/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * 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 GOOGLE INC. AND ITS CONTRIBUTORS
 * "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 GOOGLE INC.
 * OR ITS 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "ContentSearchUtilities.h"

#include "InspectorValues.h"
#include "RegularExpression.h"
#include "Yarr.h"
#include "YarrInterpreter.h"
#include <wtf/BumpPointerAllocator.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/StringBuilder.h>

using namespace JSC::Yarr;

namespace Inspector {
namespace ContentSearchUtilities {

static const char regexSpecialCharacters[] = "[](){}+-*.,?\\^$|";

static String createSearchRegexSource(const String& text)
{
    StringBuilder result;

    for (unsigned i = 0; i < text.length(); i++) {
        UChar character = text[i];
        if (isASCII(character) && strchr(regexSpecialCharacters, character))
            result.append('\\');
        result.append(character);
    }

    return result.toString();
}

static inline size_t sizetExtractor(const size_t* value)
{
    return *value;
}

TextPosition textPositionFromOffset(size_t offset, const Vector<size_t>& lineEndings)
{
    const size_t* foundNextStart = approximateBinarySearch<size_t, size_t>(lineEndings, lineEndings.size(), offset, sizetExtractor);
    size_t lineIndex = foundNextStart - &lineEndings.at(0);
    if (offset >= *foundNextStart)
        ++lineIndex;
    size_t lineStartOffset = lineIndex > 0 ? lineEndings.at(lineIndex - 1) : 0;
    size_t column = offset - lineStartOffset;
    return TextPosition(OrdinalNumber::fromZeroBasedInt(lineIndex), OrdinalNumber::fromZeroBasedInt(column));
}

static Vector<std::pair<size_t, String>> getRegularExpressionMatchesByLines(const JSC::Yarr::RegularExpression& regex, const String& text)
{
    Vector<std::pair<size_t, String>> result;
    if (text.isEmpty())
        return result;

    std::unique_ptr<Vector<size_t>> endings(lineEndings(text));
    size_t size = endings->size();
    size_t start = 0;

    for (size_t lineNumber = 0; lineNumber < size; ++lineNumber) {
        size_t nextStart = endings->at(lineNumber);
        String line = text.substring(start, nextStart - start);

        int matchLength;
        if (regex.match(line, 0, &matchLength) != -1)
            result.append(std::pair<size_t, String>(lineNumber, line));

        start = nextStart;
    }

    return result;
}

std::unique_ptr<Vector<size_t>> lineEndings(const String& text)
{
    auto result = std::make_unique<Vector<size_t>>();

    size_t start = 0;
    while (start < text.length()) {
        size_t nextStart = text.find('\n', start);
        if (nextStart == notFound || nextStart == (text.length() - 1)) {
            result->append(text.length());
            break;
        }

        nextStart += 1;
        result->append(nextStart);
        start = nextStart;
    }

    result->append(text.length());

    return result;
}

static Ref<Inspector::Protocol::GenericTypes::SearchMatch> buildObjectForSearchMatch(size_t lineNumber, const String& lineContent)
{
    return Inspector::Protocol::GenericTypes::SearchMatch::create()
        .setLineNumber(lineNumber)
        .setLineContent(lineContent)
        .release();
}

JSC::Yarr::RegularExpression createSearchRegex(const String& query, bool caseSensitive, bool isRegex)
{
    String regexSource = isRegex ? query : createSearchRegexSource(query);
    return JSC::Yarr::RegularExpression(regexSource, caseSensitive ? TextCaseSensitive : TextCaseInsensitive);
}

int countRegularExpressionMatches(const JSC::Yarr::RegularExpression& regex, const String& content)
{
    if (content.isEmpty())
        return 0;

    int result = 0;
    int position;
    unsigned start = 0;
    int matchLength;
    while ((position = regex.match(content, start, &matchLength)) != -1) {
        if (start >= content.length())
            break;
        if (matchLength > 0)
            ++result;
        start = position + 1;
    }
    return result;
}

Ref<Inspector::Protocol::Array<Inspector::Protocol::GenericTypes::SearchMatch>> searchInTextByLines(const String& text, const String& query, const bool caseSensitive, const bool isRegex)
{
    Ref<Inspector::Protocol::Array<Inspector::Protocol::GenericTypes::SearchMatch>> result = Inspector::Protocol::Array<Inspector::Protocol::GenericTypes::SearchMatch>::create();

    JSC::Yarr::RegularExpression regex = ContentSearchUtilities::createSearchRegex(query, caseSensitive, isRegex);
    Vector<std::pair<size_t, String>> matches = getRegularExpressionMatchesByLines(regex, text);

    for (const auto& match : matches) {
        Ref<Inspector::Protocol::GenericTypes::SearchMatch> matchObject = buildObjectForSearchMatch(match.first, match.second);
        result->addItem(WTFMove(matchObject));
    }

    return result;
}

static String stylesheetCommentPattern(const String& name)
{
    // "/*# <name>=<value> */" and deprecated "/*@"
    return "/\\*[#@][\040\t]" + name + "=[\040\t]*([^\\s\'\"]*)[\040\t]*\\*/";
}

static String findMagicComment(const String& content, const String& patternString)
{
    ASSERT(!content.isNull());
    const char* error = nullptr;
    JSC::Yarr::YarrPattern pattern(patternString, JSC::RegExpFlags::FlagMultiline, &error);
    ASSERT(!error);
    BumpPointerAllocator regexAllocator;
    auto bytecodePattern = JSC::Yarr::byteCompile(pattern, &regexAllocator);
    ASSERT(bytecodePattern);

    ASSERT(pattern.m_numSubpatterns == 1);
    Vector<int, 4> matches;
    matches.resize(4);
    unsigned result = JSC::Yarr::interpret(bytecodePattern.get(), content, 0, reinterpret_cast<unsigned*>(matches.data()));
    if (result == JSC::Yarr::offsetNoMatch)
        return String();

    ASSERT(matches[2] > 0 && matches[3] > 0);
    return content.substring(matches[2], matches[3] - matches[2]);
}

String findStylesheetSourceMapURL(const String& content)
{
    return findMagicComment(content, stylesheetCommentPattern(ASCIILiteral("sourceMappingURL")));
}

} // namespace ContentSearchUtilities
} // namespace Inspector