using FinalFactory.Rendezvous.Contracts;
using FinalFactory.Rendezvous.Server.State;

namespace FinalFactory.Rendezvous.Tests.State;

public sealed class InMemoryEphemeralRendezvousStoreTests
{
    [Fact]
    public void IdempotencyRetentionMustCoverResourceLifetimes()
    {
        ManualRendezvousClock clock = new();
        Assert.Throws<ArgumentOutOfRangeException>(() => new InMemoryEphemeralRendezvousStore(
            new EphemeralStoreOptions { IdempotencyLifetime = TimeSpan.FromSeconds(5) },
            clock,
            clock));
    }

    [Fact]
    public void DuplicateRegistrationIsIdempotentButChangedRequestConflicts()
    {
        EphemeralStateFixture fixture = new();
        CreateListingCommand command = fixture.ListingCommand();

        StoreResult<StoredListing> first = fixture.Store.CreateListing(command);
        StoreResult<StoredListing> duplicate = fixture.Store.CreateListing(command);
        StoreResult<StoredListing> changed = fixture.Store.CreateListing(command with { RequestFingerprint = "different" });

        Assert.True(first.Succeeded);
        Assert.True(duplicate.Succeeded);
        Assert.True(duplicate.IsIdempotentReplay);
        Assert.Equal(first.Value!.Definition.ListingId, duplicate.Value!.Definition.ListingId);
        Assert.Equal(StoreResultCode.Conflict, changed.Code);
    }

    [Fact]
    public void LeaseAndPresenceExpiryUseMonotonicTime()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);

        fixture.Clock.Advance(TimeSpan.FromSeconds(20));
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(listing.Definition.ListingId, true).Code);
        Assert.True(fixture.Store.GetListing(listing.Definition.ListingId, false).Succeeded);

        fixture.Clock.Advance(TimeSpan.FromSeconds(40));
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(listing.Definition.ListingId, false).Code);
    }

    [Fact]
    public void WallClockMovementDoesNotExpireOrExtendLease()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out CreateListingCommand command);

        fixture.Clock.MoveWall(TimeSpan.FromDays(30));
        Assert.True(fixture.Store.GetListing(listing.Definition.ListingId, false).Succeeded);
        fixture.Clock.Advance(TimeSpan.FromSeconds(1));
        StoreResult<StoredListing> renewed = fixture.Store.RenewLease(new(
            listing.Definition.ListingId,
            listing.Definition.LeaseId,
            listing.Definition.LeaseFingerprint,
            listing.Definition.OwnerSubject,
            listing.Version));
        Assert.Equal(new DateTimeOffset(2026, 7, 16, 0, 1, 1, TimeSpan.Zero), renewed.Value!.LeaseExpiresAt);
        fixture.Clock.MoveWall(TimeSpan.FromDays(-60));
        fixture.Clock.Advance(TimeSpan.FromSeconds(59));
        Assert.True(fixture.Store.GetListing(listing.Definition.ListingId, false).Succeeded);
        fixture.Clock.Advance(TimeSpan.FromSeconds(1));
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(command.Listing.ListingId, false).Code);
    }

    [Fact]
    public async Task RenewDeleteRaceIsAtomicAndDeleteAlwaysWinsEventually()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out CreateListingCommand command);
        using ManualResetEventSlim start = new(false);

        Task<StoreResult<StoredListing>> renew = Task.Run(() =>
        {
            start.Wait();
            return fixture.Store.RenewLease(new(
                listing.Definition.ListingId,
                listing.Definition.LeaseId,
                listing.Definition.LeaseFingerprint,
                listing.Definition.OwnerSubject,
                listing.Version));
        });
        Task<StoreResult<bool>> delete = Task.Run(() =>
        {
            start.Wait();
            return fixture.Store.DeleteListing(new(
                command.Listing.ListingId,
                command.Listing.LeaseId,
                command.Listing.LeaseFingerprint,
                command.Listing.OwnerSubject));
        });

        start.Set();
        await Task.WhenAll(renew, delete);
        StoreResult<StoredListing> renewResult = await renew;
        StoreResult<bool> deleteResult = await delete;

