Puddles & spreader refactor (#15191)

Content.Shared/Fluids/SharedPuddleSystem.cs

@@ -0,0 +1,44 @@
+using Content.Shared.Chemistry.Components;
+using Content.Shared.DragDrop;
+using Content.Shared.Fluids.Components;
+
+namespace Content.Shared.Fluids;
+
+public abstract class SharedPuddleSystem : EntitySystem
+{
+    /// <summary>
+    /// The lowest threshold to be considered for puddle sprite states as well as slipperiness of a puddle.
+    /// </summary>
+    public const float LowThreshold = 0.3f;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<RefillableSolutionComponent, CanDragEvent>(OnRefillableCanDrag);
+        SubscribeLocalEvent<RefillableSolutionComponent, CanDropDraggedEvent>(OnRefillableCanDropDragged);
+        SubscribeLocalEvent<DrainableSolutionComponent, CanDropTargetEvent>(OnDrainCanDropTarget);
+    }
+
+    private void OnRefillableCanDrag(EntityUid uid, RefillableSolutionComponent component, ref CanDragEvent args)
+    {
+        args.Handled = true;
+    }
+
+    private void OnDrainCanDropTarget(EntityUid uid, DrainableSolutionComponent component, ref CanDropTargetEvent args)
+    {
+        if (HasComp<RefillableSolutionComponent>(args.Dragged))
+        {
+            args.CanDrop = true;
+            args.Handled = true;
+        }
+    }
+
+    private void OnRefillableCanDropDragged(EntityUid uid, RefillableSolutionComponent component, ref CanDropDraggedEvent args)
+    {
+        if (!HasComp<DrainableSolutionComponent>(args.Target) && !HasComp<DrainComponent>(args.Target))
+            return;
+
+        args.CanDrop = true;
+        args.Handled = true;
+    }
+}