///////////////////////////////////////////////////////////////////////

// File:        ambigs.cpp

// Description: Functions for dealing with ambiguities

//              (training and recognition).

// Author:      Daria Antonova

//

// (C) Copyright 2008, 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.

//

///////////////////////////////////////////////////////////////////////

#include "ambigs.h"

#include "helpers.h"

#include "universalambigs.h"

#include <cstdio>

#if defined(_WIN32) && !defined(__GNUC__)

#  define strtok_r(str, delim, saveptr) strtok_s(str, delim, saveptr)

#endif /* _WIN32 && !__GNUC__ */

namespace tesseract {

static const char kAmbigDelimiters[] = "\t ";

static const char kIllegalMsg[] = "Illegal ambiguity specification on line %d\n";

static const char kIllegalUnicharMsg[] = "Illegal unichar %s in ambiguity specification\n";

// Maximum line size:

//   10 for sizes of ambigs, tabs, abmig type and newline

//   UNICHAR_LEN * (MAX_AMBIG_SIZE + 1) for each part of the ambig

const int kMaxAmbigStringSize = UNICHAR_LEN * (MAX_AMBIG_SIZE + 1);

AmbigSpec::AmbigSpec() : correct_ngram_id(INVALID_UNICHAR_ID), type(NOT_AMBIG), wrong_ngram_size(0) {

  wrong_ngram[0] = INVALID_UNICHAR_ID;

  correct_fragments[0] = INVALID_UNICHAR_ID;

}

// Initializes the ambigs by adding a nullptr pointer to each table.

void UnicharAmbigs::InitUnicharAmbigs(const UNICHARSET &unicharset, bool use_ambigs_for_adaption) {

  for (unsigned i = 0; i < unicharset.size(); ++i) {

    replace_ambigs_.push_back(nullptr);

    dang_ambigs_.push_back(nullptr);

    one_to_one_definite_ambigs_.push_back(nullptr);

    if (use_ambigs_for_adaption) {

      ambigs_for_adaption_.push_back(nullptr);

      reverse_ambigs_for_adaption_.push_back(nullptr);

    }

  }

}

// Loads the universal ambigs that are useful for any language.

void UnicharAmbigs::LoadUniversal(const UNICHARSET &encoder_set, UNICHARSET *unicharset) {

  TFile file;

  if (!file.Open(kUniversalAmbigsFile, ksizeofUniversalAmbigsFile)) {

    return;

  }

  LoadUnicharAmbigs(encoder_set, &file, 0, false, unicharset);

}

void UnicharAmbigs::LoadUnicharAmbigs(const UNICHARSET &encoder_set, TFile *ambig_file,

                                      int debug_level, bool use_ambigs_for_adaption,

                                      UNICHARSET *unicharset) {

  UnicharIdVector *adaption_ambigs_entry;

  if (debug_level) {

    tprintf("Reading ambiguities\n");

  }

  int test_ambig_part_size;

  int replacement_ambig_part_size;

  // The space for buffer is allocated on the heap to avoid

  // GCC frame size warning.

  const int kBufferSize = 10 + 2 * kMaxAmbigStringSize;

  char *buffer = new char[kBufferSize];

  char replacement_string[kMaxAmbigStringSize];

  UNICHAR_ID test_unichar_ids[MAX_AMBIG_SIZE + 1];

  int line_num = 0;

  int type = NOT_AMBIG;

  // Determine the version of the ambigs file.

  int version = 0;

  ASSERT_HOST(ambig_file->FGets(buffer, kBufferSize) != nullptr && buffer[0] != '\0');

  if (*buffer == 'v') {

    version = static_cast<int>(strtol(buffer + 1, nullptr, 10));

    ++line_num;

  } else {

    ambig_file->Rewind();

  }

  while (ambig_file->FGets(buffer, kBufferSize) != nullptr) {

    chomp_string(buffer);

    if (debug_level > 2) {

      tprintf("read line %s\n", buffer);

    }

    ++line_num;

    if (!ParseAmbiguityLine(line_num, version, debug_level, encoder_set, buffer,

                            &test_ambig_part_size, test_unichar_ids, &replacement_ambig_part_size,

                            replacement_string, &type)) {

      continue;

    }

    // Construct AmbigSpec and add it to the appropriate AmbigSpec_LIST.

