/*  $Id: unicode.cpp 619576 2020-11-06 16:13:14Z gouriano $
 * ==========================================================================
 *
 *                            PUBLIC DOMAIN NOTICE
 *               National Center for Biotechnology Information
 *
 *  This software/database is a "United States Government Work" under the
 *  terms of the United States Copyright Act.  It was written as part of
 *  the author's official duties as a United States Government employee and
 *  thus cannot be copyrighted.  This software/database is freely available
 *  to the public for use. The National Library of Medicine and the U.S.
 *  Government have not placed any restriction on its use or reproduction.
 *
 *  Although all reasonable efforts have been taken to ensure the accuracy
 *  and reliability of the software and data, the NLM and the U.S.
 *  Government do not and cannot warrant the performance or results that
 *  may be obtained by using this software or data. The NLM and the U.S.
 *  Government disclaim all warranties, express or implied, including
 *  warranties of performance, merchantability or fitness for any particular
 *  purpose.
 *
 *  Please cite the author in any work or product based on this material.
 *
 * ==========================================================================
 *
 * Author: Aleksey Vinokurov
 *
 * File Description:
 *    Unicode transformation library
 *
 */

#include <ncbi_pch.hpp>
#include <util/unicode.hpp>
#include <util/util_exception.hpp>
#include <util/util_misc.hpp>
#include <util/error_codes.hpp>
#include <corelib/ncbifile.hpp>
#include <corelib/ncbi_safe_static.hpp>

#define NCBI_USE_ERRCODE_X   Util_Unicode

BEGIN_NCBI_SCOPE
BEGIN_SCOPE(utf8)

#include "unicode_plans.inl"


static TUnicodeTable g_DefaultUnicodeTable =
{
    &s_Plan_00h, &s_Plan_01h, &s_Plan_02h, &s_Plan_03h, &s_Plan_04h, 0, 0, 0,  // Plan 00 - 07
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 08 - 0F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 10 - 17
    0, 0, 0, 0, 0, 0, &s_Plan_1Eh, 0,  // Plan 18 - 1F

    &s_Plan_20h, &s_Plan_21h, &s_Plan_22h, &s_Plan_23h, &s_Plan_24h, &s_Plan_25h, &s_Plan_26h, &s_Plan_27h,  // Plan 20 - 27
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 28 - 2F

    &s_Plan_30h, 0, 0, 0, 0, 0, 0, 0,  // Plan 30 - 37
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 38 - 3F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 40 - 47
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 48 - 4F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 50 - 57
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 58 - 5F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 60 - 67
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 68 - 6F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 70 - 77
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 78 - 7F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 80 - 87
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 88 - 8F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 90 - 97
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan 98 - 9F

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan A0 - A7
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan A8 - AF

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan B0 - B7
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan B8 - BF

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan C0 - C7
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan C8 - CF

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan D0 - D7
    0, 0, 0, 0, 0, 0, 0, 0,  // Plan D8 - DF

    &s_Plan_E0h, 0, &s_Plan_E2h, &s_Plan_E3h, &s_Plan_E4h, &s_Plan_E5h, &s_Plan_E6h, &s_Plan_E7h,  // Plan E0 - E7
    &s_Plan_E8h, 0, &s_Plan_EAh, &s_Plan_EBh, 0, 0, 0, 0,  // Plan E8 - EF

    0, 0, 0, 0, 0, 0, 0, 0,  // Plan F0 - F7
    0, 0, 0, &s_Plan_FBh, 0, 0, &s_Plan_FEh, 0   // Plan F8 - FF
};

/////////////////////////////////////////////////////////////////////////////
// Declare the parameter to get UnicodeToAscii translation table.
// Registry file:
//     [NCBI]
//     UnicodeToAscii = ...
// Environment variable:
//     NCBI_CONFIG__NCBI__UNICODETOASCII
//
static string s_FindUnicodeToAscii(void)
{
    return g_FindDataFile("unicode_to_ascii.txt");
}
NCBI_PARAM_DECL(string, NCBI, UnicodeToAscii); 
NCBI_PARAM_DEF_WITH_INIT (string, NCBI, UnicodeToAscii, "", s_FindUnicodeToAscii);

/////////////////////////////////////////////////////////////////////////////
// CUnicodeToAsciiTranslation helper class

class CUnicodeToAsciiTranslation : public CObject
{
public:
    CUnicodeToAsciiTranslation(void);
    virtual ~CUnicodeToAsciiTranslation(void);
    bool IsInitialized(void) const
    {
        return m_initialized;
    }
    const SUnicodeTranslation* GetTranslation( TUnicode symbol) const;
private:
    void x_Initialize(const string& name);
    static int  x_ParseLine(string& line, TUnicode& symbol, string& translation);
    bool m_initialized;
    char *m_pool;
    map<TUnicode, SUnicodeTranslation> m_SymbolToTranslation;
    
