// Copyright (C) 2011 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: Lara Rennie
// Author: Tao Huang
//
// Implementation of a stateful class that finds and extracts telephone numbers
// from text.

#include "phonenumbers/phonenumbermatcher.h"

#ifndef I18N_PHONENUMBERS_USE_ICU_REGEXP
#error phonenumbermatcher depends on ICU \
    (i.e. I18N_PHONENUMBERS_USE_ICU_REGEXP must be set)
#endif  // I18N_PHONENUMBERS_USE_ICU_REGEXP

#include <ctype.h>
#include <iostream>
#include <limits>
#include <map>
#include <stddef.h>
#include <string>
#include <utility>
#include <vector>

#include <unicode/uchar.h>

#include "phonenumbers/alternate_format.h"
#include "phonenumbers/base/logging.h"
#include "phonenumbers/base/memory/scoped_ptr.h"
#include "phonenumbers/base/memory/singleton.h"
#include "phonenumbers/callback.h"
#include "phonenumbers/default_logger.h"
#include "phonenumbers/encoding_utils.h"
#include "phonenumbers/normalize_utf8.h"
#include "phonenumbers/phonemetadata.pb.h"
#include "phonenumbers/phonenumber.pb.h"
#include "phonenumbers/phonenumbermatch.h"
#include "phonenumbers/phonenumberutil.h"
#include "phonenumbers/regexp_adapter.h"
#include "phonenumbers/regexp_adapter_icu.h"
#include "phonenumbers/stringutil.h"

#ifdef I18N_PHONENUMBERS_USE_RE2
#include "phonenumbers/regexp_adapter_re2.h"
#endif  // I18N_PHONENUMBERS_USE_RE2_AND_ICU

using std::cerr;
using std::endl;
using std::make_pair;
using std::map;
using std::numeric_limits;
using std::string;
using std::vector;

namespace i18n {
namespace phonenumbers {

namespace {
// Returns a regular expression quantifier with an upper and lower limit.
string Limit(int lower, int upper) {
  DCHECK_GE(lower, 0);
  DCHECK_GT(upper, 0);
  DCHECK_LT(lower, upper);
  return StrCat("{", lower, ",", upper, "}");
}

bool IsInvalidPunctuationSymbol(char32 character) {
  return character == '%' || u_charType(character) == U_CURRENCY_SYMBOL;
}

bool ContainsOnlyValidXChars(const PhoneNumber& number, const string& candidate,
                             const PhoneNumberUtil& util) {
  // The characters 'x' and 'X' can be (1) a carrier code, in which case they
  // always precede the national significant number or (2) an extension sign,
  // in which case they always precede the extension number. We assume a
  // carrier code is more than 1 digit, so the first case has to have more than
  // 1 consecutive 'x' or 'X', whereas the second case can only have exactly 1
  // 'x' or 'X'.
  size_t found;
  found = candidate.find_first_of("xX");
  // We ignore the character if 'x' or 'X' appears as the last character of
  // the string.
  while (found != string::npos && found < candidate.length() - 1) {
    // We only look for 'x' or 'X' in ASCII form.
    char next_char = candidate[found + 1];
    if (next_char == 'x' || next_char == 'X') {
      // This is the carrier code case, in which the 'X's always precede the
      // national significant number.
      ++found;
      if (util.IsNumberMatchWithOneString(
              number, candidate.substr(found, candidate.length() - found))
          != PhoneNumberUtil::NSN_MATCH) {
        return false;
      }
    } else {
      string normalized_extension(candidate.substr(found,
                                                   candidate.length() - found));
      util.NormalizeDigitsOnly(&normalized_extension);
      if (normalized_extension != number.extension()) {
        return false;
      }
    }
    found = candidate.find_first_of("xX", found + 1);
  }
  return true;
}

