// Copyright (C) 2012 The Libphonenumber Authors
//
// 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.

// Author: Patrick Mezard

#include "phonenumbers/geocoding/phonenumber_offline_geocoder.h"

#include <algorithm>
#include <string>

#include <unicode/unistr.h>  // NOLINT(build/include_order)

#include "phonenumbers/geocoding/area_code_map.h"
#include "phonenumbers/geocoding/geocoding_data.h"
#include "phonenumbers/geocoding/mapping_file_provider.h"
#include "phonenumbers/phonenumberutil.h"
#include "phonenumbers/stl_util.h"

namespace i18n {
namespace phonenumbers {

using icu::UnicodeString;
using std::string;

namespace {

// Returns true if s1 comes strictly before s2 in lexicographic order.
bool IsLowerThan(const char* s1, const char* s2) {
  return strcmp(s1, s2) < 0;
}

}  // namespace

PhoneNumberOfflineGeocoder::PhoneNumberOfflineGeocoder() {
  Init(get_country_calling_codes(), get_country_calling_codes_size(),
       get_country_languages, get_prefix_language_code_pairs(),
       get_prefix_language_code_pairs_size(), get_prefix_descriptions);
}

PhoneNumberOfflineGeocoder::PhoneNumberOfflineGeocoder(
    const int* country_calling_codes, int country_calling_codes_size,
    country_languages_getter get_country_languages,
    const char** prefix_language_code_pairs,
    int prefix_language_code_pairs_size,
    prefix_descriptions_getter get_prefix_descriptions) {
  Init(country_calling_codes, country_calling_codes_size,
       get_country_languages, prefix_language_code_pairs,
       prefix_language_code_pairs_size, get_prefix_descriptions);
}

void PhoneNumberOfflineGeocoder::Init(
    const int* country_calling_codes, int country_calling_codes_size,
    country_languages_getter get_country_languages,
    const char** prefix_language_code_pairs,
    int prefix_language_code_pairs_size,
    prefix_descriptions_getter get_prefix_descriptions) {
  phone_util_ = PhoneNumberUtil::GetInstance();
  provider_.reset(new MappingFileProvider(country_calling_codes,
                                          country_calling_codes_size,
                                          get_country_languages));
  prefix_language_code_pairs_ = prefix_language_code_pairs;
  prefix_language_code_pairs_size_ = prefix_language_code_pairs_size;
  get_prefix_descriptions_ = get_prefix_descriptions;
}

PhoneNumberOfflineGeocoder::~PhoneNumberOfflineGeocoder() {
  gtl::STLDeleteContainerPairSecondPointers(
      available_maps_.begin(), available_maps_.end());
}

const AreaCodeMap* PhoneNumberOfflineGeocoder::GetPhonePrefixDescriptions(
    int prefix, const string& language, const string& script,
    const string& region) const {
  string filename;
  provider_->GetFileName(prefix, language, script, region, &filename);
  if (filename.empty()) {
    return NULL;
  }
  AreaCodeMaps::const_iterator it = available_maps_.find(filename);
  if (it == available_maps_.end()) {
    return LoadAreaCodeMapFromFile(filename);
  }
  return it->second;
}

const AreaCodeMap* PhoneNumberOfflineGeocoder::LoadAreaCodeMapFromFile(
    const string& filename) const {
  const char** const prefix_language_code_pairs_end =
      prefix_language_code_pairs_ + prefix_language_code_pairs_size_;
  const char** const prefix_language_code_pair =
      std::lower_bound(prefix_language_code_pairs_,
                       prefix_language_code_pairs_end,
                       filename.c_str(), IsLowerThan);
  if (prefix_language_code_pair != prefix_language_code_pairs_end &&
      filename.compare(*prefix_language_code_pair) == 0) {
    AreaCodeMap* const m = new AreaCodeMap();
    m->ReadAreaCodeMap(get_prefix_descriptions_(
            prefix_language_code_pair - prefix_language_code_pairs_));
    return available_maps_.insert(AreaCodeMaps::value_type(filename, m))
        .first->second;
  }
  return NULL;
}

