// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "third_party/blink/renderer/platform/fonts/script_run_iterator.h"

#include <array>
#include <utility>

#include "base/compiler_specific.h"
#include "base/logging.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/blink/renderer/platform/wtf/text/format.h"
#include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/threading.h"

namespace blink {

struct ScriptTestRun {
  const char* const text;
  UScriptCode code;
};

struct ScriptExpectedRun {
  unsigned limit;
  UScriptCode code;

  ScriptExpectedRun(unsigned the_limit, UScriptCode the_code)
      : limit(the_limit), code(the_code) {}

  bool operator==(const ScriptExpectedRun& other) const {
    return limit == other.limit && code == other.code;
  }
};

std::ostream& operator<<(std::ostream& output, const ScriptExpectedRun& run) {
  return output << Format("{}:{} ({})", run.limit, run.code,
                          uscript_getName(run.code));
}

class MockScriptData : public ScriptData {
 public:
  ~MockScriptData() override = default;

  static const MockScriptData* Instance() {
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const MockScriptData, mock_script_data, ());
    return &mock_script_data;
  }

  void GetScripts(UChar32 ch, UScriptCodeList& dst) const override {
    DCHECK_GE(ch, kMockCharMin);
    DCHECK_LT(ch, kMockCharLimit);

    int code = ch - kMockCharMin;
    dst.clear();
    switch (code & kCodeSpecialMask) {
      case kCodeSpecialCommon:
        dst.push_back(USCRIPT_COMMON);
        break;
      case kCodeSpecialInherited:
        dst.push_back(USCRIPT_INHERITED);
        break;
      default:
        break;
    }
    int list_bits = kTable[code & kCodeListIndexMask];
    if (dst.empty() && list_bits == 0) {
      dst.push_back(USCRIPT_UNKNOWN);
      return;
    }
    while (list_bits) {
      switch (list_bits & kListMask) {
        case 0:
          break;
        case kLatin:
          dst.push_back(USCRIPT_LATIN);
          break;
        case kHan:
          dst.push_back(USCRIPT_HAN);
          break;
        case kGreek:
          dst.push_back(USCRIPT_GREEK);
          break;
      }
      list_bits >>= kListShift;
    }
  }

  UChar32 GetPairedBracket(UChar32 ch) const override {
    switch (GetPairedBracketType(ch)) {
      case PairedBracketType::kBracketTypeClose:
        return ch - kBracketDelta;
      case PairedBracketType::kBracketTypeOpen:
        return ch + kBracketDelta;
      default:
        return ch;
    }
  }

  PairedBracketType GetPairedBracketType(UChar32 ch) const override {
    DCHECK_GE(ch, kMockCharMin);
    DCHECK_LT(ch, kMockCharLimit);
    int code = ch - kMockCharMin;
    if ((code & kCodeBracketBit) == 0) {
      return PairedBracketType::kBracketTypeNone;
    }
    if (code & kCodeBracketCloseBit) {
      return PairedBracketType::kBracketTypeClose;
    }
    return PairedBracketType::kBracketTypeOpen;
  }

  RunExtensionLookups GetSafeToExtendExistingRun(
      UScriptCode script) const override {
    return {nullptr, nullptr};
  }

  static int TableLookup(int value) {
    for (int i = 0; i < 16; ++i) {
      if (kTable[i] == value) {
        return i;
      }
    }
    DLOG(ERROR) << "Table does not contain value 0x" << std::hex << value;
    return 0;
  }

