///////////////////////////////////////////////////////////////////////
// File:        tessdatamanager.h
// Description: Functions to handle loading/combining tesseract data files.
// Author:      Daria Antonova
//
// (C) Copyright 2009, Google Inc.
// 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 TESSERACT_CCUTIL_TESSDATAMANAGER_H_
#define TESSERACT_CCUTIL_TESSDATAMANAGER_H_

#include <tesseract/baseapi.h> // FileReader
#include <string>              // std::string
#include <vector>              // std::vector
#include "serialis.h"          // FileWriter

static const char kTrainedDataSuffix[] = "traineddata";

// When adding new tessdata types and file suffixes, please make sure to
// update TessdataType enum, kTessdataFileSuffixes and kTessdataFileIsText.
static const char kLangConfigFileSuffix[] = "config";
static const char kUnicharsetFileSuffix[] = "unicharset";
static const char kAmbigsFileSuffix[] = "unicharambigs";
static const char kBuiltInTemplatesFileSuffix[] = "inttemp";
static const char kBuiltInCutoffsFileSuffix[] = "pffmtable";
static const char kNormProtoFileSuffix[] = "normproto";
static const char kPuncDawgFileSuffix[] = "punc-dawg";
static const char kSystemDawgFileSuffix[] = "word-dawg";
static const char kNumberDawgFileSuffix[] = "number-dawg";
static const char kFreqDawgFileSuffix[] = "freq-dawg";
static const char kFixedLengthDawgsFileSuffix[] = "fixed-length-dawgs";
static const char kCubeUnicharsetFileSuffix[] = "cube-unicharset";
static const char kCubeSystemDawgFileSuffix[] = "cube-word-dawg";
static const char kShapeTableFileSuffix[] = "shapetable";
static const char kBigramDawgFileSuffix[] = "bigram-dawg";
static const char kUnambigDawgFileSuffix[] = "unambig-dawg";
static const char kParamsModelFileSuffix[] = "params-model";
static const char kLSTMModelFileSuffix[] = "lstm";
static const char kLSTMPuncDawgFileSuffix[] = "lstm-punc-dawg";
static const char kLSTMSystemDawgFileSuffix[] = "lstm-word-dawg";
static const char kLSTMNumberDawgFileSuffix[] = "lstm-number-dawg";
static const char kLSTMUnicharsetFileSuffix[] = "lstm-unicharset";
static const char kLSTMRecoderFileSuffix[] = "lstm-recoder";
static const char kVersionFileSuffix[] = "version";

namespace tesseract {

enum TessdataType {
  TESSDATA_LANG_CONFIG,        // 0
  TESSDATA_UNICHARSET,         // 1
  TESSDATA_AMBIGS,             // 2
  TESSDATA_INTTEMP,            // 3
  TESSDATA_PFFMTABLE,          // 4
  TESSDATA_NORMPROTO,          // 5
  TESSDATA_PUNC_DAWG,          // 6
  TESSDATA_SYSTEM_DAWG,        // 7
  TESSDATA_NUMBER_DAWG,        // 8
  TESSDATA_FREQ_DAWG,          // 9
  TESSDATA_FIXED_LENGTH_DAWGS, // 10  // deprecated
  TESSDATA_CUBE_UNICHARSET,    // 11  // deprecated
  TESSDATA_CUBE_SYSTEM_DAWG,   // 12  // deprecated
  TESSDATA_SHAPE_TABLE,        // 13
  TESSDATA_BIGRAM_DAWG,        // 14
  TESSDATA_UNAMBIG_DAWG,       // 15
  TESSDATA_PARAMS_MODEL,       // 16
  TESSDATA_LSTM,               // 17
  TESSDATA_LSTM_PUNC_DAWG,     // 18
  TESSDATA_LSTM_SYSTEM_DAWG,   // 19
  TESSDATA_LSTM_NUMBER_DAWG,   // 20
  TESSDATA_LSTM_UNICHARSET,    // 21
  TESSDATA_LSTM_RECODER,       // 22
  TESSDATA_VERSION,            // 23

  TESSDATA_NUM_ENTRIES
};

/**
 * kTessdataFileSuffixes[i] indicates the file suffix for
 * tessdata of type i (from TessdataType enum).
 */
static const char *const kTessdataFileSuffixes[] = {
    kLangConfigFileSuffix,       // 0
    kUnicharsetFileSuffix,       // 1
    kAmbigsFileSuffix,           // 2
    kBuiltInTemplatesFileSuffix, // 3
    kBuiltInCutoffsFileSuffix,   // 4
    kNormProtoFileSuffix,        // 5
    kPuncDawgFileSuffix,         // 6
    kSystemDawgFileSuffix,       // 7
    kNumberDawgFileSuffix,       // 8
    kFreqDawgFileSuffix,         // 9
    kFixedLengthDawgsFileSuffix, // 10  // deprecated
    kCubeUnicharsetFileSuffix,   // 11  // deprecated
    kCubeSystemDawgFileSuffix,   // 12  // deprecated
    kShapeTableFileSuffix,       // 13
    kBigramDawgFileSuffix,       // 14
    kUnambigDawgFileSuffix,      // 15
    kParamsModelFileSuffix,      // 16
    kLSTMModelFileSuffix,        // 17
    kLSTMPuncDawgFileSuffix,     // 18
    kLSTMSystemDawgFileSuffix,   // 19
    kLSTMNumberDawgFileSuffix,   // 20
    kLSTMUnicharsetFileSuffix,   // 21
    kLSTMRecoderFileSuffix,      // 22
    kVersionFileSuffix,          // 23
};

