using System.Numerics;
using AcDream.App.Input;
using AcDream.App.Rendering;
using AcDream.App.Streaming;
using AcDream.App.Update;
using AcDream.App.World;
using AcDream.Content;
using AcDream.Core.Net;
using AcDream.Core.Net.Messages;
using AcDream.Core.Physics;
using AcDream.Core.World;
using AcDream.Runtime;
using AcDream.Runtime.Entities;
using AcDream.Runtime.Gameplay;
using AcDream.Runtime.Physics;
using AcDream.Runtime.Session;
using AcDream.Runtime.World;
using DatReaderWriter.Enums;

namespace AcDream.App.Tests.Streaming;

public sealed class LocalPlayerTeleportControllerTests
{
    [Fact]
    public void DeferredNetworkOwnedBindingReleasesExactlyAndAllowsRebind()
    {
        var deferred = new DeferredLocalPlayerTeleportNetworkSink();
        var first = new FakeNetworkSink();
        var second = new FakeNetworkSink();

        IDisposable firstBinding = deferred.BindOwned(first);
        Assert.Throws<InvalidOperationException>(() => deferred.BindOwned(second));

        firstBinding.Dispose();
        using IDisposable secondBinding = deferred.BindOwned(second);
        firstBinding.Dispose();
        deferred.OnTeleportStarted(9);

        Assert.Empty(first.Starts);
        Assert.Equal([9u], second.Starts);
    }

    [Fact]
    public void DestinationBeforeStart_IsReplayedOnceAfterPresentationActivates()
    {
        var harness = new Harness();
        RuntimeTeleportDestination destination = Position(
            cellId: 0x20210001u,
            teleportSequence: 7,
            x: 12f,
            y: 34f,
            z: 5f);

        harness.OfferDestination(
            destination,
            teleportTimestampAdvanced: true);
        Assert.Empty(harness.Streaming.Reservations);

        harness.Controller.OnTeleportStarted(7);

        Assert.Equal(1, harness.Input.EndCount);
        Assert.Equal(1, harness.Mode.EnterPortalCount);
        Assert.Equal(Matrix4x4.Identity, harness.Presentation.BeginProjection);
        Assert.Equal(
            (1L, 0x20210001u, harness.RevealWindow.FarRadius),
            Assert.Single(harness.Streaming.Reservations));
        Assert.True(harness.Reveal.Snapshot.IsActive);
        Assert.Equal(RuntimePortalKind.Portal, harness.Reveal.Snapshot.Kind);

        harness.OfferDestination(
            destination,
            teleportTimestampAdvanced: false);
        Assert.Single(harness.Streaming.Reservations);
    }

    [Fact]
    public void MissingPlayerController_KeepsStartAndDestinationPendingUntilProjectionExists()
    {
        var harness = new Harness();
        harness.Mode.Controller = null;

        harness.Controller.OnTeleportStarted(2);
        harness.OfferDestination(
            Position(0x20210001u, 2, 7f, 8f, 9f),
            teleportTimestampAdvanced: true);

        Assert.False(harness.Controller.IsActive);
        Assert.Equal(0u, harness.Controller.ActiveDestinationCell);
        Assert.Null(harness.Presentation.BeginProjection);

        harness.Mode.Controller = new PlayerMovementController(new PhysicsEngine());
        harness.Mode.Controller.SeedPlacementForTest(
            Vector3.Zero,
            0x20210001u,
            Vector3.Zero);
        harness.Controller.Tick(0.016f);

        Assert.True(harness.Controller.IsActive);
        Assert.Equal(0x20210001u, harness.Controller.ActiveDestinationCell);
        Assert.NotNull(harness.Presentation.BeginProjection);
        Assert.Single(harness.Streaming.Reservations);
    }

    [Fact]
    public void ControllerWithdrawnAfterActivation_KeepsAcceptedDestinationUntilItReturns()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(14);
        Assert.True(harness.Controller.IsActive);

        harness.Mode.Controller = null;
        harness.OfferDestination(
            Position(0x20210001u, 14, 7f, 8f, 9f),
            teleportTimestampAdvanced: true);

        Assert.Equal(0u, harness.Controller.ActiveDestinationCell);
        Assert.Empty(harness.Streaming.Reservations);

        harness.Mode.Controller = new PlayerMovementController(new PhysicsEngine());
        harness.Mode.Controller.SeedPlacementForTest(Vector3.Zero, 0x20210001u, Vector3.Zero);
        harness.Controller.Tick(0.016f);

        Assert.Equal(0x20210001u, harness.Controller.ActiveDestinationCell);
        Assert.Single(harness.Streaming.Reservations);
    }

    // C4 route 3 root-caused (closed): the earlier "bare-fixture InvalidData"
    // diagnosis was WRONG - these never reached
    // RuntimeSetPositionMoverPreparer.TryBuild at all. The real defect was in
    // LocalPlayerTeleportController.TryExecuteCanonicalPortalPlacement: it
    // re-read _transit.TryGetAcceptedTeleportDestination at Place time, but
    // RuntimeWorldTransitState.TryBeginPortalReveal (driven by AimDestination
    // via WorldRevealCoordinator.TryBeginPortal) atomically CONSUMES that one
    // accepted-destination slot the instant Aim claims the reveal generation
    // - so the Place-time re-read always found it empty and refused with
    // "cause=host-token-unavailable" before ever building a mover. Fixed by
    // caching the destination at Aim time (_pendingDestination), mirroring
    // the existing _pendingCell/_pendingRotation/_pendingRevealGeneration
    // pattern in the same method. Production fix, not a fixture workaround.
    [Fact]
    public void ControllerWithdrawnAfterAim_HoldsPresentationUntilModeRebuildsIt()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(15);
        harness.OfferDestination(
            Position(0x20210001u, 15, 7f, 8f, 9f),
            teleportTimestampAdvanced: true);
        harness.Mode.Controller = null;
        harness.Presentation.Enqueue(TeleportAnimEvent.Place);

        harness.Controller.Tick(0.016f);

        Assert.False(harness.Placement.Called);
        Assert.Empty(harness.Presentation.WorldReadyValues);

        harness.Mode.RebuildOnEnter = () =>
        {
            var controller = new PlayerMovementController(new PhysicsEngine());
            controller.SeedPlacementForTest(Vector3.Zero, 0x20210001u, Vector3.Zero);
            return controller;
        };
        harness.Controller.Tick(0.016f);

        Assert.NotNull(harness.Mode.Controller);
        Assert.True(harness.Placement.Called);
        // A6 review fix: assert the REAL canonical body resolved the
        // offered destination (7,8,9), not just that the acknowledge-only
        // suffix ran.
        Assert.Equal(
            new Vector3(7f, 8f, 9f),
            harness.Movement.Controller!.Position);
        Assert.Equal(0x20210001u, harness.Movement.Controller.CellId);
    }

    [Fact]
    public void SameLandblockDestination_DoesNotRecenterAndKeepsTranslatedPosition()
    {
        var harness = new Harness(centerX: 0x20, centerY: 0x21);
        // 0x20210123 is an INDOOR cell (low word 0x0123 >= 0x0100) within the
        // same landblock the constructor already committed. It still needs
        // its own synthetic CellStruct - PhysicsEngine.IsSpawnCellReady
        // requires DataCache.GetCellStruct to resolve for indoor cells, and
        // a bare AddLandblock never populates one.
        harness.AddSyntheticIndoorCell(0x20210123u);
        harness.Controller.OnTeleportStarted(3);
        harness.OfferDestination(
            Position(0x20210123u, 3, 20f, 30f, 4f),
            teleportTimestampAdvanced: true);
        harness.Presentation.EmitPlaceWhenReady = true;

        harness.Controller.Tick(0.016f);