    auto *ambig_spec = new AmbigSpec();

    if (!InsertIntoTable((type == REPLACE_AMBIG) ? replace_ambigs_ : dang_ambigs_,

                         test_ambig_part_size, test_unichar_ids, replacement_ambig_part_size,

                         replacement_string, type, ambig_spec, unicharset)) {

      continue;

    }

    // Update one_to_one_definite_ambigs_.

    if (test_ambig_part_size == 1 && replacement_ambig_part_size == 1 && type == DEFINITE_AMBIG) {

      if (one_to_one_definite_ambigs_[test_unichar_ids[0]] == nullptr) {

        one_to_one_definite_ambigs_[test_unichar_ids[0]] = new UnicharIdVector();

      }

      one_to_one_definite_ambigs_[test_unichar_ids[0]]->push_back(ambig_spec->correct_ngram_id);

    }

    // Update ambigs_for_adaption_.

    if (use_ambigs_for_adaption) {

      std::vector<UNICHAR_ID> encoding;

      // Silently ignore invalid strings, as before, so it is safe to use a

      // universal ambigs file.

      if (unicharset->encode_string(replacement_string, true, &encoding, nullptr, nullptr)) {

        for (int i = 0; i < test_ambig_part_size; ++i) {

          if (ambigs_for_adaption_[test_unichar_ids[i]] == nullptr) {

            ambigs_for_adaption_[test_unichar_ids[i]] = new UnicharIdVector();

          }

          adaption_ambigs_entry = ambigs_for_adaption_[test_unichar_ids[i]];

          for (int id_to_insert : encoding) {

            ASSERT_HOST(id_to_insert != INVALID_UNICHAR_ID);

            // Add the new unichar id to adaption_ambigs_entry (only if the

            // vector does not already contain it) keeping it in sorted order.

            size_t j;

            for (j = 0;

                 j < adaption_ambigs_entry->size() && (*adaption_ambigs_entry)[j] > id_to_insert;

                 ++j) {

            }

            if (j < adaption_ambigs_entry->size()) {

              if ((*adaption_ambigs_entry)[j] != id_to_insert) {

                adaption_ambigs_entry->insert(adaption_ambigs_entry->begin() + j, id_to_insert);

              }

            } else {

              adaption_ambigs_entry->push_back(id_to_insert);

            }

          }

        }

      }

    }

  }

  delete[] buffer;

  // Fill in reverse_ambigs_for_adaption from ambigs_for_adaption vector.

  if (use_ambigs_for_adaption) {

    for (size_t i = 0; i < ambigs_for_adaption_.size(); ++i) {

      adaption_ambigs_entry = ambigs_for_adaption_[i];

      if (adaption_ambigs_entry == nullptr) {

        continue;

      }

      for (size_t j = 0; j < adaption_ambigs_entry->size(); ++j) {

        UNICHAR_ID ambig_id = (*adaption_ambigs_entry)[j];

        if (reverse_ambigs_for_adaption_[ambig_id] == nullptr) {

          reverse_ambigs_for_adaption_[ambig_id] = new UnicharIdVector();

        }

        reverse_ambigs_for_adaption_[ambig_id]->push_back(i);

      }

    }

  }

  // Print what was read from the input file.

  if (debug_level > 1) {

    for (int tbl = 0; tbl < 2; ++tbl) {

      const UnicharAmbigsVector &print_table = (tbl == 0) ? replace_ambigs_ : dang_ambigs_;

      for (size_t i = 0; i < print_table.size(); ++i) {

        AmbigSpec_LIST *lst = print_table[i];

        if (lst == nullptr) {

          continue;

        }

        if (!lst->empty()) {

          tprintf("%s Ambiguities for %s:\n", (tbl == 0) ? "Replaceable" : "Dangerous",

                  unicharset->debug_str(i).c_str());

        }

        AmbigSpec_IT lst_it(lst);

        for (lst_it.mark_cycle_pt(); !lst_it.cycled_list(); lst_it.forward()) {

          AmbigSpec *ambig_spec = lst_it.data();

          tprintf("wrong_ngram:");

          UnicharIdArrayUtils::print(ambig_spec->wrong_ngram, *unicharset);

          tprintf("correct_fragments:");

          UnicharIdArrayUtils::print(ambig_spec->correct_fragments, *unicharset);

