Rendezvous/tests/FinalFactory.Rendezvous.Tests/Client/ConnectionTicketValidatorTests.cs

using FinalFactory.Rendezvous.Client;
using FinalFactory.Rendezvous.Contracts;

namespace FinalFactory.Rendezvous.Tests.Client;

public sealed class ConnectionTicketValidatorTests
{
    private static readonly DateTimeOffset Now = new(2026, 7, 16, 12, 0, 0, TimeSpan.Zero);

    [Fact]
    public void AuthorizedTicketIsAcceptedExactlyOnce()
    {
        ManualConnectionTicketClock clock = new();
        using ConnectionTicketValidator validator = new(1_024, clock);
        JoinAttemptId attempt = NewAttempt();
        string ticket = Ticket('A');
        Assert.True(validator.TryAuthorize(attempt, ticket, Now.AddSeconds(20)));
        Assert.True(validator.TryAuthorize(attempt, ticket, Now.AddSeconds(20)));

        Assert.Equal(
            ConnectionTicketConsumptionResult.Accepted,
            validator.Consume(attempt, ticket));
        Assert.Equal(
            ConnectionTicketConsumptionResult.AlreadyConsumed,
            validator.Consume(attempt, ticket));
    }

    [Fact]
    public void AlteredCrossAttemptExpiredAndRevokedTicketsAreRejected()
    {
        ManualConnectionTicketClock clock = new();
        using ConnectionTicketValidator validator = new(1_024, clock);
        JoinAttemptId first = NewAttempt();
        JoinAttemptId second = NewAttempt();
        Assert.True(validator.TryAuthorize(first, Ticket('A'), Now.AddSeconds(20)));
        Assert.True(validator.TryAuthorize(second, Ticket('B'), Now.AddSeconds(40)));

        Assert.Equal(
            ConnectionTicketConsumptionResult.Rejected,
            validator.Consume(first, Ticket('B')));
        clock.Advance(TimeSpan.FromSeconds(20));
        Assert.Equal(
            ConnectionTicketConsumptionResult.Expired,
            validator.Consume(first, Ticket('A')));
        Assert.True(validator.Revoke(second));
        Assert.Equal(
            ConnectionTicketConsumptionResult.Revoked,
            validator.Consume(second, Ticket('B')));
    }

    [Fact]
    public async Task ConcurrentConsumptionHasOneWinner()
    {
        ManualConnectionTicketClock clock = new();
        using ConnectionTicketValidator validator = new(1_024, clock);
        JoinAttemptId attempt = NewAttempt();
        string ticket = Ticket('C');
        Assert.True(validator.TryAuthorize(attempt, ticket, Now.AddSeconds(20)));
        using ManualResetEventSlim start = new(false);
        Task<ConnectionTicketConsumptionResult> left = Task.Run(() =>
        {
            start.Wait();
            return validator.Consume(attempt, ticket);
        });
        Task<ConnectionTicketConsumptionResult> right = Task.Run(() =>
        {
            start.Wait();
            return validator.Consume(attempt, ticket);
        });

        start.Set();
        ConnectionTicketConsumptionResult[] results = await Task.WhenAll(left, right);

        Assert.Single(results, static result => result == ConnectionTicketConsumptionResult.Accepted);
        Assert.Single(results, static result => result == ConnectionTicketConsumptionResult.AlreadyConsumed);
    }

    [Fact]
    public void ValidatorIsBoundedDisposableAndRedacted()
    {
        ManualConnectionTicketClock clock = new();
        ConnectionTicketValidator validator = new(1, clock);
        Assert.True(validator.TryAuthorize(NewAttempt(), Ticket('A'), Now.AddSeconds(20)));
        Assert.False(validator.TryAuthorize(NewAttempt(), Ticket('B'), Now.AddSeconds(20)));
        Assert.DoesNotContain(Ticket('A'), validator.ToString(), StringComparison.Ordinal);

        validator.Dispose();

        Assert.Throws<ObjectDisposedException>(() => validator.Revoke(NewAttempt()));
        Assert.Throws<ObjectDisposedException>(() => validator.Consume(default, string.Empty));
    }

    private static JoinAttemptId NewAttempt() => new(Guid.NewGuid());
    private static string Ticket(char value) => new(value, 43);

    private sealed class ManualConnectionTicketClock : IConnectionTicketClock
    {
        public DateTimeOffset UtcNow { get; set; } = Now;

        public void Advance(TimeSpan duration) => UtcNow += duration;
    }
}