        Assert.True(deleteResult.Succeeded);
        Assert.Contains(renewResult.Code, new[] { StoreResultCode.Success, StoreResultCode.NotFound });
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(command.Listing.ListingId, false).Code);
    }

    [Fact]
    public void CompareAndSwapPreventsStaleRenewal()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);
        RenewLeaseCommand command = new(
            listing.Definition.ListingId,
            listing.Definition.LeaseId,
            listing.Definition.LeaseFingerprint,
            listing.Definition.OwnerSubject,
            listing.Version);

        StoreResult<StoredListing> first = fixture.Store.RenewLease(command);
        StoreResult<StoredListing> stale = fixture.Store.RenewLease(command);

        Assert.Equal(2, first.Value!.Version);
        Assert.Equal(StoreResultCode.Conflict, stale.Code);
        Assert.Equal(2, stale.Value!.Version);
    }

    [Fact]
    public void JoinRequiresExactScopeProtocolAndFreshHostPresence()
    {
        EphemeralStateFixture fixture = new();
        CreateListingCommand listingCommand = fixture.ListingCommand();
        StoredListing listing = fixture.Store.CreateListing(listingCommand).Value!;
        CreateJoinAttemptCommand attempt = fixture.AttemptCommand(listing);

        Assert.Equal(StoreResultCode.NotFound, fixture.Store.CreateJoinAttempt(attempt).Code);
        fixture.Store.BindHostPresence(new(
            listingCommand.Listing.HostPresenceHandle,
            listingCommand.Listing.HostPresenceFingerprint,
            EphemeralStateFixture.PublicEndpoint(40_000),
            null));
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.CreateJoinAttempt(attempt with { ProtocolVersion = 8 }).Code);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.CreateJoinAttempt(attempt with
        {
            Scope = new(new("other-game"), new("test")),
        }).Code);
        Assert.True(fixture.Store.CreateJoinAttempt(attempt).Succeeded);
    }

    [Fact]
    public void DuplicateJoinIsIdempotentAndDoesNotAllocateTwice()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);
        CreateJoinAttemptCommand command = fixture.AttemptCommand(listing);

        StoreResult<StoredJoinAttempt> first = fixture.Store.CreateJoinAttempt(command);
        StoreResult<StoredJoinAttempt> duplicate = fixture.Store.CreateJoinAttempt(command);

        Assert.True(first.Succeeded);
        Assert.True(duplicate.Succeeded);
        Assert.True(duplicate.IsIdempotentReplay);
        Assert.Equal(first.Value!.AttemptId, duplicate.Value!.AttemptId);
    }

    [Fact]
    public void BrowseReturnsOnlyFreshPublicCompatibleListingsInStableOrder()
    {
        EphemeralStateFixture fixture = new();
        StoredListing visible = fixture.CreateVisibleListing(out _);
        CreateListingCommand staleCommand = fixture.ListingCommand();
        fixture.Store.CreateListing(staleCommand);
        CreateListingCommand unlistedCommand = fixture.ListingCommand();
        unlistedCommand = unlistedCommand with
        {
            Listing = unlistedCommand.Listing with { Visibility = ListingVisibility.Unlisted },
        };
        fixture.Store.CreateListing(unlistedCommand);
        fixture.Store.BindHostPresence(new(
            unlistedCommand.Listing.HostPresenceHandle,
            unlistedCommand.Listing.HostPresenceFingerprint,
            EphemeralStateFixture.PublicEndpoint(40_099),
            null));

        StoreResult<IReadOnlyList<StoredListing>> result = fixture.Store.BrowseVisibleListings(new(
            fixture.Scope,
            visible.Definition.ProtocolVersion,
            visible.Definition.RegionId));

        Assert.True(result.Succeeded);
        Assert.Collection(result.Value!, item => Assert.Equal(visible.Definition.ListingId, item.Definition.ListingId));
    }

