Implements AI Switching

AI/AIRunner/Program.cs

@@ -5,6 +5,8 @@ using PkmnLib.Dynamic.AI;
 using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Plugin.Gen7;
 using Serilog;
+using Serilog.Core;
+using Serilog.Events;
 
 namespace AIRunner;
 
@@ -12,9 +14,12 @@ internal static class Program
 {
     private static List<PokemonAI>? _availableAIs;
 
+    internal static LoggingLevelSwitch LogLevelSwitch { get; } = new(LogEventLevel.Information);
+
     private static Task<int> Main(string[] args)
     {
-        Log.Logger = new LoggerConfiguration().MinimumLevel.Information().WriteTo.Console().CreateLogger();
+        Log.Logger = new LoggerConfiguration().MinimumLevel.ControlledBy(LogLevelSwitch).WriteTo.Console()
+            .CreateLogger();
         Log.Information("Starting AI Runner...");
         AILogging.LogHandler = Log.Debug;
         var library = DynamicLibraryImpl.Create([
@@ -24,6 +29,10 @@ internal static class Program
 
         var testCommand = new Command("test", "Run two AIs against each other")
         {
+            new Option<bool>("--debug")
+            {
+                Description = "Enable debug logging.",
+            },
             new Option<string>("--ai1")
             {
                 Description = "The name of the first AI script to run against the second AI.",
@@ -55,6 +64,9 @@ internal static class Program
         };
         testCommand.SetAction(result =>
         {
+            var debug = result.GetValue<bool>("--debug");
+            LogLevelSwitch.MinimumLevel = debug ? LogEventLevel.Debug : LogEventLevel.Information;
+
             var ai1Name = result.GetRequiredValue<string>("--ai1");
             var ai2Name = result.GetRequiredValue<string>("--ai2");
             var ai1 = _availableAIs!.First(a =>

AI/AIRunner/TestCommandRunner.cs

@@ -32,6 +32,7 @@ public static class TestCommandRunner
             randoms[i] = new RandomImpl(rootRandom.GetInt());
             battleTasks[i] = Task.CompletedTask; // Initialize tasks to avoid null references
         }
+        const int pokemonPerParty = 6;
 
         // Show a progress bar if debug logging is not enabled.
         // We disable this if debug logging is on, to prevent annoying console output where the progress bar is drawn in
@@ -55,7 +56,7 @@ public static class TestCommandRunner
             {
                 Log.Debug("Battle {BattleNumber}: {AI1} vs {AI2}", index + 1, ai1.Name, ai2.Name);
                 var random = randoms[taskIndex];
-                var battle = GenerateBattle(library, 3, random);
+                var battle = GenerateBattle(library, pokemonPerParty, random);
                 var timePerTurn = new List<double>(20);
                 while (!battle.HasEnded)
                 {

