/*
 * Stack.cpp
 *
 *  Created on: 24 Oct 2015
 *      Author: hieu
 */
#include <algorithm>
#include <boost/foreach.hpp>
#include "Stack.h"
#include "../Hypothesis.h"
#include "../Manager.h"
#include "../../Scores.h"
#include "../../System.h"

using namespace std;

namespace Moses2
{

namespace NSCubePruningBitmapStack
{
MiniStack::MiniStack(const Manager &mgr)
  :m_coll()
  ,m_sortedHypos(NULL)
{}

StackAdd MiniStack::Add(const Hypothesis *hypo)
{
  std::pair<_HCType::iterator, bool> addRet = m_coll.insert(hypo);

  // CHECK RECOMBINATION
  if (addRet.second) {
    // equiv hypo doesn't exists
    return StackAdd(true, NULL);
  } else {
    const Hypothesis *hypoExisting = *addRet.first;
    if (hypo->GetScores().GetTotalScore() > hypoExisting->GetScores().GetTotalScore()) {
      // incoming hypo is better than the one we have
      const Hypothesis *const &hypoExisting1 = *addRet.first;
      const Hypothesis *&hypoExisting2 = const_cast<const Hypothesis *&>(hypoExisting1);
      hypoExisting2 = hypo;

      return StackAdd(true, const_cast<Hypothesis*>(hypoExisting));
    } else {
      // already storing the best hypo. discard incoming hypo
      return StackAdd(false, const_cast<Hypothesis*>(hypo));
    }
  }

  assert(false);
}

Hypotheses &MiniStack::GetSortedAndPruneHypos(const Manager &mgr) const
{
  if (m_sortedHypos == NULL) {
    // create sortedHypos first
    MemPool &pool = mgr.GetPool();
    m_sortedHypos = new (pool.Allocate< Vector<const Hypothesis*> >()) Vector<const Hypothesis*>(pool, m_coll.size());

    size_t ind = 0;
    BOOST_FOREACH(const Hypothesis *hypo, m_coll) {
      (*m_sortedHypos)[ind] = hypo;
      ++ind;
    }

    SortAndPruneHypos(mgr);
  }

  return *m_sortedHypos;
}

void MiniStack::SortAndPruneHypos(const Manager &mgr) const
{
  size_t stackSize = mgr.system.stackSize;
  Recycler<Hypothesis*> &recycler = mgr.GetHypoRecycle();

  /*
  cerr << "UNSORTED hypos:" << endl;
  for (size_t i = 0; i < hypos.size(); ++i) {
    const Hypothesis *hypo = hypos[i];
    cerr << *hypo << endl;
  }
  cerr << endl;
  */
  Hypotheses::iterator iterMiddle;
  iterMiddle = (stackSize == 0 || m_sortedHypos->size() < stackSize)
               ? m_sortedHypos->end()
               : m_sortedHypos->begin() + stackSize;

  std::partial_sort(m_sortedHypos->begin(), iterMiddle, m_sortedHypos->end(),
                    HypothesisFutureScoreOrderer());

  // prune
  if (stackSize && m_sortedHypos->size() > stackSize) {
    for (size_t i = stackSize; i < m_sortedHypos->size(); ++i) {
      Hypothesis *hypo = const_cast<Hypothesis*>((*m_sortedHypos)[i]);
      recycler.Recycle(hypo);
    }
    m_sortedHypos->resize(stackSize);
  }

  /*
  cerr << "sorted hypos:" << endl;
  for (size_t i = 0; i < hypos.size(); ++i) {
    const Hypothesis *hypo = hypos[i];
    cerr << hypo << " " << *hypo << endl;
  }
  cerr << endl;
  */

}

void MiniStack::Clear()
{
  m_sortedHypos = NULL;
  m_coll.clear();
}

///////////////////////////////////////////////////////////////
Stack::Stack(const Manager &mgr)
  :m_mgr(mgr)
  ,m_coll()
  ,m_miniStackRecycler()
{
}

