/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you 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 .

 */

#include <sal/config.h>

#include <cstdlib>

#include <string_view>

#include <i18nlangtag/languagetag.hxx>

#include <i18nutil/searchopt.hxx>

#include <i18nutil/transliteration.hxx>

#include <com/sun/star/util/TextSearch2.hpp>

#include <com/sun/star/util/SearchAlgorithms2.hpp>

#include <com/sun/star/util/SearchFlags.hpp>

#include <unotools/charclass.hxx>

#include <comphelper/processfactory.hxx>

#include <unotools/textsearch.hxx>

#include <rtl/ustrbuf.hxx>

#include <comphelper/diagnose_ex.hxx>

#include <mutex>

using namespace ::com::sun::star::util;

using namespace ::com::sun::star::uno;

using namespace ::com::sun::star::lang;

namespace utl

{

SearchParam::SearchParam( const OUString &rText,

                                SearchType eType,

                                bool bCaseSensitive,

                                sal_uInt32 cWildEscChar,

                                bool bWildMatchSel )

{

    sSrchStr        = rText;

    m_eSrchType     = eType;

    m_cWildEscChar  = cWildEscChar;

    m_bCaseSense    = bCaseSensitive;

    m_bWildMatchSel = bWildMatchSel;

}

SearchParam::SearchParam( const SearchParam& rParam )

{

    sSrchStr        = rParam.sSrchStr;

    m_eSrchType     = rParam.m_eSrchType;

    m_cWildEscChar  = rParam.m_cWildEscChar;

    m_bCaseSense    = rParam.m_bCaseSense;

    m_bWildMatchSel = rParam.m_bWildMatchSel;

}

SearchParam::~SearchParam() {}

static bool lcl_Equals( const i18nutil::SearchOptions2& rSO1, const i18nutil::SearchOptions2& rSO2 )

{

    return

        rSO1.AlgorithmType2 == rSO2.AlgorithmType2 &&

        rSO1.WildcardEscapeCharacter == rSO2.WildcardEscapeCharacter &&

        rSO1.searchFlag == rSO2.searchFlag &&

        rSO1.searchString == rSO2.searchString &&

        rSO1.replaceString == rSO2.replaceString &&

        rSO1.changedChars == rSO2.changedChars &&

        rSO1.deletedChars == rSO2.deletedChars &&

        rSO1.insertedChars == rSO2.insertedChars &&

        rSO1.Locale.Language == rSO2.Locale.Language &&

        rSO1.Locale.Country == rSO2.Locale.Country &&

        rSO1.Locale.Variant == rSO2.Locale.Variant &&

        rSO1.transliterateFlags == rSO2.transliterateFlags;

}

namespace

{

    struct CachedTextSearch

    {

        std::mutex mutex;

        i18nutil::SearchOptions2 Options;

        css::uno::Reference< css::util::XTextSearch2 > xTextSearch;

    };

}

Reference<XTextSearch2> TextSearch::getXTextSearch( const i18nutil::SearchOptions2& rPara )

{

    static CachedTextSearch theCachedTextSearch;

    std::scoped_lock aGuard(theCachedTextSearch.mutex);

    if ( lcl_Equals(theCachedTextSearch.Options, rPara) )

        return theCachedTextSearch.xTextSearch;

    const Reference< XComponentContext >& xContext = ::comphelper::getProcessComponentContext();

    theCachedTextSearch.xTextSearch.set( ::TextSearch2::create(xContext) );

    theCachedTextSearch.xTextSearch->setOptions2( rPara.toUnoSearchOptions2() );

    theCachedTextSearch.Options = rPara;

    return theCachedTextSearch.xTextSearch;

}

TextSearch::TextSearch(const SearchParam & rParam, LanguageType eLang )

{

    if( LANGUAGE_NONE == eLang )

        eLang = LANGUAGE_SYSTEM;

    css::lang::Locale aLocale( LanguageTag::convertToLocale( eLang ) );

    Init( rParam, aLocale);

}

TextSearch::TextSearch(const SearchParam & rParam, const CharClass& rCClass )

{

    Init( rParam, rCClass.getLanguageTag().getLocale() );

}

TextSearch::TextSearch( const i18nutil::SearchOptions2& rPara )

{

    xTextSearch = getXTextSearch( rPara );

}

void TextSearch::Init( const SearchParam & rParam,

                        const css::lang::Locale& rLocale )

{

    // convert SearchParam to the UNO SearchOptions2

    i18nutil::SearchOptions2 aSOpt;

    switch( rParam.GetSrchType() )

    {

    case SearchParam::SearchType::Wildcard:

        aSOpt.AlgorithmType2 = SearchAlgorithms2::WILDCARD;

        aSOpt.WildcardEscapeCharacter = rParam.GetWildEscChar();

        if (rParam.IsWildMatchSel())

            aSOpt.searchFlag |= SearchFlags::WILD_MATCH_SELECTION;

        break;

    case SearchParam::SearchType::Regexp:

        aSOpt.AlgorithmType2 = SearchAlgorithms2::REGEXP;

        break;

    case SearchParam::SearchType::Normal:

        aSOpt.AlgorithmType2 = SearchAlgorithms2::ABSOLUTE;

        break;

    default:

        for (;;) std::abort();

