Rendezvous/src/FinalFactory.Rendezvous.Client/ConnectionOutcomes/RendezvousConnectionOutcome.cs

using FinalFactory.Rendezvous.Contracts;
using LiteNetLib;

namespace FinalFactory.Rendezvous.Client;

public enum RendezvousConnectionOutcomeSource
{
    RendezvousService = 1,
    LocalTraversal = 2,
    RemoteHost = 3,
    Caller = 4,
    Lifecycle = 5,
}

public enum RendezvousConnectionFailureCategory
{
    None = 0,
    Directory = 1,
    Compatibility = 2,
    Authorization = 3,
    Capacity = 4,
    HostPresence = 5,
    Service = 6,
    Mediation = 7,
    NatTraversal = 8,
    DirectConnection = 9,
    Lifecycle = 10,
}

public enum RendezvousConnectionPhase
{
    Directory = 1,
    Authorization = 2,
    Mediation = 3,
    NatTraversal = 4,
    DirectConnection = 5,
    Complete = 6,
}

public sealed class RendezvousConnectionOutcome
{
    private readonly NetworkEndpoint? _dedicatedFallback;

    private RendezvousConnectionOutcome(
        ConnectionOutcomeKind kind,
        RendezvousConnectionOutcomeSource source,
        RendezvousConnectionFailureCategory category,
        RendezvousConnectionPhase phase,
        TimeSpan elapsed,
        RendezvousErrorCode? serviceError,
        NetworkEndpoint? dedicatedFallback,
        NetPeer? peer)
    {
        if (elapsed < TimeSpan.Zero)
        {
            throw new ArgumentOutOfRangeException(nameof(elapsed));
        }

        if (dedicatedFallback is not null
            && !ContractValidation.IsNetworkEndpointValid(dedicatedFallback))
        {
            throw new ArgumentException("The dedicated fallback endpoint is invalid.", nameof(dedicatedFallback));
        }

        Kind = kind;
        Source = source;
        Category = category;
        Phase = phase;
        Elapsed = elapsed;
        ServiceError = serviceError;
        _dedicatedFallback = RendezvousEndpoint.Copy(dedicatedFallback);
        Peer = peer;
    }

    public ConnectionOutcomeKind Kind { get; }
    public RendezvousConnectionOutcomeSource Source { get; }
    public RendezvousConnectionFailureCategory Category { get; }
    public RendezvousConnectionPhase Phase { get; }
    public TimeSpan Elapsed { get; }
    public RendezvousErrorCode? ServiceError { get; }
    public NetworkEndpoint? DedicatedFallback => RendezvousEndpoint.Copy(_dedicatedFallback);
    public NetPeer? Peer { get; }
    public bool IsSuccess => Kind == ConnectionOutcomeKind.Connected;
    public bool HasDedicatedFallback => _dedicatedFallback is not null;

    public static RendezvousConnectionOutcome FromServiceError(
        RendezvousErrorCode error,
        TimeSpan elapsed,
        NetworkEndpoint? dedicatedFallback = null)
    {
        if (error == RendezvousErrorCode.None)
        {
            throw new ArgumentException("A service failure outcome requires an error.", nameof(error));
        }

        (ConnectionOutcomeKind kind, RendezvousConnectionFailureCategory category, RendezvousConnectionPhase phase) =
            error switch
            {
                RendezvousErrorCode.NotFound => (
                    ConnectionOutcomeKind.DirectoryNotFound,
                    RendezvousConnectionFailureCategory.Directory,
                    RendezvousConnectionPhase.Directory),
                RendezvousErrorCode.Expired => (
                    ConnectionOutcomeKind.AttemptExpired,
                    RendezvousConnectionFailureCategory.Authorization,
                    RendezvousConnectionPhase.Authorization),
                RendezvousErrorCode.IncompatibleProtocol => (
                    ConnectionOutcomeKind.IncompatibleProtocol,
                    RendezvousConnectionFailureCategory.Compatibility,
                    RendezvousConnectionPhase.Directory),
                RendezvousErrorCode.AuthenticationRequired
                    or RendezvousErrorCode.Forbidden
                    or RendezvousErrorCode.ReplayRejected => (
                        ConnectionOutcomeKind.Unauthorized,
                        RendezvousConnectionFailureCategory.Authorization,
                        RendezvousConnectionPhase.Authorization),
                RendezvousErrorCode.RateLimited
                    or RendezvousErrorCode.CapacityExceeded => (
                        ConnectionOutcomeKind.RateLimited,
                        RendezvousConnectionFailureCategory.Capacity,
                        RendezvousConnectionPhase.Authorization),
                RendezvousErrorCode.StaleHost => (
                    ConnectionOutcomeKind.NoHostPresence,
                    RendezvousConnectionFailureCategory.HostPresence,
                    RendezvousConnectionPhase.Mediation),
                RendezvousErrorCode.ServiceUnavailable => (
                    ConnectionOutcomeKind.ServiceUnavailable,
                    RendezvousConnectionFailureCategory.Service,
                    RendezvousConnectionPhase.Authorization),
                _ => (
                    ConnectionOutcomeKind.ServiceRejected,
                    RendezvousConnectionFailureCategory.Service,
                    RendezvousConnectionPhase.Authorization),
            };
        return new(
            kind,
            RendezvousConnectionOutcomeSource.RendezvousService,
            category,
            phase,
            elapsed,
            error,
            dedicatedFallback,
            null);
    }

    public static ConnectionElapsedBucket BucketElapsed(TimeSpan elapsed)
    {
        if (elapsed < TimeSpan.Zero)
        {
            throw new ArgumentOutOfRangeException(nameof(elapsed));
        }

        return elapsed.TotalSeconds switch
        {
            < 1 => ConnectionElapsedBucket.UnderOneSecond,
            < 5 => ConnectionElapsedBucket.OneToFiveSeconds,
            < 15 => ConnectionElapsedBucket.FiveToFifteenSeconds,
            < 30 => ConnectionElapsedBucket.FifteenToThirtySeconds,
            _ => ConnectionElapsedBucket.ThirtySecondsOrMore,
        };
    }

    public override string ToString() =>
        $"[RendezvousConnectionOutcome {Kind}; {Source}; credentials redacted]";

    internal static RendezvousConnectionOutcome Create(
        ConnectionOutcomeKind kind,
        RendezvousConnectionOutcomeSource source,
        RendezvousConnectionFailureCategory category,
        RendezvousConnectionPhase phase,
        TimeSpan elapsed,
        NetworkEndpoint? dedicatedFallback = null,
        NetPeer? peer = null) => new(
            kind,
            source,
            category,
            phase,
            elapsed,
            null,
            dedicatedFallback,
            peer);

}