        Assert.Empty(harness.Streaming.Recenters);
        // C4 route 3: the canonical Runtime arm - not this fake - resolves
        // and commits the destination; the acknowledge-only suffix carries
        // no position/cell to capture (D-T4). The observable fact left at
        // this layer is that the committed receipt reached the suffix.
        Assert.True(harness.Placement.Called);
        // A6/R4 review fix: assert the REAL canonical body resolved the
        // offered destination, not just that the suffix ran.
        Assert.Equal(
            new Vector3(20f, 30f, 4f),
            harness.Movement.Controller!.Position);
        Assert.Equal(0x20210123u, harness.Movement.Controller.CellId);
    }

    /// <summary>
    /// A1/R1 review fix (2026-08-05): the retail/architecture review's own
    /// required test — "refused arm -&gt; the anim stream does not reach
    /// RevealWorldViewport/FireLoginComplete with an unplaced body." Forces
    /// a genuine Runtime-level Contention refusal (a competing operation
    /// already owns the entity's placement token, same shape as the Runtime
    /// layer's <c>PortalContention_WhenTheEntityAlreadyOwnsAnActiveOperation</c>)
    /// and drives several ticks past where the OLD unconditional-march code
    /// would have already fired LoginComplete. The player must still be
    /// standing at the origin, in portal space, with the transit still
    /// active — never released into the world unplaced.
    /// </summary>
    [Fact]
    public void RefusedPlace_HoldsTheStreamAndConvergesOnlyAfterContentionClears()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(50);
        harness.OfferDestination(
            Position(0x20210001u, 50, 11f, 12f, 13f),
            teleportTimestampAdvanced: true);
        harness.Presentation.EmitPlaceWhenReady = true;
        Vector3 positionBefore = harness.Movement.Controller!.Position;

        // A competing operation already owns the entity's placement token -
        // the canonical Runtime Begin call inside TryAdvancePortalCommit
        // refuses with Contention, exactly like the Runtime-layer
        // PortalContention_WhenTheEntityAlreadyOwnsAnActiveOperation test.
        RuntimeEntityRecord record = harness.Lifetime.Entities
            .TryGetActive(0x50000001u, out RuntimeEntityRecord active)
            ? active
            : throw new InvalidOperationException("fixture entity missing");
        RuntimeEntityPlacementToken displaced = harness.Lifetime.Physics
            .SetPosition.TryBeginExclusiveAuthoredPlacement(
                record,
                record.PositionAuthorityVersion,
                RuntimeSetPositionOperationKind.LocalAuthoritative);
        Assert.True(displaced.IsValid);

        // Several ticks, well past where the pre-fix code would already
        // have reached PlayExitSound -> WorldFadeIn -> FireLoginComplete
        // and reset the transit (the tunnel's own retail timing is 2-5s;
        // this drives 3x that in 0.1s steps).
        for (int i = 0; i < 100; i++)
            harness.Controller.Tick(0.1f);

        Assert.False(harness.Placement.Called);
        Assert.Equal(positionBefore, harness.Movement.Controller.Position);
        Assert.True(harness.Controller.IsActive);
        Assert.False(harness.Reveal.Snapshot.Completed);
        Assert.Equal(0, harness.Session.LoginCompleteCount);

        // Release the competing operation - the SAME `dataReady` predicate
        // that already held the stream in Tunnel now lets the commit
        // succeed on the very next tick (D-T5 row 2's "next Tick
        // re-attempts the Place edge", made real without ever touching
        // TeleportAnimSequencer).
        RuntimePlacementCancellationReceipt cancellation = harness.Lifetime
            .Physics.SetPosition.ForgetExactPlacement(displaced);
        if (cancellation.IsValid)
            harness.Lifetime.Physics.SetPosition.PublishCancellation(cancellation);

        harness.Controller.Tick(0.1f);

        Assert.True(harness.Placement.Called);
        Assert.Equal(
            new Vector3(11f, 12f, 13f),
            harness.Movement.Controller.Position);
    }

    /// <summary>
    /// B1 review fix (2026-08-05): the required test #1 — a DeferredCell
    /// park killed by an ORDINARY merge-time <c>Forget</c> (not a
    /// collision-generation commit) must NOT be latched as "committed".
    /// The destination landblock is never committed
    /// (<c>CommitLandblockCollision</c> is deliberately not called), so the
    /// portal parks; an unrelated ordinary accepted Position for the same
    /// entity then Forgets the outstanding operation exactly like a normal
    /// 5-10 Hz ACE broadcast would — <c>RuntimeSetPositionState</c>'s own
    /// doc names this the EXPECTED way a far-destination park resolves
    /// without committing. Before the fix, <c>PendingCount</c> hitting 0
    /// made the host gate latch <c>_placementCommitted = true</c>, release
    /// the sequencer, and run the ENTIRE completion sequence
    /// (materialize/reveal/LoginComplete) against the unmoved body.
    /// </summary>
    [Fact]
    public void ParkedPlace_ForgottenByOrdinaryMergeDoesNotLatchAsCommitted()
    {
        var harness = new Harness();
        const uint destinationLandblock = 0x40410000u;
        harness.Controller.OnTeleportStarted(60);
        harness.OfferDestination(
            Position(destinationLandblock | 0x0001u, 60, 21f, 22f, 23f),
            teleportTimestampAdvanced: true);
        harness.Presentation.EmitPlaceWhenReady = true;

        // First tick: destinationLandblock's collision generation was never
        // committed, so the canonical arm parks DeferredCell.
        harness.Controller.Tick(0.016f);
        Assert.False(harness.Placement.Called);
        Assert.Equal(1, harness.AcceptedPositionDrive.PendingCount);

        // An ordinary, UNRELATED accepted Position for the same entity -
        // no new teleport, just a normal broadcast - Forgets the parked
        // operation the same way ACE's 5-10 Hz cadence would.
        harness.MergeOrdinaryPosition(
            new Vector3(48f, 49f, 50f), 0x20210001u, teleportSequence: 60);
        // Forget (inside TryApplyPosition) cancels the underlying
        // RuntimeSetPositionState operation immediately, but the drive's
        // OWN _pending cache only notices on its next Advance() pump - the
        // App host's real per-frame retry lease does this; the test drives
        // it explicitly.
        harness.AcceptedPositionDrive.Advance();
        Assert.Equal(0, harness.AcceptedPositionDrive.PendingCount);

        // Drive well past where the pre-fix inference would have latched
        // "committed" on the very next tick and then marched to
        // LoginComplete.
        for (int i = 0; i < 100; i++)
            harness.Controller.Tick(0.1f);

        // NOTE: the body's Position/CellId are NOT asserted unchanged here.
        // The DeferredCell park's dormant stage (RuntimeSetPositionState's
        // SubmitPreparedPlacementCore deferred-commit path,
        // StageDormantCellFrame) already writes the staged destination onto
        // the body's controller while body.InWorld stays false and the
        // canonical placement has not committed - the reader-visible
        // Position/CellId moving early is that benign staging mechanism, not
        // evidence the placement committed (see the analogous headless test
        // HeadlessPortalPrepareDestinationParksThenCommitsOnCollisionGenerationWake
        // for the same finding). The discriminators below - the presentation
        // suffix never running, no materialize/reveal/LoginComplete, and the
        // controller staying active in an incomplete transit - are what
        // actually distinguish "committed" from "parked-then-forgotten".
        Assert.False(harness.Placement.Called);
        Assert.Equal(0, harness.Reveal.PortalMaterializationCount);
        Assert.Equal(0, harness.Session.LoginCompleteCount);
        Assert.True(harness.Controller.IsActive);
        Assert.False(harness.Reveal.Snapshot.Completed);
    }