PkmnLib.Dynamic/AI/Explicit/ExplicitAI.Switch.cs

@@ -0,0 +1,153 @@
+using System.Diagnostics.CodeAnalysis;
+using PkmnLib.Dynamic.Models;
+using PkmnLib.Dynamic.Models.Choices;
+using PkmnLib.Dynamic.ScriptHandling;
+using PkmnLib.Static.Moves;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Dynamic.AI.Explicit;
+
+public partial class ExplicitAI
+{
+    private bool TryChooseToSwitchOut(IBattle battle, IPokemon pokemon, bool terribleMoves,
+        [NotNullWhen(true)] out ITurnChoice? choice)
+    {
+        choice = null;
+        if (battle.IsWildBattle)
+            return false;
+        if (TrainerHighSkill)
+        {
+            var opponentSide = battle.Sides.First(x => x != pokemon.BattleData?.BattleSide);
+            var foeCanAct = opponentSide.Pokemon.WhereNotNull().Any(CanAttack);
+            if (!foeCanAct)
+                return false;
+        }
+        var party = battle.Parties.FirstOrDefault(x => x.IsResponsibleForIndex(
+            new ResponsibleIndex(pokemon.BattleData!.SideIndex, pokemon.BattleData.Position)));
+        if (party is null)
+            return false;
+        var usablePokemon = party.GetUsablePokemonNotInField().ToList();
+        if (!terribleMoves)
+        {
+            if (!_skillFlags.ConsiderSwitching)
+                return false;
+            if (!usablePokemon.Any())
+                return false;
+            var shouldSwitch = _handlers.ShouldSwitch(this, pokemon, battle, usablePokemon);
+            if (shouldSwitch && TrainerMediumSkill)
+            {
+                if (_handlers.ShouldNotSwitch(this, pokemon, battle, usablePokemon))
+                {
+                    shouldSwitch = false;
+                }
+            }
+            if (!shouldSwitch)
+                return false;
+        }
+        var battleSide = pokemon.BattleData!.BattleSide;
+        var bestReplacement =
+            ChooseBestReplacementPokemon(pokemon.BattleData!.Position, terribleMoves, usablePokemon, battleSide);
+        if (bestReplacement is null)
+        {
+            AILogging.LogInformation(
+                $"ExplicitAI: No suitable replacement Pokemon found for {pokemon} at position {pokemon.BattleData.Position}.");
+            return false;
+        }
+        choice = new SwitchChoice(pokemon, bestReplacement);
+        return true;
+    }
+
+    private IPokemon? ChooseBestReplacementPokemon(byte position, bool terribleMoves,
+        IReadOnlyList<IPokemon> usablePokemon, IBattleSide battleSide)
+    {
+        var options = usablePokemon.Where((pokemon, index) =>
+        {
+            if (_skillFlags.ReserveLastPokemon && index == usablePokemon.Count - 1 && usablePokemon.Count > 1)
+                return false; // Don't switch to the last Pokemon if there are others available.
+            if (_skillFlags.UsePokemonInOrder && index != 0)
+                return false;
+            return true;
+        }).ToList();
+        if (options.Count == 0)
+            return null;
+        var ratedOptions = options
+            .Select(pokemon => new { Pokemon = pokemon, Score = RateReplacementPokemon(pokemon, battleSide) })
+            .OrderBy(x => x.Score).ToList();
+        if (TrainerHighSkill && !terribleMoves)
+        {
+            if (ratedOptions.First().Score < 100)
+                return null;
+        }
+        return ratedOptions.First().Pokemon;
+    }
+
+    private static readonly StringKey HeavyDutyBootsName = "heavy_duty_boots";
+    private static readonly StringKey ToxicSpikesName = "toxic_spikes";
+    private static readonly StringKey StickyWebName = "sticky_web";
+
+    private int RateReplacementPokemon(IPokemon pokemon, IBattleSide battleSide)
+    {
+        var score = 0;
+        var types = pokemon.Types;
+        var entryDamage = CalculateEntryHazardDamage(pokemon, battleSide);
+        if (entryDamage >= pokemon.CurrentHealth)
+            score -= 50;
+        else if (entryDamage > 0)
+            score -= 50 * (int)Math.Round((double)entryDamage / pokemon.MaxHealth, MidpointRounding.AwayFromZero);
+        if (!pokemon.HasHeldItem(HeavyDutyBootsName) && !pokemon.IsFloating)
+        {
+            if (battleSide.VolatileScripts.Contains(ToxicSpikesName) && CanBePoisoned(pokemon, battleSide.Battle))
+            {
+                score -= 20;
+            }
+            if (battleSide.VolatileScripts.Contains(StickyWebName))
+            {
+                score -= 15;
+            }
+        }
+        var opponentSide = battleSide.Battle.Sides.First(x => x != battleSide);
+        foreach (var foe in opponentSide.Pokemon.WhereNotNull())
+        {
+            var lastMoveUsed = foe.BattleData?.LastMoveChoice;
+            if (lastMoveUsed is null || lastMoveUsed.ChosenMove.MoveData.Category == MoveCategory.Status)
+                continue;
+            var moveType = lastMoveUsed.ChosenMove.MoveData.MoveType;
+            var effectiveness = pokemon.Library.StaticLibrary.Types.GetEffectiveness(moveType, types);
+            score -= (int)(lastMoveUsed.ChosenMove.MoveData.BasePower * effectiveness / 5);
+        }
+        foreach (var learnedMove in pokemon.Moves.WhereNotNull())
+        {
+            if (learnedMove.MoveData.BasePower == 0 || learnedMove is { CurrentPp: 0, MaxPp: > 0 })
+                continue;
+            foreach (var foe in opponentSide.Pokemon.WhereNotNull())
+            {
+                if (CanAbsorbMove(foe, learnedMove.MoveData, learnedMove.MoveData.MoveType, battleSide.Battle))
+                    continue;
+                var effectiveness =
+                    pokemon.Library.StaticLibrary.Types.GetEffectiveness(learnedMove.MoveData.MoveType, foe.Types);
+                score += (int)(learnedMove.MoveData.BasePower * effectiveness / 10);
+            }
+        }
+
+        return score;
+    }
+
+    public static uint CalculateEntryHazardDamage(IPokemon pokemon, IBattleSide side)
+    {
+        var damage = 0u;
+        side.RunScriptHook<IAIInfoScriptExpectedEntryDamage>(x => x.ExpectedEntryDamage(pokemon, ref damage));
+        return damage;
+    }
+
+    private static bool CanSwitch(IPokemon pokemon)
+    {
+        var battleData = pokemon.BattleData;
+        if (battleData == null)
+            return false;
+        if (battleData.Battle.IsWildBattle)
+            return false;
+        var partyForIndex = battleData.Battle.Parties.FirstOrDefault(x =>
+            x.IsResponsibleForIndex(new ResponsibleIndex(battleData.SideIndex, battleData.Position)));
+        return partyForIndex != null && partyForIndex.HasUsablePokemonNotInField();
+    }
+}

