/******************************************************************************
**  libDXFrw - Library to read/write DXF files (ascii & binary)              **
**                                                                           **
**  Copyright (C) 2011-2015 José F. Soriano, rallazz@gmail.com               **
**                                                                           **
**  This library is free software, licensed under the terms of the GNU       **
**  General Public License as published by the Free Software Foundation,     **
**  either version 2 of the License, or (at your option) any later version.  **
**  You should have received a copy of the GNU General Public License        **
**  along with this program.  If not, see <http://www.gnu.org/licenses/>.    **
******************************************************************************/

#include <sstream>
#include "drw_dbg.h"
#include "dwgutil.h"
#include "rscodec.h"
#include "../libdwgr.h"

/** utility function
 * convert a int to string in hex
 **/
namespace DRW {
std::string toHexStr(int n){
#if defined(__APPLE__)
    char buffer[9]= {'\0'};
    snprintf(buffer,9, "%X", n);
    return std::string(buffer);
#else
    std::ostringstream Convert;
    Convert << std::uppercase << std::hex << n;
    return Convert.str();
#endif
}
}

/**
 * @brief dwgRSCodec::decode239I
 * @param in : input data (at least 255*blk bytes)
 * @param out : output data (at least 239*blk bytes)
 * @param blk number of codewords ( 1 cw == 255 bytes)
 */
void dwgRSCodec::decode239I(unsigned char *in, unsigned char *out, duint32 blk){
    int k=0;
    unsigned char data[255];
    RScodec rsc(0x96, 8, 8); //(255, 239)
    for (duint32 i=0; i<blk; i++){
        k = i;
        for (int j=0; j<255; j++) {
            data[j] = in[k];
            k +=blk;
        }
        int r = rsc.decode(data);
        if (r<0)
            DRW_DBG("\nWARNING: dwgRSCodec::decode239I, can't correct all errors");
        k = i*239;
        for (int j=0; j<239; j++) {
            out[k++] = data[j];
        }
    }
}

/**
 * @brief dwgRSCodec::decode251I
 * @param in : input data (at least 255*blk bytes)
 * @param out : output data (at least 251*blk bytes)
 * @param blk number of codewords ( 1 cw == 255 bytes)
 */
void dwgRSCodec::decode251I(unsigned char *in, unsigned char *out, duint32 blk){
    int k=0;
    unsigned char data[255];
    RScodec rsc(0xB8, 8, 2); //(255, 251)
    for (duint32 i=0; i<blk; i++){
        k = i;
        for (int j=0; j<255; j++) {
            data[j] = in[k];
            k +=blk;
        }
        int r = rsc.decode(data);
        if (r<0)
            DRW_DBG("\nWARNING: dwgRSCodec::decode251I, can't correct all errors");
        k = i*251;
        for (int j=0; j<251; j++) {
            out[k++] = data[j];
        }
    }
}

duint8 *dwgCompressor::compressedBuffer {nullptr};
duint32 dwgCompressor::compressedSize {0};
duint32 dwgCompressor::compressedPos {0};
bool    dwgCompressor::compressedGood {true};
duint8 *dwgCompressor::decompBuffer {nullptr};
duint32 dwgCompressor::decompSize {0};
duint32 dwgCompressor::decompPos {0};
bool    dwgCompressor::decompGood {true};

duint32 dwgCompressor::twoByteOffset(duint32 *ll){
    duint32 cont = 0;
    duint8 fb = compressedByte();
    cont = (fb >> 2) | (compressedByte() << 6);
    *ll = (fb & 0x03);
    return cont;
}

duint32 dwgCompressor::longCompressionOffset(){
    duint32 cont = 0;
    duint8 ll = compressedByte();
    while (ll == 0x00 && compressedGood) {
        cont += 0xFF;
        ll = compressedByte();
    }
    cont += ll;
    return cont;
}

duint32 dwgCompressor::long20CompressionOffset(){
//    duint32 cont = 0;
    duint32 cont = 0x0F;
    duint8 ll = compressedByte();
    while (ll == 0x00 && compressedGood){
//        cont += 0xFF;
        ll = compressedByte();
    }
    cont += ll;
    return cont;
}

duint32 dwgCompressor::litLength18(){
    duint32 cont = 0;
    duint8 ll = compressedByte();
    //no literal length, this byte is next opCode
    if (ll > 0x0F) {
        --compressedPos;
        return 0;
    }

    if (ll == 0x00) {
        cont = 0x0F;
        ll = compressedByte();
        while (ll == 0x00 && compressedGood) {//repeat until ll != 0x00
            cont += 0xFF;
            ll = compressedByte();
        }
    }

    return cont + ll + 3;
}

bool dwgCompressor::decompress18(duint8 *cbuf, duint8 *dbuf, duint64 csize, duint64 dsize){
    compressedBuffer = cbuf;
    decompBuffer = dbuf;
    compressedSize = csize;
    decompSize = dsize;
    compressedPos = 0;
    decompPos = 0;
    compressedGood = true;
    decompGood = true;