    [Fact]
    public async Task ConcurrentEndpointBindingAcceptsOneCompleteEndpointOnly()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);
        CreateJoinAttemptCommand command = fixture.AttemptCommand(listing);
        fixture.Store.CreateJoinAttempt(command);
        BindAttemptEndpointCommand first = new(
            command.MediationHandle,
            AttemptPeerRole.Client,
            command.ClientCapabilityFingerprint,
            EphemeralStateFixture.PublicEndpoint(40_001),
            EphemeralStateFixture.LocalEndpoint(40_001));
        BindAttemptEndpointCommand second = first with
        {
            PublicEndpoint = EphemeralStateFixture.OtherPublicEndpoint(50_001),
            LocalEndpoint = null,
        };
        using ManualResetEventSlim start = new(false);

        Task<StoreResult<StoredJoinAttempt>> left = Task.Run(() => { start.Wait(); return fixture.Store.BindAttemptEndpoint(first); });
        Task<StoreResult<StoredJoinAttempt>> right = Task.Run(() => { start.Wait(); return fixture.Store.BindAttemptEndpoint(second); });
        start.Set();
        await Task.WhenAll(left, right);
        StoreResult<StoredJoinAttempt> leftResult = await left;
        StoreResult<StoredJoinAttempt> rightResult = await right;

        Assert.Equal(1, new[] { leftResult, rightResult }.Count(static result => result.Succeeded));
        Assert.Equal(1, new[] { leftResult, rightResult }.Count(static result => result.Code == StoreResultCode.ReplayRejected));
    }

    [Fact]
    public void AttemptCapabilitiesAndIntroductionAreOneTime()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);
        CreateJoinAttemptCommand command = fixture.AttemptCommand(listing);
        fixture.Store.CreateJoinAttempt(command);
        BindAttemptEndpointCommand host = new(
            command.MediationHandle,
            AttemptPeerRole.Host,
            command.HostCapabilityFingerprint,
            EphemeralStateFixture.PublicEndpoint(40_010),
            null);
        BindAttemptEndpointCommand client = new(
            command.MediationHandle,
            AttemptPeerRole.Client,
            command.ClientCapabilityFingerprint,
            EphemeralStateFixture.OtherPublicEndpoint(40_020),
            null);

        Assert.True(fixture.Store.BindAttemptEndpoint(host).Succeeded);
        Assert.True(fixture.Store.BindAttemptEndpoint(client).Succeeded);
        Assert.True(fixture.Store.BindAttemptEndpoint(client).IsIdempotentReplay);
        Assert.True(fixture.Store.ConsumeIntroduction(command.MediationHandle).Succeeded);
        Assert.Equal(StoreResultCode.ReplayRejected, fixture.Store.ConsumeIntroduction(command.MediationHandle).Code);
        Assert.Equal(StoreResultCode.ReplayRejected, fixture.Store.BindAttemptEndpoint(client with
        {
            PublicEndpoint = EphemeralStateFixture.OtherPublicEndpoint(40_021),
        }).Code);
    }

    [Fact]
    public void ExpiredAttemptCannotBeObservedBoundOrConsumed()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);
        CreateJoinAttemptCommand command = fixture.AttemptCommand(listing);
        fixture.Store.CreateJoinAttempt(command);

        fixture.Clock.Advance(TimeSpan.FromSeconds(30));

        Assert.Equal(StoreResultCode.NotFound, fixture.Store.BindAttemptEndpoint(new(
            command.MediationHandle,
            AttemptPeerRole.Client,
            command.ClientCapabilityFingerprint,
            EphemeralStateFixture.PublicEndpoint(40_050),
            null)).Code);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.ConsumeIntroduction(command.MediationHandle).Code);
    }

    [Fact]
    public void GenericReplayConsumptionIsBoundedAndExpires()
    {
        EphemeralStoreOptions options = new() { MaxReplayEntries = 1 };
        EphemeralStateFixture fixture = new(options);

        Assert.True(fixture.Store.ConsumeReplay(new("ticket", "one")).Succeeded);
        Assert.Equal(StoreResultCode.ReplayRejected, fixture.Store.ConsumeReplay(new("ticket", "one")).Code);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.ConsumeReplay(new("ticket", "two")).Code);
        fixture.Clock.Advance(options.ReplayLifetime);
        Assert.True(fixture.Store.ConsumeReplay(new("ticket", "two")).Succeeded);
    }

