crystall-punk-14/Content.Shared/Buckle/SharedBuckleSystem.cs

using Content.Shared.Buckle.Components;
using Content.Shared.Interaction.Events;
using Content.Shared.Movement;
using Content.Shared.Movement.Events;
using Content.Shared.Standing;
using Content.Shared.Throwing;
using Robust.Shared.Physics.Dynamics;
using Robust.Shared.Physics.Events;
using Robust.Shared.Timing;

namespace Content.Shared.Buckle
{
    public abstract class SharedBuckleSystem : EntitySystem
    {
        [Dependency] protected readonly IGameTiming GameTiming = default!;

        public override void Initialize()
        {
            base.Initialize();
            SubscribeLocalEvent<SharedStrapComponent, MoveEvent>(OnStrapRotate);

            SubscribeLocalEvent<SharedBuckleComponent, PreventCollideEvent>(PreventCollision);
            SubscribeLocalEvent<SharedBuckleComponent, DownAttemptEvent>(HandleDown);
            SubscribeLocalEvent<SharedBuckleComponent, StandAttemptEvent>(HandleStand);
            SubscribeLocalEvent<SharedBuckleComponent, ThrowPushbackAttemptEvent>(HandleThrowPushback);
            SubscribeLocalEvent<SharedBuckleComponent, UpdateCanMoveEvent>(HandleMove);
            SubscribeLocalEvent<SharedBuckleComponent, ChangeDirectionAttemptEvent>(OnBuckleChangeDirectionAttempt);
        }

        private void OnStrapRotate(EntityUid uid, SharedStrapComponent component, ref MoveEvent args)
        {
            // TODO: This looks dirty af.
            // On rotation of a strap, reattach all buckled entities.
            // This fixes buckle offsets and draw depths.
            // This is mega cursed. Please somebody save me from Mr Buckle's wild ride.
            // Oh god I'm back here again. Send help.

            // Consider a chair that has a player strapped to it. Then the client receives a new server state, showing
            // that the player entity has moved elsewhere, and the chair has rotated. If the client applies the player
            // state, then the chairs transform comp state, and then the buckle state. The transform state will
            // forcefully teleport the player back to the chair (client-side only). This causes even more issues if the
            // chair was teleporting in from nullspace after having left PVS.
            //
            // One option is to just never trigger re-buckles during state application.
            // another is to.. just not do this? Like wtf is this code. But I CBF with buckle atm.

            if (GameTiming.ApplyingState || args.NewRotation == args.OldRotation)
                return;

            foreach (var buckledEntity in component.BuckledEntities)
            {
                if (!EntityManager.TryGetComponent(buckledEntity, out SharedBuckleComponent? buckled))
                {
                    continue;
                }

                if (!buckled.Buckled || buckled.LastEntityBuckledTo != uid)
                {
                    Logger.Error($"A moving strap entity {ToPrettyString(uid)} attempted to re-parent an entity that does not 'belong' to it {ToPrettyString(buckledEntity)}");
                    continue;
                }

                buckled.ReAttach(component);
                Dirty(buckled);
            }
        }

        public bool IsBuckled(EntityUid uid, SharedBuckleComponent? component = null)
        {
            return Resolve(uid, ref component, false) && component.Buckled;
        }

        private void OnBuckleChangeDirectionAttempt(EntityUid uid, SharedBuckleComponent component, ChangeDirectionAttemptEvent args)
        {
            if (component.Buckled)
                args.Cancel();
        }

        private void HandleMove(EntityUid uid, SharedBuckleComponent component, UpdateCanMoveEvent args)
        {
            if (component.LifeStage > ComponentLifeStage.Running)
                return;

            if (component.Buckled)
                args.Cancel();
        }

        private void HandleStand(EntityUid uid, SharedBuckleComponent component, StandAttemptEvent args)
        {
            if (component.Buckled)
            {
                args.Cancel();
            }
        }

        private void HandleDown(EntityUid uid, SharedBuckleComponent component, DownAttemptEvent args)
        {
            if (component.Buckled)
            {
                args.Cancel();
            }
        }

        private void HandleThrowPushback(EntityUid uid, SharedBuckleComponent component, ThrowPushbackAttemptEvent args)
        {
            if (!component.Buckled) return;
            args.Cancel();
        }

        private void PreventCollision(EntityUid uid, SharedBuckleComponent component, ref PreventCollideEvent args)
        {
            if (args.BodyB.Owner != component.LastEntityBuckledTo) return;

            if (component.Buckled || component.DontCollide)
            {
                args.Cancelled = true;
            }
        }
    }
}