bool AllNumberGroupsRemainGrouped(
    const PhoneNumberUtil& util,
    const PhoneNumber& phone_number,
    const string& normalized_candidate,
    const vector<string>& formatted_number_groups) {
  size_t from_index = 0;
  // Check each group of consecutive digits are not broken into separate
  // groupings in the normalized_candidate string.
  for (size_t i = 0; i < formatted_number_groups.size(); ++i) {
    // Fails if the substring of normalized_candidate starting from from_index
    // doesn't contain the consecutive digits in formatted_number_groups.at(i).
    from_index = normalized_candidate.find(formatted_number_groups.at(i),
                                           from_index);
    if (from_index == string::npos) {
      return false;
    }
    // Moves from_index forward.
    from_index += formatted_number_groups.at(i).length();
    if (i == 0 && from_index < normalized_candidate.length()) {
      // We are at the position right after the NDC. Note although
      // normalized_candidate might contain non-ASCII formatting characters,
      // they won't be treated as ASCII digits when converted to a char.
      if (isdigit(normalized_candidate.at(from_index))) {
        // This means there is no formatting symbol after the NDC. In this case,
        // we only accept the number if there is no formatting symbol at all in
        // the number, except for extensions.
        string national_significant_number;
        util.GetNationalSignificantNumber(
            phone_number, &national_significant_number);
        return HasPrefixString(normalized_candidate.substr(
            from_index - formatted_number_groups.at(i).length()),
            national_significant_number);
        }
      }
    }
    // The check here makes sure that we haven't mistakenly already used the
    // extension to match the last group of the subscriber number. Note the
    // extension cannot have formatting in-between digits.
    return normalized_candidate.substr(from_index)
        .find(phone_number.extension()) != string::npos;
}

bool LoadAlternateFormats(PhoneMetadataCollection* alternate_formats) {
#if defined(I18N_PHONENUMBERS_USE_ALTERNATE_FORMATS)
  if (!alternate_formats->ParseFromArray(alternate_format_get(),
                                         alternate_format_size())) {
    cerr << "Could not parse binary data." << endl;
    return false;
  }
  return true;
#else
  return false;
#endif
}

}  // namespace

class PhoneNumberMatcherRegExps : public Singleton<PhoneNumberMatcherRegExps> {
 private:
  friend class Singleton<PhoneNumberMatcherRegExps>;

  string opening_parens_;
  string closing_parens_;
  string non_parens_;
  // Limit on the number of pairs of brackets in a phone number.
  string bracket_pair_limit_;
  // Helper strings for the matching_brackets_ pattern.
  // An opening bracket at the beginning may not be closed, but subsequent ones
  // should be. It's also possible that the leading bracket was dropped, so we
  // shouldn't be surprised if we see a closing bracket first.
  string leading_maybe_matched_bracket_;
  string bracket_pairs_;
  // Limit on the number of leading (plus) characters.
  string lead_limit_;
  // Limit on the number of consecutive punctuation characters.
  string punctuation_limit_;
  // The maximum number of digits allowed in a digit-separated block. As we
  // allow all digits in a single block, this should be set high enough to
  // accommodate the entire national number and the international country code.
  int digit_block_limit_;
  // Limit on the number of blocks separated by punctuation. Uses
  // kDigitBlockLimit since some formats use spaces to separate each digit.
  string block_limit_;
  // A punctuation sequence allowing white space.
  string punctuation_;
  // A digits block without punctuation.
  string digit_sequence_;
  // Punctuation that may be at the start of a phone number - brackets and plus
  // signs.
  string lead_class_chars_;
  // Same as lead_class_chars_, but enclosed as a character class.
  string lead_class_;
  // Extra helper strings that form part of pattern_. These are stored
  // separately since StrCat has a limit of 12 args.
  string opening_punctuation_;
  string optional_extn_pattern_;

 public:
  // We use two different reg-ex factories here for performance reasons. RE2 is
  // much faster for smaller reg-ex patterns, but the main pattern cannot be
  // handled by RE2 in an efficient way.
  scoped_ptr<const AbstractRegExpFactory> regexp_factory_for_pattern_;
  scoped_ptr<const AbstractRegExpFactory> regexp_factory_;