  static String ToTestString(const std::string& input) {
    StringBuilder result;
    result.Ensure16Bit();
    bool in_set = false;
    int seen = 0;
    int code = 0;
    int list = 0;
    int current_shift = 0;
    for (char c : input) {
      if (in_set) {
        switch (c) {
          case '(':
            DCHECK_EQ(seen, 0);
            seen |= kSawBracket;
            code |= kCodeBracketBit;
            break;
          case '[':
            DCHECK_EQ(seen, 0);
            seen |= kSawBracket;
            code |= kCodeBracketBit | kCodeSquareBracketBit;
            break;
          case ')':
            DCHECK_EQ(seen, 0);
            seen |= kSawBracket;
            code |= kCodeBracketBit | kCodeBracketCloseBit;
            break;
          case ']':
            DCHECK_EQ(seen, 0);
            seen |= kSawBracket;
            code |=
                kCodeBracketBit | kCodeSquareBracketBit | kCodeBracketCloseBit;
            break;
          case 'i':
            DCHECK_EQ(seen, 0);  // brackets can't be inherited
            seen |= kSawSpecial;
            code |= kCodeSpecialInherited;
            break;
          case 'c':
            DCHECK_EQ((seen & ~kSawBracket), 0);
            seen |= kSawSpecial;
            code |= kCodeSpecialCommon;
            break;
          case 'l':
            DCHECK_EQ((seen & kSawLatin), 0);
            DCHECK_LT(current_shift, 3);
            seen |= kSawLatin;
            list |= kLatin << (2 * current_shift++);
            break;
          case 'h':
            DCHECK_EQ((seen & kSawHan), 0);
            DCHECK_LT(current_shift, 3);
            seen |= kSawHan;
            list |= kHan << (2 * current_shift++);
            break;
          case 'g':
            DCHECK_EQ((seen & kSawGreek), 0);
            DCHECK_LT(current_shift, 3);
            seen |= kSawGreek;
            list |= kGreek << (2 * current_shift++);
            break;
          case '>':
            DCHECK_NE(seen, 0);
            code |= TableLookup(list);
            result.Append(static_cast<UChar>(kMockCharMin + code));
            in_set = false;
            break;
          default:
            DLOG(ERROR) << "Illegal mock string set char: '" << c << "'";
            break;
        }
        continue;
      }
      // not in set
      switch (c) {
        case '<':
          seen = 0;
          code = 0;
          list = 0;
          current_shift = 0;
          in_set = true;
          break;
        case '(':
          code = kCodeBracketBit | kCodeSpecialCommon;
          break;
        case '[':
          code = kCodeBracketBit | kCodeSquareBracketBit | kCodeSpecialCommon;
          break;
        case ')':
          code = kCodeBracketBit | kCodeBracketCloseBit | kCodeSpecialCommon;
          break;
        case ']':
          code = kCodeBracketBit | kCodeSquareBracketBit |
                 kCodeBracketCloseBit | kCodeSpecialCommon;
          break;
        case 'i':
          code = kCodeSpecialInherited;
          break;
        case 'c':
          code = kCodeSpecialCommon;
          break;
        case 'l':
          code = kLatin;
          break;
        case 'h':
          code = kHan;
          break;
        case 'g':
          code = kGreek;
          break;
        case '?':
          code = 0;  // unknown
          break;
        default:
          DLOG(ERROR) << "Illegal mock string set char: '" << c << "'";
      }
      if (!in_set) {
        result.Append(static_cast<UChar>(kMockCharMin + code));
      }
    }
    return result.ToString();
  }

  // We determine properties based on the offset from kMockCharMin:
  // bits 0-3 represent the list of l, h, c scripts (index into table)
  // bit 4-5 means: 0 plain, 1 common, 2 inherited, 3 illegal
  // bit 6 clear means non-bracket, open means bracket
  // bit 7 clear means open bracket, set means close bracket
  // bit 8 clear means paren, set means bracket
  // if it's a bracket, the matching bracket is 64 code points away
  static const UChar32 kMockCharMin = 0xe000;
  static const UChar32 kMockCharLimit = kMockCharMin + 0x200;
  static const int kLatin = 1;
  static const int kHan = 2;
  static const int kGreek = 3;
  static const int kCodeListIndexMask = 0xf;
  static const int kCodeSpecialMask = 0x30;
  static const int kCodeSpecialCommon = 0x10;
  static const int kCodeSpecialInherited = 0x20;
  static const int kCodeBracketCloseBit = 0x40;
  static const int kCodeBracketBit = 0x80;
  static const int kCodeSquareBracketBit = 0x100;
  static const int kListShift = 2;
  static const int kListMask = 0x3;
  static const int kBracketDelta = kCodeBracketCloseBit;
  static const std::array<int, 16> kTable;

  static const int kSawBracket = 0x1;
  static const int kSawSpecial = 0x2;
  static const int kSawLatin = 0x4;
  static const int kSawHan = 0x8;
  static const int kSawGreek = 0x10;
};

static const int kLatin2 = MockScriptData::kLatin << 2;
static const int kHan2 = MockScriptData::kHan << 2;
static const int kGreek2 = MockScriptData::kGreek << 2;
static const int kLatin3 = MockScriptData::kLatin << 4;
static const int kHan3 = MockScriptData::kHan << 4;
static const int kGreek3 = MockScriptData::kGreek << 4;
const std::array<int, 16> MockScriptData::kTable = {{
    0,
    kLatin,
    kHan,
    kGreek,
    kLatin2 + kHan,
    kLatin2 + kGreek,
    kHan2 + kLatin,
    kHan2 + kGreek,
    kGreek2 + kLatin,
    kGreek2 + kHan,
    kLatin3 + kHan2 + kGreek,
    kLatin3 + kGreek2 + kHan,
    kHan3 + kLatin2 + kGreek,
    kHan3 + kGreek2 + kLatin,
    kGreek3 + kLatin2 + kHan,
    kGreek3 + kHan2 + kLatin,
}};