    }

    aSOpt.searchString = rParam.GetSrchStr();

    aSOpt.replaceString = "";

    aSOpt.Locale = rLocale;

    aSOpt.transliterateFlags = TransliterationFlags::NONE;

    if( !rParam.IsCaseSensitive() )

    {

        aSOpt.searchFlag |= SearchFlags::ALL_IGNORE_CASE;

        aSOpt.transliterateFlags |= TransliterationFlags::IGNORE_CASE;

    }

    xTextSearch = getXTextSearch( aSOpt );

}

void TextSearch::SetLocale( const i18nutil::SearchOptions2& rOptions,

                            const css::lang::Locale& rLocale )

{

    i18nutil::SearchOptions2 aSOpt( rOptions );

    aSOpt.Locale = rLocale;

    xTextSearch = getXTextSearch( aSOpt );

}

TextSearch::~TextSearch()

{

}

/*

 * General search methods. These methods will call the respective

 * methods, such as ordinary string searching or regular expression

 * matching, using the method pointer.

 */

bool TextSearch::SearchForward( const OUString &rStr,

                    sal_Int32* pStart, sal_Int32* pEnd,

                    css::util::SearchResult* pRes)

{

    bool bRet = false;

    try

    {

        if( xTextSearch.is() )

        {

            SearchResult aRet( xTextSearch->searchForward( rStr, *pStart, *pEnd ));

            if( aRet.subRegExpressions > 0 )

            {

                bRet = true;

                // the XTextsearch returns in startOffset the higher position

                // and the endposition is always exclusive.

                // The caller of this function will have in startPos the

                // lower pos. and end

                *pStart = aRet.startOffset[ 0 ];

                *pEnd = aRet.endOffset[ 0 ];

                if( pRes )

                    *pRes = std::move(aRet);

            }

        }

    }

    catch ( Exception& )

    {

        TOOLS_WARN_EXCEPTION("unotools.i18n", "" );

    }

    return bRet;

}

bool TextSearch::searchForward( const OUString &rStr )

{

    sal_Int32 pStart = 0;

    sal_Int32 pEnd = rStr.getLength();

    bool bResult = SearchForward(rStr, &pStart, &pEnd);

    return bResult;

}

bool TextSearch::SearchBackward( const OUString & rStr, sal_Int32* pStart,

                                sal_Int32* pEnd, SearchResult* pRes )

{

    bool bRet = false;

    try

    {

        if( xTextSearch.is() )

        {

            SearchResult aRet( xTextSearch->searchBackward( rStr, *pStart, *pEnd ));

            if( aRet.subRegExpressions )

            {

                bRet = true;

                // the XTextsearch returns in startOffset the higher position

                // and the endposition is always exclusive.

                // The caller of this function will have in startPos the

                // lower pos. and end

                *pEnd = aRet.startOffset[ 0 ];

                *pStart = aRet.endOffset[ 0 ];

                if( pRes )

                    *pRes = std::move(aRet);

            }

        }

    }

    catch ( Exception& )

    {

        TOOLS_WARN_EXCEPTION("unotools.i18n", "" );

    }

    return bRet;

}

// static

void TextSearch::ReplaceBackReferences( OUString& rReplaceStr, std::u16string_view rStr, const SearchResult& rResult )

{

    if( rResult.subRegExpressions <= 0 )

        return;

    sal_Unicode sFndChar;

    sal_Int32 i;

    OUStringBuffer sBuff(rReplaceStr.getLength()*4);

    for(i = 0; i < rReplaceStr.getLength(); i++)

    {

        if( rReplaceStr[i] == '&')

        {

            sal_Int32 nStart = rResult.startOffset[0];

            sal_Int32 nLength = rResult.endOffset[0] - rResult.startOffset[0];

            sBuff.append(rStr.substr(nStart, nLength));

        }

        else if((i < rReplaceStr.getLength() - 1) && rReplaceStr[i] == '$')

        {

            sFndChar = rReplaceStr[ i + 1 ];

            switch(sFndChar)

            {   // placeholder for a backward reference?

            case '0':

            case '1':

            case '2':

            case '3':

            case '4':

            case '5':

            case '6':

            case '7':

            case '8':

            case '9':

                {

                    int j = sFndChar - '0'; // index

                    if(j < rResult.subRegExpressions)

                    {

                        sal_Int32 nSttReg = rResult.startOffset[j];

                        sal_Int32 nRegLen = rResult.endOffset[j];

                        if (nSttReg < 0 || nRegLen < 0) // A "not found" optional capture

                        {

                            nSttReg = nRegLen = 0; // Copy empty string

                        }

                        else if (nRegLen >= nSttReg)

