rublon-ssh/PAM/ssh/include/rublon/error.hpp

#pragma once

#include <tl/expected.hpp>

#include <rublon/non_owning_ptr.hpp>
#include <rublon/stdlib.hpp>

namespace rublon {

template < typename... Types >
constexpr std::array< std::string_view, sizeof...(Types) > make_array(Types... names) {
    return {std::forward< Types >(names)...};
}

class ConfigurationError {
  public:
    enum class ErrorClass { RequiredValueNotFound, BadFailMode, BadInput, Empty };
    constexpr static auto errorClassPrettyName = make_array("RequiredValueNotFound", "BadFailMode", "BadInput", "Empty");
    constexpr static auto prettyName           = "Configurtion Error";

    constexpr ConfigurationError(ErrorClass e = ErrorClass::RequiredValueNotFound) : errorClass{e} {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    ErrorClass errorClass;
};

class ConnectionError {
  public:
    enum ErrorClass { Timeout, HttpError, ClientError };
    constexpr static auto errorClassPrettyName = make_array("Timeout", "Error", "Client Error");
    constexpr static auto prettyName           = "Connection Error";

    constexpr ConnectionError() : errorClass{Timeout}, httpCode(200) {}
    constexpr ConnectionError(ErrorClass e, long httpCode) : errorClass{e}, httpCode(httpCode) {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    ErrorClass errorClass;
    long httpCode;
};

class CoreHandlerError {
  public:
    enum ErrorClass { BadSigature, RublonCoreException, BrokenData, APIException, TransactionException };
    constexpr static auto errorClassPrettyName =
      make_array("BadSigature", "RublonCoreException", "BrokenData", "APIException", "TransactionException");
    constexpr static auto prettyName = "Core Handler Error";

    // APIException -> code: 10
    // TransactionException -> code: 11

    CoreHandlerError(ErrorClass e = BadSigature, std::string r = "") : errorClass{e}, reson{std::move(r)} {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    ErrorClass errorClass;
    std::string reson; // TODO dynamic mem
};

class MethodError {
  public:
    enum ErrorClass { BadMethod, BadUserInput, NoMethodAvailable };
    constexpr static auto errorClassPrettyName = make_array("BadMethod", "BadUserInput", "NoMethodAvailable");
    constexpr static auto prettyName           = "Method Error";

    constexpr MethodError(ErrorClass e = BadMethod) : errorClass{e} {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    ErrorClass errorClass;
};

class WerificationError {
  public:
    enum ErrorClass {
        BadInput,         // User input has incorrect characters or length
        PasscodeException // Exception from core
    };
    constexpr static auto errorClassPrettyName = make_array("BadInput", "PasscodeException");
    constexpr static inline auto prettyName    = "Werification Error";

    constexpr WerificationError(ErrorClass e = PasscodeException) : errorClass{e} {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    static std::optional< WerificationError > fromString(std::string_view name) {
        for(std::size_t i{}; i < errorClassPrettyName.size(); i++) {
            if(errorClassPrettyName.at(i) == name) {
                return std::make_optional(WerificationError{static_cast< ErrorClass >(i)});
            }
        }
        return std::nullopt;
    }

    ErrorClass errorClass;
};

class RublonAuthenticationInterrupt {
  public:
    // UserPending -> user has no methods configured
    enum ErrorClass { UserBaypass, UserDenied, UserPending, UserWaiting, UserNotFound };
    constexpr static auto errorClassPrettyName =
      make_array("UserBypassedException", "UserDenied", "UserPending", "UserWaiting", "UserNotFoundException");
    constexpr static auto prettyName = "Rublon Authentication Interrupt";

    RublonAuthenticationInterrupt(ErrorClass e = UserBaypass) : errorClass{e} {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    static std::optional< RublonAuthenticationInterrupt > fromString(std::string_view name) {
        for(std::size_t i{}; i < errorClassPrettyName.size(); i++) {
            if(errorClassPrettyName.at(i) == name) {
                return std::make_optional(RublonAuthenticationInterrupt{static_cast< ErrorClass >(i)});
            }
        }
        return std::nullopt;
    }

