/* -*- Mode: C++ -*- */
// Copyright 2010 University of Helsinki
//
//  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.

#if HAVE_CONFIG_H
#  include <config.h>
#endif

// C
#if HAVE_LIBARCHIVE
#  include <archive.h>
#  include <archive_entry.h>
#endif
// C++
#if HAVE_LIBXML
#  include <libxml++/libxml++.h>
#endif
#include <string>
#include <map>

using std::string;
using std::map;

// local
#include "ospell.h"
#include "hfst-ol.h"
#include "ZHfstOspeller.h"

namespace hfst_ospell
  {

#if HAVE_LIBARCHIVE
inline std::string extract_to_mem(archive* ar, archive_entry* entry) {
    size_t full_length = 0;
    const struct stat* st = archive_entry_stat(entry);
    size_t buffsize = st->st_size;
    if (buffsize == 0) {
        std::cerr << archive_error_string(ar) << std::endl;
        throw ZHfstZipReadingError("Reading archive resulted in zero length entry");
    }

    std::string buff(buffsize, 0);
    for (;;) {
        ssize_t curr = archive_read_data(ar, &buff[0] + full_length, buffsize - full_length);
        if (0 == curr) {
            break;
        }
        else if (ARCHIVE_RETRY == curr) {
            continue;
        }
        else if (ARCHIVE_FAILED == curr) {
            throw ZHfstZipReadingError("Archive broken (ARCHIVE_FAILED)");
        }
        else if (curr < 0) {
            throw ZHfstZipReadingError("Archive broken...");
        }
        else {
            full_length += curr;
        }
    }

    if (full_length == 0) {
        std::cerr << archive_error_string(ar) << std::endl;
        throw ZHfstZipReadingError("Reading archive resulted in zero length");
    }

    return buff;
}

inline Transducer* transducer_to_mem(archive* ar, archive_entry* entry) {
    std::string buff = extract_to_mem(ar, entry);
    Transducer *trans = new Transducer(&buff[0]);
    return trans;
}

inline char* extract_to_tmp_dir(archive* ar) {
    char* rv = strdup("/tmp/zhfstospellXXXXXXXX");
    int temp_fd = mkstemp(rv);
    int rr = archive_read_data_into_fd(ar, temp_fd);
    if ((rr != ARCHIVE_EOF) && (rr != ARCHIVE_OK)) {
        throw ZHfstZipReadingError("Archive not EOF'd or OK'd");
    }
    close(temp_fd);
    return rv;
}

inline Transducer* transducer_to_tmp_dir(archive* ar) {
    char *filename = extract_to_tmp_dir(ar);
    FILE* f = fopen(filename, "rb");
    if (f == nullptr) {
        throw ZHfstTemporaryWritingError("reading acceptor back from temp file");
    }
    return new Transducer(f);
}

#endif // HAVE_LIBARCHIVE

ZHfstOspeller::ZHfstOspeller() :
    suggestions_maximum_(0),
    maximum_weight_(-1.0),
    beam_(-1.0),
    time_cutoff_(0.0),
    can_spell_(false),
    can_correct_(false),
    can_analyse_(true),
    current_speller_(0),
    current_sugger_(0)
    {
    }

ZHfstOspeller::~ZHfstOspeller()
  {
    if ((current_speller_ != NULL) && (current_sugger_ != NULL))
      {
        if (current_speller_ != current_sugger_)
          {
            delete current_speller_;
            delete current_sugger_;
          }
        else
          {
            delete current_speller_;
          }
        current_sugger_ = 0;
        current_speller_ = 0;
      }
    for (auto& acceptor : acceptors_)
      {
        delete acceptor.second;
      }
    for (auto& errmodel : errmodels_)
      {
        delete errmodel.second;
      }
    can_spell_ = false;
    can_correct_ = false;
  }

void
ZHfstOspeller::inject_speller(Speller * s)
  {
      current_speller_ = s;
      current_sugger_ = s;
      can_spell_ = true;
      can_correct_ = true;
  }

void
ZHfstOspeller::set_queue_limit(unsigned long limit)
  {
    suggestions_maximum_ = limit;
  }

void
ZHfstOspeller::set_weight_limit(Weight limit)
  {
    maximum_weight_ = limit;
  }

void
ZHfstOspeller::set_beam(Weight beam)
  {
      beam_ = beam;
  }

void
ZHfstOspeller::set_time_cutoff(float time_cutoff)
  {
      time_cutoff_ = time_cutoff;
  }

bool
ZHfstOspeller::spell(const string& wordform)
  {
    if (can_spell_ && (current_speller_ != 0))
      {
        char* wf = strdup(wordform.c_str());
        bool rv = current_speller_->check(wf);
        free(wf);
        return rv;
      }
    return false;
  }