class ScriptRunIteratorTest : public testing::Test {
 protected:
  void CheckRuns(const Vector<ScriptTestRun>& runs) {
    StringBuilder text;
    text.Ensure16Bit();
    Vector<ScriptExpectedRun> expect;
    for (auto& run : runs) {
      text.Append(String::FromUtf8(run.text));
      expect.push_back(ScriptExpectedRun(text.length(), run.code));
    }
    ScriptRunIterator script_run_iterator(text.Span16());
    VerifyRuns(&script_run_iterator, expect);
  }

  // FIXME crbug.com/527329 - CheckMockRuns should be replaced by finding
  // suitable equivalent real codepoint sequences instead.
  void CheckMockRuns(const Vector<ScriptTestRun>& runs) {
    StringBuilder text;
    text.Ensure16Bit();
    Vector<ScriptExpectedRun> expect;
    for (const ScriptTestRun& run : runs) {
      text.Append(MockScriptData::ToTestString(run.text));
      expect.push_back(ScriptExpectedRun(text.length(), run.code));
    }

    ScriptRunIterator script_run_iterator(text.Span16(),
                                          MockScriptData::Instance());
    VerifyRuns(&script_run_iterator, expect);
  }

  void VerifyRuns(ScriptRunIterator* script_run_iterator,
                  const Vector<ScriptExpectedRun>& expect) {
    Vector<ScriptExpectedRun> actual;
    unsigned limit;
    UScriptCode code;
    while (script_run_iterator->Consume(&limit, &code))
      actual.emplace_back(limit, code);
    EXPECT_THAT(actual, testing::ContainerEq(expect));
  }
};

TEST_F(ScriptRunIteratorTest, Empty) {
  String empty(g_empty_string16_bit);
  ScriptRunIterator script_run_iterator(empty.Span16());
  unsigned limit = 0;
  UScriptCode code = USCRIPT_INVALID_CODE;
  DCHECK(!script_run_iterator.Consume(&limit, &code));
  ASSERT_EQ(limit, 0u);
  ASSERT_EQ(code, USCRIPT_INVALID_CODE);
}

#define CHECK_SCRIPT_RUNS(...)              \
  Vector<ScriptTestRun> runs = __VA_ARGS__; \
  CheckRuns(runs);

#define CHECK_MOCK_SCRIPT_RUNS(...)         \
  Vector<ScriptTestRun> runs = __VA_ARGS__; \
  CheckMockRuns(runs);

TEST_F(ScriptRunIteratorTest, Whitespace) {
  CHECK_SCRIPT_RUNS({{" \t ", USCRIPT_COMMON}});
}

TEST_F(ScriptRunIteratorTest, Common) {
  CHECK_SCRIPT_RUNS({{" ... !?", USCRIPT_COMMON}});
}

TEST_F(ScriptRunIteratorTest, CombiningCircle) {
#if U_ICU_VERSION_MAJOR_NUM >= 76
  const UScriptCode script = USCRIPT_LATIN;
#else
  const UScriptCode script = USCRIPT_COMMON;
#endif
  CHECK_SCRIPT_RUNS({{"◌́◌̀◌̈◌̂◌̄◌̊", script}});
}

TEST_F(ScriptRunIteratorTest, Latin) {
  CHECK_SCRIPT_RUNS({{"latin", USCRIPT_LATIN}});
}

TEST_F(ScriptRunIteratorTest, Chinese) {
  CHECK_SCRIPT_RUNS({{"萬國碼", USCRIPT_HAN}});
}

struct JapaneseMixedScript {
  const char* string;
  // The expected primary_script when the string alone was evaluated.
  UScriptCode script;
} japanese_mixed_scripts[] = {{"あ", USCRIPT_HIRAGANA},
                              // Katakana should be normalized to Hiragana
                              {"ア", USCRIPT_HIRAGANA},
                              // Script_Extensions=Hira Kana
                              {"\u30FC", USCRIPT_HIRAGANA},
                              // Script_Extensions=Hani Hira Kana
                              {"\u303C", USCRIPT_HAN},
                              // Script_Extensions=Bopo Hang Hani Hira Kana
                              {"\u3003", USCRIPT_BOPOMOFO},
                              // Script_Extensions=Bopo Hang Hani Hira Kana Yiii
                              {"\u3001", USCRIPT_BOPOMOFO}};

class JapaneseMixedScriptTest
    : public ScriptRunIteratorTest,
      public testing::WithParamInterface<JapaneseMixedScript> {};