    ErrorClass errorClass;
};

class RublonCheckApplicationException {
  public:
    enum ErrorClass { ApplicationNotFoundException, InvalidSignatureException, UnsupportedVersionException };

    constexpr static auto errorClassPrettyName =
      make_array("ApplicationNotFoundException", "InvalidSignatureException", "UnsupportedVersionException");
    constexpr static auto prettyName = "Rublon Check Application Interrupt";

    RublonCheckApplicationException(ErrorClass e = ApplicationNotFoundException) : errorClass{e} {}

    constexpr const char * what() const {
        return errorClassPrettyName[static_cast< int >(errorClass)].data();
    }

    static std::optional< RublonCheckApplicationException > fromString(std::string_view name) {
        for(std::size_t i{}; i < errorClassPrettyName.size(); i++) {
            if(errorClassPrettyName.at(i) == name) {
                return std::make_optional(RublonCheckApplicationException{static_cast< ErrorClass >(i)});
            }
        }
        return std::nullopt;
    }

    ErrorClass errorClass;
};

class Error {
    using Error_t = std::variant< ConfigurationError,
      CoreHandlerError,
      ConnectionError,
      WerificationError,
      MethodError,
      RublonAuthenticationInterrupt,
      RublonCheckApplicationException >;
    Error_t _error;

  public:
    enum Category {
        k_ConfigurationError,
        k_CoreHandlerError,
        k_ConnectionError,
        k_WerificationError,
        k_MethodError,
        k_RublonAuthenticationInterrupt,
        k_RublonCheckApplication
    };

    Error() = default;

    Error(ConfigurationError error) : _error{error} {}
    Error(CoreHandlerError error) : _error{error} {}
    Error(ConnectionError error) : _error{error} {}
    Error(MethodError error) : _error{error} {}
    Error(WerificationError error) : _error{error} {}
    Error(RublonAuthenticationInterrupt error) : _error{error} {}
    Error(RublonCheckApplicationException error) : _error{error} {}

    Error(const Error &) = default;
    Error(Error &&)      = default;

    Error & operator=(const Error &) = default;
    Error & operator=(Error &&)      = default;

  public:
    constexpr bool coreError() const {
        return _error.index() == 1;
    }

    constexpr bool sockerError() const {
        return _error.index() == 2;
    }

    constexpr Category category() const noexcept {
        return static_cast< Category >(_error.index());
    }

    constexpr const char * categoryName() const noexcept {
        return std::visit([](const auto & e) { return e.what(); }, _error);
    }

    constexpr int errorClass() const noexcept {
        return std::visit([](const auto & e) { return static_cast< int >(e.errorClass); }, _error);
    }

    constexpr const char * errorClassName() const noexcept {
        return std::visit([](const auto & e) { return e.prettyName; }, _error);
    }

    template < typename E >
    constexpr bool is() const {
        return category() == Error{E{}}.category();
    }

    template < typename E >
    constexpr bool is(typename E::ErrorClass errorClass) const {
        return is< E >() && hasSameErrorClassAs(errorClass);
    }

    template < typename E >
    constexpr bool isSameCategoryAs(const E & e) const {
        return category() == Error{e}.category();
    }

    constexpr bool hasClass(int _class) const {
        return errorClass() == _class;
    }

    template < typename E >
    constexpr bool hasSameErrorClassAs(E e) const {
        assert(isSameCategoryAs(e));
        return errorClass() == Error{e}.errorClass();
    }

    template < typename E >
    constexpr const E & get() const {
        return std::get< E >(_error);
    }
};

constexpr bool operator==(const Error & e, const ConnectionError & socket) {
    return e.sockerError() && e.errorClass() == socket.errorClass;
}

template < typename T >
constexpr bool operator==(const Error & lhs, const T & rhs) {
    return lhs.isSameCategoryAs(rhs) && lhs.hasSameErrorClassAs(rhs);
}

} // namespace rublon