Add hot potato (#14204)

Co-authored-by: AJCM <AJCM@tutanota.com>

Content.Server/HotPotato/HotPotatoSystem.cs

@@ -0,0 +1,55 @@
+using Content.Server.Explosion.EntitySystems;
+using Content.Shared.Hands.Components;
+using Content.Shared.Hands.EntitySystems;
+using Content.Shared.HotPotato;
+using Content.Shared.Popups;
+using Content.Shared.Weapons.Melee.Events;
+
+namespace Content.Server.HotPotato;
+
+public sealed class HotPotatoSystem : SharedHotPotatoSystem
+{
+    [Dependency] private readonly SharedHandsSystem _hands = default!;
+    [Dependency] private readonly SharedPopupSystem _popup = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<HotPotatoComponent, ActiveTimerTriggerEvent>(OnActiveTimer);
+        SubscribeLocalEvent<HotPotatoComponent, MeleeHitEvent>(OnMeleeHit);
+    }
+
+    private void OnActiveTimer(EntityUid uid, HotPotatoComponent comp, ref ActiveTimerTriggerEvent args)
+    {
+        EnsureComp<ActiveHotPotatoComponent>(uid);
+        comp.CanTransfer = false;
+        Dirty(comp);
+    }
+
+    private void OnMeleeHit(EntityUid uid, HotPotatoComponent comp, MeleeHitEvent args)
+    {
+        if (!HasComp<ActiveHotPotatoComponent>(uid))
+            return;
+
+        comp.CanTransfer = true;
+        foreach (var hitEntity in args.HitEntities)
+        {
+            if (!TryComp<HandsComponent>(hitEntity, out var hands))
+                continue;
+
+            if (!_hands.IsHolding(hitEntity, uid, out _, hands) && _hands.TryForcePickupAnyHand(hitEntity, uid, handsComp: hands))
+            {
+                _popup.PopupEntity(Loc.GetString("hot-potato-passed",
+                    ("from", args.User), ("to", hitEntity)), uid, PopupType.Medium);
+                break;
+            }
+
+            _popup.PopupEntity(Loc.GetString("hot-potato-failed",
+                ("to", hitEntity)), uid, PopupType.Medium);
+
+            break;
+        }
+        comp.CanTransfer = false;
+        Dirty(comp);
+    }
+}