    DRW_DBG("dwgCompressor::decompress, last 2 bytes: ");
    DRW_DBGH(compressedBuffer[compressedSize - 2]);DRW_DBG(" ");DRW_DBGH(compressedBuffer[compressedSize - 1]);DRW_DBG("\n");

    duint32 compBytes {0};
    duint32 compOffset {0};
    duint32 litCount {litLength18()};

    //copy first literal length
    for (duint32 i = 0; i < litCount && buffersGood(); ++i) {
        decompSet( compressedByte());
    }

    while (buffersGood()) {
        duint8 oc = compressedByte(); //next opcode
        if (oc == 0x10){
            compBytes = longCompressionOffset()+ 9;
            compOffset = twoByteOffset(&litCount) + 0x3FFF;
            if (litCount == 0)
                litCount= litLength18();
        } else if (oc > 0x11 && oc< 0x20){
            compBytes = (oc & 0x0F) + 2;
            compOffset = twoByteOffset(&litCount) + 0x3FFF;
            if (litCount == 0)
                litCount= litLength18();
        } else if (oc == 0x20){
            compBytes = longCompressionOffset() + 0x21;
            compOffset = twoByteOffset(&litCount);
            if (litCount == 0)
                litCount= litLength18();
        } else if (oc > 0x20 && oc< 0x40){
            compBytes = oc - 0x1E;
            compOffset = twoByteOffset(&litCount);
            if (litCount == 0)
                litCount= litLength18();
        } else if ( oc > 0x3F){
            compBytes = ((oc & 0xF0) >> 4) - 1;
            duint8 ll2 = compressedByte();
            compOffset =  (ll2 << 2) | ((oc & 0x0C) >> 2);
            litCount = oc & 0x03;
            if (litCount < 1){
                litCount= litLength18();}
        } else if (oc == 0x11){
            DRW_DBG("dwgCompressor::decompress, end of input stream, Cpos: ");
            DRW_DBG(compressedPos);DRW_DBG(", Dpos: ");DRW_DBG(decompPos);DRW_DBG("\n");
            return true; //end of input stream
        } else { //ll < 0x10
            DRW_DBG("WARNING dwgCompressor::decompress, failed, illegal char: "); DRW_DBGH(oc);
            DRW_DBG(", Cpos: "); DRW_DBG(compressedPos);
            DRW_DBG(", Dpos: "); DRW_DBG(decompPos); DRW_DBG("\n");
            return false; //fails, not valid
        }

        //copy "compressed data", if size allows
        if (decompSize < decompPos + compBytes) {
            DRW_DBG("WARNING dwgCompressor::decompress18, bad compBytes size, Cpos: ");
            DRW_DBG(compressedPos);DRW_DBG(", Dpos: ");DRW_DBG(decompPos);DRW_DBG(", need ");DRW_DBG(compBytes);DRW_DBG(", available ");DRW_DBG(decompSize - decompPos);DRW_DBG("\n");
            // only copy what we can fit
            compBytes = decompSize - decompPos;
        }
        duint32 j {decompPos - compOffset - 1};
        for (duint32 i = 0; i < compBytes && buffersGood(); i++) {
            decompSet( decompByte( j++));
        }

        //copy "uncompressed data", if size allows
        if (decompSize < decompPos + litCount) {
            DRW_DBG("WARNING dwgCompressor::decompress18, bad litCount size, Cpos: ");
            DRW_DBG(compressedPos);DRW_DBG(", Dpos: ");DRW_DBG(decompPos);DRW_DBG(", need ");DRW_DBG(litCount);DRW_DBG(", available ");DRW_DBG(decompSize - decompPos);DRW_DBG("\n");
            // only copy what we can fit
            litCount = decompSize - decompPos;
        }
        for (duint32 i=0; i < litCount && buffersGood(); i++) {
            decompSet( compressedByte());
        }
    }