    [Fact]
    public void CrossLandblockDestination_RecentersBeforeItCanBecomeReady()
    {
        var harness = new Harness(centerX: 0x20, centerY: 0x21);
        harness.CommitLandblockCollision(0x30310000u);
        // 0x30310100 is an INDOOR cell (low word 0x0100 >= 0x0100); see the
        // AddSyntheticIndoorCell doc comment for why CommitLandblockCollision
        // alone (terrain-only) cannot make it spawn-ready.
        harness.AddSyntheticIndoorCell(0x30310100u);
        harness.Mode.Controller!.SeedPlacementForTest(
            Vector3.Zero,
            0x20210001u,
            Vector3.Zero);
        harness.Controller.OnTeleportStarted(4);
        harness.Streaming.RecenterPending = true;
        harness.OfferDestination(
            Position(0x30310100u, 4, -2f, 8f, 9f),
            teleportTimestampAdvanced: true);
        harness.Presentation.EmitPlaceWhenReady = true;

        harness.Controller.Tick(1f);

        Assert.Equal((0x30, 0x31, true), Assert.Single(harness.Streaming.Recenters));
        Assert.False(Assert.Single(harness.Presentation.WorldReadyValues));
        Assert.False(harness.Placement.Called);

        harness.Streaming.RecenterPending = false;
        harness.Controller.Tick(0.016f);
        Assert.True(harness.Placement.Called);
        // A6/R4 review fix: assert the REAL canonical body resolved the
        // cross-landblock destination, not just that the suffix ran.
        Assert.Equal(
            new Vector3(-2f, 8f, 9f),
            harness.Movement.Controller!.Position);
        Assert.Equal(0x30310100u, harness.Movement.Controller.CellId);
    }

    [Fact]
    public void ReadinessHold_NeverRevealsIncompleteWorldAndShowsWaitCueAfterFiveSeconds()
    {
        var harness = new Harness(worldReady: false);
        harness.Controller.OnTeleportStarted(5);
        harness.OfferDestination(
            Position(0x20210001u, 5, 1f, 2f, 3f),
            teleportTimestampAdvanced: true);
        harness.Presentation.EmitPlaceWhenReady = true;

        harness.Controller.Tick(4.9f);
        Assert.False(Assert.Single(harness.Presentation.WorldReadyValues));
        Assert.False(harness.Presentation.WaitCueValues[^1]);
        Assert.False(harness.Placement.Called);

        harness.Controller.Tick(0.1f);
        harness.Controller.Tick(30f);

        Assert.All(harness.Presentation.WorldReadyValues, Assert.False);
        Assert.True(harness.Presentation.WaitCueValues[^1]);
        Assert.False(harness.Placement.Called);
        Assert.True(harness.Reveal.WaitCueShown);
    }

    [Fact]
    public void Place_ReconcilesInsidePlacementBeforeRevealMaterialized()
    {
        var order = new List<string>();
        var harness = new Harness(order: order);
        harness.Controller.OnTeleportStarted(8);
        harness.OfferDestination(
            Position(0x20210001u, 8, 4f, 5f, 6f),
            teleportTimestampAdvanced: true);
        order.Clear();
        harness.Presentation.Enqueue(TeleportAnimEvent.Place);

        harness.Controller.Tick(0.016f);

        Assert.True(Index(order, "placement") < Index(order, "[world-reveal] event=materialized"));
        Assert.Equal(1, harness.Reveal.PortalMaterializationCount);
    }

    [Fact]
    public void Place_RechecksExactRuntimeLifetimeBeforeMutatingPresentation()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(81);
        harness.OfferDestination(
            Position(0x20210001u, 81, 4f, 5f, 6f),
            teleportTimestampAdvanced: true);
        long generation = harness.Reveal.Snapshot.Generation;
        Assert.True(harness.Transit.Cancel(generation));
        harness.Presentation.Enqueue(TeleportAnimEvent.Place);

        harness.Controller.Tick(0.016f);

        Assert.False(harness.Placement.Called);
        Assert.Equal(0, harness.Reveal.PortalMaterializationCount);
    }

    [Fact]
    public void LoginComplete_EntersWorldThenSendsThenCompletesAndResets()
    {
        var order = new List<string>();
        var harness = new Harness(order: order);
        harness.Controller.OnTeleportStarted(9);
        harness.OfferDestination(
            Position(0x20210001u, 9, 4f, 5f, 6f),
            teleportTimestampAdvanced: true);
        harness.Presentation.Enqueue(TeleportAnimEvent.Place);
        harness.Controller.Tick(0.016f);
        order.Clear();
        harness.Presentation.Enqueue(TeleportAnimEvent.FireLoginComplete);

        harness.Controller.Tick(0.016f);

        Assert.True(Index(order, "enter-world") < Index(order, "login-complete"));
        Assert.True(Index(order, "login-complete") < Index(order, "[world-reveal] event=complete"));
        Assert.True(Index(order, "[world-reveal] event=complete") < Index(order, "presentation-reset"));
        Assert.False(harness.Controller.IsActive);
        Assert.Equal(0u, harness.Controller.ActiveDestinationCell);
        Assert.Equal(1, harness.Session.LoginCompleteCount);
        Assert.True(harness.Reveal.Snapshot.Completed);
        Assert.False(harness.Reveal.Snapshot.Cancelled);
    }

    [Fact]
    public void ExitSound_ReleasesDestinationBeforeHidingTunnelButKeepsProtocolActive()
    {
        var order = new List<string>();
        var harness = new Harness(order: order);
        harness.Controller.OnTeleportStarted(91);
        harness.OfferDestination(
            Position(0x20210001u, 91, 4f, 5f, 6f),
            teleportTimestampAdvanced: true);
        harness.Streaming.ReservationEnds.Clear();
        harness.Presentation.Enqueue(TeleportAnimEvent.PlayExitSound);

        harness.Controller.Tick(0.016f);

        Assert.False(harness.Presentation.IsPortalViewportVisible);
        Assert.True(harness.Controller.IsActive);
        Assert.False(harness.Reveal.Snapshot.Completed);
        Assert.Single(harness.Streaming.ReservationEnds);
    }

    [Fact]
    public void NewerStart_ReplacesOldDestinationWithoutReusingIt()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(10);
        harness.OfferDestination(
            Position(0x20210001u, 10, 1f, 1f, 1f),
            teleportTimestampAdvanced: true);

        harness.Controller.OnTeleportStarted(11);
        harness.Controller.Tick(30f);

        Assert.False(harness.Placement.Called);
        Assert.Equal(0u, harness.Controller.ActiveDestinationCell);

        harness.OfferDestination(
            Position(0x20210001u, 11, 2f, 2f, 2f),
            teleportTimestampAdvanced: true);
        harness.Presentation.Enqueue(TeleportAnimEvent.Place);
        harness.Controller.Tick(0.016f);
        Assert.True(harness.Placement.Called);
        // A6 review fix: this is the specific test A6 named — the removed
        // assertion was the ONLY thing proving the SECOND destination
        // (2,2,2) placed and not the superseded first one (1,1,1).
        // Assert.True(Placement.Called) alone cannot distinguish them. X/Y
        // are exact; Z settles to the Harness's uniform terrain height (5)
        // because both candidate wire Z values (1 and 2) sit BELOW the
        // floor and the placement resolve's anti-penetration push-out is
        // instant (unlike gravity settling from ABOVE the floor, which
        // takes further physics ticks this test never runs) - X/Y alone
        // already discriminate (1,1) from (2,2) unambiguously.
        Assert.Equal(2f, harness.Movement.Controller!.Position.X);
        Assert.Equal(2f, harness.Movement.Controller.Position.Y);
        Assert.Equal(0x20210001u, harness.Movement.Controller.CellId);
    }

