// $Id$
// vim:tabstop=2
/***********************************************************************
Moses - factored phrase-based language decoder
Copyright (C) 2006 University of Edinburgh

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
***********************************************************************/

#ifndef moses_BlockHashIndex_h
#define moses_BlockHashIndex_h

#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <cstring>
#include <cstdio>

#include "MurmurHash3.h"
#include "StringVector.h"
#include "PackedArray.h"
#include "util/exception.hh"

#ifdef WITH_THREADS
#include "moses/ThreadPool.h"
#else
#include <ctime>
#endif

#include <boost/shared_ptr.hpp>

namespace Moses
{

class BlockHashIndex
{
private:
  std::priority_queue<int> m_queue;

  size_t m_orderBits;
  size_t m_fingerPrintBits;

  std::FILE* m_fileHandle;
  size_t m_fileHandleStart;

  StringVector<unsigned char, unsigned long> m_landmarks;

  std::vector<void*> m_hashes;
  std::vector<clock_t> m_clocks;
  std::vector<PairedPackedArray<>*> m_arrays;

  std::vector<size_t> m_seekIndex;

  size_t m_size;
  int m_lastSaved;
  int m_lastDropped;
  size_t m_numLoadedRanges;

#ifdef WITH_THREADS
  ThreadPool m_threadPool;
  boost::mutex m_mutex;

  template <typename Keys>
  class HashTask : public Task
  {
  public:
    HashTask(int id, BlockHashIndex& hash, Keys& keys)
      : m_id(id), m_hash(hash), m_keys(new Keys(keys)) {}

    virtual void Run() {
      m_hash.CalcHash(m_id, *m_keys);
    }

    virtual ~HashTask() {
      delete m_keys;
    }

  private:
    int m_id;
    BlockHashIndex& m_hash;
    Keys* m_keys;
  };
#endif

  size_t GetFprint(const char* key) const;
  size_t GetHash(size_t i, const char* key);

public:
#ifdef WITH_THREADS
  BlockHashIndex(size_t orderBits, size_t fingerPrintBits,
                 size_t threadsNum = 2);
#else
  BlockHashIndex(size_t orderBits, size_t fingerPrintBits);
#endif

  ~BlockHashIndex();

  size_t GetHash(const char* key);
  size_t GetHash(std::string key);

  size_t operator[](std::string key);
  size_t operator[](char* key);

  void BeginSave(std::FILE* mphf);
  void SaveRange(size_t i);
  void SaveLastRange();
  size_t FinalizeSave();

#ifdef WITH_THREADS
  void WaitAll();
#endif

  void DropRange(size_t i);
  void DropLastRange();

  size_t LoadIndex(std::FILE* mphf);
  void LoadRange(size_t i);

  size_t Save(std::string filename);
  size_t Save(std::FILE * mphf);

  size_t Load(std::string filename);
  size_t Load(std::FILE * mphf);

  size_t GetSize() const;

  void KeepNLastRanges(float ratio = 0.1, float tolerance = 0.1);

  template <typename Keys>
  void AddRange(Keys &keys) {
    size_t current = m_landmarks.size();

    if(m_landmarks.size() && m_landmarks.back().str() >= keys[0]) {
      std::stringstream strme;
      strme << "ERROR: Input file does not appear to be sorted with  LC_ALL=C sort" << std::endl;
      strme << "1: " << m_landmarks.back().str() << std::endl;
      strme << "2: " << keys[0] << std::endl;
      UTIL_THROW2(strme.str());
    }

    m_landmarks.push_back(keys[0]);
    m_size += keys.size();

    if(keys.size() == 1) {
      // add dummy key to avoid null hash
      keys.push_back("###DUMMY_KEY###");
    }

#ifdef WITH_THREADS

    boost::shared_ptr<HashTask<Keys> >
    ht(new HashTask<Keys>(current, *this, keys));
    m_threadPool.Submit(ht);
#else
    CalcHash(current, keys);
#endif
  }

  template <typename Keys>
  void CalcHash(size_t current, Keys &keys) {
#ifdef HAVE_CMPH
    void* source = vectorAdapter(keys);
    CalcHash(current, source);
#endif
  }

  void CalcHash(size_t current, void* source);

#ifdef HAVE_CMPH
  void* vectorAdapter(std::vector<std::string>& v);
  void* vectorAdapter(StringVector<unsigned, size_t, std::allocator>& sv);
  void* vectorAdapter(StringVector<unsigned, size_t, MmapAllocator>& sv);
#endif
};

}
#endif