string PhoneNumberOfflineGeocoder::GetCountryNameForNumber(
    const PhoneNumber& number, const Locale& language) const {
  string region_code;
  phone_util_->GetRegionCodeForNumber(number, &region_code);
  return GetRegionDisplayName(&region_code, language);
}

string PhoneNumberOfflineGeocoder::GetRegionDisplayName(
    const string* region_code, const Locale& language) const {
  if (region_code == NULL || region_code->compare("ZZ") == 0 ||
      region_code->compare(
         PhoneNumberUtil::kRegionCodeForNonGeoEntity) == 0) {
    return "";
  }
  UnicodeString udisplay_country;
  icu::Locale("", region_code->c_str()).getDisplayCountry(
      language, udisplay_country);
  string display_country;
  udisplay_country.toUTF8String(display_country);
  return display_country;
}

string PhoneNumberOfflineGeocoder::GetDescriptionForValidNumber(
    const PhoneNumber& number, const Locale& language) const {
  const char* const description = GetAreaDescription(
      number, language.getLanguage(), "", language.getCountry());
  return *description != '\0'
        ? description
        : GetCountryNameForNumber(number, language);
}

string PhoneNumberOfflineGeocoder::GetDescriptionForValidNumber(
    const PhoneNumber& number, const Locale& language,
    const string& user_region) const {
  // If the user region matches the number's region, then we just show the
  // lower-level description, if one exists - if no description exists, we will
  // show the region(country) name for the number.
  string region_code;
  phone_util_->GetRegionCodeForNumber(number, &region_code);
  if (user_region.compare(region_code) == 0) {
    return GetDescriptionForValidNumber(number, language);
  }
  // Otherwise, we just show the region(country) name for now.
  return GetRegionDisplayName(&region_code, language);
}

string PhoneNumberOfflineGeocoder::GetDescriptionForNumber(
    const PhoneNumber& number, const Locale& locale) const {
  PhoneNumberUtil::PhoneNumberType number_type =
      phone_util_->GetNumberType(number);
  if (number_type == PhoneNumberUtil::UNKNOWN) {
    return "";
  } else if (!phone_util_->IsNumberGeographical(number_type,
                                                number.country_code())) {
    return GetCountryNameForNumber(number, locale);
  }
  return GetDescriptionForValidNumber(number, locale);
}

string PhoneNumberOfflineGeocoder::GetDescriptionForNumber(
    const PhoneNumber& number, const Locale& language,
    const string& user_region) const {
  PhoneNumberUtil::PhoneNumberType number_type =
      phone_util_->GetNumberType(number);
  if (number_type == PhoneNumberUtil::UNKNOWN) {
    return "";
  } else if (!phone_util_->IsNumberGeographical(number_type,
                                                number.country_code())) {
    return GetCountryNameForNumber(number, language);
  }
  return GetDescriptionForValidNumber(number, language, user_region);
}

const char* PhoneNumberOfflineGeocoder::GetAreaDescription(
    const PhoneNumber& number, const string& lang, const string& script,
    const string& region) const {
  const int country_calling_code = number.country_code();
  // NANPA area is not split in C++ code.
  const int phone_prefix = country_calling_code;
  const AreaCodeMap* const descriptions = GetPhonePrefixDescriptions(
      phone_prefix, lang, script, region);
  const char* description = descriptions ? descriptions->Lookup(number) : NULL;
  // When a location is not available in the requested language, fall back to
  // English.
  if ((!description || *description == '\0') && MayFallBackToEnglish(lang)) {
    const AreaCodeMap* default_descriptions = GetPhonePrefixDescriptions(
        phone_prefix, "en", "", "");
    if (!default_descriptions) {
      return "";
    }
    description = default_descriptions->Lookup(number);
  }
  return description ? description : "";
}

// Don't fall back to English if the requested language is among the following:
// - Chinese
// - Japanese
// - Korean
bool PhoneNumberOfflineGeocoder::MayFallBackToEnglish(
    const string& lang) const {
  return lang.compare("zh") && lang.compare("ja") && lang.compare("ko");
}

}  // namespace phonenumbers
}  // namespace i18n