/*
 * Copyright (C) 2018-present ScyllaDB
 */

/*
 * SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
 */

#include <seastar/core/iostream.hh>
#include <seastar/core/temporary_buffer.hh>
#include <seastar/util/memory-data-sink.hh>
#include "utils/small_vector.hh"

#include "seastarx.hh"

#pragma once

// Accumulates data sent to the memory_data_sink allowing it
// to be examined later.
class memory_data_sink_buffers {
    using buffers_type = utils::small_vector<temporary_buffer<char>, 1>;
    buffers_type _bufs;
    size_t _size = 0;
public:
    using value_type = temporary_buffer<char>; // for std::back_inserter to work

    size_t size() const { return _size; }
    buffers_type& buffers() { return _bufs; }
    const buffers_type& buffers() const { return _bufs; }

    // Strong exception guarantees
    void push_back(temporary_buffer<char>&& buf) {
        auto size = buf.size();
        _bufs.emplace_back(std::move(buf));
        _size += size;
    }

    void clear() {
        _bufs.clear();
        _size = 0;
    }

    memory_data_sink_buffers() = default;

    memory_data_sink_buffers(memory_data_sink_buffers&& other)
            : _bufs(std::move(other._bufs))
            , _size(std::exchange(other._size, 0))
    {
    }
};

inline void append_buffers(memory_data_sink_buffers& c, std::span<temporary_buffer<char>> bufs) {
    std::ranges::move(bufs, std::back_inserter(c));
}

using memory_data_sink = seastar::util::basic_memory_data_sink<memory_data_sink_buffers, 128*1024>;