Fix Mailing Units (space-wizards/space-station-14#30174 + Other) (#2485)

# Description

_Upstream: space-wizards/space-station-14#30174_

This fixes mailing units so their UI works again alongside their
sprites. It also adds a convenience feature to reset the destination on
send since it can trip up players as it makes sense to put in an item
_then_ choose a location.

# Changelog

🆑
- fix: Mailing Unit UI is now fixed
- fix: Mailing Units' no longer use the wrong sprite when charging
- tweak: Mailing Units clear target on send or selecting the same target

---------

Co-authored-by: themias <89101928+themias@users.noreply.github.com>

Content.Client/Disposal/Systems/DisposalUnitSystem.cs

@@ -153,7 +153,7 @@ public sealed class DisposalUnitSystem : SharedDisposalUnitSystem
             }
         }
         else if (state == VisualState.OverlayCharging)
-            sprite.LayerSetState(DisposalUnitVisualLayers.OverlayFlush, new RSI.StateId("disposal-charging"));
+            sprite.LayerSetState(DisposalUnitVisualLayers.OverlayFlush, chargingState);
         else
             _animationSystem.Stop(uid, AnimationKey);
 

Content.Client/Disposal/UI/MailingUnitWindow.xaml.cs

@@ -2,6 +2,7 @@ using Content.Shared.Disposal;
 using Robust.Client.AutoGenerated;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.UserInterface.XAML;
+using Robust.Shared.Timing;
 
 namespace Content.Client.Disposal.UI
 {
@@ -11,6 +12,8 @@ namespace Content.Client.Disposal.UI
     [GenerateTypedNameReferences]
     public sealed partial class MailingUnitWindow : DefaultWindow
     {
+        public TimeSpan FullPressure;
+
         public MailingUnitWindow()
         {
             RobustXamlLoader.Load(this);
@@ -26,6 +29,7 @@ namespace Content.Client.Disposal.UI
 
             Title = Loc.GetString("ui-mailing-unit-window-title", ("tag", state.Tag ?? " "));
             UnitState.Text = disposalState.UnitState;
+            FullPressure = disposalState.FullPressureTime;
             var pressureReached = PressureBar.UpdatePressure(disposalState.FullPressureTime);
             Power.Pressed = disposalState.Powered;
             Engage.Pressed = disposalState.Engaged;
@@ -42,9 +46,10 @@ namespace Content.Client.Disposal.UI
             return !disposalState.Powered || pressureReached;
         }
 
-        public bool UpdatePressure(TimeSpan stateFullPressureTime)
+        protected override void FrameUpdate(FrameEventArgs args)
         {
-            return PressureBar.UpdatePressure(stateFullPressureTime);
+            base.FrameUpdate(args);
+            PressureBar.UpdatePressure(FullPressure);
         }
     }
 }

Content.Server/Disposal/Mailing/MailingUnitSystem.cs

@@ -9,6 +9,7 @@ using Content.Shared.Disposal;
 using Content.Shared.Interaction;
 using Robust.Server.GameObjects;
 using Robust.Shared.Player;
+using Robust.Shared.Utility;
 
 namespace Content.Server.Disposal.Mailing;
 
@@ -35,7 +36,7 @@ public sealed class MailingUnitSystem : EntitySystem
         SubscribeLocalEvent<MailingUnitComponent, DeviceNetworkPacketEvent>(OnPacketReceived);
         SubscribeLocalEvent<MailingUnitComponent, BeforeDisposalFlushEvent>(OnBeforeFlush);
         SubscribeLocalEvent<MailingUnitComponent, ConfigurationSystem.ConfigurationUpdatedEvent>(OnConfigurationUpdated);
-        SubscribeLocalEvent<MailingUnitComponent, ActivateInWorldEvent>(HandleActivate);
+        SubscribeLocalEvent<MailingUnitComponent, ActivateInWorldEvent>(HandleActivate, before: new[] { typeof(DisposalUnitSystem) });
         SubscribeLocalEvent<MailingUnitComponent, DisposalUnitUIStateUpdatedEvent>(OnDisposalUnitUIStateChange);
         SubscribeLocalEvent<MailingUnitComponent, TargetSelectedMessage>(OnTargetSelected);
     }
@@ -89,13 +90,17 @@ public sealed class MailingUnitSystem : EntitySystem
         if (string.IsNullOrEmpty(component.Target))
         {
             args.Cancel();
-            return;
         }
+        else
+        {
+            args.Tags.Add(MailTag);
+            args.Tags.Add(component.Target);
 
-        args.Tags.Add(MailTag);
-        args.Tags.Add(component.Target);
+            BroadcastSentMessage(uid, component);
 
-        BroadcastSentMessage(uid, component);
+            component.Target = null;
+        }
+        UpdateUserInterface(uid, component);
     }
 
     /// <summary>
@@ -179,13 +184,15 @@ public sealed class MailingUnitSystem : EntitySystem
         if (component.DisposalUnitInterfaceState == null)
             return;
 
-        var state = new MailingUnitBoundUserInterfaceState(component.DisposalUnitInterfaceState, component.Target, component.TargetList, component.Tag);
+        var state = new MailingUnitBoundUserInterfaceState(component.DisposalUnitInterfaceState, component.Target, component.TargetList.ShallowClone(), component.Tag);
         _userInterfaceSystem.SetUiState(uid, MailingUnitUiKey.Key, state);
     }
 
     private void OnTargetSelected(EntityUid uid, MailingUnitComponent component, TargetSelectedMessage args)
     {
-        component.Target = args.Target;
+        // Clear the Target if we select the same one
+        component.Target =
+            args.Target != component.Target ? args.Target : null;
         UpdateUserInterface(uid, component);
     }