/*
  $Id$

  Copyright (C) 2007 by The Regents of the University of California

  Redistribution of this file is permitted under the terms of the 
  BSD license

  Date: 01/14/2006
  Author: Rares Vernica <rares (at) ics.uci.edu>
*/

#include "closerand.h"

CloseRand::CloseRand(const vector<string> *d, Clusters *c, ContQueryPivot *q, 
                     const unsigned samplePer, const unsigned queueSize): 
  PPDSample(d, c, q, samplePer), queueSize(queueSize)
{
  // init - sample 
  sample = Sample(max(1u, 
                      static_cast<unsigned>(static_cast<float>(samplePer) / 
                                            100 * data->size())), 
                  data->size());
 
  // init - loop
  sampleIt = sample.begin();
  buildQueue();
  unsigned j = samplePair.begin()->index;
  samplePair.erase(samplePair.begin());
  cluster = clusters->getCluster(j);
  stringIt = cluster.begin();
}

void CloseRand::step() 
{
  stringIt++;
  if (stringIt == cluster.end()) {
    queryPivot->
      insert(std::make_pair(cluster.getPivot(), 
                            QueryVect(*sampleIt, 
                                      SimVect((*data)[*sampleIt], 
                                              (*data)[cluster.getPivot()]))));
    if (samplePair.empty()) {
      sampleIt++;
      if (sampleIt == sample.end()) 
        return;
      buildQueue();
    }
    unsigned i = samplePair.begin()->index;
    samplePair.erase(samplePair.begin());
    cluster = clusters->getCluster(i);
    stringIt = cluster.begin();
  }
}

bool CloseRand::hasNext() const 
{
  if (sampleIt != sample.end())
    return true;
  return false;
}

PPDTriple CloseRand::next() 
{
  const unsigned q=*sampleIt;
  const unsigned p=cluster.getPivot();
  const unsigned s=*stringIt;

  PPDTriple triple=PPDTriple(q,
                             p,
                             s,
                             SimVect((*data)[q], (*data)[p]),
                             SimVect((*data)[p], (*data)[s]),
                             SimDist((*data)[q], (*data)[s]));

  // increment
  step();

  return triple;
}

void CloseRand::buildQueue() 
{
  for (unsigned i = 0; i < clusters->sizeCluster(); i++) {
    const unsigned p = clusters->getCluster(i).getPivot();
    const unsigned q = *sampleIt;
    SimType dist = SimDist((*data)[q], (*data)[p]);
    if (samplePair.size() < queueSize || dist < samplePair.begin()->dist) {
      samplePair.insert(IndexEntry(i, dist));
      if (samplePair.size() > queueSize) 
        samplePair.erase(samplePair.begin());
    }
  }
}