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#ifndef MOZC_REWRITER_REWRITER_INTERFACE_H_
#define MOZC_REWRITER_REWRITER_INTERFACE_H_

#include <cstddef>  // for size_t

namespace mozc {

class Segments;

class RewriterInterface {
 public:
  virtual ~RewriterInterface() {}

  enum CapabilityType {
    NOT_AVAILABLE = 0,
    CONVERSION = 1,
    PREDICTION = 2,
    SUGGESTION = 4,
    ALL = (1 | 2 | 4),
  };

  // return capablity of this rewriter.
  // If (capability() & CONVERSION), this rewriter
  // is called after StartConversion().
  virtual int capability() const {
    return CONVERSION;
  }

  // Rewrite request and/or result.
  virtual bool Rewrite(Segments *segments) const = 0;

  // This method is mainly called when user puts SPACE key
  // and changes the focused candidate.
  // In this method, Converter will find bracketing matching.
  // e.g., when user selects "「",  corresponding closing bracket "」"
  // is chosen in the preedit.
  virtual bool Focus(Segments *segments,
                     size_t segment_index,
                     int candidate_index) const {
    return true;
  }

  // Hook(s) for all mutable operations
  virtual void Finish(Segments *segments) {}

  // sync internal data to local file system.
  virtual bool Sync() { return true; }

  // reload internal data from local file system.
  virtual bool Reload() { return true; }

  // clear internal data
  virtual void Clear() {}

 protected:
  RewriterInterface() {}
};

// factory for making "default" rewriter
class RewriterFactory {
 public:
  // return singleton object
  static RewriterInterface *GetRewriter();

  // dependency injection for unittesting
  static void SetRewriter(RewriterInterface *rewriter);

 private:
  RewriterFactory();
  ~RewriterFactory();
};

}  // mozc

#endif  // MOZC_REWRITER_REWRITER_INTERFACE_H_