  // Matches strings that look like publication pages. Example:
  // Computing Complete Answers to Queries in the Presence of Limited Access
  // Patterns. Chen Li. VLDB J. 12(3): 211-227 (2003).
  //
  // The string "211-227 (2003)" is not a telephone number.
  scoped_ptr<const RegExp> pub_pages_;
  // Matches strings that look like dates using "/" as a separator. Examples:
  // 3/10/2011, 31/10/96 or 08/31/95.
  scoped_ptr<const RegExp> slash_separated_dates_;
  // Matches timestamps. Examples: "2012-01-02 08:00". Note that the reg-ex does
  // not include trailing ":\d\d" -- that is covered by time_stamps_suffix_.
  scoped_ptr<const RegExp> time_stamps_;
  scoped_ptr<const RegExp> time_stamps_suffix_;
  // Pattern to check that brackets match. Opening brackets should be closed
  // within a phone number. This also checks that there is something inside the
  // brackets. Having no brackets at all is also fine.
  scoped_ptr<const RegExp> matching_brackets_;
  // Matches white-space, which may indicate the end of a phone number and the
  // start of something else (such as a neighbouring zip-code). If white-space
  // is found, continues to match all characters that are not typically used to
  // start a phone number.
  scoped_ptr<const RegExp> group_separator_;
  scoped_ptr<const RegExp> capture_up_to_second_number_start_pattern_;
  scoped_ptr<const RegExp> capturing_ascii_digits_pattern_;
  // Compiled reg-ex representing lead_class_;
  scoped_ptr<const RegExp> lead_class_pattern_;
  // Phone number pattern allowing optional punctuation.
  scoped_ptr<const RegExp> pattern_;

  PhoneNumberMatcherRegExps()
      : opening_parens_("(\\[\xEF\xBC\x88\xEF\xBC\xBB" /* "(\\[（［" */),
        closing_parens_(")\\]\xEF\xBC\x89\xEF\xBC\xBD" /* ")\\]）］" */),
        non_parens_(StrCat("[^", opening_parens_, closing_parens_, "]")),
        bracket_pair_limit_(Limit(0, 3)),
        leading_maybe_matched_bracket_(StrCat(
            "(?:[", opening_parens_, "])?",
            "(?:", non_parens_, "+[", closing_parens_, "])?")),
        bracket_pairs_(StrCat(
            "(?:[", opening_parens_, "]", non_parens_, "+",
            "[", closing_parens_, "])", bracket_pair_limit_)),
        lead_limit_(Limit(0, 2)),
        punctuation_limit_(Limit(0, 4)),
        digit_block_limit_(PhoneNumberUtil::kMaxLengthForNsn +
                           PhoneNumberUtil::kMaxLengthCountryCode),
        block_limit_(Limit(0, digit_block_limit_)),
        punctuation_(StrCat("[", PhoneNumberUtil::kValidPunctuation, "]",
                            punctuation_limit_)),
        digit_sequence_(StrCat("\\p{Nd}", Limit(1, digit_block_limit_))),
        lead_class_chars_(StrCat(opening_parens_, PhoneNumberUtil::kPlusChars)),
        lead_class_(StrCat("[", lead_class_chars_, "]")),
        opening_punctuation_(StrCat("(?:", lead_class_, punctuation_, ")")),
        optional_extn_pattern_(StrCat(
            "(?i)(?:",
            PhoneNumberUtil::GetInstance()->GetExtnPatternsForMatching(),
            ")?")),
        regexp_factory_for_pattern_(new ICURegExpFactory()),
#ifdef I18N_PHONENUMBERS_USE_RE2
        regexp_factory_(new RE2RegExpFactory()),
#else
        regexp_factory_(new ICURegExpFactory()),
#endif  // I18N_PHONENUMBERS_USE_RE2
        pub_pages_(regexp_factory_->CreateRegExp(
            "\\d{1,5}-+\\d{1,5}\\s{0,4}\\(\\d{1,4}")),
        slash_separated_dates_(regexp_factory_->CreateRegExp(
            "(?:(?:[0-3]?\\d/[01]?\\d)|"
            "(?:[01]?\\d/[0-3]?\\d))/(?:[12]\\d)?\\d{2}")),
        time_stamps_(regexp_factory_->CreateRegExp(
            "[12]\\d{3}[-/]?[01]\\d[-/]?[0-3]\\d [0-2]\\d$")),
        time_stamps_suffix_(regexp_factory_->CreateRegExp(":[0-5]\\d")),
        matching_brackets_(regexp_factory_->CreateRegExp(
            StrCat(leading_maybe_matched_bracket_, non_parens_, "+",
                   bracket_pairs_, non_parens_, "*"))),
        group_separator_(regexp_factory_->CreateRegExp(
            StrCat("\\p{Z}", "[^", lead_class_chars_, "\\p{Nd}]*"))),
        capture_up_to_second_number_start_pattern_(
            regexp_factory_->CreateRegExp(
                PhoneNumberUtil::kCaptureUpToSecondNumberStart)),
        capturing_ascii_digits_pattern_(
            regexp_factory_->CreateRegExp("(\\d+)")),
        lead_class_pattern_(regexp_factory_->CreateRegExp(lead_class_)),
        pattern_(regexp_factory_for_pattern_->CreateRegExp(
            StrCat("(", opening_punctuation_, lead_limit_,
                   digit_sequence_, "(?:", punctuation_, digit_sequence_, ")",
                   block_limit_, optional_extn_pattern_, ")"))) {
  }