INSTANTIATE_TEST_SUITE_P(ScriptRunIteratorTest,
                         JapaneseMixedScriptTest,
                         testing::ValuesIn(japanese_mixed_scripts));

TEST_P(JapaneseMixedScriptTest, Data) {
  const auto& data = GetParam();
  std::string string(data.string);

  CheckRuns({{string.data(), data.script}});

  // If the string follows Hiragana or Katakana, or is followed by Hiragnaa or
  // Katakana, it should be normalized as Hiragana.
  std::string hiragana("か");
  std::string katakana("カ");
  CheckRuns({{(hiragana + string).data(), USCRIPT_HIRAGANA}});
  CheckRuns({{(string + hiragana).data(), USCRIPT_HIRAGANA}});

  CheckRuns({{(katakana + string).data(), USCRIPT_HIRAGANA}});
  CheckRuns({{(string + katakana).data(), USCRIPT_HIRAGANA}});

  CheckRuns({{(hiragana + string + katakana).data(), USCRIPT_HIRAGANA}});
  CheckRuns({{(katakana + string + hiragana).data(), USCRIPT_HIRAGANA}});
}

// Close bracket without matching open is ignored
TEST_F(ScriptRunIteratorTest, UnbalancedParens1) {
  CHECK_SCRIPT_RUNS(
      {{"(萬", USCRIPT_HAN}, {"a]", USCRIPT_LATIN}, {")", USCRIPT_HAN}});
}

// Open bracket without matching close is popped when inside
// matching close brackets, so doesn't match later close.
TEST_F(ScriptRunIteratorTest, UnbalancedParens2) {
  CHECK_SCRIPT_RUNS(
      {{"(萬", USCRIPT_HAN}, {"a[", USCRIPT_LATIN}, {")]", USCRIPT_HAN}});
}

// space goes with leading script
TEST_F(ScriptRunIteratorTest, LatinHan) {
  CHECK_SCRIPT_RUNS({{"Unicode ", USCRIPT_LATIN}, {"萬國碼", USCRIPT_HAN}});
}

// space goes with leading script
TEST_F(ScriptRunIteratorTest, HanLatin) {
  CHECK_SCRIPT_RUNS({{"萬國碼 ", USCRIPT_HAN}, {"Unicode", USCRIPT_LATIN}});
}

TEST_F(ScriptRunIteratorTest, ParenEmptyParen) {
  CHECK_SCRIPT_RUNS({{"()", USCRIPT_COMMON}});
}

TEST_F(ScriptRunIteratorTest, ParenChineseParen) {
  CHECK_SCRIPT_RUNS({{"(萬國碼)", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, ParenLatinParen) {
  CHECK_SCRIPT_RUNS({{"(Unicode)", USCRIPT_LATIN}});
}

// open paren gets leading script
TEST_F(ScriptRunIteratorTest, LatinParenChineseParen) {
  CHECK_SCRIPT_RUNS({{"Unicode (", USCRIPT_LATIN},
                     {"萬國碼", USCRIPT_HAN},
                     {")", USCRIPT_LATIN}});
}

// open paren gets first trailing script if no leading script
TEST_F(ScriptRunIteratorTest, ParenChineseParenLatin) {
  CHECK_SCRIPT_RUNS({{"(萬國碼) ", USCRIPT_HAN}, {"Unicode", USCRIPT_LATIN}});
}

