Slight cleanup, do some TODOs

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

@@ -1,7 +1,52 @@
+using PkmnLib.Plugin.Gen7.Scripts.Utils;
+using PkmnLib.Static.Moves;
+
 namespace PkmnLib.Plugin.Gen7.Scripts.Moves;
 
 [Script(ScriptCategory.Move, "nature_power")]
 public class NaturePower : Script
 {
-    // FIXME: Implement this. How to get the terrain in a sane manner?
+    /// <inheritdoc />
+    public override void ChangeMove(IMoveChoice choice, ref StringKey moveName)
+    {
+        var battleData = choice.User.BattleData;
+        if (battleData is null)
+            return;
+        var newMoveName = GetMoveName(battleData.Battle);
+        if (newMoveName is null)
+        {
+            choice.Fail();
+            return;
+        }
+        moveName = newMoveName.Value;
+    }
+
+    private static StringKey? GetMoveName(IBattle battle)
+    {
+        var movesLibrary = battle.Library.StaticLibrary.Moves;
+        var environmentCategory = battle.GetEnvironmentCategory();
+        var moveName = environmentCategory switch
+        {
+            EnvironmentHelper.EnvironmentCategory.Electric when movesLibrary.TryGet("thunderbolt",
+                out var thunderboltMove) => (StringKey?)thunderboltMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Fairy when movesLibrary.TryGet("moonblast", out var moonblastMove) =>
+                moonblastMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Grass when movesLibrary.TryGet("energy_ball", out var energyballMove)
+                => energyballMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Psychic when movesLibrary.TryGet("psychic", out var psychicMove) =>
+                psychicMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Rock when movesLibrary.TryGet("power_gem", out var rockMove) =>
+                rockMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Ground when movesLibrary.TryGet("earth_power", out var groundMove) =>
+                groundMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Ice when movesLibrary.TryGet("ice_beam", out var iceMove) => iceMove
+                .Name,
+            EnvironmentHelper.EnvironmentCategory.Water when movesLibrary.TryGet("hydro_pump", out var waterMove) =>
+                waterMove.Name,
+            EnvironmentHelper.EnvironmentCategory.Normal when movesLibrary.TryGet("tri_attack", out var normalMove) =>
+                normalMove.Name,
+            _ => null,
+        };
+        return moveName;
+    }
 }