Some initial work on prescient AI, AI runner, and some random fixes

PkmnLib.Dynamic/AI/PrescientAI.cs

@@ -0,0 +1,87 @@
+using PkmnLib.Dynamic.Models;
+using PkmnLib.Dynamic.Models.Choices;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Dynamic.AI;
+
+/// <summary>
+/// PrescientAI is an AI that predicts the best move based on the current state of the battle.
+/// This is slightly cheaty, as it simulates the battle with each possible move to find the best one.
+/// </summary>
+public class PrescientAI : PokemonAI
+{
+    private static readonly PokemonAI OpponentAI = new HighestDamageAI();
+
+    /// <inheritdoc />
+    public PrescientAI() : base("Prescient")
+    {
+    }
+
+    /// <inheritdoc />
+    public override ITurnChoice GetChoice(IBattle battle, IPokemon pokemon)
+    {
+        var opponentSide = pokemon.BattleData!.SideIndex == 0 ? (byte)1 : (byte)0;
+        var moves = pokemon.Moves.WhereNotNull().Where(x => battle.CanUse(new MoveChoice(pokemon, x, opponentSide, 0)))
+            .ToList();
+
+        var choices = ScoreChoices(battle, moves, pokemon).OrderByDescending(x => x.Score).ToList();
+        if (choices.Count == 0)
+        {
+            return battle.Library.MiscLibrary.ReplacementChoice(pokemon, opponentSide, 0);
+        }
+        var bestChoice = choices.First().Choice;
+        return bestChoice;
+    }
+
+    private static IEnumerable<(ITurnChoice Choice, float Score)> ScoreChoices(IBattle battle,
+        IReadOnlyList<ILearnedMove> moves, IPokemon pokemon)
+    {
+        var opponentSide = pokemon.BattleData!.SideIndex == 0 ? (byte)1 : (byte)0;
+        foreach (var learnedMoveOriginal in moves.WhereNotNull())
+        {
+            var battleClone = battle.DeepClone();
+            var pokemonClone = battleClone.Sides[pokemon.BattleData!.SideIndex].Pokemon[pokemon.BattleData.Position]!;
+            var learnedMove = pokemonClone.Moves.WhereNotNull()
+                .First(m => m.MoveData.Name == learnedMoveOriginal.MoveData.Name);
+            var choice = new MoveChoice(pokemonClone, learnedMove, opponentSide, 0);
+            var opponentChoice = GetOpponentChoice(battleClone, pokemonClone);
+            if (!battleClone.TrySetChoice(opponentChoice))
+            {
+                var replacementChoice =
+                    battleClone.Library.MiscLibrary.ReplacementChoice(pokemonClone, opponentSide, 0);
+                if (!battleClone.TrySetChoice(replacementChoice))
+                {
+                    throw new InvalidOperationException(
+                        "Could not set opponent choice or replacement choice in battle clone.");
+                }
+            }
+            if (battleClone.TrySetChoice(choice))
+            {
+                var score = CalculateScore(battleClone.Parties[pokemon.BattleData.SideIndex],
+                    battleClone.Parties[opponentSide]);
+                var realChoice = new MoveChoice(pokemon, learnedMoveOriginal, opponentSide, 0);
+                yield return (realChoice, score);
+            }
+        }
+    }
+
+    private static ITurnChoice GetOpponentChoice(IBattle battle, IPokemon pokemon)
+    {
+        var opponentSide = pokemon.BattleData!.SideIndex == 0 ? (byte)1 : (byte)0;
+        var opponent = battle.Sides[opponentSide].Pokemon[0];
+        if (opponent is null)
+        {
+            throw new InvalidOperationException("Opponent Pokemon is null.");
+        }
+        if (battle.HasForcedTurn(opponent, out var forcedChoice))
+        {
+            return forcedChoice;
+        }
+
+        return OpponentAI.GetChoice(battle, opponent);
+    }
+
+    private static float CalculateScore(IBattleParty ownParty, IBattleParty opponentParty) =>
+        ownParty.Party.WhereNotNull().Sum(x => x.CurrentHealth / (float)x.MaxHealth) -
+        opponentParty.Party.WhereNotNull().Sum(x => x.CurrentHealth / (float)x.MaxHealth);
+}