// leading common and open paren get first trailing script.
// TODO(dougfelt): we don't do quote matching, but probably should figure out
// something better then doing nothing.
TEST_F(ScriptRunIteratorTest, QuoteParenChineseParenLatinQuote) {
  CHECK_SCRIPT_RUNS(
      {{"\"(萬國碼) ", USCRIPT_HAN}, {"Unicode\"", USCRIPT_LATIN}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens1) {
  CHECK_SCRIPT_RUNS({{"「あ", USCRIPT_HIRAGANA},
                     // The consecutive punctuation should not be split.
                     {"国。」", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens2) {
  CHECK_SCRIPT_RUNS({{"あ「あ", USCRIPT_HIRAGANA},
                     // The consecutive punctuation should not be split.
                     {"国（国）」", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens3) {
  CHECK_SCRIPT_RUNS({{"国「国", USCRIPT_HAN},
                     {"ア（", USCRIPT_HIRAGANA},
                     {"A", USCRIPT_LATIN},
                     // The consecutive punctuation should not be split.
                     {"）」", USCRIPT_HIRAGANA}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens4) {
  CHECK_SCRIPT_RUNS({{"A", USCRIPT_LATIN},
                     // CJK puncutuation after non-CJK resolves to Bopomofo,
                     // because it's the first script extension in the Unicode
                     // data. It's not correct but ok because GPOS/GSUB in CJK
                     // fonts usually include the same features for all CJK
                     // scripts including Bopomofo, even when they are not
                     // intended for Traditional Chinese.
                     {"「", USCRIPT_BOPOMOFO},
                     {"A", USCRIPT_LATIN},
                     {"あ（", USCRIPT_HIRAGANA},
                     // The consecutive punctuation should not be split.
                     {"国）」", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens5) {
  CHECK_SCRIPT_RUNS({{"「あ", USCRIPT_HIRAGANA},
                     {"国", USCRIPT_HAN},
                     {"A", USCRIPT_LATIN},
                     {"」", USCRIPT_HIRAGANA}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens6) {
  CHECK_SCRIPT_RUNS({{"A", USCRIPT_LATIN},
                     {"「", USCRIPT_BOPOMOFO},  // See CJKConsecutiveParens4
                     {"A", USCRIPT_LATIN},
                     {"あ（", USCRIPT_HIRAGANA},
                     {"国）", USCRIPT_HAN},
                     {"A", USCRIPT_LATIN},
                     {"」", USCRIPT_BOPOMOFO}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens7) {
  CHECK_SCRIPT_RUNS({
      {"「あ", USCRIPT_HIRAGANA},
      {"国1」", USCRIPT_HAN},
  });
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens8) {
  CHECK_SCRIPT_RUNS({
      {"A", USCRIPT_LATIN},
      {"「", USCRIPT_BOPOMOFO},  // See CJKConsecutiveParens4
      {"A", USCRIPT_LATIN},
      {"あ（", USCRIPT_HIRAGANA},
      {"国）1」", USCRIPT_HAN},
  });
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens9) {
  CHECK_SCRIPT_RUNS({{"「あ", USCRIPT_HIRAGANA},
                     {"国", USCRIPT_HAN},
                     {"A1", USCRIPT_LATIN},
                     {"」", USCRIPT_HIRAGANA}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParens10) {
  CHECK_SCRIPT_RUNS({{"A", USCRIPT_LATIN},
                     {"「", USCRIPT_BOPOMOFO},  // See CJKConsecutiveParens4
                     {"A", USCRIPT_LATIN},
                     {"あ（", USCRIPT_HIRAGANA},
                     {"国）", USCRIPT_HAN},
                     {"A1", USCRIPT_LATIN},
                     {"」", USCRIPT_BOPOMOFO}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParensLatin1) {
  CHECK_SCRIPT_RUNS({{"「", USCRIPT_BOPOMOFO},  // See CJKConsecutiveParens4
                     {"A", USCRIPT_LATIN},
                     {"「", USCRIPT_BOPOMOFO},
                     {"A", USCRIPT_LATIN},
                     {"」」", USCRIPT_BOPOMOFO}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParensLatin2) {
  CHECK_SCRIPT_RUNS({{"「", USCRIPT_BOPOMOFO},  // See CJKConsecutiveParens4
                     {"A", USCRIPT_LATIN},
                     {"（", USCRIPT_BOPOMOFO},
                     {"A", USCRIPT_LATIN},
                     {"）」", USCRIPT_BOPOMOFO}});
}

TEST_F(ScriptRunIteratorTest, CJKConsecutiveParensLatin3) {
  CHECK_SCRIPT_RUNS({{"「", USCRIPT_BOPOMOFO},  // See CJKConsecutiveParens4
                     {"A", USCRIPT_LATIN},
                     {"（国）」", USCRIPT_HAN}});
}

// Emojies are resolved to the leading script.
TEST_F(ScriptRunIteratorTest, EmojiCommon) {
  CHECK_SCRIPT_RUNS({{"百家姓🌱🌲🌳🌴", USCRIPT_HAN}});
}

// Unmatched close brace gets leading context
TEST_F(ScriptRunIteratorTest, UnmatchedClose) {
  CHECK_SCRIPT_RUNS({{"Unicode (", USCRIPT_LATIN},
                     {"萬國碼] ", USCRIPT_HAN},
                     {") Unicode\"", USCRIPT_LATIN}});
}

