acdream/src/AcDream.App/Input/LocalPlayerProjectionController.cs

using AcDream.Core.World;

namespace AcDream.App.Input;

/// <summary>
/// Projects the canonical local physics body into world rendering and spatial
/// buckets without advancing it.
/// </summary>
public sealed class LocalPlayerProjectionController
{
    private readonly Func<WorldEntity?> _resolveEntity;
    private readonly Func<int> _liveCenterX;
    private readonly Func<int> _liveCenterY;
    private readonly Action<WorldEntity, uint> _syncShadow;
    private readonly Action<uint, uint> _rebucket;
    private readonly Func<WorldEntity, bool> _isCurrentVisibleProjection;
    private readonly Action<WorldEntity> _suspendShadow;

    public LocalPlayerProjectionController(
        Func<WorldEntity?> resolveEntity,
        Func<int> liveCenterX,
        Func<int> liveCenterY,
        Action<WorldEntity, uint> syncShadow,
        Action<uint, uint> rebucket,
        Func<WorldEntity, bool> isCurrentVisibleProjection,
        Action<WorldEntity> suspendShadow)
    {
        _resolveEntity = resolveEntity ?? throw new ArgumentNullException(nameof(resolveEntity));
        _liveCenterX = liveCenterX ?? throw new ArgumentNullException(nameof(liveCenterX));
        _liveCenterY = liveCenterY ?? throw new ArgumentNullException(nameof(liveCenterY));
        _syncShadow = syncShadow ?? throw new ArgumentNullException(nameof(syncShadow));
        _rebucket = rebucket ?? throw new ArgumentNullException(nameof(rebucket));
        _isCurrentVisibleProjection = isCurrentVisibleProjection
            ?? throw new ArgumentNullException(nameof(isCurrentVisibleProjection));
        _suspendShadow = suspendShadow
            ?? throw new ArgumentNullException(nameof(suspendShadow));
    }

    public void Project(
        PlayerMovementController controller,
        MovementResult movement,
        bool hidden)
    {
        WorldEntity? entity = _resolveEntity();
        if (entity is null)
            return;

        entity.SetPosition(movement.RenderPosition);
        entity.ParentCellId = movement.CellId;
        // Retail's root is a complete Frame. Project the authoritative body
        // quaternion directly so pitch/roll from a server correction or DAT
        // root frame cannot be flattened by the presentation layer.
        entity.Rotation = controller.BodyOrientation;

        uint currentLandblock;
        if (movement.CellId != 0 && (movement.CellId & 0xFFFFu) >= 0x0100u)
        {
            // Indoor positions belong to the cell's landblock. Dungeon frame
            // origins can be negative, so render XYZ is not a landblock key.
            currentLandblock = (movement.CellId & 0xFFFF0000u) | 0xFFFFu;
        }
        else
        {
            System.Numerics.Vector3 position = controller.Position;
            int landblockX = _liveCenterX() + (int)Math.Floor(position.X / 192f);
            int landblockY = _liveCenterY() + (int)Math.Floor(position.Y / 192f);
            currentLandblock = (uint)((landblockX << 24) | (landblockY << 16) | 0xFFFF);
        }

        // The teleport owner alone projects the destination while the local
        // controller deliberately retains its frozen source cell.
        if (controller.State == PlayerState.PortalSpace)
            return;

        // SetPositionInternal commits the complete root before changing cell
        // membership, then replaces collision rows only while the object still
        // owns a loaded cell. Rebucket is a synchronous callback boundary: it
        // can move this incarnation to pending or replace the GUID entirely.
        _rebucket(entity.ServerGuid, currentLandblock);
        if (hidden
            || movement.CellId == 0
            || !_isCurrentVisibleProjection(entity))
        {
            _suspendShadow(entity);
            return;
        }

        _syncShadow(entity, movement.CellId);
    }
}