#include <Common/config.h>

#if USE_BROTLI
#    include <brotli/decode.h>
#    include "BrotliReadBuffer.h"

namespace DB
{

namespace ErrorCodes
{
    extern const int BROTLI_READ_FAILED;
}


class BrotliReadBuffer::BrotliStateWrapper
{
public:
    BrotliStateWrapper()
        : state(BrotliDecoderCreateInstance(nullptr, nullptr, nullptr))
        , result(BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT)
    {
    }

    ~BrotliStateWrapper()
    {
        BrotliDecoderDestroyInstance(state);
    }

    BrotliDecoderState * state;
    BrotliDecoderResult result;
};

BrotliReadBuffer::BrotliReadBuffer(std::unique_ptr<ReadBuffer> in_, size_t buf_size, char *existing_memory, size_t alignment)
    : CompressedReadBufferWrapper(std::move(in_), buf_size, existing_memory, alignment)
    , brotli(std::make_unique<BrotliStateWrapper>())
    , in_available(0)
    , in_data(nullptr)
    , out_capacity(0)
    , out_data(nullptr)
    , eof_flag(false)
{
}

BrotliReadBuffer::~BrotliReadBuffer() = default;

bool BrotliReadBuffer::nextImpl()
{
    if (eof_flag)
        return false;

    do
    {
        if (!in_available)
        {
            in->nextIfAtEnd();
            in_available = in->buffer().end() - in->position();
            in_data = reinterpret_cast<uint8_t *>(in->position());
        }

        if (brotli->result == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT && (!in_available || in->eof()))
        {
            throw Exception("brotli decode error", ErrorCodes::BROTLI_READ_FAILED);
        }

        out_capacity = internal_buffer.size();
        out_data = reinterpret_cast<uint8_t *>(internal_buffer.begin());

        brotli->result = BrotliDecoderDecompressStream(brotli->state, &in_available, &in_data, &out_capacity, &out_data, nullptr);

        in->position() = in->buffer().end() - in_available;
    }
    while (brotli->result == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT && out_capacity == internal_buffer.size());

    working_buffer.resize(internal_buffer.size() - out_capacity);

    if (brotli->result == BROTLI_DECODER_RESULT_SUCCESS)
    {
        if (in->eof())
        {
            eof_flag = true;
            return !working_buffer.empty();
        }
        else
        {
            throw Exception("brotli decode error", ErrorCodes::BROTLI_READ_FAILED);
        }
    }

    if (brotli->result == BROTLI_DECODER_RESULT_ERROR)
    {
        throw Exception("brotli decode error", ErrorCodes::BROTLI_READ_FAILED);
    }

    return true;
}
}

#endif