// Match up to 32 bracket pairs
TEST_F(ScriptRunIteratorTest, Match32Brackets) {
  CHECK_SCRIPT_RUNS({{"[萬國碼 ", USCRIPT_HAN},
                     {"Unicode (((((((((((((((((((((((((((((((!"
                      ")))))))))))))))))))))))))))))))",
                      USCRIPT_LATIN},
                     {"]", USCRIPT_HAN}});
}

// Matches 32 most recent bracket pairs. More than that, and we revert to
// surrounding script.
TEST_F(ScriptRunIteratorTest, Match32MostRecentBrackets) {
  CHECK_SCRIPT_RUNS({{"((([萬國碼 ", USCRIPT_HAN},
                     {"Unicode (((((((((((((((((((((((((((((((", USCRIPT_LATIN},
                     {"萬國碼!", USCRIPT_HAN},
                     {")))))))))))))))))))))))))))))))", USCRIPT_LATIN},
                     {"]", USCRIPT_HAN},
                     {"But )))", USCRIPT_LATIN}});
}

// A char with multiple scripts that match both leading and trailing context
// gets the leading context.
TEST_F(ScriptRunIteratorTest, ExtensionsPreferLeadingContext) {
  CHECK_MOCK_SCRIPT_RUNS({{"h<lh>", USCRIPT_HAN}, {"l", USCRIPT_LATIN}});
}

// A char with multiple scripts that only match trailing context gets the
// trailing context.
TEST_F(ScriptRunIteratorTest, ExtensionsMatchTrailingContext) {
  CHECK_MOCK_SCRIPT_RUNS({{"h", USCRIPT_HAN}, {"<gl>l", USCRIPT_LATIN}});
}

// Retain first established priority script.  <lhg><gh> produce the script <gh>
// with g as priority, because of the two priority scripts l and g, only g
// remains.  Then <gh><hgl> retains g as priority, because of the two priority
// scripts g and h that remain, g was encountered first.
TEST_F(ScriptRunIteratorTest, ExtensionsRetainFirstPriorityScript) {
  CHECK_MOCK_SCRIPT_RUNS({{"<lhg><gh><hgl>", USCRIPT_GREEK}});
}

// Parens can have scripts that break script runs.
TEST_F(ScriptRunIteratorTest, ExtensionsParens) {
  CHECK_MOCK_SCRIPT_RUNS({{"<gl><(lg>", USCRIPT_GREEK},
                          {"h<[hl>", USCRIPT_HAN},
                          {"l", USCRIPT_LATIN},
                          {"<]hl>", USCRIPT_HAN},
                          {"<)lg>", USCRIPT_GREEK}});
}

// The close paren might be encountered before we've established the open
// paren's script, but when this is the case the current set is still valid, so
// this doesn't affect it nor break the run.
TEST_F(ScriptRunIteratorTest, ExtensionsParens2) {
  CHECK_MOCK_SCRIPT_RUNS({{"<(lhg><gh><)lhg>", USCRIPT_GREEK}});
}

// A common script with a single extension should be treated as common, but
// with the extended script as a default.  If we encounter anything other than
// common, that takes priority.  If we encounter other common scripts with a
// single extension, the current priority remains.
TEST_F(ScriptRunIteratorTest, CommonWithPriority) {
  CHECK_MOCK_SCRIPT_RUNS({{"<ch>", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, CommonWithPriority2) {
  CHECK_MOCK_SCRIPT_RUNS({{"<ch><lh>", USCRIPT_LATIN}});
}

TEST_F(ScriptRunIteratorTest, CommonWithPriority3) {
  CHECK_MOCK_SCRIPT_RUNS({{"<ch><cl><cg>", USCRIPT_HAN}});
}

// UDatta (\xE0\xA5\x91) is inherited with LATIN, DEVANAGARI, BENGALI and
// other Indic scripts. Since it has LATIN, and the
// dotted circle U+25CC (\xE2\x97\x8C) is COMMON and has adopted the
// preceding LATIN, it gets the LATIN. This is standard.
TEST_F(ScriptRunIteratorTest, LatinDottedCircleUdatta) {
  CHECK_SCRIPT_RUNS({{"Latin \xE2\x97\x8C\xE0\xA5\x91", USCRIPT_LATIN}});
}