PkmnLib.Dynamic/AI/Explicit/ExplicitAI.Utilities.cs

@@ -0,0 +1,89 @@
+using PkmnLib.Dynamic.Models;
+using PkmnLib.Static;
+using PkmnLib.Static.Moves;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Dynamic.AI.Explicit;
+
+public partial class ExplicitAI
+{
+    private static readonly StringKey MistyTerrainName = "misty_terrain";
+    private static readonly StringKey PoisonName = "poison";
+    private static readonly StringKey SteelName = "steel";
+    private static readonly StringKey ImmunityName = "immunity";
+    private static readonly StringKey PastelVeilName = "pastel_veil";
+    private static readonly StringKey FlowerVeilName = "flower_veil";
+    private static readonly StringKey LeafGuardName = "leaf_guard";
+    private static readonly StringKey ComatoseName = "comatose";
+    private static readonly StringKey ShieldsDownName = "shields_down";
+    private static readonly StringKey HarshSunlightName = "harsh_sunlight";
+    private static readonly StringKey DesolateLandsName = "desolate_lands";
+    private static readonly StringKey BulletproofName = "bulletproof";
+    private static readonly StringKey FlashFireName = "flash_fire";
+    private static readonly StringKey LightningRodName = "lightning_rod";
+    private static readonly StringKey MotorDriveName = "motor_drive";
+    private static readonly StringKey VoltAbsorbName = "volt_absorb";
+    private static readonly StringKey SapSipperName = "sap_sipper";
+    private static readonly StringKey SoundproofName = "soundproof";
+    private static readonly StringKey StormDrainName = "storm_drain";
+    private static readonly StringKey WaterAbsorbName = "water_absorb";
+    private static readonly StringKey DrySkinName = "dry_skin";
+    private static readonly StringKey TelepathyName = "telepathy";
+    private static readonly StringKey WonderGuardName = "wonder_guard";
+    private static readonly StringKey FireName = "fire";
+    private static readonly StringKey ElectricName = "electric";
+    private static readonly StringKey WaterName = "water";
+
+    private static bool CanBePoisoned(IPokemon pokemon, IBattle battle)
+    {
+        if (battle.TerrainName == MistyTerrainName)
+            return false;
+        if (pokemon.Types.Any(x => x.Name == PoisonName || x.Name == SteelName))
+            return false;
+        if (pokemon.ActiveAbility?.Name == ImmunityName)
+            return false;
+        if (pokemon.ActiveAbility?.Name == PastelVeilName)
+            return false;
+        if (pokemon.ActiveAbility?.Name == FlowerVeilName && pokemon.Types.Any(x => x.Name == GrassName))
+            return false;
+        if ((pokemon.ActiveAbility?.Name == LeafGuardName && battle.WeatherName == HarshSunlightName) ||
+            battle.WeatherName == DesolateLandsName)
+            return false;
+        if (pokemon.ActiveAbility?.Name == ComatoseName && pokemon.Species.Name == "komala")
+            return false;
+        if (pokemon.ActiveAbility?.Name == ShieldsDownName && pokemon.Species.Name == "minior" &&
+            pokemon.Form.Name.Contains("-meteor"))
+            return false;
+        return true;
+    }
+
+    private static bool CanAbsorbMove(IPokemon pokemon, IMoveData move, TypeIdentifier moveType, IBattle battle)
+    {
+        if (pokemon.ActiveAbility == null)
+            return false;
+
+        var abilityName = pokemon.ActiveAbility.Name;
+
+        if (abilityName == BulletproofName)
+            return move.HasFlag("bomb");
+        if (abilityName == FlashFireName)
+            return moveType.Name == FireName;
+        if (abilityName == LightningRodName || abilityName == MotorDriveName || abilityName == VoltAbsorbName)
+            return moveType.Name == ElectricName;
+        if (abilityName == SapSipperName)
+            return moveType.Name == GrassName;
+        if (abilityName == SoundproofName)
+            return move.HasFlag("sound");
+        if (abilityName == StormDrainName || abilityName == WaterAbsorbName || abilityName == DrySkinName)
+            return moveType.Name == WaterName;
+        if (abilityName == TelepathyName)
+            return false;
+        if (abilityName == WonderGuardName)
+        {
+            var effectiveness = battle.Library.StaticLibrary.Types.GetEffectiveness(moveType, pokemon.Types);
+            return effectiveness <= 1.0f;
+        }
+
+        return false;
+    }
+}