    [Fact]
    public void SessionReset_ClearsTransitAndLetsRecenterConvergeAcrossLaterFrames()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(12);
        harness.OfferDestination(
            Position(0x20210001u, 12, 1f, 2f, 3f),
            teleportTimestampAdvanced: true);

        harness.Controller.ResetSession();

        Assert.False(harness.Controller.IsActive);
        Assert.Equal(RuntimePortalSnapshot.Idle, harness.Reveal.Snapshot);
        Assert.True(harness.Streaming.LastResetWasSessionEnding);

        var failed = new Harness();
        failed.Streaming.ResetResult = false;
        failed.Controller.ResetSession();
        Assert.False(failed.Controller.IsActive);
        Assert.True(failed.Streaming.LastResetWasSessionEnding);
    }

    [Fact]
    public void StaleStart_DoesNotMutateInputModeOrPresentation()
    {
        var harness = new Harness();
        harness.Authority.IsFresh = false;

        harness.Controller.OnTeleportStarted(13);

        Assert.Equal(0, harness.Input.EndCount);
        Assert.Equal(0, harness.Mode.EnterPortalCount);
        Assert.Null(harness.Presentation.BeginProjection);
        Assert.False(harness.Controller.IsActive);
    }

    [Fact]
    public void ReentrantNewStartDuringPlacement_CannotBeCompletedByOldTail()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(20);
        harness.OfferDestination(
            Position(0x20210001u, 20, 1f, 2f, 3f),
            teleportTimestampAdvanced: true);
        harness.Streaming.ReservationEnds.Clear();
        harness.Placement.OnPlace = () => harness.Controller.OnTeleportStarted(21);
        harness.Presentation.Enqueue(TeleportAnimEvent.Place);

        harness.Controller.Tick(0.016f);

        Assert.True(harness.Controller.IsActive);
        Assert.Equal(0u, harness.Controller.ActiveDestinationCell);
        Assert.Equal(0, harness.Reveal.PortalMaterializationCount);
        Assert.Single(harness.Streaming.ReservationEnds);
    }

    [Fact]
    public void ReentrantNewStartDuringLoginComplete_PreservesReplacementLifetime()
    {
        var harness = new Harness();
        harness.Controller.OnTeleportStarted(30);
        harness.OfferDestination(
            Position(0x20210001u, 30, 1f, 2f, 3f),
            teleportTimestampAdvanced: true);
        harness.Session.OnSend = () => harness.Controller.OnTeleportStarted(31);
        harness.Presentation.Enqueue(TeleportAnimEvent.FireLoginComplete);

        harness.Controller.Tick(0.016f);

        Assert.True(harness.Controller.IsActive);
        Assert.Equal(0u, harness.Controller.ActiveDestinationCell);
        Assert.False(harness.Reveal.Snapshot.Completed);
        Assert.Equal(1, harness.Session.LoginCompleteCount);
    }

    [Fact]
    public void DisposeFailure_CanBeRetriedWithoutDoubleDisposingAfterSuccess()
    {
        var harness = new Harness();
        harness.Presentation.DisposeFailuresRemaining = 1;

        Assert.Throws<InvalidOperationException>(() => harness.Controller.Dispose());
        harness.Controller.Dispose();
        harness.Controller.Dispose();

        Assert.Equal(2, harness.Presentation.DisposeCount);
    }

    [Fact]
    public void ConcretePlacement_CommitsEntityControllerAndOneSpatialReconcile()
    {
        const uint guid = 0x50000001u;
        const uint cell = 0x20210001u;
        var world = new GpuWorldState();
        world.AddLandblock(new LoadedLandblock(
            0x2021FFFFu,
            new DatReaderWriter.DBObjs.LandBlock(),
            Array.Empty<WorldEntity>()));
        var runtime = LiveEntityRuntimeFixture.Create(world, new NullResources());
        runtime.RegisterLiveEntity(Spawn(guid, cell));
        WorldEntity entity = runtime.MaterializeLiveEntity(
            guid,
            cell,
            id => new WorldEntity
            {
                Id = id,
                ServerGuid = guid,
                SourceGfxObjOrSetupId = 0x02000001u,
                Position = Vector3.Zero,
                Rotation = Quaternion.Identity,
                MeshRefs = Array.Empty<MeshRef>(),
            })!;
        var identity = new LocalPlayerIdentityState { ServerGuid = guid };
        var controllerSlot = new RuntimeLocalPlayerMovementState
        {
            Controller = new PlayerMovementController(new PhysicsEngine()),
        };
        var position = new Vector3(12f, 24f, 6f);
        Quaternion rotation = Quaternion.CreateFromAxisAngle(Vector3.UnitZ, 0.5f);
        // C4 route 3: the canonical Runtime commit (RuntimeSetPositionState
        // .CommitCanonical, driven by RuntimeAcceptedPositionDriveController
        // .ReconcileAndAcknowledgePortal -> PlayerMovementController
        // .CommitCanonicalTeleportFrame in production) already resolves the
        // body/cell/orientation BEFORE this suffix runs. Reproduce that
        // pre-state directly rather than re-resolving it here - Place() no
        // longer resolves anything (D-T4).
        controllerSlot.Controller.SeedPlacementForTest(position, cell, position);
        controllerSlot.Controller.SetBodyOrientation(rotation);
        var cameras = new ChaseCameraInputState
        {
            Legacy = new ChaseCamera(),
            Retail = new RetailChaseCamera(),
        };
        var spatial = new FakeSpatialReconcile(() => new PlacementSnapshot(
            entity.Position,
            entity.ParentCellId ?? 0u,
            entity.Rotation,
            controllerSlot.Controller.Position,
            controllerSlot.Controller.CellId,
            controllerSlot.Controller.BodyOrientation));
        var placement = new LocalPlayerTeleportPlacement(
            runtime,
            identity,
            controllerSlot,
            new LocalPlayerPhysicsHostSlot(),
            cameras,
            spatial);

        placement.Place(rotation);

        Assert.Equal(entity.Position, controllerSlot.Controller.Position);
        Assert.Equal(entity.ParentCellId, controllerSlot.Controller.CellId);
        Assert.Equal(cell & 0xFFFF0000u, entity.ParentCellId & 0xFFFF0000u);
        Assert.Equal(rotation, entity.Rotation);
        Assert.Equal(rotation, controllerSlot.Controller.BodyOrientation);
        Assert.Equal(1, spatial.Count);
        Assert.Equal(entity.Position, spatial.Snapshot.EntityPosition);
        Assert.Equal(entity.ParentCellId, spatial.Snapshot.EntityCell);
        Assert.Equal(entity.Rotation, spatial.Snapshot.EntityRotation);
        Assert.Equal(
            controllerSlot.Controller.Position,
            spatial.Snapshot.ControllerPosition);
        Assert.Equal(
            controllerSlot.Controller.CellId,
            spatial.Snapshot.ControllerCell);
        Assert.Equal(
            controllerSlot.Controller.BodyOrientation,
            spatial.Snapshot.ControllerRotation);
    }