    DRW_DBG("WARNING dwgCompressor::decompress, bad out, Cpos: ");DRW_DBG(compressedPos);DRW_DBG(", Dpos: ");DRW_DBG(decompPos);DRW_DBG("\n");
    return false;
}

duint8 dwgCompressor::compressedByte(void)
{
    duint8 result {0};

    compressedGood = (compressedPos < compressedSize);
    if (compressedGood) {
        result = compressedBuffer[compressedPos];
        ++compressedPos;
    }

    return result;
}

duint8 dwgCompressor::compressedByte(const duint32 index)
{
    if (index < compressedSize) {
        return compressedBuffer[index];
    }

    return 0;
}

duint32 dwgCompressor::compressedHiByte(void)
{
    return static_cast<duint32>(compressedByte()) << 8;
}

bool dwgCompressor::compressedInc(const dint32 inc /*= 1*/)
{
    compressedPos += inc;
    compressedGood = (compressedPos <= compressedSize);

    return compressedGood;
}

duint8 dwgCompressor::decompByte(const duint32 index)
{
    if (index < decompSize) {
        return decompBuffer[index];
    }

    return 0;
}

void dwgCompressor::decompSet(const duint8 value)
{
    decompGood = (decompPos < decompSize);
    if (decompGood) {
        decompBuffer[decompPos] = value;
        ++decompPos;
    }
}

bool dwgCompressor::buffersGood(void)
{
    return compressedGood && decompGood;
}

void dwgCompressor::decrypt18Hdr(duint8 *buf, duint64 size, duint64 offset){
    duint8 max = size / 4;
    duint32 secMask = 0x4164536b ^ offset;
    duint32* pHdr = reinterpret_cast<duint32*>(buf);
    for (duint8 j = 0; j < max; j++)
        *pHdr++ ^= secMask;
}

/*void dwgCompressor::decrypt18Data(duint8 *buf, duint32 size, duint32 offset){
    duint8 max = size / 4;
    duint32 secMask = 0x4164536b ^ offset;
    duint32* pHdr = (duint32*)buf;
    for (duint8 j = 0; j < max; j++)
        *pHdr++ ^= secMask;
}*/

duint32 dwgCompressor::litLength21(duint8 opCode)
{
    duint32 length = 8u + opCode;
    if (0x17 == length) {
        duint32 n = compressedByte();
        length += n;
        if (0xffu == n) {
            do {
                n = compressedByte();
                n |= compressedHiByte();
                length += n;
            }
            while (0xffffu == n);
        }
    }

    return length;
}

bool dwgCompressor::decompress21(duint8 *cbuf, duint8 *dbuf, duint64 csize, duint64 dsize){
    compressedBuffer = cbuf;
    decompBuffer = dbuf;
    compressedSize = csize;
    decompSize = dsize;
    compressedPos = 0;
    decompPos = 0;
    compressedGood = true;
    decompGood = true;

    duint32 length {0};
    duint32 sourceOffset {0};
    duint8 opCode {compressedByte()};
    if ((opCode >> 4) == 2){
        compressedInc( 2);
        length = compressedByte() & 0x07;
    }

    while (buffersGood()) {
        if (length == 0) {
            length = litLength21(opCode);
        }
        copyCompBytes21( length);

        if (decompPos >= decompSize) {
            break; //check if last chunk are compressed & terminate
        }

        length = 0;
        opCode = compressedByte();
        readInstructions21( opCode,  sourceOffset,  length);
        while (true) {
            //prevent crash with corrupted data
            if (sourceOffset > decompPos) {
                DRW_DBG("\nWARNING dwgCompressor::decompress21 => sourceOffset> dstIndex.\n");
                DRW_DBG("csize = "); DRW_DBG(compressedSize); DRW_DBG("  srcIndex = "); DRW_DBG(compressedPos);
                DRW_DBG("\ndsize = "); DRW_DBG(decompSize); DRW_DBG("  dstIndex = "); DRW_DBG(decompPos);
                sourceOffset = decompPos;
            }
            //prevent crash with corrupted data
            if (length > decompSize - decompPos){
                DRW_DBG("\nWARNING dwgCompressor::decompress21 => length > dsize - dstIndex.\n");
                DRW_DBG("csize = "); DRW_DBG(compressedSize); DRW_DBG("  srcIndex = "); DRW_DBG(compressedPos);
                DRW_DBG("\ndsize = "); DRW_DBG(decompSize); DRW_DBG("  dstIndex = "); DRW_DBG(decompPos);
                length = decompSize - decompPos;
                compressedPos = compressedSize; //force exit
                compressedGood = false;
            }
            sourceOffset = decompPos - sourceOffset;
            for (duint32 i=0; i< length; i++)
                decompSet( decompByte( sourceOffset + i));