// In this situation, UDatta U+0951 (\xE0\xA5\x91) doesn't share a script
// with the value inherited by the dotted circle U+25CC (\xE2\x97\x8C).
// It captures the preceding dotted circle and breaks it from the run it would
// normally have been in. U+0951 is used in multiple scripts (DEVA, BENG, LATN,
// etc) and has multiple values for Script_Extension property. At the moment,
// getScripts() treats the script with the lowest script code as 'true' primary,
// and BENG comes before DEVA in the script enum so that we get BENGALI.
// Taking into account a Unicode block and returning DEVANAGARI would be
// slightly better.
TEST_F(ScriptRunIteratorTest, HanDottedCircleUdatta) {
  CHECK_SCRIPT_RUNS({{"萬國碼 ", USCRIPT_HAN},
                     {"\xE2\x97\x8C\xE0\xA5\x91", USCRIPT_BENGALI}});
}

// Tatweel is \xD9\x80 Lm, Fathatan is \xD9\x8B Mn. The script of tatweel is
// common, that of Fathatan is inherited.  The script extensions for Fathatan
// are Arabic and Syriac. The Syriac script is 34 in ICU, Arabic is 2. So the
// preferred script for Fathatan is Arabic, according to Behdad's
// heuristic. This is exactly analogous to the Udatta tests above, except
// Tatweel is Lm. But we don't take properties into account, only scripts.
TEST_F(ScriptRunIteratorTest, LatinTatweelFathatan) {
  CHECK_SCRIPT_RUNS(
      {{"Latin ", USCRIPT_LATIN}, {"\xD9\x80\xD9\x8B", USCRIPT_ARABIC}});
}

// Another case where if the mark accepts a script that was inherited by the
// preceding common-script character, they both continue in that script.
// SYRIAC LETTER NUN \xDC\xA2
// ARABIC TATWEEL \xD9\x80
// ARABIC FATHATAN \xD9\x82
TEST_F(ScriptRunIteratorTest, SyriacTatweelFathatan) {
  CHECK_SCRIPT_RUNS({{"\xDC\xA2\xD9\x80\xD9\x8B", USCRIPT_SYRIAC}});
}

// The Udatta (\xE0\xA5\x91) is inherited, so will share runs with anything that
// is not common.
TEST_F(ScriptRunIteratorTest, HanUdatta) {
  CHECK_SCRIPT_RUNS({{"萬國碼\xE0\xA5\x91", USCRIPT_HAN}});
}

// The Udatta U+0951 (\xE0\xA5\x91) is inherited, and will capture the space
// and turn it into Bengali because SCRIPT_BENAGLI is 4 and SCRIPT_DEVANAGARI
// is 10. See TODO comment for |getScripts| and HanDottedCircleUdatta.
TEST_F(ScriptRunIteratorTest, HanSpaceUdatta) {
  CHECK_SCRIPT_RUNS(
      {{"萬國碼", USCRIPT_HAN}, {" \xE0\xA5\x91", USCRIPT_BENGALI}});
}

// Corresponds to one test in RunSegmenter, where orientation of the
// space character is sidesways in vertical.
TEST_F(ScriptRunIteratorTest, Hangul) {
  CHECK_SCRIPT_RUNS({{"키스의 고유조건은", USCRIPT_HANGUL}});
}

// Corresponds to one test in RunSegmenter, which tests that the punctuation
// characters mixed in are actually sideways in vertical. The ScriptIterator
// should report one run, but the RunSegmenter should report three, with the
// middle one rotated sideways.
TEST_F(ScriptRunIteratorTest, HiraganaMixedPunctuation) {
  CHECK_SCRIPT_RUNS({{"いろはに.…¡ほへと", USCRIPT_HIRAGANA}});
}

// Make sure Mock code works too.
TEST_F(ScriptRunIteratorTest, MockHanInheritedGL) {
  CHECK_MOCK_SCRIPT_RUNS({{"h<igl>", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, MockHanCommonInheritedGL) {
  CHECK_MOCK_SCRIPT_RUNS({{"h", USCRIPT_HAN}, {"c<igl>", USCRIPT_GREEK}});
}

// Leading inherited just act like common, except there's no preferred script.
TEST_F(ScriptRunIteratorTest, MockLeadingInherited) {
  CHECK_MOCK_SCRIPT_RUNS({{"<igl>", USCRIPT_COMMON}});
}

// Leading inherited just act like common, except there's no preferred script.
TEST_F(ScriptRunIteratorTest, MockLeadingInherited2) {
  CHECK_MOCK_SCRIPT_RUNS({{"<igl><ih>", USCRIPT_COMMON}});
}

