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#ifndef MOZC_PREDICTION_PREDICTOR_INTERFACE_H_
#define MOZC_PREDICTION_PREDICTOR_INTERFACE_H_

#include <cstdint>
#include <vector>

#include "absl/strings/string_view.h"
#include "absl/types/span.h"
#include "prediction/result.h"
#include "request/conversion_request.h"

namespace mozc::prediction {

class PredictorInterface {
 public:
  virtual ~PredictorInterface() = default;

  // Returns suggestions.
  // You may need to change the behavior according to the
  // Segments::request_type flag
  // SUGGESTION: automatic suggestions
  // PREDICTION: invoked only when user pushes "tab" key.
  // less aggressive than SUGGESTION mode.
  virtual std::vector<Result> Predict(
      const ConversionRequest& request) const = 0;

  // Finish the conversion. Stores the history for penalization.
  // results[0] stores the committed result.
  // We can revert the Finish operation with the revert_id and Revert method.
  virtual void Finish(const ConversionRequest& request,
                      absl::Span<const Result> results, uint32_t revert_id) {}

  // Reverts the last Finish operation.
  virtual void Revert(uint32_t revert_id) {}

  // Syncs user-modified context.
  virtual void CommitContext(const ConversionRequest& request) const {}

  // Clears all history data of UserHistoryPredictor.
  virtual bool ClearAllHistory() { return true; }

  // Clears unused history data of UserHistoryPredictor.
  virtual bool ClearUnusedHistory() { return true; }

  // Clears a specific history data of UserHistoryPredictor.
  virtual bool ClearHistoryEntry(absl::string_view key,
                                 absl::string_view value) {
    return true;
  }

  virtual bool AddHistoryEntry(absl::string_view key, absl::string_view value) {
    return true;
  }

  // Syncs user history to local disk.
  virtual bool Sync() { return true; }

  // Reloads user history data from local disk.
  virtual bool Reload() { return true; }

  // Waits for syncer thread to complete.
  virtual bool Wait() { return true; }

  virtual absl::string_view GetPredictorName() const = 0;
};

}  // namespace mozc::prediction

#endif  // MOZC_PREDICTION_PREDICTOR_INTERFACE_H_