    [Fact]
    public void ConcretePlacement_CommitsDestinationSpatialBucketBeforeReconcile()
    {
        const uint guid = 0x50000001u;
        const uint sourceCell = 0x20210001u;
        const uint destinationCell = 0x30310001u;
        var world = new GpuWorldState();
        world.AddLandblock(new LoadedLandblock(
            sourceCell & 0xFFFF0000u | 0xFFFFu,
            new DatReaderWriter.DBObjs.LandBlock(),
            Array.Empty<WorldEntity>()));
        world.AddLandblock(new LoadedLandblock(
            destinationCell & 0xFFFF0000u | 0xFFFFu,
            new DatReaderWriter.DBObjs.LandBlock(),
            Array.Empty<WorldEntity>()));
        var runtime = LiveEntityRuntimeFixture.Create(world, new NullResources());
        runtime.RegisterLiveEntity(Spawn(guid, sourceCell));
        WorldEntity entity = runtime.MaterializeLiveEntity(
            guid,
            sourceCell,
            id => new WorldEntity
            {
                Id = id,
                ServerGuid = guid,
                SourceGfxObjOrSetupId = 0x02000001u,
                Position = Vector3.Zero,
                Rotation = Quaternion.Identity,
                MeshRefs = Array.Empty<MeshRef>(),
            })!;
        var identity = new LocalPlayerIdentityState { ServerGuid = guid };
        var controllerSlot = new RuntimeLocalPlayerMovementState
        {
            Controller = new PlayerMovementController(new PhysicsEngine()),
        };
        controllerSlot.Controller.SeedPlacementForTest(
            Vector3.Zero,
            sourceCell,
            Vector3.Zero);
        // C4 route 3: reproduce the canonical Runtime commit's pre-state
        // (body/cell already resolved) - Place() no longer resolves it.
        var destinationPosition = new Vector3(12f, 24f, 6f);
        controllerSlot.Controller.SeedPlacementForTest(
            destinationPosition,
            destinationCell,
            destinationPosition);
        var cameras = new ChaseCameraInputState
        {
            Legacy = new ChaseCamera(),
            Retail = new RetailChaseCamera(),
        };
        LiveEntityRecord? recordAtReconcile = null;
        var spatial = new FakeSpatialReconcile(() =>
        {
            Assert.True(runtime.TryGetRecord(guid, out recordAtReconcile));
            return new PlacementSnapshot(
                entity.Position,
                entity.ParentCellId ?? 0u,
                entity.Rotation,
                controllerSlot.Controller.Position,
                controllerSlot.Controller.CellId,
                controllerSlot.Controller.BodyOrientation);
        });
        var placement = new LocalPlayerTeleportPlacement(
            runtime,
            identity,
            controllerSlot,
            new LocalPlayerPhysicsHostSlot(),
            cameras,
            spatial);

        placement.Place(Quaternion.Identity);

        Assert.NotNull(recordAtReconcile);
        uint resolvedDestinationCell = controllerSlot.Controller.CellId;
        Assert.Equal(
            destinationCell & 0xFFFF0000u,
            resolvedDestinationCell & 0xFFFF0000u);
        Assert.Equal(resolvedDestinationCell, recordAtReconcile.FullCellId);
        Assert.Equal(
            destinationCell & 0xFFFF0000u | 0xFFFFu,
            recordAtReconcile.CanonicalLandblockId);
        Assert.True(recordAtReconcile.IsSpatiallyProjected);
        Assert.True(recordAtReconcile.IsSpatiallyVisible);
        Assert.Contains(entity, world.Entities);
        Assert.Equal(resolvedDestinationCell, entity.ParentCellId);
        Assert.Equal(1, spatial.Count);
    }

    private static int Index(IReadOnlyList<string> events, string prefix)
    {
        for (int i = 0; i < events.Count; i++)
        {
            if (events[i].StartsWith(prefix, StringComparison.Ordinal))
                return i;
        }

        return int.MaxValue;
    }

    private static RuntimeTeleportDestination Position(
        uint cellId,
        ushort teleportSequence,
        float x,
        float y,
        float z) => new(
            EntityGuid: 0x50000001u,
            InstanceSequence: 1,
            PositionSequence: 1,
            TeleportSequence: teleportSequence,
            ForcePositionSequence: 1,
            Position: new Position(
                cellId,
                new Vector3(x, y, z),
                Quaternion.Identity));

    private static WorldSession.EntitySpawn Spawn(uint guid, uint cell) => new WorldSession.EntitySpawn(
        Guid: guid,
        Position: new CreateObject.ServerPosition(
            cell,
            0f,
            0f,
            0f,
            1f,
            0f,
            0f,
            0f),
        SetupTableId: 0x02000001u,
        AnimPartChanges: [],
        TextureChanges: [],
        SubPalettes: [],
        BasePaletteId: null,
        ObjScale: null,
        Name: "player",
        ItemType: null,
        MotionState: null,
        MotionTableId: null).WithConsistentPhysics();

    private sealed class NullResources : ILiveEntityResourceLifecycle
    {
        public void Register(WorldEntity entity) { }
        public void Unregister(WorldEntity entity) { }
    }

    private sealed class FakeSpatialReconcile : ILiveSpatialReconcilePhase
    {
        private readonly Func<PlacementSnapshot> _capture;

        public FakeSpatialReconcile(Func<PlacementSnapshot> capture) =>
            _capture = capture;

        public int Count;
        public PlacementSnapshot Snapshot;

        public void Reconcile()
        {
            Snapshot = _capture();
            Count++;
        }
    }

    private readonly record struct PlacementSnapshot(
        Vector3 EntityPosition,
        uint EntityCell,
        Quaternion EntityRotation,
        Vector3 ControllerPosition,
        uint ControllerCell,
        Quaternion ControllerRotation);

    /// <summary>
    /// C4 route 3: the Place edge now drives a REAL
    /// <see cref="RuntimeAcceptedPositionDriveController"/> portal arm
    /// against a REAL (bare, session-less) local-player canonical record -
    /// the class this file's <c>LocalPlayerTeleportController</c> fake
    /// wiring cannot substitute (it is a sealed Runtime type, not an
    /// interface). <see cref="OfferDestination"/> also performs the SAME
    /// upstream merge production runs before ever offering a destination
    /// (<c>RuntimeEntityObjectLifetime.TryApplyPosition</c>, called by
    /// <c>LiveEntityNetworkUpdateController.OnPosition</c> before
    /// <c>OfferDestination</c>) so <c>BeginAcceptedPlacementCore</c>'s
    /// portal-vs-latest-cell gate sees the SAME destination the offer
    /// carries - exactly the production ordering, not a shortcut.
    /// </summary>
    private sealed class Harness
    {
        private const uint PlayerGuid = 0x50000001u;
        private const uint HomeCell = 0x20210001u;
        private ushort _mergePositionSequence = 1;

        public readonly FakeAuthority Authority = new();
        public readonly FakeInput Input = new();
        public readonly FakeMode Mode;
        public readonly FakeStreaming Streaming;
        public readonly FakePlacement Placement;
        public readonly FakeSession Session;
        public readonly FakePresentation Presentation;
        public readonly RuntimeWorldTransitState Transit;
        public readonly WorldRevealCoordinator Reveal;