TEST_F(ScriptRunIteratorTest, LeadingInheritedHan) {
  // DEVANAGARI STRESS SIGN UDATTA \xE0\xA5\x91
  CHECK_SCRIPT_RUNS({{"\xE0\xA5\x91萬國碼", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, LeadingInheritedHan2) {
  // DEVANAGARI STRESS SIGN UDATTA \xE0\xA5\x91
  // ARABIC FATHATAN \xD9\x8B
  CHECK_SCRIPT_RUNS({{"\xE0\xA5\x91\xD9\x8B萬國碼", USCRIPT_HAN}});
}

TEST_F(ScriptRunIteratorTest, OddLatinString) {
  CHECK_SCRIPT_RUNS({{"ç̈", USCRIPT_LATIN}});
}

TEST_F(ScriptRunIteratorTest, CommonMalayalam) {
  CHECK_SCRIPT_RUNS({{"100-ാം", USCRIPT_MALAYALAM}});
}

TEST_F(ScriptRunIteratorTest, IdeographicCommaDoesNotCountAsLatin) {
  CHECK_SCRIPT_RUNS({{"也：", USCRIPT_HAN},
                     {"ABC", USCRIPT_LATIN},
                     {"、", USCRIPT_BOPOMOFO},
                     {"DEF", USCRIPT_LATIN}});
}

std::pair<int, UChar32> MaximumScriptExtensions() {
  int max_extensions = 0;
  UChar32 max_extensionscp = 0;
  for (UChar32 cp = 0; cp < 0x11000; ++cp) {
    UErrorCode status = U_ZERO_ERROR;
    int count = uscript_getScriptExtensions(cp, nullptr, 0, &status);
    if (count > max_extensions) {
      max_extensions = count;
      max_extensionscp = cp;
    }
  }
  return std::make_pair(max_extensions, max_extensionscp);
}

TEST_F(ScriptRunIteratorTest, MaxUnicodeScriptExtensions) {
  int max_extensions = 0;
  UChar32 max_extensionscp = 0;
  std::tie(max_extensions, max_extensionscp) = MaximumScriptExtensions();
  // If this test fails (as a result of an ICU update, most likely), it means
  // we need to change kMaxUnicodeScriptExtensions.
  EXPECT_LE(max_extensions, ScriptRunIterator::kMaxUnicodeScriptExtensions);
}

class ScriptRunIteratorICUDataTest : public testing::Test {
 public:
  ScriptRunIteratorICUDataTest() {
    std::tie(max_extensions_, max_extensions_codepoint_) =
        MaximumScriptExtensions();
  }

 protected:
  UChar32 GetACharWithMaxExtensions(int* num_extensions) {
    if (num_extensions) {
      *num_extensions = max_extensions_;
    }
    return max_extensions_codepoint_;
  }

 private:
  int max_extensions_;
  UChar32 max_extensions_codepoint_;
};

// Validate that ICU never returns more than our maximum expected number of
// script extensions.
TEST_F(ScriptRunIteratorICUDataTest, ValidateICUMaxScriptExtensions) {
  int max_extensions;
  UChar32 cp = GetACharWithMaxExtensions(&max_extensions);
  ASSERT_LT(max_extensions, ScriptData::kMaxScriptCount)
      << "char " << std::hex << cp << std::dec;
}

// Check that ICUScriptData returns all of a character's scripts.
// This only checks one likely character, but doesn't check all cases.
TEST_F(ScriptRunIteratorICUDataTest, ICUDataGetScriptsReturnsAllExtensions) {
  int max_extensions;
  UChar32 cp = GetACharWithMaxExtensions(&max_extensions);
  ScriptData::UScriptCodeList extensions;
  ICUScriptData::Instance()->GetScripts(cp, extensions);

  // It's possible that GetScripts adds the primary script to the list of
  // extensions, resulting in one more script than the raw extension count.
  ASSERT_GE(static_cast<int>(extensions.size()), max_extensions)
      << "char " << std::hex << cp << std::dec;
}

TEST_F(ScriptRunIteratorICUDataTest, CommonHaveNoMoreThanOneExtension) {
  ScriptData::UScriptCodeList extensions;
  for (UChar32 cp = 0; cp < 0x110000; ++cp) {
    ICUScriptData::Instance()->GetScripts(cp, extensions);
    UScriptCode primary = extensions.at(0);
    if (primary == USCRIPT_COMMON) {
      ASSERT_LE(extensions.size(), 2ul) << "cp: " << std::hex << cp << std::dec;
    }
  }
}

// ZWJ is \u200D Cf (Format, other) and its script is inherited.  I'm going to
// ignore this for now, as I think it shouldn't matter which run it ends up
// in. HarfBuzz needs to be able to use it as context and shape each
// neighboring character appropriately no matter what run it got assigned to.

}  // namespace blink