CorrectionQueue
ZHfstOspeller::suggest(const string& wordform)
  {
    CorrectionQueue rv;
    if ((can_correct_) && (current_sugger_ != 0))
      {
        char* wf = strdup(wordform.c_str());
        rv = current_sugger_->correct(wf,
                                      suggestions_maximum_,
                                      maximum_weight_,
                                      beam_,
                                      time_cutoff_);
        free(wf);
        return rv;
      }
    return rv;
  }

AnalysisQueue
ZHfstOspeller::analyse(const string& wordform, bool ask_sugger)
  {
    AnalysisQueue rv;
    char* wf = strdup(wordform.c_str());
    if ((can_analyse_) && (!ask_sugger) && (current_speller_ != 0))
      {
          rv = current_speller_->analyse(wf);
      }
    else if ((can_analyse_) && (ask_sugger) && (current_sugger_ != 0))
      {
          rv = current_sugger_->analyse(wf);
      }
    free(wf);
    return rv;
  }

AnalysisSymbolsQueue
ZHfstOspeller::analyseSymbols(const string& wordform, bool ask_sugger)
  {
    AnalysisSymbolsQueue rv;
    char* wf = strdup(wordform.c_str());
    if ((can_analyse_) && (!ask_sugger) && (current_speller_ != 0))
      {
          rv = current_speller_->analyseSymbols(wf);
      }
    else if ((can_analyse_) && (ask_sugger) && (current_sugger_ != 0))
      {
          rv = current_sugger_->analyseSymbols(wf);
      }
    free(wf);
    return rv;
  }

AnalysisCorrectionQueue
ZHfstOspeller::suggest_analyses(const string& wordform)
  {
    AnalysisCorrectionQueue rv;
    // FIXME: should be atomic
    CorrectionQueue cq = suggest(wordform);
    while (cq.size() > 0)
      {
        AnalysisQueue aq = analyse(cq.top().first, true);
        while (aq.size() > 0)
          {
            StringPair sp(cq.top().first, aq.top().first);
            StringPairWeightPair spwp(sp, aq.top().second);
            rv.push(spwp);
            aq.pop();
          }
        cq.pop();
      }
    return rv;
  }

void
ZHfstOspeller::read_zhfst(const string& filename)
  {
#if HAVE_LIBARCHIVE
    struct archive* ar = archive_read_new();
    struct archive_entry* entry = 0;

#if USE_LIBARCHIVE_2
    archive_read_support_compression_all(ar);
#else
    archive_read_support_filter_all(ar);
#endif // USE_LIBARCHIVE_2

    archive_read_support_format_all(ar);
    int rr = archive_read_open_filename(ar, filename.c_str(), 10240);
    if (rr != ARCHIVE_OK)
      {
        throw ZHfstZipReadingError("Archive not OK");
      }
    for (int rr = archive_read_next_header(ar, &entry);
         rr != ARCHIVE_EOF;
         rr = archive_read_next_header(ar, &entry))
      {
        if (rr != ARCHIVE_OK)
          {
            throw ZHfstZipReadingError("Archive not OK");
          }
        char* filename = strdup(archive_entry_pathname(entry));
        if (strncmp(filename, "acceptor.", strlen("acceptor.")) == 0) {
            Transducer* trans = nullptr;

#if ZHFST_EXTRACT_TO_MEM == 1
            // Try to memory first...
            try {
                trans = transducer_to_mem(ar, entry);
            }
            catch (...) {
                // If that failed, try to /tmp
                //std::cerr << "Failed to memory - falling back to /tmp" << std::endl;
                trans = transducer_to_tmp_dir(ar);
            }
#else
            // Try to /tmp first...
            try {
                trans = transducer_to_tmp_dir(ar);
            }
            catch (...) {
                // If that failed, try to memory
                //std::cerr << "Failed to /tmp - falling back to memory" << std::endl;
                trans = transducer_to_mem(ar, entry);
            }
#endif
            if (trans == nullptr) {
                throw ZHfstZipReadingError("Failed to extract acceptor");
            }

            char* p = filename;
            p += strlen("acceptor.");
            size_t descr_len = 0;
            for (const char* q = p; *q != '\0'; q++)
              {
                if (*q == '.')
                  {
                    break;
                  }
                else
                    {
                      descr_len++;
                    }
              }

            char* descr = hfst_strndup(p, descr_len);
            acceptors_[descr] = trans;
            free(descr);
          }
        else if (strncmp(filename, "errmodel.", strlen("errmodel.")) == 0) {
            Transducer* trans = nullptr;

