String TextCheckingHelper::findFirstMisspellingOrBadGrammar(bool& outIsSpelling, int& outFirstFoundOffset, GrammarDetail& outGrammarDetail)
{
    if (!unifiedTextCheckerEnabled())
        return "";

    String firstFoundItem;
    String misspelledWord;
    String badGrammarPhrase;

    // Initialize out parameters; these will be updated if we find something to return.
    outIsSpelling = true;
    outFirstFoundOffset = 0;
    outGrammarDetail.location = -1;
    outGrammarDetail.length = 0;
    outGrammarDetail.guesses.clear();
    outGrammarDetail.userDescription = "";

    // Expand the search range to encompass entire paragraphs, since text checking needs that much context.
    // Determine the character offset from the start of the paragraph to the start of the original search range,
    // since we will want to ignore results in this area.
    Position paragraphStart = startOfParagraph(createVisiblePosition(m_start)).toParentAnchoredPosition();
    Position paragraphEnd = m_end;
    int totalRangeLength = TextIterator::rangeLength(paragraphStart, paragraphEnd);
    paragraphEnd = endOfParagraph(createVisiblePosition(m_start)).toParentAnchoredPosition();

    int rangeStartOffset = TextIterator::rangeLength(paragraphStart, m_start);
    int totalLengthProcessed = 0;

    bool firstIteration = true;
    bool lastIteration = false;
    while (totalLengthProcessed < totalRangeLength) {
        // Iterate through the search range by paragraphs, checking each one for spelling and grammar.
        int currentLength = TextIterator::rangeLength(paragraphStart, paragraphEnd);
        int currentStartOffset = firstIteration ? rangeStartOffset : 0;
        int currentEndOffset = currentLength;
        if (inSameParagraph(createVisiblePosition(paragraphStart), createVisiblePosition(m_end))) {
            // Determine the character offset from the end of the original search range to the end of the paragraph,
            // since we will want to ignore results in this area.
            currentEndOffset = TextIterator::rangeLength(paragraphStart, m_end);
            lastIteration = true;
        }
        if (currentStartOffset < currentEndOffset) {
            String paragraphString = plainText(EphemeralRange(paragraphStart, paragraphEnd));
            if (paragraphString.length() > 0) {
                bool foundGrammar = false;
                int spellingLocation = 0;
                int grammarPhraseLocation = 0;
                int grammarDetailLocation = 0;
                unsigned grammarDetailIndex = 0;

                Vector<TextCheckingResult> results;
                TextCheckingTypeMask checkingTypes = TextCheckingTypeSpelling | TextCheckingTypeGrammar;
                checkTextOfParagraph(m_client->textChecker(), paragraphString, checkingTypes, results);

                for (unsigned i = 0; i < results.size(); i++) {
                    const TextCheckingResult* result = &results[i];
                    if (result->decoration == TextDecorationTypeSpelling && result->location >= currentStartOffset && result->location + result->length <= currentEndOffset) {
                        ASSERT(result->length > 0 && result->location >= 0);
                        spellingLocation = result->location;
                        misspelledWord = paragraphString.substring(result->location, result->length);
                        ASSERT(misspelledWord.length());
                        break;
                    }
                    if (result->decoration == TextDecorationTypeGrammar && result->location < currentEndOffset && result->location + result->length > currentStartOffset) {
                        ASSERT(result->length > 0 && result->location >= 0);
                        // We can't stop after the first grammar result, since there might still be a spelling result after
                        // it begins but before the first detail in it, but we can stop if we find a second grammar result.
                        if (foundGrammar)
                            break;
                        for (unsigned j = 0; j < result->details.size(); j++) {
                            const GrammarDetail* detail = &result->details[j];
                            ASSERT(detail->length > 0 && detail->location >= 0);
                            if (result->location + detail->location >= currentStartOffset && result->location + detail->location + detail->length <= currentEndOffset && (!foundGrammar || result->location + detail->location < grammarDetailLocation)) {
                                grammarDetailIndex = j;
                                grammarDetailLocation = result->location + detail->location;
                                foundGrammar = true;
                            }
                        }
                        if (foundGrammar) {
                            grammarPhraseLocation = result->location;
                            outGrammarDetail = result->details[grammarDetailIndex];
                            badGrammarPhrase = paragraphString.substring(result->location, result->length);
                            ASSERT(badGrammarPhrase.length());
                        }
                    }
                }

                if (!misspelledWord.isEmpty() && (badGrammarPhrase.isEmpty() || spellingLocation <= grammarDetailLocation)) {
                    int spellingOffset = spellingLocation - currentStartOffset;
                    if (!firstIteration)
                        spellingOffset += TextIterator::rangeLength(m_start, paragraphStart);
                    outIsSpelling = true;
                    outFirstFoundOffset = spellingOffset;
                    firstFoundItem = misspelledWord;
                    break;
                }
                if (!badGrammarPhrase.isEmpty()) {
                    int grammarPhraseOffset = grammarPhraseLocation - currentStartOffset;
                    if (!firstIteration)
                        grammarPhraseOffset += TextIterator::rangeLength(m_start, paragraphStart);
                    outIsSpelling = false;
                    outFirstFoundOffset = grammarPhraseOffset;
                    firstFoundItem = badGrammarPhrase;
                    break;
                }
            }
        }
        if (lastIteration || totalLengthProcessed + currentLength >= totalRangeLength)
            break;
        VisiblePosition newParagraphStart = startOfNextParagraph(createVisiblePosition(paragraphEnd));
        paragraphStart = newParagraphStart.toParentAnchoredPosition();
        paragraphEnd = endOfParagraph(newParagraphStart).toParentAnchoredPosition();
        firstIteration = false;
        totalLengthProcessed += currentLength;
    }
    return firstFoundItem;
}