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

    File: BlobArbitraryReader.hpp
    Date: 2021-6-10
    Author: Reece
***/
#pragma once

namespace Aurora::IO::Buffered
{
    class BlobArbitraryReader : public IArbitraryStreamer
    {
    public:
        AU_NO_COPY_NO_MOVE(BlobArbitraryReader)

        BlobArbitraryReader(const AuList<AuUInt8> &buffer) : buffer_(buffer) {}
        BlobArbitraryReader() {}
        ~BlobArbitraryReader(){}

        virtual EStreamError Open() override
        {
            return EStreamError::eErrorNone;
        }

        virtual EStreamError ArbitraryRead(AuUInt32 offset, void *buffer, AuUInt32 &len) override
        {
            auto oldLen = std::exchange(len, 0);
            if (buffer_.empty()) return EStreamError::eErrorEndOfStream;

            auto endOffset = offset + oldLen;
            auto realEndOffset = std::min(AuUInt32(buffer_.size()), endOffset);
            auto actualLength = realEndOffset - offset;

            if (actualLength < 0) return EStreamError::eErrorEndOfStream;

            len = actualLength;
            std::memcpy(buffer, buffer_.data() + offset, len);

            return EStreamError::eErrorNone;
        }

        virtual void Close() override
        {
            buffer_.clear();
        }

    private:
        AuList<AuUInt8> buffer_;
    };
}