            length = opCode & 7;
            if ((length != 0) || (compressedPos >= compressedSize)) {
                break;
            }
            opCode = compressedByte();
            if ((opCode >> 4) == 0) {
                break;
            }
            if ((opCode >> 4) == 15) {
                opCode &= 15;
            }
            readInstructions21( opCode, sourceOffset, length);
        }

        if (compressedPos >= compressedSize) {
            break;
        }
    }
    DRW_DBG("\ncsize = "); DRW_DBG(compressedSize); DRW_DBG("  srcIndex = "); DRW_DBG(compressedPos);
    DRW_DBG("\ndsize = "); DRW_DBG(decompSize); DRW_DBG("  dstIndex = "); DRW_DBG(decompPos);DRW_DBG("\n");

    return buffersGood();
}

void dwgCompressor::readInstructions21(duint8 &opCode, duint32 &sourceOffset, duint32 &length){

    switch (opCode >> 4) {
    case 0:
        length = (opCode & 0x0f) + 0x13;
        sourceOffset = compressedByte();
        opCode = compressedByte();
        length = ((opCode >> 3) & 0x10) + length;
        sourceOffset = ((opCode & 0x78) << 5) + 1 + sourceOffset;
        break;
    case 1:
        length = (opCode & 0xf) + 3;
        sourceOffset = compressedByte();
        opCode = compressedByte();
        sourceOffset = ((opCode & 0xf8) << 5) + 1 + sourceOffset;
        break;
    case 2:
        sourceOffset = compressedByte();
        sourceOffset = (compressedHiByte() & 0xff00) | sourceOffset;
        length = opCode & 7;
        if ((opCode & 8) == 0) {
            opCode = compressedByte();
            length = (opCode & 0xf8) + length;
        } else {
            ++sourceOffset;
            length = (static_cast<duint32>(compressedByte()) << 3) + length;
            opCode = compressedByte();
            length = (((opCode & 0xf8) << 8) + length) + 0x100;
        }
        break;
    default:
        length = opCode >> 4;
        sourceOffset = opCode & 15;
        opCode = compressedByte();
        sourceOffset = (((opCode & 0xf8) << 1) + sourceOffset) + 1;
        break;
    }
}

const duint8 dwgCompressor::CopyOrder21_01[] = {0};
const duint8 dwgCompressor::CopyOrder21_02[] = {1,0};
const duint8 dwgCompressor::CopyOrder21_03[] = {2,1,0};
const duint8 dwgCompressor::CopyOrder21_04[] = {0,1,2,3};
const duint8 dwgCompressor::CopyOrder21_05[] = {4,0,1,2,3};
const duint8 dwgCompressor::CopyOrder21_06[] = {5,1,2,3,4,0};
const duint8 dwgCompressor::CopyOrder21_07[] = {6,5,1,2,3,4,0};
const duint8 dwgCompressor::CopyOrder21_08[] = {0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_09[] = {8,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_10[] = {9,1,2,3,4,5,6,7,8,0};
const duint8 dwgCompressor::CopyOrder21_11[] = {10,9,1,2,3,4,5,6,7,8,0};
const duint8 dwgCompressor::CopyOrder21_12[] = {8,9,10,11,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_13[] = {12,8,9,10,11,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_14[] = {13,9,10,11,12,1,2,3,4,5,6,7,8,0};
const duint8 dwgCompressor::CopyOrder21_15[] = {14,13,9,10,11,12,1,2,3,4,5,6,7,8,0};
const duint8 dwgCompressor::CopyOrder21_16[] = {8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_17[] = {9,10,11,12,13,14,15,16,8,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_18[] = {17,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,0};
const duint8 dwgCompressor::CopyOrder21_19[] = {18,17,16,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_20[] = {16,17,18,19,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_21[] = {20,16,17,18,19,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_22[] = {21,20,16,17,18,19,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_23[] = {22,21,20,16,17,18,19,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_24[] = {16,17,18,19,20,21,22,23,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_25[] = {17,18,19,20,21,22,23,24,16,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_26[] = {25,17,18,19,20,21,22,23,24,16,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_27[] = {26,25,17,18,19,20,21,22,23,24,16,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_28[] = {24,25,26,27,16,17,18,19,20,21,22,23,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_29[] = {28,24,25,26,27,16,17,18,19,20,21,22,23,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_30[] = {29,28,24,25,26,27,16,17,18,19,20,21,22,23,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 dwgCompressor::CopyOrder21_31[] = {30,26,27,28,29,18,19,20,21,22,23,24,25,10,11,12,13,14,15,16,17,2,3,4,5,6,7,8,9,1,0};
const duint8 dwgCompressor::CopyOrder21_32[] = {24,25,26,27,28,29,30,31,16,17,18,19,20,21,22,23,8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7};
const duint8 *dwgCompressor::CopyOrder21[dwgCompressor::Block21OrderArray] = {
        nullptr,
        CopyOrder21_01, CopyOrder21_02, CopyOrder21_03, CopyOrder21_04,
        CopyOrder21_05, CopyOrder21_06, CopyOrder21_07, CopyOrder21_08,
        CopyOrder21_09, CopyOrder21_10, CopyOrder21_11, CopyOrder21_12,
        CopyOrder21_13, CopyOrder21_14, CopyOrder21_15, CopyOrder21_16,
        CopyOrder21_17, CopyOrder21_18, CopyOrder21_19, CopyOrder21_20,
        CopyOrder21_21, CopyOrder21_22, CopyOrder21_23, CopyOrder21_24,
        CopyOrder21_25, CopyOrder21_26, CopyOrder21_27, CopyOrder21_28,
        CopyOrder21_29, CopyOrder21_30, CopyOrder21_31, CopyOrder21_32
};

