error.hpp

#ifndef POLYNET_ERROR_HPP_
#define POLYNET_ERROR_HPP_

#include "string.hpp"
#include <errno.h>
#include <expected>
#include <string>
#include <system_error>
#ifdef _WIN32
    #include <winsock2.h>
    #include <ws2tcpip.h>
#endif

#ifdef Status
    #undef Status
#endif

namespace pn {
    enum ErrorType {
        PN_ERROR_NONE,
        PN_ERROR_INVALID_ADDRESS,
        PN_ERROR_USER_CALLBACK,
        PN_ERROR_TLS,
        PN_ERROR_ALREADY_INITIALIZED,
    };

    const std::error_category& polynet_category() noexcept;
    const std::error_category& winsock_category() noexcept;
    const std::error_category& address_info_category() noexcept;

    inline std::error_code polynet_error_code(ErrorType error) noexcept {
        return {error, polynet_category()};
    }

    inline std::error_code socket_error_code(int error) noexcept {
#ifdef _WIN32
        return {error, winsock_category()};
#else
        // POSIX errno values have portable std::errc equivalents
        return {error, std::generic_category()};
#endif
    }

    inline std::error_code last_socket_error_code() noexcept {
#ifdef _WIN32
        return socket_error_code(WSAGetLastError());
#else
        return socket_error_code(errno);
#endif
    }

    inline std::error_code address_info_error_code(int error) noexcept {
        return {error, address_info_category()};
    }

    struct Error {
        std::error_code code;
        StringView operation;

        explicit operator bool() const noexcept {
            return code.value();
        }

        std::string message() const {
            return operation.empty() ? code.message() : std::string(operation) + ": " + code.message();
        }
    };

    template <typename T>
    using Result = std::expected<T, Error>;

    using Status = Result<void>;

    inline Error make_polynet_error(ErrorType error, StringView operation = {}) noexcept {
        return {polynet_error_code(error), operation};
    }

    inline Error make_socket_error(int error, StringView operation = {}) noexcept {
        return {socket_error_code(error), operation};
    }

    inline Error make_last_socket_error(StringView operation = {}) noexcept {
        return {last_socket_error_code(), operation};
    }

    inline Error make_address_info_error(int error, StringView operation = {}) noexcept {
        return {address_info_error_code(error), operation};
    }

} // namespace pn

#endif