 private:
  DISALLOW_COPY_AND_ASSIGN(PhoneNumberMatcherRegExps);
};

class AlternateFormats : public Singleton<AlternateFormats> {
 public:
  PhoneMetadataCollection format_data_;

  map<int, const PhoneMetadata*> calling_code_to_alternate_formats_map_;

  AlternateFormats()
      : format_data_(),
        calling_code_to_alternate_formats_map_() {
    if (!LoadAlternateFormats(&format_data_)) {
      LOG(DFATAL) << "Could not parse compiled-in metadata.";
      return;
    }
    for (RepeatedPtrField<PhoneMetadata>::const_iterator it =
             format_data_.metadata().begin();
         it != format_data_.metadata().end();
         ++it) {
      calling_code_to_alternate_formats_map_.insert(
          make_pair(it->country_code(), &*it));
    }
  }

  const PhoneMetadata* GetAlternateFormatsForCountry(int country_calling_code)
      const {
    map<int, const PhoneMetadata*>::const_iterator it =
        calling_code_to_alternate_formats_map_.find(country_calling_code);
    if (it != calling_code_to_alternate_formats_map_.end()) {
      return it->second;
    }
    return NULL;
  }

 private:
  DISALLOW_COPY_AND_ASSIGN(AlternateFormats);
};

PhoneNumberMatcher::PhoneNumberMatcher(const PhoneNumberUtil& util,
                                       const string& text,
                                       const string& region_code,
                                       PhoneNumberMatcher::Leniency leniency,
                                       int max_tries)
    : reg_exps_(PhoneNumberMatcherRegExps::GetInstance()),
      alternate_formats_(AlternateFormats::GetInstance()),
      phone_util_(util),
      text_(text),
      preferred_region_(region_code),
      leniency_(leniency),
      max_tries_(max_tries),
      state_(NOT_READY),
      last_match_(NULL),
      search_index_(0) {
}

PhoneNumberMatcher::PhoneNumberMatcher(const string& text,
                                       const string& region_code)
    : reg_exps_(PhoneNumberMatcherRegExps::GetInstance()),
      alternate_formats_(NULL),  // Not used.
      phone_util_(*PhoneNumberUtil::GetInstance()),
      text_(text),
      preferred_region_(region_code),
      leniency_(VALID),
      max_tries_(numeric_limits<int>::max()),
      state_(NOT_READY),
      last_match_(NULL),
      search_index_(0) {
}

PhoneNumberMatcher::~PhoneNumberMatcher() {
}

// static
bool PhoneNumberMatcher::IsLatinLetter(char32 letter) {
  // Combining marks are a subset of non-spacing-mark.
  if (!u_isalpha(letter) && (u_charType(letter) != U_NON_SPACING_MARK)) {
    return false;
  }
  UBlockCode block = ublock_getCode(letter);
  return ((block == UBLOCK_BASIC_LATIN) ||
      (block == UBLOCK_LATIN_1_SUPPLEMENT) ||
      (block == UBLOCK_LATIN_EXTENDED_A) ||
      (block == UBLOCK_LATIN_EXTENDED_ADDITIONAL) ||
      (block == UBLOCK_LATIN_EXTENDED_B) ||
      (block == UBLOCK_COMBINING_DIACRITICAL_MARKS));
}

bool PhoneNumberMatcher::ParseAndVerify(const string& candidate, int offset,
                                        PhoneNumberMatch* match) {
  DCHECK(match);
  // Check the candidate doesn't contain any formatting which would indicate
  // that it really isn't a phone number.
  if (!reg_exps_->matching_brackets_->FullMatch(candidate)) {
    return false;
  }