    [Fact]
    public void PresenceAttemptAndRevocationPoolsShedWithoutPartialMutation()
    {
        EphemeralStoreOptions options = new()
        {
            MaxPresenceBindings = 1,
            MaxJoinAttempts = 1,
            MaxRevocations = 1,
        };
        EphemeralStateFixture fixture = new(options);
        StoredListing first = fixture.CreateVisibleListing(out CreateListingCommand firstCommand);
        CreateListingCommand secondCommand = fixture.ListingCommand(owner: "publisher-2");
        fixture.Store.CreateListing(secondCommand);

        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.BindHostPresence(new(
            secondCommand.Listing.HostPresenceHandle,
            secondCommand.Listing.HostPresenceFingerprint,
            EphemeralStateFixture.OtherPublicEndpoint(42_000),
            null)).Code);
        Assert.True(fixture.Store.CreateJoinAttempt(fixture.AttemptCommand(first)).Succeeded);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.CreateJoinAttempt(fixture.AttemptCommand(first, "client-2")).Code);
        Assert.True(fixture.Store.RevokePrincipal("unrelated", TimeSpan.FromMinutes(1)).Succeeded);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.RevokePrincipal(firstCommand.Listing.OwnerSubject, TimeSpan.FromMinutes(1)).Code);
        Assert.True(fixture.Store.GetListing(first.Definition.ListingId, true).Succeeded);
        Assert.True(fixture.Store.GetListing(secondCommand.Listing.ListingId, false).Succeeded);
    }

    [Fact]
    public void ExhaustionShedsNewListingWithoutMutatingExistingState()
    {
        EphemeralStoreOptions options = new() { MaxListings = 1 };
        EphemeralStateFixture fixture = new(options);
        CreateListingCommand first = fixture.ListingCommand();
        CreateListingCommand second = fixture.ListingCommand();

        Assert.True(fixture.Store.CreateListing(first).Succeeded);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.CreateListing(second).Code);
        Assert.True(fixture.Store.GetListing(first.Listing.ListingId, false).Succeeded);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(second.Listing.ListingId, false).Code);
    }

    [Fact]
    public void IdempotencyPoolExhaustionDoesNotCreateUntrackedResource()
    {
        EphemeralStoreOptions options = new() { MaxListings = 2, MaxIdempotencyEntries = 1 };
        EphemeralStateFixture fixture = new(options);
        CreateListingCommand first = fixture.ListingCommand();
        CreateListingCommand second = fixture.ListingCommand();

        Assert.True(fixture.Store.CreateListing(first).Succeeded);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.CreateListing(second).Code);
        Assert.True(fixture.Store.GetListing(first.Listing.ListingId, false).Succeeded);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(second.Listing.ListingId, false).Code);
    }

    [Fact]
    public void PolicyQuotasAreCheckedInsideAtomicCreation()
    {
        EphemeralStateFixture fixture = new();
        CreateListingCommand first = fixture.ListingCommand(owner: "publisher-quota") with { OwnerListingLimit = 1 };
        CreateListingCommand second = fixture.ListingCommand(owner: "publisher-quota") with { OwnerListingLimit = 1 };
        Assert.True(fixture.Store.CreateListing(first).Succeeded);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.CreateListing(second).Code);

        fixture.Store.BindHostPresence(new(
            first.Listing.HostPresenceHandle,
            first.Listing.HostPresenceFingerprint,
            EphemeralStateFixture.PublicEndpoint(42_100),
            null));
        StoredListing listing = fixture.Store.GetListing(first.Listing.ListingId, true).Value!;
        CreateJoinAttemptCommand attempt = fixture.AttemptCommand(listing) with { ScopeAttemptLimit = 1 };
        Assert.True(fixture.Store.CreateJoinAttempt(attempt).Succeeded);
        Assert.Equal(StoreResultCode.CapacityExceeded, fixture.Store.CreateJoinAttempt(
            fixture.AttemptCommand(listing, "client-quota-2") with { ScopeAttemptLimit = 1 }).Code);
    }

    [Fact]
    public void InvalidDefaultSecurityValuesCannotEnterStore()
    {
        EphemeralStateFixture fixture = new();
        CreateListingCommand command = fixture.ListingCommand();

