Implement most pokeballs

Plugins/PkmnLib.Plugin.Gen7/Scripts/Items/Pokeballs/LevelBall.cs

@@ -0,0 +1,31 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Items.Pokeballs;
+
+[ItemScript("level_ball")]
+public class LevelBall : PokeballScript
+{
+    /// <inheritdoc />
+    public LevelBall(IItem item) : base(item)
+    {
+    }
+
+    /// <inheritdoc />
+    public override void ChangeCatchRate(IPokemon target, ref byte catchRate)
+    {
+        if (target.BattleData is null)
+            return;
+        var opponentSide = target.BattleData.SideIndex == 0 ? 1 : 0;
+        var opponent = target.BattleData.Battle.Sides[opponentSide].Pokemon.FirstOrDefault(x => x is not null);
+        if (opponent is null)
+            return;
+
+        var levelDifferenceModifier = (float)target.Level / opponent.Level;
+        var catchModifier = levelDifferenceModifier switch
+        {
+            >= 1f => 1f,
+            >= 0.5f => 2f,
+            >= 0.25f => 4f,
+            _ => 8f,
+        };
+        catchRate = catchRate.MultiplyOrMax(catchModifier);
+    }
+}