/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.

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 TENSORFLOW_MODELS_SEQ_FLOW_LITE_TF_OPS_PROJECTION_NORMALIZER_UTIL_H_
#define TENSORFLOW_MODELS_SEQ_FLOW_LITE_TF_OPS_PROJECTION_NORMALIZER_UTIL_H_

#include <string>
#include <unordered_set>
#include <vector>

#include "libutf/utf.h"

// Normalizes the input with the given |separators| by adding a space before and
// after each separator. When |normalize_repetition| is true, it removes the
// repeated characters (except numbers) which consecutively appeared more than
// twice in a word. When |normalize_spaces| is true, it removes spaces from
// the beginning and ending of the input, as well as repeated spaces.
// Examples: arwwwww -> arww, good!!!!! -> good!!, hahaha => haha.
class ProjectionNormalizer {
 public:
  explicit ProjectionNormalizer(const std::string& separators,
                                bool normalize_repetition = false,
                                bool normalize_spaces = false)
      : normalize_repetition_(normalize_repetition),
        normalize_spaces_(normalize_spaces) {
    InitializeSeparators(separators);
  }

  // Normalizes the repeated characters (except numbers) which consecutively
  // appeared more than twice in a word.
  std::string Normalize(const std::string& input, size_t max_input = 300);
  std::string Normalize(const char* input_ptr, size_t len,
                        size_t max_input = 300);

 private:
  // Parses and extracts supported separators.
  void InitializeSeparators(const std::string& separators);

  // Removes repeated chars.
  std::string NormalizeInternal(const char* input_ptr, size_t len);

  std::unordered_set<char> separators_;
  bool normalize_repetition_;
  bool normalize_spaces_;
};

#endif  // TENSORFLOW_MODELS_SEQ_FLOW_LITE_TF_OPS_PROJECTION_NORMALIZER_UTIL_H_