/**
 * TessdataType could be updated to contain more entries, however
 * we do not expect that number to be astronomically high.
 * In order to automatically detect endianness TessdataManager will
 * flip the bits if actual_tessdata_num_entries_ is larger than
 * kMaxNumTessdataEntries.
 */
static const int kMaxNumTessdataEntries = 1000;

class TESS_API TessdataManager {
public:
  TessdataManager();
  explicit TessdataManager(FileReader reader);

  ~TessdataManager() = default;

  bool swap() const {
    return swap_;
  }
  bool is_loaded() const {
    return is_loaded_;
  }

  // Lazily loads from the given filename. Won't actually read the file
  // until it needs it.
  void LoadFileLater(const char *data_file_name);
  /**
   * Opens and reads the given data file right now.
   * @return true on success.
   */
  bool Init(const char *data_file_name);
  // Loads from the given memory buffer as if a file, remembering name as some
  // arbitrary source id for caching.
  bool LoadMemBuffer(const char *name, const char *data, int size);
  // Overwrites a single entry of the given type.
  void OverwriteEntry(TessdataType type, const char *data, int size);

  // Saves to the given filename.
  bool SaveFile(const char *filename, FileWriter writer) const;
  // Serializes to the given vector.
  void Serialize(std::vector<char> *data) const;
  // Resets to the initial state, keeping the reader.
  void Clear();

  // Prints a directory of contents.
  void Directory() const;

  // Returns true if the component requested is present.
  bool IsComponentAvailable(TessdataType type) const {
    return !entries_[type].empty();
  }
  // Opens the given TFile pointer to the given component type.
  // Returns false in case of failure.
  bool GetComponent(TessdataType type, TFile *fp);
  // As non-const version except it can't load the component if not already
  // loaded.
  bool GetComponent(TessdataType type, TFile *fp) const;

  // Returns the current version string.
  std::string VersionString() const;
  // Sets the version string to the given v_str.
  void SetVersionString(const std::string &v_str);

  // Returns true if the base Tesseract components are present.
  bool IsBaseAvailable() const {
    return !entries_[TESSDATA_UNICHARSET].empty() && !entries_[TESSDATA_INTTEMP].empty();
  }

  // Returns true if the LSTM components are present.
  bool IsLSTMAvailable() const {
    return !entries_[TESSDATA_LSTM].empty();
  }

  // Return the name of the underlying data file.
  const std::string &GetDataFileName() const {
    return data_file_name_;
  }

  /**
   * Reads all the standard tesseract config and data files for a language
   * at the given path and bundles them up into one binary data file.
   * Returns true if the combined traineddata file was successfully written.
   */
  bool CombineDataFiles(const char *language_data_path_prefix, const char *output_filename);

  /**
   * Gets the individual components from the data_file_ with which the class was
   * initialized. Overwrites the components specified by component_filenames.
   * Writes the updated traineddata file to new_traineddata_filename.
   */
  bool OverwriteComponents(const char *new_traineddata_filename, char **component_filenames,
                           int num_new_components);

  /**
   * Extracts tessdata component implied by the name of the input file from
   * the combined traineddata loaded into TessdataManager.
   * Writes the extracted component to the file indicated by the file name.
   * E.g. if the filename given is somepath/somelang.unicharset, unicharset
   * will be extracted from the data loaded into the TessdataManager and will
   * be written to somepath/somelang.unicharset.
   * @return true if the component was successfully extracted, false if the
   * component was not present in the traineddata loaded into TessdataManager.
   */
  bool ExtractToFile(const char *filename);

private:
  // Use libarchive.
  bool LoadArchiveFile(const char *filename);

  /**
   * Fills type with TessdataType of the tessdata component represented by the
   * given file name. E.g. tessdata/eng.unicharset -> TESSDATA_UNICHARSET.
   * @return true if the tessdata component type could be determined
   * from the given file name.
   */
  static bool TessdataTypeFromFileSuffix(const char *suffix, TessdataType *type);

  /**
   * Tries to determine tessdata component file suffix from filename,
   * returns true on success.
   */
  static bool TessdataTypeFromFileName(const char *filename, TessdataType *type);

  // Name of file it came from.
  std::string data_file_name_;
  // Function to load the file when we need it.
  FileReader reader_;
  // True if the file has been loaded.
  bool is_loaded_;
  // True if the bytes need swapping.
  bool swap_;
  // Contents of each element of the traineddata file.
  std::vector<char> entries_[TESSDATA_NUM_ENTRIES];
};

} // namespace tesseract

#endif // TESSERACT_CCUTIL_TESSDATAMANAGER_H_