#ifndef _DTRAIN_SCORE_H_
#define _DTRAIN_SCORE_H_


#include <iostream>
#include <vector>
#include <map>
#include <cassert>
#include <cmath>

#include "wordid.h"

using namespace std;


namespace dtrain
{


/*
 * NgramCounts
 *
 */
struct NgramCounts
{
  NgramCounts( const size_t N ) : N_( N ) {
    reset();
  } 
  size_t N_;
  map<size_t, size_t> clipped;
  map<size_t, size_t> sum;

  void
  operator+=( const NgramCounts& rhs )
  {
    assert( N_ == rhs.N_ );
    for ( size_t i = 0; i < N_; i++ ) {
      this->clipped[i] += rhs.clipped.find(i)->second;
      this->sum[i] += rhs.sum.find(i)->second;
    }
  }

  const NgramCounts
  operator+( const NgramCounts &other ) const
  {
    NgramCounts result = *this;
    result += other;
    return result;
  }

  void
  add( size_t count, size_t ref_count, size_t i )
  {
    assert( i < N_ );
    if ( count > ref_count ) {
      clipped[i] += ref_count;
      sum[i] += count;
    } else {
      clipped[i] += count;
      sum[i] += count;
    }
  }

  void
  reset()
  {
    size_t i;
    for ( i = 0; i < N_; i++ ) {
      clipped[i] = 0;
      sum[i] = 0;
    }
  }

  void
  print()
  {
    for ( size_t i = 0; i < N_; i++ ) {
      cout << i+1 << "grams (clipped):\t" << clipped[i] << endl;
      cout << i+1 << "grams:\t\t\t" << sum[i] << endl;
    }
  }
};


typedef map<vector<WordID>, size_t> Ngrams;
Ngrams make_ngrams( vector<WordID>& s, size_t N );
NgramCounts make_ngram_counts( vector<WordID> hyp, vector<WordID> ref, size_t N );

double brevity_penaly( const size_t hyp_len, const size_t ref_len );
double bleu( NgramCounts& counts, const size_t hyp_len, const size_t ref_len, const size_t N,
             vector<float> weights = vector<float>() );
double stupid_bleu( NgramCounts& counts, const size_t hyp_len, const size_t ref_len, size_t N,
                    vector<float> weights = vector<float>() );
double smooth_bleu( NgramCounts& counts, const size_t hyp_len, const size_t ref_len, const size_t N,
                    vector<float> weights = vector<float>() );
double approx_bleu( NgramCounts& counts, const size_t hyp_len, const size_t ref_len, const size_t N,
                    vector<float> weights = vector<float>() );


} // namespace


#endif