PkmnLib.Dynamic/AI/Explicit/ExplicitAI.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics.CodeAnalysis;
 using PkmnLib.Dynamic.BattleFlow;
 using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
@@ -8,21 +9,27 @@ using PkmnLib.Static.Utils;
 
 namespace PkmnLib.Dynamic.AI.Explicit;
 
+public interface IExplicitAI
+{
+    public bool TrainerHighSkill { get; }
+    public bool TrainerMediumSkill { get; }
+    public IRandom Random { get; }
+}
+
 /// <summary>
 /// An explicit AI that has explicitly written logic for each Pokémon and move.
 /// </summary>
 /// <remarks>
 /// This is heavily based on the AI used in <a href="https://github.com/Maruno17/pokemon-essentials">Pokémon Essentials</a>
 /// </remarks>
-public class ExplicitAI : PokemonAI
+public partial class ExplicitAI : PokemonAI, IExplicitAI
 {
     public const int MoveFailScore = 20;
     public const int MoveUselessScore = 60;
     public const int MoveBaseScore = 100;
 
     private const float TrainerSkill = 100; // TODO: This should be configurable
-    private bool CanPredictMoveFailure => true; // TODO: This should be configurable
-    private bool ScoreMoves => true; // TODO: This should be configurable
+    private SkillFlags _skillFlags = new();
 
     private float MoveScoreThreshold => (float)(0.6f + 0.35f * Math.Sqrt(Math.Min(TrainerSkill, 100) / 100f));
 
@@ -30,17 +37,39 @@ public class ExplicitAI : PokemonAI
 
     private readonly IRandom _random = new RandomImpl();
 
+    public class SkillFlags
+    {
+        // TODO: Make these configurable
+        public bool CanPredictMoveFailure { get; set; } = true;
+        public bool ScoreMoves { get; set; } = true;
+        public bool ConsiderSwitching { get; set; } = true;
+        public bool ReserveLastPokemon { get; set; } = true;
+        public bool UsePokemonInOrder { get; set; } = true;
+    }
+
     /// <inheritdoc />
     public ExplicitAI(IDynamicLibrary library) : base("explicit")
     {
         _handlers = library.ExplicitAIHandlers;
     }
 
