/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
 * rights reserved.
 * Copyright (C) 2005 Alexey Proskuryakov.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "third_party/blink/renderer/platform/text/unicode_utilities.h"

#include <unicode/normalizer2.h>
#include <unicode/utf16.h>

#include "third_party/blink/renderer/platform/wtf/text/character_names.h"
#include "third_party/blink/renderer/platform/wtf/text/string_buffer.h"

namespace blink {

enum VoicedSoundMarkType {
  kNoVoicedSoundMark,
  kVoicedSoundMark,
  kSemiVoicedSoundMark
};

template <typename CharType>
static inline CharType FoldQuoteMarkOrSoftHyphen(CharType c) {
  switch (static_cast<UChar>(c)) {
    case kHebrewPunctuationGershayimCharacter:
    case kLeftDoubleQuotationMarkCharacter:
    case kRightDoubleQuotationMarkCharacter:
      return '"';
    case kHebrewPunctuationGereshCharacter:
    case kLeftSingleQuotationMarkCharacter:
    case kRightSingleQuotationMarkCharacter:
      return '\'';
    case kSoftHyphenCharacter:
      // Replace soft hyphen with an ignorable character so that their presence
      // or absence will
      // not affect string comparison.
      return 0;
    default:
      return c;
  }
}

void FoldQuoteMarksAndSoftHyphens(base::span<UChar> data) {
  for (UChar& ch : data) {
    ch = FoldQuoteMarkOrSoftHyphen(ch);
  }
}

void FoldQuoteMarksAndSoftHyphens(String& s) {
  s.Replace(kHebrewPunctuationGereshCharacter, '\'');
  s.Replace(kHebrewPunctuationGershayimCharacter, '"');
  s.Replace(kLeftDoubleQuotationMarkCharacter, '"');
  s.Replace(kLeftSingleQuotationMarkCharacter, '\'');
  s.Replace(kRightDoubleQuotationMarkCharacter, '"');
  s.Replace(kRightSingleQuotationMarkCharacter, '\'');
  // Replace soft hyphen with an ignorable character so that their presence or
  // absence will
  // not affect string comparison.
  s.Replace(kSoftHyphenCharacter, static_cast<UChar>('\0'));
}

static bool IsNonLatin1Separator(UChar32 character) {
  DCHECK_GE(character, 256);
  return U_GET_GC_MASK(character) & (U_GC_P_MASK | U_GC_Z_MASK | U_GC_CF_MASK);
}

bool IsSeparator(UChar32 character) {
  // clang-format off
  static constexpr auto kLatin1SeparatorTable = std::to_array<uint8_t>({
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      // space ! " # $ % & ' ( ) * + , - . /
      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
      //                         : ; < = > ?
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,
      //   @
      1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      //                         [ \ ] ^ _
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1,
      //   `
      1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      //                           { | } ~
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,
      1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0
  });
  // clang-format on
  if (character < 256)
    return static_cast<bool>(kLatin1SeparatorTable[character]);

  return IsNonLatin1Separator(character);
}

bool ContainsOnlySeparatorsOrEmpty(const String& pattern) {
  unsigned index = 0;
  while (index < pattern.length()) {
    const UChar32 character = pattern.CharacterStartingAt(index);
    if (!IsSeparator(character)) {
      return false;
    }
    index += U16_LENGTH(character);
  }
  return true;
}

// ICU's search ignores the distinction between small kana letters and ones
// that are not small, and also characters that differ only in the voicing
// marks when considering only primary collation strength differences.
// This is not helpful for end users, since these differences make words
// distinct, so for our purposes we need these to be considered.
// The Unicode folks do not think the collation algorithm should be
// changed. To work around this, we would like to tailor the ICU searcher,
// but we can't get that to work yet. So instead, we check for cases where
// these differences occur, and skip those matches.

