sn < sn0) {
    throw RangeCheckError("requested sample before first");
  }

  if (sn >= sn0 + segmentSize*segments.size()) {
    cout << "BufferView : read fault for " << sn << endl;
    sync();
    while (sn >= sn0 + segmentSize*segments.size()) {
      wait();
      cout << "BufferView : waiting for " << sn << endl;
      sync();
    }
    cout << "BufferView : resuming for " << sn << endl;    
  }
}

void TOISegmented::BufferView::sync() { /* Single-thread */
  master->updateView(this); // update me !
}

void TOISegmented::BufferView::wait() { /* From reader thread */
  pthread_mutex_lock(&mutex);
  master->addToWaitList(this); // needing wake-up call
  pthread_cond_wait(&condv, &mutex);
  pthread_mutex_unlock(&mutex);
}

void TOISegmented::BufferView::signal() { /* From masterview, writer thread */
  pthread_mutex_lock(&mutex);
  pthread_cond_signal(&condv); // only one thread can be sleeping
  master->removeFromWaitList(this);
  pthread_mutex_unlock(&mutex);  
}


/*******************************/
/********** MasterView *********/
/*******************************/

TOISegmented::MasterView::MasterView(int bufsz, int maxseg) {
  currentSegment = NULL;
  maxSegments    = maxseg;
  segmentSize    = bufsz;
  sn0            = -1;
  
  pthread_mutex_init(&views_mutex, NULL);
  pthread_mutex_init(&write_mutex, NULL);
  pthread_cond_init(&condv, NULL);
  pthread_key_create(&buffer_key, BufferDestroy);

  waitStatus = NO_WAIT;
}

TOISegmented::MasterView::~MasterView() {
  pthread_mutex_destroy(&views_mutex);
  pthread_mutex_destroy(&write_mutex);
  pthread_cond_destroy(&condv);
  pthread_key_delete(buffer_key);

  // There should not be any BufferView left... Check ?
  
  // decrement count for segments ?
}

void TOISegmented::MasterView::putData(int sn, double data, uint_8 flags) {
  // can fit in current segment ?
  if (!(currentSegment != NULL &&
	sn >= currentSegment->sn0 &&
	sn < currentSegment->sn0 + currentSegment->bufferSize)) {
    nextSegment();
  }
  currentSegment->putData(sn, data, flags);
}

double TOISegmented::MasterView::getData(int sn) {
  return getView()->getData(sn);
}

uint_8 TOISegmented::MasterView::getFlag(int sn) {
  return getView()->getFlag(sn);
}

void TOISegmented::MasterView::addToWaitList(BufferView* bv) { /* reader thread */
  // A view needs to wait for new data.

  // There is a possible deadlock if no view can free old segments
  // and we are waiting for write.

  // we need to record "wont need before" for each view, and 
  // signal deadlock if any view that needs first segment data is sleeping
  // while we are asleep

  pthread_mutex_lock(&views_mutex);
  waitingBuffers.insert(bv);
  pthread_mutex_unlock(&views_mutex);
  checkDeadLock();
}

void TOISegmented::MasterView::removeFromWaitList(BufferView* bv) { /* reader thread */
  pthread_mutex_lock(&views_mutex);
  waitingBuffers.erase(bv);
  pthread_mutex_unlock(&views_mutex);  
}

TOISegmented::BufferView* TOISegmented::MasterView::getView() { /* reader thread */
  BufferView* bv = (BufferView*) pthread_getspecific(buffer_key);
  if (bv == NULL) {
    bv = createView();
    pthread_setspecific(buffer_key, bv);
  }
  return bv;
}