// $Id$
// 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_InputType_h
#define moses_InputType_h

#include <string>
#include "TypeDef.h"
#include "Phrase.h"
#include "TargetPhraseCollection.h"
#include "ReorderingConstraint.h"
#include "NonTerminal.h"

namespace Moses
{

class WordsRange;
class Factor;
class PhraseDictionary;
class TranslationOptionCollection;
class TranslationSystem;

//! base class for sentences and confusion networks
class InputType
{
protected:
  long m_translationId; 	//< contiguous Id
  bool m_hasMetaData;
  long m_segId;
  ReorderingConstraint m_reorderingConstraint; /**< limits on reordering specified either by "-mp" switch or xml tags */

public:

  // used in -continue-partial-translation
  std::vector<bool> m_sourceCompleted;
  std::string m_initialTargetPhrase;
  size_t m_frontSpanCoveredLength;
  // how many words from the beginning are covered

  InputType(long translationId = 0);
  virtual ~InputType();

  virtual InputTypeEnum GetType() const = 0;

  long GetTranslationId() const {
    return m_translationId;
  }
  void SetTranslationId(long translationId) {
    m_translationId = translationId;
  }
  //! returns the number of words moved
  virtual int ComputeDistortionDistance(const WordsRange& prev, const WordsRange& current) const;

  //! In a word lattice, tells you if there's a path from node start to node end
  virtual bool CanIGetFromAToB(size_t start, size_t end) const;

  //! is there a path covering [range] (lattice only, otherwise true)
  inline bool IsCoveragePossible(const WordsRange& range) const {
    return CanIGetFromAToB(range.GetStartPos(), range.GetEndPos() + 1);
  }

  //! In a word lattice, you can't always get from node A to node B
  inline bool IsExtensionPossible(const WordsRange& prev, const WordsRange& current) const {
    //  return ComputeDistortionDistance(prev, current) < 100000;
    size_t t = prev.GetEndPos()+1;  // 2
    size_t l = current.GetEndPos()+1;   //l=1
    size_t r = l;
    if (l<t) {
      r = t;  //r=2
    } else {
      l = t;
    }
    if (!CanIGetFromAToB(l,r)) return false;

    // there's another check here: a current span may end at a place that previous could get to,
    // but it may not *START* at a place it can get to. We'll also have to check if we're going left or right

    r = current.GetStartPos();
    l = prev.GetEndPos()+1;
    if (l == r) return true;
    if (prev.GetEndPos() > current.GetStartPos()) {
      r = prev.GetStartPos();
      l = current.GetEndPos()+1;
      if (r == l) return true;
    }
    return CanIGetFromAToB(l,r);
  }

  //! number of words in this sentence/confusion network
  virtual size_t GetSize() const =0;

  //! populate this InputType with data from in stream
  virtual int Read(std::istream& in,const std::vector<FactorType>& factorOrder) =0;

  //! Output debugging info to stream out
  virtual void Print(std::ostream&) const =0;

  //! create trans options specific to this InputType
  virtual TranslationOptionCollection* CreateTranslationOptionCollection(const TranslationSystem* system) const=0;

  //! return substring. Only valid for Sentence class. TODO - get rid of this fn
  virtual Phrase GetSubString(const WordsRange&) const =0;

  //! return substring at a particular position. Only valid for Sentence class. TODO - get rid of this fn
  virtual const Word& GetWord(size_t pos) const=0;

  //! Returns the reordering constraints
  const ReorderingConstraint& GetReorderingConstraint() const {
    return m_reorderingConstraint;
  };

  virtual const NonTerminalSet &GetLabelSet(size_t startPos, size_t endPos) const = 0;

  TO_STRING();

};

std::ostream& operator<<(std::ostream&,InputType const&);

}

#endif