// We refer to the above technique as the "kana workaround". The next few
// functions are helper functinos for the kana workaround.

bool IsKanaLetter(UChar character) {
  // Hiragana letters.
  if (character >= 0x3041 && character <= 0x3096)
    return true;

  // Katakana letters.
  if (character >= 0x30A1 && character <= 0x30FA)
    return true;
  if (character >= 0x31F0 && character <= 0x31FF)
    return true;

  // Halfwidth katakana letters.
  if (character >= 0xFF66 && character <= 0xFF9D && character != 0xFF70)
    return true;

  return false;
}

bool IsSmallKanaLetter(UChar character) {
  DCHECK(IsKanaLetter(character));

  switch (character) {
    case 0x3041:  // HIRAGANA LETTER SMALL A
    case 0x3043:  // HIRAGANA LETTER SMALL I
    case 0x3045:  // HIRAGANA LETTER SMALL U
    case 0x3047:  // HIRAGANA LETTER SMALL E
    case 0x3049:  // HIRAGANA LETTER SMALL O
    case 0x3063:  // HIRAGANA LETTER SMALL TU
    case 0x3083:  // HIRAGANA LETTER SMALL YA
    case 0x3085:  // HIRAGANA LETTER SMALL YU
    case 0x3087:  // HIRAGANA LETTER SMALL YO
    case 0x308E:  // HIRAGANA LETTER SMALL WA
    case 0x3095:  // HIRAGANA LETTER SMALL KA
    case 0x3096:  // HIRAGANA LETTER SMALL KE
    case 0x30A1:  // KATAKANA LETTER SMALL A
    case 0x30A3:  // KATAKANA LETTER SMALL I
    case 0x30A5:  // KATAKANA LETTER SMALL U
    case 0x30A7:  // KATAKANA LETTER SMALL E
    case 0x30A9:  // KATAKANA LETTER SMALL O
    case 0x30C3:  // KATAKANA LETTER SMALL TU
    case 0x30E3:  // KATAKANA LETTER SMALL YA
    case 0x30E5:  // KATAKANA LETTER SMALL YU
    case 0x30E7:  // KATAKANA LETTER SMALL YO
    case 0x30EE:  // KATAKANA LETTER SMALL WA
    case 0x30F5:  // KATAKANA LETTER SMALL KA
    case 0x30F6:  // KATAKANA LETTER SMALL KE
    case 0x31F0:  // KATAKANA LETTER SMALL KU
    case 0x31F1:  // KATAKANA LETTER SMALL SI
    case 0x31F2:  // KATAKANA LETTER SMALL SU
    case 0x31F3:  // KATAKANA LETTER SMALL TO
    case 0x31F4:  // KATAKANA LETTER SMALL NU
    case 0x31F5:  // KATAKANA LETTER SMALL HA
    case 0x31F6:  // KATAKANA LETTER SMALL HI
    case 0x31F7:  // KATAKANA LETTER SMALL HU
    case 0x31F8:  // KATAKANA LETTER SMALL HE
    case 0x31F9:  // KATAKANA LETTER SMALL HO
    case 0x31FA:  // KATAKANA LETTER SMALL MU
    case 0x31FB:  // KATAKANA LETTER SMALL RA
    case 0x31FC:  // KATAKANA LETTER SMALL RI
    case 0x31FD:  // KATAKANA LETTER SMALL RU
    case 0x31FE:  // KATAKANA LETTER SMALL RE
    case 0x31FF:  // KATAKANA LETTER SMALL RO
    case 0xFF67:  // HALFWIDTH KATAKANA LETTER SMALL A
    case 0xFF68:  // HALFWIDTH KATAKANA LETTER SMALL I
    case 0xFF69:  // HALFWIDTH KATAKANA LETTER SMALL U
    case 0xFF6A:  // HALFWIDTH KATAKANA LETTER SMALL E
    case 0xFF6B:  // HALFWIDTH KATAKANA LETTER SMALL O
    case 0xFF6C:  // HALFWIDTH KATAKANA LETTER SMALL YA
    case 0xFF6D:  // HALFWIDTH KATAKANA LETTER SMALL YU
    case 0xFF6E:  // HALFWIDTH KATAKANA LETTER SMALL YO
    case 0xFF6F:  // HALFWIDTH KATAKANA LETTER SMALL TU
      return true;
  }
  return false;
}

static inline VoicedSoundMarkType ComposedVoicedSoundMark(UChar character) {
  DCHECK(IsKanaLetter(character));