        /// <summary>
        /// The live streaming window this harness's reveal barrier derives its
        /// outdoor radius from (#280). Assertions read this rather than a
        /// literal so the test cannot silently re-encode the value under test.
        /// </summary>
        public StreamingRevealWindow RevealWindow { get; set; } =
            new(NearRadius: 1, FarRadius: 1);
        public readonly LocalPlayerTeleportController Controller;
        public readonly RuntimeEntityObjectLifetime Lifetime;
        public readonly RuntimeAcceptedPositionDriveController AcceptedPositionDrive;
        /// <summary>
        /// A6/R4/A5 review fix (2026-08-05): exposed so tests can assert the
        /// REAL canonical body's resolved position/cell after a committed
        /// portal placement, not just <c>Placement.Called</c> — the property
        /// that let A6's superseded-teleport test lose its destination
        /// discriminator (which of two destinations actually placed).
        /// </summary>
        public readonly RuntimeLocalPlayerMovementState Movement;
        public IPreparedCollisionSource DiagnosticCollisionSource => new UnusedCollisionSource();

        public Harness(
            int centerX = 0x20,
            int centerY = 0x21,
            bool worldReady = true,
            List<string>? order = null)
        {
            order ??= new List<string>();
            Mode = new FakeMode(order);
            Streaming = new FakeStreaming(centerX, centerY, order);
            Placement = new FakePlacement(order);
            Session = new FakeSession(order);
            Presentation = new FakePresentation(order);
            Transit = new RuntimeWorldTransitState(order.Add);
            Reveal = new WorldRevealCoordinator(
                Transit,
                revealWindow: () => RevealWindow,
                isRenderNeighborhoodReady: (_, _, _) => worldReady,
                isSpawnCellReady: _ => worldReady,
                isTerrainNeighborhoodReady: (_, _) => worldReady,
                areCompositeTexturesReady: () => worldReady,
                prepareCompositeTextures: (_, _) => { },
                invalidateCompositeTextures: () => { },
                isSpawnClaimUnhydratable: _ => false,
                streaming: Streaming);

            var engine = new PhysicsEngine { DataCache = new PhysicsDataCache() };
            var heights = new byte[81];
            Array.Fill(heights, (byte)5f);
            var heightTable = new float[256];
            for (int i = 0; i < heightTable.Length; i++)
                heightTable[i] = i;
            engine.AddLandblock(
                HomeCell & 0xFFFF0000u,
                new TerrainSurface(heights, heightTable),
                Array.Empty<CellSurface>(),
                Array.Empty<PortalPlane>(),
                worldOffsetX: 0f,
                worldOffsetY: 0f);
            Lifetime = new RuntimeEntityObjectLifetime(engine);
            // The bare AddLandblock above only seeds the ENGINE's terrain -
            // TryPrepareAndSubmitAuthoredPlacement's DeferredCell park keys
            // off the SEPARATE collision-GENERATION ledger
            // (RuntimeSetPositionState.BeginCollisionGeneration/
            // CommitCollisionGeneration), which a bare AddLandblock never
            // touches. Commit it too, or every placement parks forever.
            Lifetime.Physics.SetPosition.BeginCollisionGeneration(
                HomeCell & 0xFFFF0000u, 1UL);
            Lifetime.Physics.SetPosition.CommitCollisionGeneration(
                HomeCell & 0xFFFF0000u, 1UL, ready: true);
            Lifetime.Physics.ObserveLocalWorldFrame(HomeCell, teleportAdvanced: false);
            Lifetime.BindEventContext(
                static () => new RuntimeGenerationToken(1UL),
                static () => 1UL);
            Movement = new RuntimeLocalPlayerMovementState();
            RuntimeLocalPlayerMovementState movement = Movement;
            var identity = new RuntimeLocalPlayerIdentityState
            {
                ServerGuid = PlayerGuid,
            };
            movement.AttachPhysicsPublication(new RuntimeLocalPlayerPhysicsPublicationState(
                Lifetime.Entities, Lifetime.Physics, movement, identity));
            Lifetime.LocalPlayerFirstEntry.BindPublication(movement.PhysicsPublication);
            Lifetime.BindLiveInputs(() => false, () => movement.Controller?.Position);
            var clock = new GameRuntimeClock();
            // C4 route 3 fixture note: RuntimeFirstEntryDriveController's
            // ctor subscribes to RuntimeEntityObjectLifetime
            // .BindInitialResidenceBeginNotification - it must exist BEFORE
            // RegisterEntityWithInitialResidence runs, or it misses the
            // notification and never learns the residence exists at all
            // (production constructs it once per host session, ahead of
            // every Create).
            var firstEntry = new RuntimeFirstEntryDriveController(
                Lifetime,
                clock,
                new UnusedCollisionSource(),
                () => PlayerMovementConstructionOptions.Fallback,
                static _ => new RuntimeLocalPlayerPhysicsActivationPreparation(
                    0.48f, 1.835f, RuntimeLocalPlayerShadowDisposition.ProvenShapeless));
            // Production's OnSpawned shape: RegisterEntityWithInitialResidence
            // then ApplyAcceptedSpawn (RuntimeLiveEntitySessionController.cs).
            RuntimeEntityRegistrationResult registration =
                Lifetime.RegisterEntityWithInitialResidence(
                    Spawn(PlayerGuid, HomeCell), isLocalPlayer: true);
            RuntimeEntityRecord canonical = registration.Canonical
                ?? throw new InvalidOperationException(
                    "fixture failed to register the local player");
            Lifetime.ApplyAcceptedSpawn(
                canonical,
                canonical.CreateIntegrationVersion,
                canonical.Snapshot,
                replaceGeneration: registration.Inbound.Disposition
                    is CreateObjectTimestampDisposition.NewGeneration);
            for (int attempt = 0; attempt < 8 && firstEntry.PendingCount != 0; attempt++)
            {
                firstEntry.DriveAll();
                DrainPlacementFifo();
            }
            Assert.Equal(0, firstEntry.PendingCount);
            Assert.True(
                Lifetime.Entities.TryGetActive(PlayerGuid, out RuntimeEntityRecord seeded),
                "fixture failed to register the local player");
            Assert.False(
                Lifetime.TryGetInitialCreateResidence(seeded, out _),
                "fixture left the local player's initial-create residence open");

            AcceptedPositionDrive = new RuntimeAcceptedPositionDriveController(
                Lifetime,
                clock,
                new UnusedCollisionSource(),
                new LocalPlayerOutboundController((_, _, _, _, _, _) => { }),
                () => new RuntimeGenerationToken(1UL),
                () => PlayerGuid,
                () => movement.Controller,
                () => false,
                () => null,
                () => movement);

            Controller = new LocalPlayerTeleportController(
                Authority,
                Input,
                Mode,
                Streaming,
                Transit,
                Reveal,
                Placement,
                Session,
                Presentation,
                AcceptedPositionDrive);
        }

        /// <summary>
        /// Merges the destination into the SAME canonical record the portal
        /// arm reads from, exactly like production's upstream merge, then
        /// offers it to the controller.
        /// </summary>
        public void OfferDestination(
            RuntimeTeleportDestination destination,
            bool teleportTimestampAdvanced)
        {
            _mergePositionSequence++;
            var update = new WorldSession.EntityPositionUpdate(
                destination.EntityGuid,
                new CreateObject.ServerPosition(
                    destination.Position.ObjCellId,
                    destination.Position.Frame.Origin.X,
                    destination.Position.Frame.Origin.Y,
                    destination.Position.Frame.Origin.Z,
                    destination.Position.Frame.Orientation.W,
                    destination.Position.Frame.Orientation.X,
                    destination.Position.Frame.Orientation.Y,
                    destination.Position.Frame.Orientation.Z),
                Velocity: null,
                PlacementId: null,
                IsGrounded: true,
                InstanceSequence: 1,
                PositionSequence: _mergePositionSequence,
                TeleportSequence: destination.TeleportSequence,
                ForcePositionSequence: 0);
            Lifetime.TryApplyPosition(
                update,
                isLocalPlayer: true,
                forcePositionRotation: Quaternion.Identity,
                currentLocalVelocity: Vector3.Zero,
                acknowledgeProjection: null,
                out _,
                out _,
                out _);
            Controller.OfferDestination(destination, teleportTimestampAdvanced);
        }

