/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Compression.cpp
    Date: 2021-6-17
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "Compression.hpp"

#include "zstd.h"

namespace Aurora::Compression
{
    AUKN_SYM bool Compress(const void *buffer, AuUInt32 length, AuList<AuUInt8> &out, int compressionLevel )
    {
        if (!AuTryResize(out, length))
        {
            return false;
        }

        auto ret = ZSTD_compress(&out[0], out.size(), buffer, length, compressionLevel);
        if (ZSTD_isError(ret))
        {
            return false;
        }

        out.resize(ret);
        return true;
    }
    
    AUKN_SYM bool Compress(const AuList<AuUInt8> &in, AuList<AuUInt8> &out, int compressionLevel)
    {
        return Compress(in.data(), in.size(), out, compressionLevel);
    }

    AUKN_SYM bool Decompress(const void *buffer, AuUInt32 length, AuList<AuUInt8> &out)
    {
        AuUInt32 read = 0;

        while (read != length)
        {
            auto startPtr = reinterpret_cast<const AuUInt8 *>(buffer) + read;
            auto deflatedLength = ZSTD_findFrameCompressedSize(startPtr, length - read);
            auto inflatedLength = ZSTD_getFrameContentSize(startPtr, length - read);

            if (inflatedLength == ZSTD_CONTENTSIZE_ERROR)
            {
                return false;
            }

            if (inflatedLength == ZSTD_CONTENTSIZE_UNKNOWN)
            {
                return false;
            }

            if (ZSTD_isError(inflatedLength))
            {
                return false;
            }
            
            auto startingSize = out.size();

            if (!AuTryResize(out, startingSize + inflatedLength))
            {
                return false;
            }

            auto ret = ZSTD_decompress(&out[startingSize], inflatedLength, buffer, length);
            if (ZSTD_isError(ret))
            {
                return false;
            }

            out.resize(startingSize + ret);

            read += deflatedLength;
        }

        return true;
    }

    AUKN_SYM bool Decompress(const AuList<AuUInt8> &in, AuList<AuUInt8> &out)
    {
        return Decompress(in.data(), in.size(), out);
    }
}