  switch (character) {
    case 0x304C:  // HIRAGANA LETTER GA
    case 0x304E:  // HIRAGANA LETTER GI
    case 0x3050:  // HIRAGANA LETTER GU
    case 0x3052:  // HIRAGANA LETTER GE
    case 0x3054:  // HIRAGANA LETTER GO
    case 0x3056:  // HIRAGANA LETTER ZA
    case 0x3058:  // HIRAGANA LETTER ZI
    case 0x305A:  // HIRAGANA LETTER ZU
    case 0x305C:  // HIRAGANA LETTER ZE
    case 0x305E:  // HIRAGANA LETTER ZO
    case 0x3060:  // HIRAGANA LETTER DA
    case 0x3062:  // HIRAGANA LETTER DI
    case 0x3065:  // HIRAGANA LETTER DU
    case 0x3067:  // HIRAGANA LETTER DE
    case 0x3069:  // HIRAGANA LETTER DO
    case 0x3070:  // HIRAGANA LETTER BA
    case 0x3073:  // HIRAGANA LETTER BI
    case 0x3076:  // HIRAGANA LETTER BU
    case 0x3079:  // HIRAGANA LETTER BE
    case 0x307C:  // HIRAGANA LETTER BO
    case 0x3094:  // HIRAGANA LETTER VU
    case 0x30AC:  // KATAKANA LETTER GA
    case 0x30AE:  // KATAKANA LETTER GI
    case 0x30B0:  // KATAKANA LETTER GU
    case 0x30B2:  // KATAKANA LETTER GE
    case 0x30B4:  // KATAKANA LETTER GO
    case 0x30B6:  // KATAKANA LETTER ZA
    case 0x30B8:  // KATAKANA LETTER ZI
    case 0x30BA:  // KATAKANA LETTER ZU
    case 0x30BC:  // KATAKANA LETTER ZE
    case 0x30BE:  // KATAKANA LETTER ZO
    case 0x30C0:  // KATAKANA LETTER DA
    case 0x30C2:  // KATAKANA LETTER DI
    case 0x30C5:  // KATAKANA LETTER DU
    case 0x30C7:  // KATAKANA LETTER DE
    case 0x30C9:  // KATAKANA LETTER DO
    case 0x30D0:  // KATAKANA LETTER BA
    case 0x30D3:  // KATAKANA LETTER BI
    case 0x30D6:  // KATAKANA LETTER BU
    case 0x30D9:  // KATAKANA LETTER BE
    case 0x30DC:  // KATAKANA LETTER BO
    case 0x30F4:  // KATAKANA LETTER VU
    case 0x30F7:  // KATAKANA LETTER VA
    case 0x30F8:  // KATAKANA LETTER VI
    case 0x30F9:  // KATAKANA LETTER VE
    case 0x30FA:  // KATAKANA LETTER VO
      return kVoicedSoundMark;
    case 0x3071:  // HIRAGANA LETTER PA
    case 0x3074:  // HIRAGANA LETTER PI
    case 0x3077:  // HIRAGANA LETTER PU
    case 0x307A:  // HIRAGANA LETTER PE
    case 0x307D:  // HIRAGANA LETTER PO
    case 0x30D1:  // KATAKANA LETTER PA
    case 0x30D4:  // KATAKANA LETTER PI
    case 0x30D7:  // KATAKANA LETTER PU
    case 0x30DA:  // KATAKANA LETTER PE
    case 0x30DD:  // KATAKANA LETTER PO
      return kSemiVoicedSoundMark;
  }
  return kNoVoicedSoundMark;
}

static inline bool IsCombiningVoicedSoundMark(UChar character) {
  switch (character) {
    case 0x3099:  // COMBINING KATAKANA-HIRAGANA VOICED SOUND MARK
    case 0x309A:  // COMBINING KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK
      return true;
  }
  return false;
}

bool ContainsKanaLetters(const String& pattern) {
  const unsigned length = pattern.length();
  for (unsigned i = 0; i < length; ++i) {
    if (IsKanaLetter(pattern[i]))
      return true;
  }
  return false;
}

Vector<UChar> NormalizeCharactersIntoNfc(base::span<const UChar> characters) {
  DCHECK(characters.size());

  UErrorCode status = U_ZERO_ERROR;
  const icu::Normalizer2* normalizer = icu::Normalizer2::getNFCInstance(status);
  DCHECK(U_SUCCESS(status));
  int32_t input_length = static_cast<int32_t>(characters.size());
  // copy-on-write.
  icu::UnicodeString normalized(false, characters.data(), input_length);
  // In the vast majority of cases, input is already NFC. Run a quick check
  // to avoid normalizing the entire input unnecessarily.
  int32_t normalized_prefix_length =
      normalizer->spanQuickCheckYes(normalized, status);
  if (normalized_prefix_length < input_length) {
    icu::UnicodeString un_normalized(normalized, normalized_prefix_length);
    normalized.truncate(normalized_prefix_length);
    normalizer->normalizeSecondAndAppend(normalized, un_normalized, status);
  }
  int32_t buffer_size = normalized.length();
  DCHECK(buffer_size);