  // If leniency is set to VALID or stricter, we also want to skip numbers that
  // are surrounded by Latin alphabetic characters, to skip cases like
  // abc8005001234 or 8005001234def.
  if (leniency_ >= VALID) {
    // If the candidate is not at the start of the text, and does not start with
    // phone-number punctuation, check the previous character.
    scoped_ptr<RegExpInput> candidate_input(
        reg_exps_->regexp_factory_->CreateInput(candidate));
    if (offset > 0 &&
        !reg_exps_->lead_class_pattern_->Consume(candidate_input.get())) {
      char32 previous_char;
      const char* previous_char_ptr =
          EncodingUtils::BackUpOneUTF8Character(text_.c_str(),
                                                text_.c_str() + offset);
      EncodingUtils::DecodeUTF8Char(previous_char_ptr, &previous_char);
      // We return false if it is a latin letter or an invalid punctuation
      // symbol.
      if (IsInvalidPunctuationSymbol(previous_char) ||
          IsLatinLetter(previous_char)) {
        return false;
      }
    }
    size_t lastCharIndex = offset + candidate.length();
    if (lastCharIndex < text_.length()) {
      char32 next_char;
      const char* next_char_ptr =
          EncodingUtils::AdvanceOneUTF8Character(
              text_.c_str() + lastCharIndex - 1);
      EncodingUtils::DecodeUTF8Char(next_char_ptr, &next_char);
      if (IsInvalidPunctuationSymbol(next_char) || IsLatinLetter(next_char)) {
        return false;
      }
    }
  }

  PhoneNumber number;
  if (phone_util_.ParseAndKeepRawInput(candidate, preferred_region_, &number) !=
      PhoneNumberUtil::NO_PARSING_ERROR) {
    return false;
  }
  if (VerifyAccordingToLeniency(leniency_, number, candidate)) {
    match->set_start(offset);
    match->set_raw_string(candidate);
    // We used ParseAndKeepRawInput to create this number, but for now we don't
    // return the extra values parsed. TODO: stop clearing all values here and
    // switch all users over to using raw_input() rather than the raw_string()
    // of PhoneNumberMatch.
    number.clear_country_code_source();
    number.clear_preferred_domestic_carrier_code();
    number.clear_raw_input();
    match->set_number(number);
    return true;
  }
  return false;
}

// Helper method to replace the verification method for each enum in the Java
// version.
bool PhoneNumberMatcher::VerifyAccordingToLeniency(
    Leniency leniency, const PhoneNumber& number,
    const string& candidate) const {
  switch (leniency) {
    case PhoneNumberMatcher::POSSIBLE:
      return phone_util_.IsPossibleNumber(number);
    case PhoneNumberMatcher::VALID:
      if (!phone_util_.IsValidNumber(number) ||
          !ContainsOnlyValidXChars(number, candidate, phone_util_)) {
        return false;
      }
      return IsNationalPrefixPresentIfRequired(number);
    case PhoneNumberMatcher::STRICT_GROUPING: {
      if (!phone_util_.IsValidNumber(number) ||
          !ContainsOnlyValidXChars(number, candidate, phone_util_) ||
          // Two or more slashes were present.
          (FindNth(candidate, '/', 2) != string::npos) ||
          !IsNationalPrefixPresentIfRequired(number)) {
        return false;
      }
      ResultCallback4<bool, const PhoneNumberUtil&, const PhoneNumber&,
                      const string&, const vector<string>&>* callback =
          NewPermanentCallback(&AllNumberGroupsRemainGrouped);
      bool is_valid = CheckNumberGroupingIsValid(number, candidate, callback);
      delete(callback);
      return is_valid;
    }
    case PhoneNumberMatcher::EXACT_GROUPING: {
      if (!phone_util_.IsValidNumber(number) ||
          !ContainsOnlyValidXChars(number, candidate, phone_util_) ||
          // Two or more slashes were present.
          (FindNth(candidate, '/', 2) != string::npos) ||
          !IsNationalPrefixPresentIfRequired(number)) {
        return false;
      }
      ResultCallback4<bool, const PhoneNumberUtil&, const PhoneNumber&,
                      const string&, const vector<string>&>* callback =
          NewPermanentCallback(
              this, &PhoneNumberMatcher::AllNumberGroupsAreExactlyPresent);
      bool is_valid = CheckNumberGroupingIsValid(number, candidate, callback);
      delete(callback);
      return is_valid;
    }
    default:
      LOG(ERROR) << "No implementation defined for verification for leniency "
                 << static_cast<int>(leniency);
      return false;
  }
}

