/*
 *  FeatureStats.h
 *  met - Minimum Error Training
 *
 *  Created by Nicola Bertoldi on 13/05/08.
 *
 */

#ifndef FEATURE_STATS_H
#define FEATURE_STATS_H

#include <cstring>
#include <fstream>
#include <iostream>
#include <map>
#include <string>
#include <vector>
#include "Types.h"

using namespace std;

// Minimal sparse vector
class SparseVector {
public:
  typedef std::map<size_t,FeatureStatsType> fvector_t;
  typedef std::map<std::string, size_t> name2id_t;
  typedef std::vector<std::string> id2name_t;

  FeatureStatsType get(const std::string& name) const;
  FeatureStatsType get(size_t id) const;
  void set(const std::string& name, FeatureStatsType value);
  void clear();
  void load(const std::string& file);
  size_t size() const {
    return fvector_.size();
  }

  void write(std::ostream& out, const std::string& sep = " ") const;

  SparseVector& operator-=(const SparseVector& rhs);
  FeatureStatsType inner_product(const SparseVector& rhs) const;

private:
  static name2id_t name2id_;
  static id2name_t id2name_;
  fvector_t fvector_;
};

SparseVector operator-(const SparseVector& lhs, const SparseVector& rhs);
FeatureStatsType inner_product(const SparseVector& lhs, const SparseVector& rhs);

class FeatureStats
{
private:
  size_t available_;
  size_t entries_;

  // TODO: Use smart pointer for exceptional-safety.
  featstats_t array_;
  SparseVector map_;

public:
  FeatureStats();
  explicit FeatureStats(const size_t size);

  ~FeatureStats();

  // We intentionally allow copying.
  FeatureStats(const FeatureStats &stats);
  FeatureStats& operator=(const FeatureStats &stats);

  void Copy(const FeatureStats &stats);

  bool isfull() const {
    return (entries_ < available_) ? 0 : 1;
  }
  void expand();
  void add(FeatureStatsType v);
  void addSparse(const string& name, FeatureStatsType v);

  void clear() {
    memset((void*)array_, 0, GetArraySizeWithBytes());
    map_.clear();
  }

  void reset() {
    entries_ = 0;
    clear();
  }

  inline FeatureStatsType get(size_t i) {
    return array_[i];
  }
  inline FeatureStatsType get(size_t i)const {
    return array_[i];
  }
  inline featstats_t getArray() const {
    return array_;
  }
  inline const SparseVector& getSparse() const {
    return map_;
  }

  void set(std::string &theString, const SparseVector& sparseWeights);

  inline size_t bytes() const {
    return GetArraySizeWithBytes();
  }

  size_t GetArraySizeWithBytes() const {
    return entries_ * sizeof(FeatureStatsType);
  }

  inline size_t size() const {
    return entries_;
  }

  inline size_t available() const {
    return available_;
  }

  void savetxt(const std::string &file);
  void savetxt(ofstream& outFile);
  void savebin(ofstream& outFile);
  inline void savetxt() {
    savetxt("/dev/stdout");
  }

  void loadtxt(ifstream& inFile, const SparseVector& sparseWeights);
  void loadbin(ifstream& inFile);

  /**
   * Write the whole object to a stream.
   */
  friend ostream& operator<<(ostream& o, const FeatureStats& e);
};

#endif  // FEATURE_STATS_H