#if ZHFST_EXTRACT_TO_MEM == 1
            // Try to memory first...
            try {
                trans = transducer_to_mem(ar, entry);
            }
            catch (...) {
                // If that failed, try to /tmp
                //std::cerr << "Failed to memory - falling back to /tmp" << std::endl;
                trans = transducer_to_tmp_dir(ar);
            }
#else
            // Try to /tmp first...
            try {
                trans = transducer_to_tmp_dir(ar);
            }
            catch (...) {
                // If that failed, try to memory
                //std::cerr << "Failed to /tmp - falling back to memory" << std::endl;
                trans = transducer_to_mem(ar, entry);
            }
#endif
            if (trans == nullptr) {
                throw ZHfstZipReadingError("Failed to extract error model");
            }

            const char* p = filename;
            p += strlen("errmodel.");
            size_t descr_len = 0;
            for (const char* q = p; *q != '\0'; q++)
              {
                if (*q == '.')
                  {
                    break;
                  }
                else
                  {
                    descr_len++;
                  }
              }

            char* descr = hfst_strndup(p, descr_len);
            errmodels_[descr] = trans;
            free(descr);
          } // if acceptor or errmodel
        else if (strcmp(filename, "index.xml") == 0) {
            // Always try to memory first, as index.xml is tiny
            try {
                std::string full_data = extract_to_mem(ar, entry);
                metadata_.read_xml(&full_data[0], full_data.size());
            }
            catch (...) {
                char* temporary = extract_to_tmp_dir(ar);
                metadata_.read_xml(temporary);
            }
          }
        else
          {
            fprintf(stderr, "Unknown file in archive %s\n", filename);
          }
        free(filename);
      } // while r != ARCHIVE_EOF
    archive_read_close(ar);

#if USE_LIBARCHIVE_2
    archive_read_finish(ar);
#else
    archive_read_free(ar);
#endif // USE_LIBARCHIVE_2

    if ((errmodels_.find("default") != errmodels_.end()) &&
        (acceptors_.find("default") != acceptors_.end()))
      {
        current_speller_ = new Speller(
                                       errmodels_["default"],
                                       acceptors_["default"]
                                       );
        current_sugger_ = current_speller_;
        can_spell_ = true;
        can_correct_ = true;
      }
    else if ((acceptors_.size() > 0) && (errmodels_.size() > 0))
      {
        fprintf(stderr, "Could not find default speller, using %s %s\n",
                acceptors_.begin()->first.c_str(),
                errmodels_.begin()->first.c_str());
        current_speller_ = new Speller(
                                       errmodels_.begin()->second,
                                       acceptors_.begin()->second
                                       );
        current_sugger_ = current_speller_;
        can_spell_ = true;
        can_correct_ = true;
      }
    else if ((acceptors_.size() > 0) &&
             (acceptors_.find("default") != acceptors_.end()))
      {
        current_speller_ = new Speller(0, acceptors_["default"]);
        current_sugger_ = current_speller_;
        can_spell_ = true;
        can_correct_ = false;
      }
    else if (acceptors_.size() > 0)
      {
        current_speller_ = new Speller(0, acceptors_.begin()->second);
        current_sugger_ = current_speller_;
        can_spell_ = true;
        can_correct_ = false;
      }
    else
      {
        throw ZHfstZipReadingError("No automata found in zip");
      }
    can_analyse_ = can_spell_ | can_correct_;
#else
    throw ZHfstZipReadingError("Zip support was disabled");
#endif // HAVE_LIBARCHIVE
  }


const ZHfstOspellerXmlMetadata&
ZHfstOspeller::get_metadata() const
  {
    return metadata_;
  }

string
ZHfstOspeller::metadata_dump() const
  {
    return metadata_.debug_dump();

  }
} // namespace hfst_ospell
