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#ifndef MOZC_REWRITER_USER_SEGMENT_HISTORY_REWRITER_H_
#define MOZC_REWRITER_USER_SEGMENT_HISTORY_REWRITER_H_

#include "rewriter/rewriter_interface.h"
#include "base/base.h"
#include "converter/segments.h"

namespace mozc {
class LRUStorage;

class UserSegmentHistoryRewriter: public RewriterInterface {
 public:
  UserSegmentHistoryRewriter();
  virtual ~UserSegmentHistoryRewriter();

  virtual bool Rewrite(Segments *segments) const;

  virtual void Finish(Segments *segments);

  virtual bool Reload();

  virtual void Clear();

  // Return the current active storage.
  // UserSegmentHistoryRewriter is basically singleton in converter thread.
  // GetStorage() returns the current active storage managed by converter.
  // TODO(taku): This design is ad-hoc. Needs refactoring.
  static LRUStorage *GetStorage();

 private:
  bool IsAvailable(const Segments &segments) const;
  bool GetScore(const Segments &segments,
                size_t segment_index,
                int candidate_index,
                uint32 *score,
                uint32 *last_access_time) const;
  bool Replaceable(const Segment::Candidate &lhs,
                   const Segment::Candidate &rhs) const;
  void RememberFirstCandidate(const Segments &segments,
                              size_t segment_index);
  void RememberNumberPreference(const Segment &segment);
  bool RewriteNumber(Segment *segment) const;
  bool ShouldRewrite(const Segment &segment,
                     size_t *max_candidates_size) const;
  void InsertTriggerKey(const Segment &segment);

  scoped_ptr<LRUStorage> storage_;
};
}

#endif  // MOZC_REWRITER_USER_SEGMENT_HISTORY_REWRITER_H_