bool PhoneNumberMatcher::ExtractInnerMatch(const string& candidate, int offset,
                                           PhoneNumberMatch* match) {
  DCHECK(match);
  // Try removing either the first or last "group" in the number and see if this
  // gives a result. We consider white space to be a possible indication of
  // the start or end of the phone number.
  scoped_ptr<RegExpInput> candidate_input(
      reg_exps_->regexp_factory_->CreateInput(candidate));
  if (reg_exps_->group_separator_->FindAndConsume(candidate_input.get(),
                                                  NULL)) {
    // Try the first group by itself.
    int group_start_index =
        candidate.length() - candidate_input->ToString().length();
    string first_group_only = candidate.substr(0, group_start_index);
    phone_util_.TrimUnwantedEndChars(&first_group_only);
    bool success = ParseAndVerify(first_group_only, offset, match);
    if (success) {
      return true;
    }
    --max_tries_;

    // Try the rest of the candidate without the first group.
    string without_first_group(candidate_input->ToString());
    phone_util_.TrimUnwantedEndChars(&without_first_group);
    success =
        ParseAndVerify(without_first_group, offset + group_start_index, match);
    if (success) {
      return true;
    }
    --max_tries_;

    if (max_tries_ > 0) {
      while (reg_exps_->group_separator_->FindAndConsume(candidate_input.get(),
                                                         NULL)) {
        // Find the last group.
      }
      int last_group_start =
          candidate.length() - candidate_input->ToString().length();
      string without_last_group = candidate.substr(0, last_group_start);
      phone_util_.TrimUnwantedEndChars(&without_last_group);
      if (without_last_group == first_group_only) {
        // If there are only two groups, then the group "without the last group"
        // is the same as the first group. In these cases, we don't want to
        // re-check the number group, so we exit already.
        return false;
      }
      success = ParseAndVerify(without_last_group, offset, match);
      if (success) {
        return true;
      }
      --max_tries_;
    }
  }
  return false;
}

bool PhoneNumberMatcher::ExtractMatch(const string& candidate, int offset,
                                      PhoneNumberMatch* match) {
  DCHECK(match);
  // Skip a match that is more likely a publication page reference or a date.
  if (reg_exps_->pub_pages_->PartialMatch(candidate) ||
      reg_exps_->slash_separated_dates_->PartialMatch(candidate)) {
    return false;
  }
  // Skip potential time-stamps.
  if (reg_exps_->time_stamps_->PartialMatch(candidate)) {
    scoped_ptr<RegExpInput> following_text(
        reg_exps_->regexp_factory_->CreateInput(
            text_.substr(offset + candidate.size())));
    if (reg_exps_->time_stamps_suffix_->Consume(following_text.get())) {
      return false;
    }
  }

  // Try to come up with a valid match given the entire candidate.
  if (ParseAndVerify(candidate, offset, match)) {
    return true;
  }