Stack::~Stack()
{
  // TODO Auto-generated destructor stub
}

void Stack::Add(const Hypothesis *hypo, Recycler<Hypothesis*> &hypoRecycle)
{
  HypoCoverageInternal key = &hypo->GetBitmap();
  StackAdd added = GetMiniStack(key).Add(hypo);

  if (added.toBeDeleted) {
    hypoRecycle.Recycle(added.toBeDeleted);
  }
}

std::vector<const Hypothesis*> Stack::GetBestHypos(size_t num) const
{
  std::vector<const Hypothesis*> ret;
  BOOST_FOREACH(const Coll::value_type &val, m_coll) {
    const MiniStack::_HCType &hypos = val.second->GetColl();
    ret.insert(ret.end(), hypos.begin(), hypos.end());
  }

  std::vector<const Hypothesis*>::iterator iterMiddle;
  iterMiddle = (num == 0 || ret.size() < num)
               ? ret.end()
               : ret.begin()+num;

  std::partial_sort(ret.begin(), iterMiddle, ret.end(),
                    HypothesisFutureScoreOrderer());

  return ret;
}

size_t Stack::GetHypoSize() const
{
  size_t ret = 0;
  BOOST_FOREACH(const Coll::value_type &val, m_coll) {
    const MiniStack::_HCType &hypos = val.second->GetColl();
    ret += hypos.size();
  }
  return ret;
}

MiniStack &Stack::GetMiniStack(const HypoCoverageInternal &key)
{
  MiniStack *ret;
  Coll::iterator iter = m_coll.find(key);
  if (iter == m_coll.end()) {
    if (m_miniStackRecycler.empty()) {
      ret = new (m_mgr.GetPool().Allocate<MiniStack>()) MiniStack(m_mgr);
    } else {
      ret = m_miniStackRecycler.back();
      ret->Clear();
      m_miniStackRecycler.pop_back();
    }

    m_coll[key] = ret;
  } else {
    ret = iter->second;
  }
  return *ret;
}

void Stack::Clear()
{
  BOOST_FOREACH(const Coll::value_type &val, m_coll) {
    MiniStack *miniStack = val.second;
    m_miniStackRecycler.push_back(miniStack);
  }

  m_coll.clear();
}

Stack::SortedHypos Stack::GetSortedAndPruneHypos(const Manager &mgr) const
{
  SortedHypos ret;

  MemPool &pool = mgr.GetPool();

  // prune and sort
  Hypotheses *allHypos = new (pool.Allocate<Hypotheses>()) Hypotheses(pool, GetHypoSize());
  size_t i = 0;

  BOOST_FOREACH(const Coll::value_type &val, m_coll) {
    const MiniStack *miniStack = val.second;
    const MiniStack::MiniStack::_HCType &hypos = miniStack->GetColl();

    BOOST_FOREACH(const Hypothesis *hypo, hypos) {
      (*allHypos)[i++] = hypo;
    }
  }

  SortAndPruneHypos(mgr, *allHypos);

  // divide hypos by [bitmap, last end pos]
  BOOST_FOREACH(const Hypothesis *hypo, *allHypos) {
    HypoCoverage key(&hypo->GetBitmap(), hypo->GetInputPath().range.GetEndPos());

    Hypotheses *hypos;
    SortedHypos::iterator iter;
    iter = ret.find(key);
    if (iter == ret.end()) {
      hypos = new (pool.Allocate<Hypotheses>()) Hypotheses(pool);
      ret[key] = hypos;
    } else {
      hypos = iter->second;
    }
    hypos->push_back(hypo);
  }

  return ret;
}

void Stack::SortAndPruneHypos(const Manager &mgr, Hypotheses &hypos) const
{
  size_t stackSize = mgr.system.stackSize;
  Recycler<Hypothesis*> &recycler = mgr.GetHypoRecycle();

  /*
  cerr << "UNSORTED hypos:" << endl;
  for (size_t i = 0; i < hypos.size(); ++i) {
    const Hypothesis *hypo = hypos[i];
    cerr << *hypo << endl;
  }
  cerr << endl;
  */
  Hypotheses::iterator iterMiddle;
  iterMiddle = (stackSize == 0 || hypos.size() < stackSize)
               ? hypos.end()
               : hypos.begin() + stackSize;

  std::partial_sort(hypos.begin(), iterMiddle, hypos.end(),
                    HypothesisFutureScoreOrderer());

  // prune
  if (stackSize && hypos.size() > stackSize) {
    for (size_t i = stackSize; i < hypos.size(); ++i) {
      Hypothesis *hypo = const_cast<Hypothesis*>(hypos[i]);
      recycler.Recycle(hypo);
    }
    hypos.resize(stackSize);
  }

  /*
  cerr << "sorted hypos:" << endl;
  for (size_t i = 0; i < hypos.size(); ++i) {
    const Hypothesis *hypo = hypos[i];
    cerr << hypo << " " << *hypo << endl;
  }
  cerr << endl;
  */

}


void Stack::DebugCounts()
{
  /*
  cerr << "counts=";
  BOOST_FOREACH(const Coll::value_type &val, GetColl()) {
  	const NSCubePruning::MiniStack &miniStack = *val.second;
  	size_t count = miniStack.GetColl().size();
  	cerr << count << " ";
  }
  cerr << endl;
  */
}

}

}