        }

      }

    }

    if (use_ambigs_for_adaption) {

      for (int vec_id = 0; vec_id < 2; ++vec_id) {

        const std::vector<UnicharIdVector *> &vec =

            (vec_id == 0) ? ambigs_for_adaption_ : reverse_ambigs_for_adaption_;

        for (size_t i = 0; i < vec.size(); ++i) {

          adaption_ambigs_entry = vec[i];

          if (adaption_ambigs_entry != nullptr) {

            tprintf("%sAmbigs for adaption for %s:\n", (vec_id == 0) ? "" : "Reverse ",

                    unicharset->debug_str(i).c_str());

            for (size_t j = 0; j < adaption_ambigs_entry->size(); ++j) {

              tprintf("%s ", unicharset->debug_str((*adaption_ambigs_entry)[j]).c_str());

            }

            tprintf("\n");

          }

        }

      }

    }

  }

}

bool UnicharAmbigs::ParseAmbiguityLine(int line_num, int version, int debug_level,

                                       const UNICHARSET &unicharset, char *buffer,

                                       int *test_ambig_part_size, UNICHAR_ID *test_unichar_ids,

                                       int *replacement_ambig_part_size, char *replacement_string,

                                       int *type) {

  if (version > 1) {

    // Simpler format is just wrong-string correct-string type\n.

    std::string input(buffer);

    std::vector<std::string> fields = split(input, ' ');

    if (fields.size() != 3) {

      if (debug_level) {

        tprintf(kIllegalMsg, line_num);

      }

      return false;

    }

    // Encode wrong-string.

    std::vector<UNICHAR_ID> unichars;

    if (!unicharset.encode_string(fields[0].c_str(), true, &unichars, nullptr, nullptr)) {

      return false;

    }

    *test_ambig_part_size = unichars.size();

    if (*test_ambig_part_size > MAX_AMBIG_SIZE) {

      if (debug_level) {

        tprintf("Too many unichars in ambiguity on line %d\n", line_num);

      }

      return false;

    }

    // Copy encoded string to output.

    for (size_t i = 0; i < unichars.size(); ++i) {

      test_unichar_ids[i] = unichars[i];

    }

    test_unichar_ids[unichars.size()] = INVALID_UNICHAR_ID;

    // Encode replacement-string to check validity.

    if (!unicharset.encode_string(fields[1].c_str(), true, &unichars, nullptr, nullptr)) {

      return false;

    }

    *replacement_ambig_part_size = unichars.size();

    if (*replacement_ambig_part_size > MAX_AMBIG_SIZE) {

      if (debug_level) {

        tprintf("Too many unichars in ambiguity on line %d\n", line_num);

      }

      return false;

    }

    if (sscanf(fields[2].c_str(), "%d", type) != 1) {

      if (debug_level) {

        tprintf(kIllegalMsg, line_num);

      }

      return false;

    }

    snprintf(replacement_string, kMaxAmbigStringSize, "%s", fields[1].c_str());

    return true;

  }

  int i;

  char *next_token;

  char *token = strtok_r(buffer, kAmbigDelimiters, &next_token);

  if (!token || sscanf(token, "%d", test_ambig_part_size) != 1 ||

      *test_ambig_part_size <= 0) {

    if (debug_level) {

      tprintf(kIllegalMsg, line_num);

    }

    return false;

  }

  if (*test_ambig_part_size > MAX_AMBIG_SIZE) {

    if (debug_level) {

      tprintf("Too many unichars in ambiguity on line %d\n", line_num);

    }

    return false;

  }

  for (i = 0; i < *test_ambig_part_size; ++i) {

    if (!(token = strtok_r(nullptr, kAmbigDelimiters, &next_token))) {

      break;

    }

    if (!unicharset.contains_unichar(token)) {

      if (debug_level) {

        tprintf(kIllegalUnicharMsg, token);

      }

      break;

    }

    test_unichar_ids[i] = unicharset.unichar_to_id(token);

  }

  test_unichar_ids[i] = INVALID_UNICHAR_ID;

  if (i != *test_ambig_part_size || !(token = strtok_r(nullptr, kAmbigDelimiters, &next_token)) ||

      sscanf(token, "%d", replacement_ambig_part_size) != 1 ||

      *replacement_ambig_part_size <= 0) {

    if (debug_level) {

      tprintf(kIllegalMsg, line_num);

    }

    return false;

  }

  if (*replacement_ambig_part_size > MAX_AMBIG_SIZE) {

    if (debug_level) {

      tprintf("Too many unichars in ambiguity on line %d\n", line_num);

    }

    return false;

  }

  replacement_string[0] = '\0';

  for (i = 0; i < *replacement_ambig_part_size; ++i) {

    if (!(token = strtok_r(nullptr, kAmbigDelimiters, &next_token))) {

      break;

    }

    strcat(replacement_string, token);

    if (!unicharset.contains_unichar(token)) {

      if (debug_level) {

        tprintf(kIllegalUnicharMsg, token);

      }

      break;

    }

  }

  if (i != *replacement_ambig_part_size) {

    if (debug_level) {

      tprintf(kIllegalMsg, line_num);

    }

    return false;

  }

  if (version > 0) {

    // The next field being true indicates that the ambiguity should

    // always be substituted (e.g. '' should always be changed to ").