        /// <summary>
        /// B1 review fix test support (2026-08-05): merges an ORDINARY
        /// accepted Position for the local player — no portal offer, no
        /// transit involvement — the same
        /// <c>RuntimeEntityObjectLifetime.TryApplyPosition</c> call every
        /// real inbound ACE broadcast makes. Its doc names this the
        /// mechanism that <c>Forget</c>s any outstanding SetPosition
        /// operation for the entity, including a DeferredCell park — "the
        /// exact far-destination case the park exists to serve".
        /// </summary>
        public void MergeOrdinaryPosition(
            Vector3 position, uint cellId, ushort teleportSequence)
        {
            _mergePositionSequence++;
            var update = new WorldSession.EntityPositionUpdate(
                PlayerGuid,
                new CreateObject.ServerPosition(
                    cellId,
                    position.X,
                    position.Y,
                    position.Z,
                    1f, 0f, 0f, 0f),
                Velocity: null,
                PlacementId: null,
                IsGrounded: true,
                InstanceSequence: 1,
                PositionSequence: _mergePositionSequence,
                // The SAME already-accepted teleport sequence, not a
                // regression - an ordinary ACE broadcast Apply during an
                // active teleport still carries it unchanged; only a NEW
                // portal advances it.
                TeleportSequence: teleportSequence,
                ForcePositionSequence: 0);
            Lifetime.TryApplyPosition(
                update,
                isLocalPlayer: true,
                forcePositionRotation: Quaternion.Identity,
                currentLocalVelocity: Vector3.Zero,
                acknowledgeProjection: null,
                out _,
                out _,
                out _);
        }

        /// <summary>
        /// Commits a SECOND landblock's collision so a cross-landblock
        /// portal destination can resolve <c>Committed</c> instead of
        /// parking <c>DeferredCell</c> - the constructor's own home
        /// landblock is the only one committed by default.
        /// </summary>
        public void CommitLandblockCollision(uint landblockId)
        {
            var heights = new byte[81];
            Array.Fill(heights, (byte)5f);
            var heightTable = new float[256];
            for (int i = 0; i < heightTable.Length; i++)
                heightTable[i] = i;
            Lifetime.Physics.SetPosition.BeginCollisionGeneration(landblockId, 1UL);
            Lifetime.Physics.Engine.AddLandblock(
                landblockId,
                new TerrainSurface(heights, heightTable),
                Array.Empty<CellSurface>(),
                Array.Empty<PortalPlane>(),
                worldOffsetX: 0f,
                worldOffsetY: 0f);
            Lifetime.Physics.SetPosition.CommitCollisionGeneration(
                landblockId, 1UL, ready: true);
        }

        /// <summary>
        /// Registers a minimal synthetic indoor cell so a portal destination
        /// whose low word is &gt;= 0x0100 can resolve <c>Committed</c> on its
        /// FIRST placement attempt instead of parking <c>DeferredCell</c>
        /// forever. <see cref="PhysicsEngine.IsSpawnCellReady"/> treats every
        /// outdoor cell (low word &lt; 0x0100) as trivially ready, but an
        /// indoor cell requires <c>DataCache.GetCellStruct</c> to resolve a
        /// real entry - the bare fixture's <c>AddLandblock</c> calls only
        /// ever pass an empty <c>CellSurface</c> list, so without this an
        /// indoor destination cell is permanently un-spawnable regardless of
        /// how many times collision generation is committed for its
        /// landblock. Mirrors
        /// <c>RuntimeSetPositionStateTests.AddSyntheticCell</c>.
        /// </summary>
        public void AddSyntheticIndoorCell(uint envCellId)
        {
            Lifetime.Physics.DataCache.RegisterCellStructForTest(
                envCellId,
                new CellPhysics
                {
                    WorldTransform = Matrix4x4.Identity,
                    InverseWorldTransform = Matrix4x4.Identity,
                    Resolved = new Dictionary<ushort, ResolvedPolygon>(),
                    Portals = [new PortalInfo(0, 0, 0)],
                    CellBSP = new DatReaderWriter.Types.CellBSPTree
                    {
                        Root = new DatReaderWriter.Types.CellBSPNode
                        {
                            Type = BSPNodeType.Leaf,
                        },
                    },
                });
            Lifetime.Physics.DataCache.CellGraph.Add(
                new AcDream.Core.World.Cells.EnvCell(
                    envCellId,
                    Matrix4x4.Identity,
                    Matrix4x4.Identity,
                    Vector3.Zero,
                    Vector3.One,
                    Array.Empty<AcDream.Core.World.Cells.CellPortal>(),
                    Array.Empty<uint>(),
                    seenOutside: false,
                    containmentBsp: null));
        }

        public void DrainPlacementFifo()
        {
            while (Lifetime.Physics.SetPosition.TryPeekProjection(
                    out RuntimePlacementProjectionSnapshot head))
            {
                if (!Lifetime.Physics.SetPosition.AcknowledgeProjection(head.Token))
                    break;
            }
        }

        private static WorldSession.EntitySpawn Spawn(uint guid, uint cell)
        {
            var position = new CreateObject.ServerPosition(
                cell, 10f, 10f, 5f, 1f, 0f, 0f, 0f);
            var timestamps = new PhysicsTimestamps(
                Position: 1,
                Movement: 1,
                State: 1,
                Vector: 1,
                Teleport: 0,
                ServerControlledMove: 1,
                ForcePosition: 0,
                ObjDesc: 1,
                Instance: 1);
            var physics = new PhysicsSpawnData(
                RawState: (uint)PhysicsStateFlags.ReportCollisions,
                Position: position,
                Movement: null,
                AnimationFrame: null,
                SetupTableId: null,
                MotionTableId: null,
                SoundTableId: null,
                PhysicsScriptTableId: null,
                Parent: null,
                Children: null,
                Scale: null,
                Friction: null,
                Elasticity: null,
                Translucency: null,
                Velocity: null,
                Acceleration: null,
                AngularVelocity: null,
                DefaultScriptType: null,
                DefaultScriptIntensity: null,
                Timestamps: timestamps);
            return new WorldSession.EntitySpawn(
                guid,
                position,
                null,
                [],
                [],
                [],
                null,
                null,
                "teleport-controller-fixture",
                null,
                null,
                null,
                PhysicsState: physics.RawState,
                InstanceSequence: 1,
                MovementSequence: 1,
                ServerControlSequence: 1,
                PositionSequence: 1,
                Physics: physics);
        }

        private sealed class UnusedCollisionSource : IPreparedCollisionSource
        {
            public PreparedAssetPresence ProbeCollision(
                AcDream.Content.Pak.PakAssetType type, uint sourceFileId) =>
                PreparedAssetPresence.Available;

            public PreparedCollisionReadResult<FlatSetupCollision> ReadSetupCollision(
                uint sourceFileId, CancellationToken cancellationToken = default) =>
                PreparedCollisionReadResult<FlatSetupCollision>.Missing;

            public PreparedCollisionReadResult<FlatGfxObjCollisionAsset> ReadGfxObjCollision(
                uint sourceFileId, CancellationToken cancellationToken = default) =>
                throw new NotSupportedException();

