//----------------------------------------------------------------------------- 
//     ___                      __ _       _
//    / _ \__ _ _ __ ___  ___  / /(_)_ __ | | __
//   / /_)/ _` | '__/ __|/ _ \/ / | | '_ \| |/ /
//  / ___/ (_| | |  \__ \  __/ /__| | | | |   <
//  \/    \__,_|_|  |___/\___\____/_|_| |_|_|\_\ .
//
//----------------------------------------------------------------------------- 
// Author: Kurt Sassenrath
// Module: Proto
//
// Session management for the "user" protocol.
//
// Copyright (c) 2023 Kurt Sassenrath.
//
// License TBD.
//----------------------------------------------------------------------------- 
#ifndef session_07eae057feface79
#define session_07eae057feface79

#include <tl/expected.hpp>

#include "parselink/msgpack/token.h"

#include <cstdint>
#include <span>
#include <string>

namespace parselink {
namespace proto {

enum class error {
    system_error,
    incomplete,
    unsupported,
    bad_data,
    too_large,
};

// Structure containing header information parsed from a buffer.
struct header_info {
    std::uint32_t message_size; // Size of the message, minus the header.
    std::uint32_t bytes_read;   // How many bytes of the buffer were used.
};

class session {
public:
    session() = default;

    // Parse the protocol header out of a buffer. This is a member function
    // as we may choose to omit data once a session is established.
    tl::expected<header_info, error> parse_header(
            std::span<std::byte const> buffer) noexcept;

    tl::expected<std::monostate, error> handle_connect(
            std::span<msgpack::token> tokens) noexcept;

    // The maximum size of a single message. Should probably depend on whether
    // the session is established or not.
    constexpr static std::uint32_t max_message_size = 128 * 1024;


    std::string user_id;
private:
};

} // namespace proto
} // namespace parselink

#endif // session_0c61530748b9f966