Gun refactor (#8301)

Co-authored-by: Kara <lunarautomaton6@gmail.com>
Co-authored-by: T-Stalker <le0nel_1van@hotmail.com>
Co-authored-by: T-Stalker <43253663+DogZeroX@users.noreply.github.com>
Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>
Co-authored-by: metalgearsloth <metalgearsloth@gmail.com>

Content.Client/Weapons/Ranged/Systems/TetherGunSystem.cs

@@ -0,0 +1,143 @@
+using Content.Client.Clickable;
+using Content.Shared.Weapons.Ranged.Systems;
+using Robust.Client.GameObjects;
+using Robust.Client.Graphics;
+using Robust.Client.Input;
+using Robust.Shared.Input;
+using Robust.Shared.Map;
+using Robust.Shared.Timing;
+
+namespace Content.Client.Weapons.Ranged.Systems;
+
+public sealed class TetherGunSystem : SharedTetherGunSystem
+{
+    [Dependency] private readonly IEyeManager _eyeManager = default!;
+    [Dependency] private readonly IGameTiming _gameTiming = default!;
+    [Dependency] private readonly IInputManager _inputManager = default!;
+    [Dependency] private readonly EntityLookupSystem _lookup = default!;
+    [Dependency] private readonly InputSystem _inputSystem = default!;
+
+    public bool Enabled { get; set; }
+
+    /// <summary>
+    /// The entity being dragged around.
+    /// </summary>
+    private EntityUid? _dragging;
+    private EntityUid? _tether;
+
+    private MapCoordinates? _lastMousePosition;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeNetworkEvent<PredictTetherEvent>(OnPredictTether);
+    }
+
+    private void OnPredictTether(PredictTetherEvent ev)
+    {
+        if (_dragging != ev.Entity) return;
+
+        _tether = ev.Entity;
+    }
+
+    public override void FrameUpdate(float frameTime)
+    {
+        base.FrameUpdate(frameTime);
+        if (!TryComp<PhysicsComponent>(_dragging, out var body)) return;
+
+        body.Predict = true;
+
+        if (TryComp<PhysicsComponent>(_tether, out var tetherBody))
+        {
+            tetherBody.Predict = true;
+        }
+    }
+
+    public override void Update(float frameTime)
+    {
+        base.Update(frameTime);
+
+        if (!Enabled || !_gameTiming.IsFirstTimePredicted) return;
+
+        var state = _inputSystem.CmdStates.GetState(EngineKeyFunctions.Use);
+
+        if (state != BoundKeyState.Down)
+        {
+            StopDragging();
+            return;
+        }
+
+        var mouseScreenPos = _inputManager.MouseScreenPosition;
+        var mousePos = _eyeManager.ScreenToMap(mouseScreenPos);
+
+        if (_dragging == null)
+        {
+            var bodyQuery = GetEntityQuery<PhysicsComponent>();
+            var lowest = new List<(int DrawDepth, uint RenderOrder, EntityUid Entity)>();
+
+            foreach (var ent in _lookup.GetEntitiesIntersecting(mousePos, LookupFlags.Approximate | LookupFlags.Anchored))
+            {
+                if (!bodyQuery.HasComponent(ent) ||
+                    !TryComp<ClickableComponent>(ent, out var clickable) ||
+                    !clickable.CheckClick(mousePos.Position, out var drawDepth, out var renderOrder)) continue;
+
+                lowest.Add((drawDepth, renderOrder, ent));
+            }
+
+            lowest.Sort((x, y) => y.DrawDepth == x.DrawDepth ? y.RenderOrder.CompareTo(x.RenderOrder) : y.DrawDepth.CompareTo(x.DrawDepth));
+
+            foreach (var ent in lowest)
+            {
+                StartDragging(ent.Entity, mousePos);
+                break;
+            }
+
+            if (_dragging == null) return;
+        }
+
+        if (!TryComp<TransformComponent>(_dragging!.Value, out var xform) ||
+            _lastMousePosition!.Value.MapId != xform.MapID ||
+            !TryComp<PhysicsComponent>(_dragging, out var body))
+        {
+            StopDragging();
+            return;
+        }
+
+        body.Predict = true;
+
+        if (TryComp<PhysicsComponent>(_tether, out var tetherBody))
+        {
+            tetherBody.Predict = true;
+        }
+
+        if (_lastMousePosition.Value.Position.EqualsApprox(mousePos.Position)) return;
+
+        _lastMousePosition = mousePos;
+
+        RaiseNetworkEvent(new TetherMoveEvent()
+        {
+            Coordinates = _lastMousePosition!.Value,
+        });
+    }
+
+    private void StopDragging()
+    {
+        if (_dragging == null) return;
+
+        RaiseNetworkEvent(new StopTetherEvent());
+        _dragging = null;
+        _lastMousePosition = null;
+        _tether = null;
+    }
+
+    private void StartDragging(EntityUid uid, MapCoordinates coordinates)
+    {
+        _dragging = uid;
+        _lastMousePosition = coordinates;
+        RaiseNetworkEvent(new StartTetherEvent()
+        {
+            Entity = _dragging!.Value,
+            Coordinates = coordinates,
+        });
+    }
+}