};

CUnicodeToAsciiTranslation::CUnicodeToAsciiTranslation(void)
    : m_initialized(false), m_pool(0)
{
    string name( NCBI_PARAM_TYPE(NCBI, UnicodeToAscii)::GetDefault() );
    if (!name.empty()) {
        x_Initialize(name);
    }
}
CUnicodeToAsciiTranslation::~CUnicodeToAsciiTranslation(void)
{
    if (m_pool) {
        free(m_pool);
    }
}

void CUnicodeToAsciiTranslation::x_Initialize(const string& name)
{
// clear existing data
    if (m_pool) {
        free(m_pool);
        m_pool = 0;
        m_SymbolToTranslation.clear();
    }
    m_initialized = false;

// find file
    CNcbiIfstream ifs(name.c_str(), IOS_BASE::in);
    if (!ifs.is_open()) {
        ERR_POST_X(1, "UnicodeToAscii table not found: " << name);
        return;
    }
    LOG_POST_X(2, Info << "Loading UnicodeToAscii table at: " << name);

// estimate memory pool size
    size_t filelen = (size_t)CFile(name).GetLength();
    size_t poolsize = filelen/2;
    m_pool = (char*)malloc(poolsize);
    if (!m_pool) {
        ERR_POST_X(3, "UnicodeToAscii table failed to load: not enough memory");
        return;
    }
    size_t poolpos=0;

// parse file
    TUnicode symbol;
    string translation;
    string line;
    line.reserve(16);
    map<TUnicode, size_t> symbolToOffset;
    while ( NcbiGetlineEOL(ifs, line) ) {
        if (x_ParseLine(line, symbol, translation) > 1) {

            if (poolpos + translation.size() + 1 > poolsize) {
                m_pool = (char*)realloc( m_pool, poolsize += filelen/4);
                if (!m_pool) {
                    ERR_POST_X(3, "UnicodeToAscii table failed to load: not enough memory");
                    return;
                }
            }
            
            symbolToOffset[symbol] = poolpos;
            memcpy(m_pool+poolpos, translation.data(), translation.size());
            poolpos += translation.size();
            *(m_pool+poolpos) = '\0';
            ++poolpos;
        }
    }
    if (poolpos == 0) {
        ERR_POST_X(1, "UnicodeToAscii table is empty: " << name);
        free(m_pool);
        m_pool = nullptr;
        return;
    } else {
        m_pool = (char*)realloc( m_pool, poolpos);
    }
    
// create translation table
    map<TUnicode, size_t>::const_iterator symend = symbolToOffset.end();
    for( map<TUnicode, size_t>::const_iterator sym = symbolToOffset.begin();
                                               sym != symend; ++sym) {
        SUnicodeTranslation tr;
        tr.Type = eString;
        tr.Subst = m_pool + sym->second;
        m_SymbolToTranslation[sym->first] = tr;
    }

    m_initialized = true;
}

int CUnicodeToAsciiTranslation::x_ParseLine(
    string& line, TUnicode& symbol, string& translation)
{
    int res = 0;
    symbol = 0;
    translation.clear();

// symbol
    string::size_type begin = line.find_first_not_of(" \t", 0);
    if (begin == string::npos) {
        return res;
    }
    string::size_type end = line.find_first_of(" \t,#",begin);
    if (end == begin) {
        return res;
    }
    if (end == string::npos) {
        end = line.size();
    }
    if (NStr::StartsWith(CTempString( line.data()+begin, end-begin), "0x")) {
        begin += 2;
    }
    symbol = NStr::StringToUInt( CTempString( line.data()+begin, end-begin), 0, 16);
    ++res;
    if ( end == line.size() || line[end] == '#') {
        return res;
    }
// translation
    end = line.find(',',end);
    if (end == string::npos) {
        return res;
    }
    begin = line.find_first_not_of(" \t", ++end);
    if (begin == string::npos) {
        return res;
    }
    if (*(line.data()+begin) != '\"') {
        return res;
    }
    const char* data = line.data()+begin;
    const char* dataend = line.data()+line.size();
    for (++data; data < dataend; ++data) {
        char c = *data;
        if (c == '"') {
            break;
        }
        if (c == '\\') {
            ++data;
            if (data < dataend) {
                c = *data;
                switch (c) {
                default:           break;
                case 'a': c = 0x7; break;
                case 'b': c = 0x8; break;
                case 't': c = 0x9; break;
                case 'n': c = 0xA; break;
                case 'v': c = 0xB; break;
                case 'f': c = 0xC; break;
                case 'r': c = 0xD; break;
                case '0': c = 0x0; break;
                case 'x':
                    if (data + 1 < dataend) {
                        begin = data + 1 - line.data();
                        end = line.find_first_not_of("0123456789abcdefABCDEF", begin);
                        if (end == string::npos) {
                            end = line.size();
                        }
                        c = (char)NStr::StringToUInt( CTempString( line.data()+begin, end-begin), 0, 16);
                        data = line.data() + end;
                    }
                    break;
                }
            }
            if (data == dataend) {
                break;
            }
        }
        translation.append(1,c);
    }
    ++res;
    return res;
}

