BuckleSystem.cs

using Content.Client.Rotation;
using Content.Shared.Buckle;
using Content.Shared.Buckle.Components;
using Content.Shared.Rotation;
using Robust.Client.GameObjects;
using Robust.Shared.GameStates;

namespace Content.Client.Buckle;

internal sealed class BuckleSystem : SharedBuckleSystem
{
    [Dependency] private readonly RotationVisualizerSystem _rotationVisualizerSystem = default!;

    public override void Initialize()
    {
        base.Initialize();

        SubscribeLocalEvent<BuckleComponent, AppearanceChangeEvent>(OnAppearanceChange);
        SubscribeLocalEvent<StrapComponent, MoveEvent>(OnStrapMoveEvent);
    }

    private void OnStrapMoveEvent(EntityUid uid, StrapComponent component, ref MoveEvent args)
    {
        // I'm moving this to the client-side system, but for the sake of posterity let's keep this comment:
        // > This is mega cursed. Please somebody save me from Mr Buckle's wild ride

        // The nice thing is its still true, this is quite cursed, though maybe not omega cursed anymore.
        // This code is garbage, it doesn't work with rotated viewports. I need to finally get around to reworking
        // sprite rendering for entity layers & direction dependent sorting.

        if (args.NewRotation == args.OldRotation)
            return;

        if (!TryComp<SpriteComponent>(uid, out var strapSprite))
            return;

        var isNorth = Transform(uid).LocalRotation.GetCardinalDir() == Direction.North;
        foreach (var buckledEntity in component.BuckledEntities)
        {
            if (!TryComp<BuckleComponent>(buckledEntity, out var buckle))
                continue;

            if (!TryComp<SpriteComponent>(buckledEntity, out var buckledSprite))
                continue;

            if (isNorth)
            {
                buckle.OriginalDrawDepth ??= buckledSprite.DrawDepth;
                buckledSprite.DrawDepth = strapSprite.DrawDepth - 1;
            }
            else if (buckle.OriginalDrawDepth.HasValue)
            {
                buckledSprite.DrawDepth = buckle.OriginalDrawDepth.Value;
                buckle.OriginalDrawDepth = null;
            }
        }
    }

    private void OnAppearanceChange(EntityUid uid, BuckleComponent component, ref AppearanceChangeEvent args)
    {
        if (!TryComp<RotationVisualsComponent>(uid, out var rotVisuals))
            return;

        if (!Appearance.TryGetData<bool>(uid, BuckleVisuals.Buckled, out var buckled, args.Component) ||
            !buckled ||
            args.Sprite == null)
        {
            // _CorvaxNext: Laying System
            //_rotationVisualizerSystem.SetHorizontalAngle((uid, rotVisuals), rotVisuals.DefaultRotation);
            return;
        }

        // Animate strapping yourself to something at a given angle
        // TODO: Dump this when buckle is better
        _rotationVisualizerSystem.AnimateSpriteRotation(uid, args.Sprite, rotVisuals.HorizontalRotation, 0.125f);
    }
}