void dwgCompressor::copyBlock21(const duint32 length)
{
    if (MaxBlock21Length < length) {
        return;
    }

    const duint8 *order {CopyOrder21[length]};
    if (nullptr == order) {
        return;
    }

    for (duint32 index = 0; (length > index) && buffersGood(); ++index) {
        decompSet( compressedByte( compressedPos + order[index]));
    }
    compressedInc( length);
}

bool dwgCompressor::copyCompBytes21(duint32 length)
{
    DRW_DBG("\ncopyCompBytes21() "); DRW_DBG(length); DRW_DBG("\n");

    while (length >= MaxBlock21Length) {
        copyBlock21( MaxBlock21Length);
        length -= MaxBlock21Length;
    }

    copyBlock21( length);

    return buffersGood();
}


secEnum::DWGSection secEnum::getEnum(const std::string &nameSec){
    //TODO: complete it
    if (nameSec=="AcDb:Header"){
        return HEADER;
    } else if (nameSec=="AcDb:Classes"){
        return CLASSES;
    } else if (nameSec=="AcDb:SummaryInfo"){
        return SUMARYINFO;
    } else if (nameSec=="AcDb:Preview"){
        return PREVIEW;
    } else if (nameSec=="AcDb:VBAProject"){
        return VBAPROY;
    } else if (nameSec=="AcDb:AppInfo"){
        return APPINFO;
    } else if (nameSec=="AcDb:FileDepList"){
        return FILEDEP;
    } else if (nameSec=="AcDb:RevHistory"){
        return REVHISTORY;
    } else if (nameSec=="AcDb:Security"){
        return SECURITY;
    } else if (nameSec=="AcDb:AcDbObjects"){
        return OBJECTS;
    } else if (nameSec=="AcDb:ObjFreeSpace"){
        return OBJFREESPACE;
    } else if (nameSec=="AcDb:Template"){
        return TEMPLATE;
    } else if (nameSec=="AcDb:Handles"){
        return HANDLES;
    } else if (nameSec=="AcDb:AcDsPrototype_1b"){
        return PROTOTYPE;
    } else if (nameSec=="AcDb:AuxHeader"){
        return AUXHEADER;
    } else if (nameSec=="AcDb:Signature"){
        return SIGNATURE;
    } else if (nameSec=="AcDb:AppInfoHistory"){ //in ac1021
        return APPINFOHISTORY;
//    } else if (nameSec=="AcDb:Extended Entity Data"){
//        return EXTEDATA;
//    } else if (nameSec=="AcDb:PROXY ENTITY GRAPHICS"){
//        return PROXYGRAPHICS;
    }
    return UNKNOWNS;
}