const SUnicodeTranslation*
CUnicodeToAsciiTranslation::GetTranslation( TUnicode symbol) const
{
    map<TUnicode, SUnicodeTranslation>::const_iterator i =
        m_SymbolToTranslation.find(symbol);
    if (i == m_SymbolToTranslation.end()) {
        return NULL;
    }
    return &(i->second);
}

CSafeStatic<CUnicodeToAsciiTranslation> g_UnicodeTranslation;

/////////////////////////////////////////////////////////////////////////////
const SUnicodeTranslation*
UnicodeToAscii(TUnicode character, const TUnicodeTable* table,
               const SUnicodeTranslation* default_translation)
{
    if (!table) {
        const CUnicodeToAsciiTranslation& t = g_UnicodeTranslation.Get();
        if (t.IsInitialized()) {
            return t.GetTranslation(character);
        }
        table = &g_DefaultUnicodeTable;
    }
    const SUnicodeTranslation* translation=NULL;
    if ((character & (~0xFFFF)) == 0) {
        unsigned int thePlanNo = (character & 0xFF00) >> 8;
        unsigned int theOffset =  character & 0xFF;
        const TUnicodePlan* thePlan = (*table)[thePlanNo];
        if ( thePlan ) {
            translation = &((*thePlan)[theOffset]);
        }
    }
    if (!translation) {
        if (!default_translation) {
            return NULL;
        }
        if (default_translation->Type == eException) {
            NCBI_THROW(CUtilException,eWrongData,
                       "UnicodeToAscii: unknown Unicode symbol");
        }
        translation = default_translation;
    }
    return translation;
}


TUnicode UTF8ToUnicode( const char* theUTF )
{
    const char *p = theUTF;
    Int1 counter = *p++;

    if ( ((*theUTF) & 0xC0) != 0xC0 ) {
        TUnicode RC = 0;
        RC |= (unsigned char)theUTF[0];
        return RC;
    }

    TUnicode acc = counter & 037;

    while ((counter = Int1(counter << 1)) < 0) {
        unsigned char c = *p++;
        if ((c & ~077) != 0200) { // Broken UTF-8 chain
            return 0;
        }
        acc = (acc << 6) | (c & 077);
    }

    return acc;
}


size_t UTF8ToUnicode( const char* theUTF, TUnicode* theUnicode )
{
    const char *p = theUTF;
    Int1 counter = *p++;

    if ( (unsigned char)theUTF[0] < 0x80 ) {
        // This is one character UTF8. I.e. regular character.
        *theUnicode = *theUTF;
        return 1;
    }

    if ( ((*theUTF) & 0xC0) != 0xC0  || ((*theUTF) & 0xFE) == 0xC0) {
        // This is not UTF8
        return 0;
    }

    TUnicode acc = counter & 037;
    if ( ((*theUTF) & 0xF8) == 0xF0 ) {
        acc = counter & 07;
    }

    while ((counter = Int1(counter << 1)) < 0) {
        unsigned char c = *p++;
        if ((c & ~077) != 0200) { // Broken UTF-8 chain
            return 0;
        }
        acc = (acc << 6) | (c & 077);
    } // while

    *theUnicode = acc;
    return (size_t)(p - theUTF);
}


string UnicodeToUTF8( TUnicode theUnicode )
{
    char theBuffer[10];
    size_t theLength = UnicodeToUTF8( theUnicode, theBuffer, 10 );
    return string( theBuffer, theLength );
}


size_t UnicodeToUTF8( TUnicode theUnicode, char *theBuffer,
                      size_t theBufLength )
{
    size_t Length = 0;

