From 8fd7df5d80140786552d746f800344be4ce9facd Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Sun, 19 Oct 2025 11:04:08 +0200
Subject: [PATCH] Don't allow switching into a Pokemon that's already in the
 field

---
 PkmnLib.Dynamic/Models/Battle.cs | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/PkmnLib.Dynamic/Models/Battle.cs b/PkmnLib.Dynamic/Models/Battle.cs
index 469e394..7c260af 100644
--- a/PkmnLib.Dynamic/Models/Battle.cs
+++ b/PkmnLib.Dynamic/Models/Battle.cs
@@ -143,7 +143,7 @@ public interface IBattle : IScriptSource, IDeepCloneable, IDisposable
     /// <summary>
     /// Volatile scripts are scripts that are not permanent and can be removed by other scripts.
     /// </summary>
-    public IScriptSet Volatile { get; }
+    IScriptSet Volatile { get; }
 
     /// <summary>
     /// Gets the current weather of the battle. If no weather is present, this returns null.
@@ -341,6 +341,16 @@ public class BattleImpl : ScriptSource, IBattle
             if (preventMove)
                 return false;
         }
+        else if (choice is ISwitchChoice switchChoice)
+        {
+            if (!switchChoice.SwitchTo.IsUsable)
+                return false;
+            // Can't switch to a Pokémon already on the field
+            if (switchChoice.SwitchTo.BattleData is { IsOnBattlefield: true })
+                return false;
+            if (switchChoice.SwitchTo == switchChoice.User)
+                return false;
+        }
 
         return true;