//-----------------------------------------------------------------------------
//     ___                      __ _       _
//    / _ \__ _ _ __ ___  ___  / /(_)_ __ | | __
//   / /_)/ _` | '__/ __|/ _ \/ / | | '_ \| |/ /
//  / ___/ (_| | |  \__ \  __/ /__| | | | |   <
//  \/    \__,_|_|  |___/\___\____/_|_| |_|_|\_\ .
//
//-----------------------------------------------------------------------------
// Author: Kurt Sassenrath
// Module: proto
//
// Session ID. Used as a handle to access an existing user session, which can
// also be used to share parse data without any linking of users.
//
// Copyright (c) 2023 Kurt Sassenrath.
//
// License TBD.
//-----------------------------------------------------------------------------
#ifndef session_id_6598f9bae1cbb501
#define session_id_6598f9bae1cbb501

#include <array>
#include <cstddef>
#include <span>

namespace parselink {
namespace proto {

struct session_id {
public:
    session_id() noexcept;

    // Not the intended way to build a session id. Ideally, they'll be randomly
    // generated.
    explicit constexpr session_id(std::array<std::byte, 32> const& v) noexcept {
        std::copy(v.begin(), v.end(), bytes_.begin());
    }

    [[nodiscard]] constexpr auto operator<=>(
            session_id const& other) const noexcept {
        return bytes_ <=> other.bytes_;
    }

    [[nodiscard]] constexpr auto operator==(
            session_id const& other) const noexcept {
        return bytes_ == other.bytes_;
    }

    [[nodiscard]] constexpr auto operator<=>(
            std::span<std::byte const> other) const noexcept {
        return std::lexicographical_compare_three_way(bytes_.begin(),
                bytes_.end(), other.begin(), other.end(),
                std::compare_three_way());
    }

    [[nodiscard]] constexpr auto operator==(
            std::span<std::byte const> other) const noexcept {
        return std::equal(bytes_.begin(), bytes_.end(), other.begin(), other.end());
    }

    constexpr std::span<std::byte const> raw() const noexcept {
        return bytes_;
    }
private:
    std::array<std::byte, 32> bytes_;
};

} // namespace proto
} // namespace parselink

#endif // session_id_6598f9bae1cbb501