                        {

                            nRegLen = nRegLen - nSttReg;

                        }

                        else

                        {

                            nRegLen = nSttReg - nRegLen;

                            nSttReg = rResult.endOffset[j];

                        }

                        // Copy reference from found string

                        sBuff.append(rStr.substr(nSttReg, nRegLen));

                    }

                    i += 1;

                }

                break;

            default:

                sBuff.append(OUStringChar(rReplaceStr[i]) + OUStringChar(rReplaceStr[i+1]));

                i += 1;

                break;

            }

        }

        else if((i < rReplaceStr.getLength() - 1) && rReplaceStr[i] == '\\')

        {

            sFndChar = rReplaceStr[ i+1 ];

            switch(sFndChar)

            {

            case '\\':

            case '&':

            case '$':

                sBuff.append(sFndChar);

                i+=1;

                break;

            case 't':

                sBuff.append('\t');

                i += 1;

                break;

            default:

                sBuff.append(OUStringChar(rReplaceStr[i]) + OUStringChar(rReplaceStr[i+1]));

                i += 1;

                break;

            }

        }

        else

        {

            sBuff.append(rReplaceStr[i]);

        }

    }

    rReplaceStr = sBuff.makeStringAndClear();

}

bool TextSearch::SimilaritySearch(const OUString& rString, const OUString& rSearchString,

                                  ::std::pair<sal_Int32, sal_Int32>& rSimilarityScore)

{

    sal_Int32 nScore = 0;

    sal_Int32 nFirstScore = GetSubstringSimilarity(rString, rSearchString, nScore, true);

    if (nFirstScore == -1)

        nFirstScore = GetSubstringSimilarity(rString, rSearchString, nScore, false);

    if (nFirstScore == -1)

    {

        if (rSearchString.getLength() == 1)

        {

            if (rString.startsWith(rSearchString))

                nFirstScore = nScore;

            else if (rString.endsWith(rSearchString))

                nFirstScore = nScore + 1;

            nScore += 2;

        }

        else if (rString.getLength() == 1 && rSearchString.getLength() < SMALL_STRING_THRESHOLD)

        {

            if (rSearchString.startsWith(rString))

                nFirstScore = nScore;

            else if (rSearchString.endsWith(rString))

                nFirstScore = nScore + 1;

            nScore += 2;

        }

    }

    sal_Int32 nSecondScore = GetWeightedLevenshteinDistance(rString, rSearchString);

    if (nFirstScore == -1 && nSecondScore >= WLD_THRESHOLD)

        return false;

    rSimilarityScore.first = (nFirstScore == -1) ? nScore : nFirstScore;

    rSimilarityScore.second = nSecondScore;

    return true;

}

sal_Int32 TextSearch::GetSubstringSimilarity(std::u16string_view rString,

                                             std::u16string_view rSearchString,

                                             sal_Int32& nInitialScore, const bool bFromStart)

{

    sal_Int32 nScore = -1;

    for (sal_Int32 length = rSearchString.length(); length > 1; length--)

    {

        sal_Int32 nStartPos = bFromStart ? 0 : rSearchString.length() - length;

        std::u16string_view rSearchSubString = rSearchString.substr(nStartPos, length);

        if (rString.starts_with(rSearchSubString))

        {

            nScore = nInitialScore;

            break;

        }

        else if (rString.ends_with(rSearchSubString))

        {

            nScore = nInitialScore + 1;

            break;

        }

        else if (rString.find(rSearchSubString) != std::u16string_view::npos)

        {

            nScore = nInitialScore + 2;

            break;

        }

        nInitialScore += 3;

    }

    return nScore;

}

sal_Int32 TextSearch::GetWeightedLevenshteinDistance(const OUString& rString,

                                                     const OUString& rSearchString)

{

    sal_Int32 n = rString.getLength();

    sal_Int32 m = rSearchString.getLength();

    std::vector<std::vector<sal_Int32>> ScoreDP(n + 1, std::vector<sal_Int32>(m + 1));

    for (sal_Int32 i = 0; i <= n; i++)

    {

        ScoreDP[i][0] = i;

    }

    for (sal_Int32 j = 0; j <= m; j++)

    {

        ScoreDP[0][j] = j;

    }

    for (sal_Int32 i = 1; i <= n; i++)

    {

        for (sal_Int32 j = 1; j <= m; j++)

        {

            sal_Int32& minE = ScoreDP[i][j];

            minE = ScoreDP[i - 1][j] + 1;

            minE = std::min(minE, ScoreDP[i][j - 1] + 1);

            if (rString[i - 1] != rSearchString[j - 1])

                minE = std::min(minE, ScoreDP[i - 1][j - 1] + 2);

            else

                minE = std::min(minE, ScoreDP[i - 1][j - 1]);

        }

    }

    return ScoreDP[n][m];

}

}   // namespace utl

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */