More moves implemented

Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Counter.cs

@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Plugin.Gen7.Scripts.Moves;
+
+[Script(ScriptCategory.Move, "counter")]
+public class Counter : Script
+{
+    /// <inheritdoc />
+    public override void OnBeforeTurnStart(ITurnChoice choice)
+    {
+        choice.User.Volatile.Add(new CounterHelperEffect());
+    }
+
+    /// <inheritdoc />
+    public override void ChangeTargets(IMoveChoice moveChoice, ref IReadOnlyList<IPokemon?> targets)
+    {
+        var counterHelper = moveChoice.User.Volatile.Get<CounterHelperEffect>();
+        var lastHitBy = counterHelper?.LastHitBy;
+        if (lastHitBy == null)
+        {
+            moveChoice.Fail();
+            return;
+        }
+        targets = [lastHitBy];
+    }
+
+    /// <inheritdoc />
+    public override void ChangeDamage(IExecutingMove move, IPokemon target, byte hit, ref uint damage)
+    {
+        var counterHelper = move.User.Volatile.Get<CounterHelperEffect>();
+        if (counterHelper == null || counterHelper.LastHitBy == null || counterHelper.LastHitBy != target)
+        {
+            move.GetHitData(target, hit).Fail();
+            return;
+        }
+        var lastDamage = counterHelper.LastDamage;
+        damage = lastDamage.MultiplyOrMax(2);
+    }
+}