#ifndef SCORER_H_
#define SCORER_H_

#include <vector>
#include <string>

#include "wordid.h"

class ViterbiEnvelope;
class ErrorSurface;

enum ScoreType { IBM_BLEU, NIST_BLEU, Koehn_BLEU, TER, BLEU_minus_TER_over_2, SER };
ScoreType ScoreTypeFromString(const std::string& st);

class Score {
 public:
  virtual ~Score();
  virtual float ComputeScore() const = 0;
  virtual void ScoreDetails(std::string* details) const = 0;
  virtual void PlusEquals(const Score& rhs) = 0;
  virtual void Subtract(const Score& rhs, Score* res) const = 0;
  virtual Score* GetZero() const = 0;
  virtual bool IsAdditiveIdentity() const = 0; // returns true if adding this delta
                                      // to another score results in no score change
				      // under any circumstances
  virtual void Encode(std::string* out) const = 0;
};

class SentenceScorer {
 public:
  virtual ~SentenceScorer();
  void ComputeErrorSurface(const ViterbiEnvelope& ve, ErrorSurface* es) const;
  virtual Score* ScoreCandidate(const std::vector<WordID>& hyp) const = 0;
  static Score* CreateScoreFromString(const ScoreType type, const std::string& in);
  static SentenceScorer* CreateSentenceScorer(const ScoreType type,
    const std::vector<std::vector<WordID> >& refs);
};

class DocScorer {
 public:
  ~DocScorer();
  DocScorer(
    const ScoreType type,
    const std::vector<std::string>& ref_files);
  int size() const { return scorers_.size(); }
  const SentenceScorer* operator[](size_t i) const { return scorers_[i]; }
 private:
  std::vector<SentenceScorer*> scorers_;
};

#endif