  // If that failed, try to find an "inner match" - there might be a phone
  // number within this candidate.
  return ExtractInnerMatch(candidate, offset, match);
}

bool PhoneNumberMatcher::HasNext() {
  if (state_ == NOT_READY) {
    PhoneNumberMatch temp_match;
    if (!Find(search_index_, &temp_match)) {
      state_ = DONE;
    } else {
      last_match_.reset(new PhoneNumberMatch(temp_match.start(),
                                             temp_match.raw_string(),
                                             temp_match.number()));
      search_index_ = last_match_->end();
      state_ = READY;
    }
  }
  return state_ == READY;
}

bool PhoneNumberMatcher::Next(PhoneNumberMatch* match) {
  DCHECK(match);
  // Check the state and find the next match as a side-effect if necessary.
  if (!HasNext()) {
    return false;
  }
  match->CopyFrom(*last_match_);
  state_ = NOT_READY;
  last_match_.reset(NULL);
  return true;
}

bool PhoneNumberMatcher::Find(int index, PhoneNumberMatch* match) {
  DCHECK(match);

  scoped_ptr<RegExpInput> text(
      reg_exps_->regexp_factory_for_pattern_->CreateInput(text_.substr(index)));
  string candidate;
  while ((max_tries_ > 0) &&
         reg_exps_->pattern_->FindAndConsume(text.get(), &candidate)) {
    int start = text_.length() - text->ToString().length() - candidate.length();
    // Check for extra numbers at the end.
    reg_exps_->capture_up_to_second_number_start_pattern_->
        PartialMatch(candidate, &candidate);
    if (ExtractMatch(candidate, start, match)) {
      return true;
    }

    index = start + candidate.length();
    --max_tries_;
  }
  return false;
}

bool PhoneNumberMatcher::CheckNumberGroupingIsValid(
    const PhoneNumber& phone_number,
    const string& candidate,
    ResultCallback4<bool, const PhoneNumberUtil&, const PhoneNumber&,
                    const string&, const vector<string>&>* checker) const {
  DCHECK(checker);
  // TODO: Evaluate how this works for other locales (testing has been limited
  // to NANPA regions) and optimise if necessary.
  string normalized_candidate =
      NormalizeUTF8::NormalizeDecimalDigits(candidate);
  vector<string> formatted_number_groups;
  GetNationalNumberGroups(phone_number, NULL,  // Use default formatting pattern
                          &formatted_number_groups);
  if (checker->Run(phone_util_, phone_number, normalized_candidate,
                   formatted_number_groups)) {
    return true;
  }
  // If this didn't pass, see if there are any alternate formats, and try them
  // instead.
  const PhoneMetadata* alternate_formats =
    alternate_formats_->GetAlternateFormatsForCountry(
        phone_number.country_code());
  if (alternate_formats) {
    for (RepeatedPtrField<NumberFormat>::const_iterator it =
             alternate_formats->number_format().begin();
         it != alternate_formats->number_format().end(); ++it) {
      formatted_number_groups.clear();
      GetNationalNumberGroups(phone_number, &*it, &formatted_number_groups);
      if (checker->Run(phone_util_, phone_number, normalized_candidate,
                       formatted_number_groups)) {
        return true;
      }
    }
  }
  return false;
}

// Helper method to get the national-number part of a number, formatted without
// any national prefix, and return it as a set of digit blocks that would be
// formatted together.
void PhoneNumberMatcher::GetNationalNumberGroups(
    const PhoneNumber& number,
    const NumberFormat* formatting_pattern,
    vector<string>* digit_blocks) const {
  string rfc3966_format;
  if (!formatting_pattern) {
    // This will be in the format +CC-DG;ext=EXT where DG represents groups of
    // digits.
    phone_util_.Format(number, PhoneNumberUtil::RFC3966, &rfc3966_format);
    // We remove the extension part from the formatted string before splitting
    // it into different groups.
    size_t end_index = rfc3966_format.find(';');
    if (end_index == string::npos) {
      end_index = rfc3966_format.length();
    }
    // The country-code will have a '-' following it.
    size_t start_index = rfc3966_format.find('-') + 1;
    SplitStringUsing(rfc3966_format.substr(start_index,
                                           end_index - start_index),
                     "-", digit_blocks);
  } else {
    // We format the NSN only, and split that according to the separator.
    string national_significant_number;
    phone_util_.GetNationalSignificantNumber(number,
                                             &national_significant_number);
    phone_util_.FormatNsnUsingPattern(national_significant_number,
                                      *formatting_pattern,
                                      PhoneNumberUtil::RFC3966,
                                      &rfc3966_format);
    SplitStringUsing(rfc3966_format, "-", digit_blocks);
  }
}

