/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef LIBTEXTCLASSIFIER_UTILS_CONTAINER_STRING_SET_H_
#define LIBTEXTCLASSIFIER_UTILS_CONTAINER_STRING_SET_H_

#include <vector>

#include "utils/strings/stringpiece.h"

namespace libtextclassifier3 {

class StringSet {
 public:
  struct Match {
    Match() {}
    Match(int id, int match_length) : id(id), match_length(match_length) {}
    int id = -1;
    int match_length = -1;
  };

  virtual ~StringSet() {}

  // Find matches that are prefixes of a string.
  virtual bool FindAllPrefixMatches(StringPiece input,
                                    std::vector<Match>* matches) const = 0;

  // Find the longest prefix match of a string.
  virtual bool LongestPrefixMatch(StringPiece input,
                                  Match* longest_match) const = 0;

  // Finds an exact string match.
  virtual bool Find(StringPiece input, int* value) const {
    Match match;
    if (LongestPrefixMatch(input, &match) &&
        match.match_length == input.length()) {
      *value = match.id;
      return true;
    }
    return false;
  }
};

}  // namespace libtextclassifier3

#endif  // LIBTEXTCLASSIFIER_UTILS_CONTAINER_STRING_SET_H_