        Assert.Throws<ArgumentException>(() => fixture.Store.CreateListing(command with
        {
            Listing = command.Listing with { LeaseFingerprint = default },
        }));
    }

    [Fact]
    public void RevocationRemovesEveryPathAndBlocksNewWorkAtomically()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out CreateListingCommand command);
        CreateJoinAttemptCommand attempt = fixture.AttemptCommand(listing, command.Listing.OwnerSubject);
        fixture.Store.CreateJoinAttempt(attempt);

        StoreResult<int> revoked = fixture.Store.RevokePrincipal(command.Listing.OwnerSubject, TimeSpan.FromMinutes(1));

        Assert.True(revoked.Succeeded);
        Assert.Equal(2, revoked.Value);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(listing.Definition.ListingId, false).Code);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.BindAttemptEndpoint(new(
            attempt.MediationHandle,
            AttemptPeerRole.Client,
            attempt.ClientCapabilityFingerprint,
            EphemeralStateFixture.PublicEndpoint(40_030),
            null)).Code);
        Assert.Equal(StoreResultCode.Revoked, fixture.Store.CreateListing(fixture.ListingCommand(owner: command.Listing.OwnerSubject)).Code);
    }

    [Fact]
    public void RestartHasNewGenerationAndNoEphemeralState()
    {
        EphemeralStateFixture before = new();
        StoredListing listing = before.CreateVisibleListing(out _);
        EphemeralStateFixture after = new();

        Assert.NotEqual(before.Store.InstanceId, after.Store.InstanceId);
        Assert.Equal(StoreResultCode.NotFound, after.Store.GetListing(listing.Definition.ListingId, false).Code);
    }

    [Fact]
    public void DrainRejectsNewWorkAllowsInflightCompletionThenClearsState()
    {
        EphemeralStoreOptions options = new() { GracefulDrainLifetime = TimeSpan.FromSeconds(5) };
        EphemeralStateFixture fixture = new(options);
        StoredListing listing = fixture.CreateVisibleListing(out _);
        CreateJoinAttemptCommand attempt = fixture.AttemptCommand(listing);
        fixture.Store.CreateJoinAttempt(attempt);
        fixture.Store.BeginDrain();

        Assert.Equal(StoreResultCode.Draining, fixture.Store.CreateListing(fixture.ListingCommand()).Code);
        Assert.Equal(StoreResultCode.Draining, fixture.Store.CreateJoinAttempt(fixture.AttemptCommand(listing)).Code);
        Assert.True(fixture.Store.BindAttemptEndpoint(new(
            attempt.MediationHandle,
            AttemptPeerRole.Client,
            attempt.ClientCapabilityFingerprint,
            EphemeralStateFixture.PublicEndpoint(41_000),
            null)).Succeeded);

        fixture.Clock.Advance(options.GracefulDrainLifetime);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(listing.Definition.ListingId, false).Code);
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.BindAttemptEndpoint(new(
            attempt.MediationHandle,
            AttemptPeerRole.Host,
            attempt.HostCapabilityFingerprint,
            EphemeralStateFixture.PublicEndpoint(41_001),
            null)).Code);
    }

    [Fact]
    public void PrecancelledOperationHasNoPartialEffect()
    {
        EphemeralStateFixture fixture = new();
        CreateListingCommand command = fixture.ListingCommand();
        using CancellationTokenSource cancellation = new();
        cancellation.Cancel();

        Assert.Throws<OperationCanceledException>(() => fixture.Store.CreateListing(command, cancellation.Token));
        Assert.Equal(StoreResultCode.NotFound, fixture.Store.GetListing(command.Listing.ListingId, false).Code);
    }

    [Fact]
    public void UnavailableStoreFailsNewAuthorizationClosedAndErasesActiveState()
    {
        EphemeralStateFixture fixture = new();
        StoredListing listing = fixture.CreateVisibleListing(out _);
        fixture.Store.MarkUnavailable();

        Assert.Equal(StoreResultCode.ServiceUnavailable, fixture.Store.GetListing(listing.Definition.ListingId, false).Code);
        Assert.Equal(StoreResultCode.ServiceUnavailable, fixture.Store.CreateJoinAttempt(fixture.AttemptCommand(listing)).Code);
    }
}