    // For such "certain" n -> m ambigs tesseract will insert character

    // fragments for the n pieces in the unicharset. AmbigsFound()

    // will then replace the incorrect ngram with the character

    // fragments of the correct character (or ngram if m > 1).

    // Note that if m > 1, an ngram will be inserted into the

    // modified word, not the individual unigrams. Tesseract

    // has limited support for ngram unichar (e.g. dawg permuter).

    token = strtok_r(nullptr, kAmbigDelimiters, &next_token);

    if (!token || sscanf(token, "%d", type) != 1) {

      if (debug_level) {

        tprintf(kIllegalMsg, line_num);

      }

      return false;

    }

  }

  return true;

}

bool UnicharAmbigs::InsertIntoTable(UnicharAmbigsVector &table, int test_ambig_part_size,

                                    UNICHAR_ID *test_unichar_ids, int replacement_ambig_part_size,

                                    const char *replacement_string, int type, AmbigSpec *ambig_spec,

                                    UNICHARSET *unicharset) {

  ambig_spec->type = static_cast<AmbigType>(type);

  if (test_ambig_part_size == 1 && replacement_ambig_part_size == 1 &&

      unicharset->to_lower(test_unichar_ids[0]) ==

          unicharset->to_lower(unicharset->unichar_to_id(replacement_string))) {

    ambig_spec->type = CASE_AMBIG;

  }

  ambig_spec->wrong_ngram_size =

      UnicharIdArrayUtils::copy(test_unichar_ids, ambig_spec->wrong_ngram);

  // Since we need to maintain a constant number of unichar positions in

  // order to construct ambig_blob_choices vector in NoDangerousAmbig(), for

  // each n->m ambiguity we will have to place n character fragments of the

  // correct ngram into the corresponding positions in the vector (e.g. given

  // "vvvvw" and vvvv->ww we will place v and |ww|0|4 into position 0, v and

  // |ww|1|4 into position 1 and so on. The correct ngram is reconstructed

  // from fragments by dawg_permute_and_select().

  // Insert the corresponding correct ngram into the unicharset.

  // Unicharset code assumes that the "base" ngram is inserted into

  // the unicharset before fragments of this ngram are inserted.

  unicharset->unichar_insert(replacement_string, OldUncleanUnichars::kTrue);

  ambig_spec->correct_ngram_id = unicharset->unichar_to_id(replacement_string);

  if (replacement_ambig_part_size > 1) {

    unicharset->set_isngram(ambig_spec->correct_ngram_id, true);

  }

  // Add the corresponding fragments of the wrong ngram to unicharset.

  int i;

  for (i = 0; i < test_ambig_part_size; ++i) {

    UNICHAR_ID unichar_id;

    if (test_ambig_part_size == 1) {

      unichar_id = ambig_spec->correct_ngram_id;

    } else {

      std::string frag_str =

          CHAR_FRAGMENT::to_string(replacement_string, i, test_ambig_part_size, false);

      unicharset->unichar_insert(frag_str.c_str(), OldUncleanUnichars::kTrue);

      unichar_id = unicharset->unichar_to_id(frag_str.c_str());

    }

    ambig_spec->correct_fragments[i] = unichar_id;

  }

  ambig_spec->correct_fragments[i] = INVALID_UNICHAR_ID;

  // Add AmbigSpec for this ambiguity to the corresponding AmbigSpec_LIST.

  // Keep AmbigSpec_LISTs sorted by AmbigSpec.wrong_ngram.

  if (table[test_unichar_ids[0]] == nullptr) {

    table[test_unichar_ids[0]] = new AmbigSpec_LIST();

  }

  if (table[test_unichar_ids[0]]->add_sorted(AmbigSpec::compare_ambig_specs, true, ambig_spec)) {

    return true;

  }

  delete ambig_spec;

  return false;

}

} // namespace tesseract