  Vector<UChar> buffer;
  buffer.resize(static_cast<wtf_size_t>(buffer_size));
  normalized.extract(buffer.data(), buffer_size, status);
  DCHECK(U_SUCCESS(status));
  return buffer;
}

// This function returns kNotFound if |first| and |second| contain different
// Kana letters.  If |first| and |second| contain the same Kana letter then
// function returns offset in characters from |first|.
// Pointers to both strings increase simultaneously so so it is possible to use
// one offset value.
static inline size_t CompareKanaLetterAndComposedVoicedSoundMarks(
    base::span<const UChar>::iterator first,
    base::span<const UChar>::iterator first_end,
    base::span<const UChar>::iterator second,
    base::span<const UChar>::iterator second_end) {
  auto start = first;
  // Check for differences in the kana letter character itself.
  if (IsSmallKanaLetter(*first) != IsSmallKanaLetter(*second))
    return kNotFound;
  if (ComposedVoicedSoundMark(*first) != ComposedVoicedSoundMark(*second))
    return kNotFound;
  ++first;
  ++second;

  // Check for differences in combining voiced sound marks found after the
  // letter.
  while (true) {
    const bool second_is_not_sound_mark =
        second == second_end || !IsCombiningVoicedSoundMark(*second);
    if (first == first_end || !IsCombiningVoicedSoundMark(*first)) {
      return second_is_not_sound_mark ? first - start : kNotFound;
    }
    if (second_is_not_sound_mark)
      return kNotFound;
    if (*first != *second)
      return kNotFound;
    ++first;
    ++second;
  }
}

bool CheckOnlyKanaLettersInStrings(base::span<const UChar> first_data,
                                   base::span<const UChar> second_data) {
  auto a = first_data.begin();
  auto a_end = first_data.end();

  auto b = second_data.begin();
  auto b_end = second_data.end();
  while (true) {
    // Skip runs of non-kana-letter characters. This is necessary so we can
    // correctly handle strings where the |firstData| and |secondData| have
    // different-length runs of characters that match, while still double
    // checking the correctness of matches of kana letters with other kana
    // letters.
    a = std::find_if(a, a_end, IsKanaLetter);
    b = std::find_if(b, b_end, IsKanaLetter);

    // If we reached the end of either the target or the match, we should have
    // reached the end of both; both should have the same number of kana
    // letters.
    if (a == a_end || b == b_end) {
      return a == a_end && b == b_end;
    }

    // Check that single Kana letters in |a| and |b| are the same.
    const size_t offset =
        CompareKanaLetterAndComposedVoicedSoundMarks(a, a_end, b, b_end);
    if (offset == kNotFound)
      return false;

    // Update values of |a| and |b| after comparing.
    a += offset;
    b += offset;
  }
}

bool CheckKanaStringsEqual(base::span<const UChar> first_data,
                           base::span<const UChar> second_data) {
  auto a = first_data.begin();
  auto a_end = first_data.end();

  auto b = second_data.begin();
  auto b_end = second_data.end();
  while (true) {
    // Check for non-kana-letter characters.
    while (a != a_end && !IsKanaLetter(*a) && b != b_end && !IsKanaLetter(*b)) {
      if (*a++ != *b++)
        return false;
    }

    // If we reached the end of either the target or the match, we should have
    // reached the end of both; both should have the same number of kana
    // letters.
    if (a == a_end || b == b_end) {
      return a == a_end && b == b_end;
    }

    if (IsKanaLetter(*a) != IsKanaLetter(*b))
      return false;

    // Check that single Kana letters in |a| and |b| are the same.
    const size_t offset =
        CompareKanaLetterAndComposedVoicedSoundMarks(a, a_end, b, b_end);
    if (offset == kNotFound)
      return false;

    // Update values of |a| and |b| after comparing.
    a += offset;
    b += offset;
  }
}

}  // namespace blink