//    Copyright (C) 2022 Jakub Melka
//
//    This file is part of PDF4QT.
//
//    PDF4QT is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Lesser General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    with the written consent of the copyright owner, any later version.
//
//    PDF4QT is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Lesser General Public License for more details.
//
//    You should have received a copy of the GNU Lesser General Public License
//    along with PDF4QT.  If not, see <https://www.gnu.org/licenses/>.

#ifndef PDF3D_U3D_H
#define PDF3D_U3D_H

#include "pdfglobal.h"

#include <QBuffer>

namespace pdf
{

namespace u3d
{

class PDF3D_U3D
{
public:

    static PDF3D_U3D parse(QByteArray data);
};

class PDF3D_U3D_ContextManager
{
public:
    bool isContextCompressed(uint32_t context) const;
    bool isContextStaticAndCompressed(uint32_t context) const;

    uint32_t getTotalSymbolFrequency(uint32_t context) const;
    uint32_t getSymbolFrequency(uint32_t context, uint32_t symbol) const;
    uint32_t getCumulativeSymbolFrequency(uint32_t context, uint32_t symbol) const;
    uint32_t getSymbolFromFrequency(uint32_t context, uint32_t symbolFrequency) const;

    void addSymbol(uint32_t context, uint32_t symbol);

private:
    struct ContextData
    {
        ContextData()
        {
            symbols= { { 0, Data{ 1, 1} } };
        }

        struct Data
        {
            uint32_t symbolCount = 0;
            uint32_t cumulativeSymbolCount = 0;
        };

        std::map<uint32_t, Data> symbols;
    };

    const ContextData* getContextData(uint32_t context) const;

    std::map<uint32_t, ContextData> m_contexts;
};

class PDF3D_U3D_Constants
{
public:
    static constexpr uint32_t S_NOT_THREE_QUARTER_MASK = 0x00003FFF;
    static constexpr uint32_t S_QUARTER_MASK = 0x00004000;
    static constexpr uint32_t S_NOT_HALF_MASK = 0x00007FFF;
    static constexpr uint32_t S_HALF_MASK = 0x00008000;
    static constexpr uint32_t S_STATIC_FULL = 0x00000400;
    static constexpr uint32_t S_MAX_RANGE = S_STATIC_FULL + 0x00003FFF;
    static constexpr uint32_t S_CONTEXT_8 = 0;

    static constexpr uint32_t S_MAX_CUMULATIVE_SYMBOL_COUNT = 0x00001fff;
    static constexpr uint32_t S_MAXIMUM_SYMBOL_IN_HISTOGRAM = 0x0000FFFF;
};

class PDF3D_U3D_DataReader
{
public:
    PDF3D_U3D_DataReader(QByteArray data);
    ~PDF3D_U3D_DataReader();

    uint8_t readU8();
    uint16_t readU16();
    uint32_t readU32();
    uint64_t readU64();
    int32_t readI32();
    float readF32();

    uint8_t readCompressedU8(uint32_t context);
    uint16_t readCompressedU16(uint32_t context);
    uint32_t readCompressedU32(uint32_t context);

private:
    uint32_t readSymbol(uint32_t context);
    uint8_t swapBits8(uint8_t source);
    uint32_t readBit();
    uint32_t read15Bits();

    QByteArray m_data;
    PDF3D_U3D_ContextManager m_contextManager;

    uint32_t m_high;
    uint32_t m_low;
    uint32_t m_underflow;
    uint32_t m_code;
    uint32_t m_position;
};

}   // namespace u3d

}   // namespace pdf

#endif // PDF3D_U3D_H