#ifndef __JABYENGINE_LZ4_DECOMPRESSOR_HPP__
#define __JABYENGINE_LZ4_DECOMPRESSOR_HPP__
#include "../../stddef.h"
#include "array_range.hpp"
#include "types.hpp"

namespace JabyEngine {
    class LZ4Decompressor {
    public:
        struct Result {
            Progress progress;
            size_t   bytes_ready;

            static constexpr Result new_error() {
                return {Progress::Error, 0};
            }

            static constexpr Result new_done(size_t bytes_ready) {
                return {Progress::Done, bytes_ready};
            }

            static constexpr Result new_in_progress(size_t bytes_ready) {
                return {Progress::InProgress, bytes_ready};
            }
        };

    private:
        struct State {
            enum struct Step {
                ReadToken,
                ObtainLiteralLength,
                CopyLiterals,
                ObtainMatchOffset,
                ObtainMatchLength,
                CopyMatch,
            };

            Step     step           = Step::ReadToken;
            size_t   literal_length = 0;
            size_t   match_length   = 0;
            uint16_t match_offset   = 0xFFFF;

            State() = default;
        };

    private:
        uint8_t* dst_adr = nullptr;
        State    state;

        static bool obtain_any_length(ArrayRange<const uint8_t>& data, uint32_t &dst_length);

        pair<bool, Result> read_token(ArrayRange<const uint8_t>& data);
        pair<bool, Result> obtain_literal_length(ArrayRange<const uint8_t>& data);
        pair<bool, Result> copy_literals(ArrayRange<const uint8_t>& data);
        pair<bool, Result> obtain_match_offset(ArrayRange<const uint8_t>& data);
        pair<bool, Result> obtain_match_length(ArrayRange<const uint8_t>& data);
        pair<bool, Result> copy_match(ArrayRange<const uint8_t>& data);

    public:
        LZ4Decompressor() = default;
        LZ4Decompressor(uint8_t* dst_adr) : LZ4Decompressor() {
            LZ4Decompressor::setup(dst_adr);
        }

        void setup(uint8_t* dst_adr);
        void reset();

        Result process(ArrayRange<const uint8_t> data);
    };
}

#endif //!__JABYENGINE_LZ4_DECOMPRESSOR_HPP__