    if (theUnicode < 0x80) {
        Length = 1;
        if ( Length > theBufLength ) return 0;
        theBuffer[0] = char(theUnicode);
    }
    else if (theUnicode < 0x800) {
        Length = 2;
        if ( Length > theBufLength ) return 0;
        theBuffer[0] = char( 0xC0 | (theUnicode>>6));
        theBuffer[1] = char( 0x80 | (theUnicode & 0x3F));
    }
    else if (theUnicode < 0x10000) {
        Length = 3;
        if ( Length > theBufLength ) return 0;
        theBuffer[0] = char( 0xE0 |  (theUnicode>>12));
        theBuffer[1] = char( 0x80 | ((theUnicode>>6) & 0x3F));
        theBuffer[2] = char( 0x80 |  (theUnicode & 0x3F));
    }
    else if (theUnicode < 0x200000) {
        Length = 4;
        if ( Length > theBufLength ) return 0;
        theBuffer[0] = char( 0xF0 |  (theUnicode>>18));
        theBuffer[1] = char( 0x80 | ((theUnicode>>12) & 0x3F));
        theBuffer[2] = char( 0x80 | ((theUnicode>>6)  & 0x3F));
        theBuffer[3] = char( 0x80 |  (theUnicode & 0x3F));
    }
    return Length;
}

ssize_t UTF8ToAscii( const char* src, char* dst, size_t dstLen,
                     const SUnicodeTranslation* default_translation,
                     const TUnicodeTable* table,
                     EConversionResult* result)
{
    if (result) {
        *result = eConvertedFine;
    }
    if ( !src || !dst || dstLen == 0 ) return 0;
    size_t srcPos = 0;
    size_t dstPos = 0;
    size_t srcLen = strlen( src );

    for ( srcPos = 0; srcPos < srcLen; ) {
        // Assign quck pointers
        char* pDst = &(dst[dstPos]);
        const char* pSrc = &(src[srcPos]);
        TUnicode theUnicode;

        size_t utfLen = UTF8ToUnicode( pSrc, &theUnicode );

        if ( utfLen == 0 ) {
            // Skip the error.
            srcPos++;
            continue;
        }

        srcPos += utfLen;

        // Find the correct substitution.
        const SUnicodeTranslation*
            pSubst = UnicodeToAscii( theUnicode, table, default_translation );
        if (result && pSubst == default_translation) {
            *result = eDefaultTranslationUsed;
        }

        // Check if the unicode has a translation
        if ( !pSubst ) {
            continue;
        }

        // Check if type is eSkip or substituting string is empty.
        if ( (pSubst->Type == eSkip) ||
             !(pSubst->Subst) ) {
            continue;
        }


        // Check if type is eAsIs
        if (pSubst->Type == eAsIs) {
            memcpy( pDst, pSrc, utfLen );
//            dstPos += utfLen;
            continue;
        }

        // Check the remaining length and put the result in there.
        size_t substLen = strlen( pSubst->Subst );
        if ( (dstPos + substLen) > dstLen ) {
            return -1; // Unsufficient space
        }

        // Copy the substituting value into the destignation string
        memcpy( pDst, pSubst->Subst, substLen );
        dstPos += substLen;
    }
    return (ssize_t) dstPos;
}

string UTF8ToAsciiString( const char* src,
                          const SUnicodeTranslation* default_translation,
                          const TUnicodeTable* table,
                          EConversionResult* result)
{
    if (result) {
        *result = eConvertedFine;
    }
    if ( !src ) return 0;
    string dst;
    size_t srcPos = 0;
    size_t srcLen = strlen( src );

    for ( srcPos = 0; srcPos < srcLen; ) {
        // Assign quck pointers
        const char* pSrc = &(src[srcPos]);
        TUnicode theUnicode;

        size_t utfLen = UTF8ToUnicode( pSrc, &theUnicode );

        if ( utfLen == 0 ) {
            // Skip the error.
            srcPos++;
            continue;
        }

        srcPos += utfLen;

        // Find the correct substitution.
        const SUnicodeTranslation*
            pSubst = UnicodeToAscii( theUnicode, table, default_translation );
        if (result && pSubst == default_translation) {
            *result = eDefaultTranslationUsed;
        }

        // Check if the unicode has a translation
        if ( !pSubst ) {
//            srcPos += utfLen;
            continue;
        }

        // Check if type is eSkip or substituting string is empty.
        if ( (pSubst->Type == eSkip) ||
             !(pSubst->Subst) ) {
//            srcPos += utfLen;
            continue;
        }


        // Check if type is eAsIs
        if (pSubst->Type == eAsIs) {
            dst += string( pSrc, utfLen );
//            srcPos += utfLen;
            continue;
        }

        // Copy the substituting value into the destignation string
        dst += pSubst->Subst;
    }
    return dst;
}


END_SCOPE(utf8)
END_NCBI_SCOPE