            public PreparedCollisionReadResult<FlatCellStructureCollisionAsset>
                ReadCellStructureCollision(
                    uint sourceFileId, CancellationToken cancellationToken = default) =>
                throw new NotSupportedException();

            public PreparedCollisionReadResult<FlatEnvCellTopology> ReadEnvCellTopology(
                uint sourceFileId, CancellationToken cancellationToken = default) =>
                throw new NotSupportedException();

            public PreparedCollisionSourceStats CollisionStats => default;

            public void Dispose()
            {
            }
        }
    }

    private sealed class FakeAuthority : ILocalPlayerTeleportAuthority
    {
        public bool IsFresh = true;
        public bool IsFreshStart(ushort sequence) => IsFresh;
    }

    private sealed class FakeInput : ILocalPlayerTeleportInputLifetime
    {
        public int EndCount;
        public void EndMouseLook() => EndCount++;
    }

    private sealed class FakeMode : ILocalPlayerTeleportModeOperations
    {
        private readonly List<string> _order;

        public FakeMode(List<string> order)
        {
            _order = order;
            Controller = new PlayerMovementController(new PhysicsEngine());
            Controller.SeedPlacementForTest(Vector3.Zero, 0x20210001u, Vector3.Zero);
        }

        public PlayerMovementController? Controller { get; set; }
        public Matrix4x4 Projection => Matrix4x4.Identity;
        public int EnterPortalCount;
        public Func<PlayerMovementController?>? RebuildOnEnter;

        public bool TryEnterPortalSpace()
        {
            EnterPortalCount++;
            Controller ??= RebuildOnEnter?.Invoke();
            if (Controller is null)
                return false;
            Controller.State = PlayerState.PortalSpace;
            return true;
        }

        public void EnterWorld()
        {
            _order.Add("enter-world");
            if (Controller is { } controller)
                controller.State = PlayerState.InWorld;
        }
    }

    private sealed class FakeStreaming
        : ILocalPlayerTeleportStreamingOperations,
          IWorldRevealStreamingScheduler
    {
        private readonly List<string> _order;

        public FakeStreaming(int centerX, int centerY, List<string> order)
        {
            CenterX = centerX;
            CenterY = centerY;
            _order = order;
        }

        public int CenterX { get; }
        public int CenterY { get; }
        public bool IsRecenterPending => RecenterPending;
        public bool RecenterPending;
        public bool ResetResult = true;
        public bool LastResetWasSessionEnding;
        public readonly List<(int X, int Y, bool Sealed)> Recenters = new();
        public readonly List<(long Generation, uint Cell, int Radius)>
            Reservations = new();
        public readonly List<long> ReservationEnds = new();

        public bool BeginRecenter(int x, int y, bool isSealedDungeon)
        {
            Recenters.Add((x, y, isSealedDungeon));
            return !RecenterPending;
        }

        public bool ResetRecenter(bool sessionEnding)
        {
            LastResetWasSessionEnding = sessionEnding;
            return ResetResult;
        }

        public bool IsSealedDungeon(uint cellId) =>
            (cellId & 0xFFFFu) >= 0x0100u;

        public void BeginDestinationReservation(
            long revealGeneration,
            uint destinationCell,
            int requiredRenderRadius) =>
            Reservations.Add(
                (revealGeneration, destinationCell, requiredRenderRadius));

        public void EndDestinationReservation(long revealGeneration)
        {
            ReservationEnds.Add(revealGeneration);
            _order.Add("reservation-end");
        }
    }

    /// <summary>
    /// C4 route 3: acknowledge-only per D-T4 - no position/cell arguments
    /// (the canonical Runtime commit already resolved them; this suffix only
    /// runs on a COMMITTED receipt, never authors one). <see cref="Called"/>
    /// stands in for the deleted <c>Position</c>/<c>CellId</c> capture: it is
    /// the fact that matters now (whether the arm committed and the Place
    /// edge acknowledged it), never a value this fake could plausibly
    /// mis-record.
    /// </summary>
    private sealed class FakePlacement : ILocalPlayerTeleportPlacement
    {
        private readonly List<string> _order;

        public FakePlacement(List<string> order) => _order = order;

        public bool Called;
        public Quaternion Rotation;
        public Action? OnPlace;

        public void Place(Quaternion rotation)
        {
            _order.Add("placement");
            Called = true;
            Rotation = rotation;
            OnPlace?.Invoke();
        }
    }

    private sealed class FakeSession : ILocalPlayerTeleportSession
    {
        private readonly List<string> _order;

        public FakeSession(List<string> order) => _order = order;

        public int LoginCompleteCount;
        public Action? OnSend;

        public void SendLoginComplete()
        {
            _order.Add("login-complete");
            LoginCompleteCount++;
            OnSend?.Invoke();
        }
    }

    private sealed class FakeNetworkSink : ILocalPlayerTeleportNetworkSink
    {
        public List<uint> Starts { get; } = [];
        public void OnTeleportStarted(uint sequence) => Starts.Add(sequence);
        public void OfferDestination(
            RuntimeTeleportDestination destination,
            bool teleportTimestampAdvanced)
        {
        }
        public void ResetSession()
        {
        }
        public void ResetGenerationPresentation()
        {
        }
    }

    private sealed class FakePresentation : ILocalPlayerTeleportPresentation
    {
        private readonly List<string> _order;
        private readonly Queue<IReadOnlyList<TeleportAnimEvent>> _events = new();

        public FakePresentation(List<string> order) => _order = order;

        public bool IsPortalViewportVisible { get; private set; }
        public int CurrentTunnelFrame => 72;
        public Matrix4x4? BeginProjection;
        public bool EmitPlaceWhenReady;
        public readonly List<bool> WorldReadyValues = new();
        public readonly List<bool> WaitCueValues = new();
        public int DisposeFailuresRemaining;
        public int DisposeCount;

        public void Enqueue(params TeleportAnimEvent[] events) => _events.Enqueue(events);

        public void Begin(Matrix4x4 projection)
        {
            BeginProjection = projection;
            _order.Add("presentation-begin");
        }

        public (TeleportAnimSnapshot Snapshot, IReadOnlyList<TeleportAnimEvent> Events)
            Tick(float deltaSeconds, bool worldReady)
        {
            WorldReadyValues.Add(worldReady);
            if (_events.Count > 0)
                return (default, _events.Dequeue());
            if (EmitPlaceWhenReady && worldReady)
            {
                EmitPlaceWhenReady = false;
                return (default, new[] { TeleportAnimEvent.Place });
            }

            return (default, Array.Empty<TeleportAnimEvent>());
        }

        public void TickTunnel(float deltaSeconds) => _order.Add("tunnel-tick");
        public void EnterTunnel() => IsPortalViewportVisible = true;
        public void ExitTunnel() => IsPortalViewportVisible = false;
        public void SetWaitCue(bool visible) => WaitCueValues.Add(visible);

        public void Reset()
        {
            _order.Add("presentation-reset");
            IsPortalViewportVisible = false;
            BeginProjection = null;
            _events.Clear();
        }

        public Matrix4x4 ApplyViewPlane(Matrix4x4 projection) => projection;
        public ICamera ApplyViewPlane(ICamera camera) => camera;
        public void DrawPortalViewport(int width, int height, Matrix4x4 projection) { }
        public void Dispose()
        {
            DisposeCount++;
            if (DisposeFailuresRemaining-- > 0)
                throw new InvalidOperationException("injected disposal failure");
        }
    }
}