bool PhoneNumberMatcher::IsNationalPrefixPresentIfRequired(
    const PhoneNumber& number) const {
  // First, check how we deduced the country code. If it was written in
  // international format, then the national prefix is not required.
  if (number.country_code_source() != PhoneNumber::FROM_DEFAULT_COUNTRY) {
    return true;
  }
  string phone_number_region;
  phone_util_.GetRegionCodeForCountryCode(
      number.country_code(), &phone_number_region);
  const PhoneMetadata* metadata =
      phone_util_.GetMetadataForRegion(phone_number_region);
  if (!metadata) {
    return true;
  }
  // Check if a national prefix should be present when formatting this number.
  string national_number;
  phone_util_.GetNationalSignificantNumber(number, &national_number);
  const NumberFormat* format_rule =
      phone_util_.ChooseFormattingPatternForNumber(metadata->number_format(),
                                                   national_number);
  // To do this, we check that a national prefix formatting rule was present and
  // that it wasn't just the first-group symbol ($1) with punctuation.
  if (format_rule && !format_rule->national_prefix_formatting_rule().empty()) {
    if (format_rule->national_prefix_optional_when_formatting()) {
      // The national-prefix is optional in these cases, so we don't need to
      // check if it was present.
      return true;
    }
    if (phone_util_.FormattingRuleHasFirstGroupOnly(
        format_rule->national_prefix_formatting_rule())) {
      // National Prefix not needed for this number.
      return true;
    }
    // Normalize the remainder.
    string raw_input_copy(number.raw_input());
    // Check if we found a national prefix and/or carrier code at the start of
    // the raw input, and return the result.
    phone_util_.NormalizeDigitsOnly(&raw_input_copy);
    return phone_util_.MaybeStripNationalPrefixAndCarrierCode(
        *metadata,
        &raw_input_copy,
        NULL);  // Don't need to keep the stripped carrier code.
  }
  return true;
}

bool PhoneNumberMatcher::AllNumberGroupsAreExactlyPresent(
    const PhoneNumberUtil& util,
    const PhoneNumber& phone_number,
    const string& normalized_candidate,
    const vector<string>& formatted_number_groups) const {
    const scoped_ptr<RegExpInput> candidate_number(
        reg_exps_->regexp_factory_->CreateInput(normalized_candidate));
  vector<string> candidate_groups;
  string digit_block;
  while (reg_exps_->capturing_ascii_digits_pattern_->FindAndConsume(
             candidate_number.get(),
             &digit_block)) {
    candidate_groups.push_back(digit_block);
  }

  // Set this to the last group, skipping it if the number has an extension.
  int candidate_number_group_index =
      phone_number.has_extension() ? candidate_groups.size() - 2
                                   : candidate_groups.size() - 1;
  // First we check if the national significant number is formatted as a block.
  // We use find and not equals, since the national significant number may be
  // present with a prefix such as a national number prefix, or the country code
  // itself.
  string national_significant_number;
  util.GetNationalSignificantNumber(phone_number,
                                    &national_significant_number);
  if (candidate_groups.size() == 1 ||
      candidate_groups.at(candidate_number_group_index).find(
          national_significant_number) != string::npos) {
    return true;
  }
  // Starting from the end, go through in reverse, excluding the first group,
  // and check the candidate and number groups are the same.
  for (int formatted_number_group_index =
           (formatted_number_groups.size() - 1);
       formatted_number_group_index > 0 &&
       candidate_number_group_index >= 0;
       --formatted_number_group_index, --candidate_number_group_index) {
    if (candidate_groups.at(candidate_number_group_index) !=
        formatted_number_groups.at(formatted_number_group_index)) {
      return false;
    }
  }
  // Now check the first group. There may be a national prefix at the start, so
  // we only check that the candidate group ends with the formatted number
  // group.
  return (candidate_number_group_index >= 0 &&
          HasSuffixString(candidate_groups.at(candidate_number_group_index),
                          formatted_number_groups.at(0)));
}

}  // namespace phonenumbers
}  // namespace i18n