+    public bool TrainerHighSkill => TrainerSkill >= 45;
+    public bool TrainerMediumSkill => TrainerSkill >= 32;
+
+    /// <inheritdoc />
+    public IRandom Random => _random;
+
     /// <inheritdoc />
     public override ITurnChoice GetChoice(IBattle battle, IPokemon pokemon)
     {
         if (battle.HasForcedTurn(pokemon, out var choice))
             return choice;
+        if (TryChooseToSwitchOut(battle, pokemon, false, out var turnChoice))
+        {
+            AILogging.LogInformation($"{pokemon} is switching out.");
+            return turnChoice;
+        }
+
         var moveChoices = GetMoveScores(pokemon, battle);
         if (moveChoices.Count == 0)
         {
@@ -48,7 +77,29 @@ public class ExplicitAI : PokemonAI
             return battle.Library.MiscLibrary.ReplacementChoice(pokemon, opponentSide, pokemon.BattleData.Position);
         }
         var maxScore = moveChoices.Max(x => x.score);
-        // TODO: Consider switching to a different pokémon if the score is too low
+        if (TrainerHighSkill && CanSwitch(pokemon))
+        {
+            var badMoves = false;
+            if (maxScore <= MoveUselessScore)
+            {
+                badMoves = CanAttack(pokemon);
+                if (!badMoves && _random.GetInt(100) < 25)
+                    badMoves = true;
+            }
+            else if (maxScore < MoveBaseScore * MoveScoreThreshold && pokemon.BattleData?.TurnsOnField > 2 &&
+                     _random.GetInt(100) < 80)
+            {
+                badMoves = true;
+            }
+            if (badMoves)
+            {
+                AILogging.LogInformation($"{pokemon} has no good moves, considering switching.");
+                if (TryChooseToSwitchOut(battle, pokemon, badMoves, out var switchChoice))
+                {
+                    return switchChoice;
+                }
+            }
+        }
 
         var threshold = (float)Math.Floor(maxScore * MoveScoreThreshold);
         var considerChoices = moveChoices.Select(x => (x, Math.Max(x.score - threshold, 0))).ToArray();
@@ -122,7 +173,7 @@ public class ExplicitAI : PokemonAI
                 }
             }
             var aiMove = new AIMoveState(user, moveData);
-            if (CanPredictMoveFailure && PredictMoveFailure(user, battle, aiMove))
+            if (_skillFlags.CanPredictMoveFailure && PredictMoveFailure(user, battle, aiMove))
             {
                 AILogging.LogInformation($"{user} is considering {aiMove.Move.Name} but it will fail.");
                 AddMoveToChoices(index, MoveFailScore);
@@ -210,8 +261,8 @@ public class ExplicitAI : PokemonAI
             return true;
 
         // Check if the move will fail based on the handlers
-        return aiMove.Move.SecondaryEffect != null &&
-               _handlers.MoveWillFail(aiMove.Move.SecondaryEffect.Name, new MoveOption(aiMove, battle, null));
+        return aiMove.Move.SecondaryEffect != null && _handlers.MoveWillFail(this, aiMove.Move.SecondaryEffect.Name,
+            new MoveOption(aiMove, battle, null));
     }
 
     private static readonly StringKey PsychicTerrainName = new("psychic_terrain");
@@ -226,8 +277,8 @@ public class ExplicitAI : PokemonAI
 
     private bool PredictMoveFailureAgainstTarget(IPokemon user, AIMoveState aiMove, IPokemon target, IBattle battle)
     {
-        if (aiMove.Move.SecondaryEffect != null && _handlers.MoveWillFailAgainstTarget(aiMove.Move.SecondaryEffect.Name,
-                new MoveOption(aiMove, battle, target)))
+        if (aiMove.Move.SecondaryEffect != null && _handlers.MoveWillFailAgainstTarget(this,
+                aiMove.Move.SecondaryEffect.Name, new MoveOption(aiMove, battle, target)))
             return true;
         if (aiMove.Move.Priority > 0)
         {
@@ -281,20 +332,20 @@ public class ExplicitAI : PokemonAI
                 score += targetScore;
                 affectedTargets++;
             }
-            if (affectedTargets == 0 && CanPredictMoveFailure)
+            if (affectedTargets == 0 && _skillFlags.CanPredictMoveFailure)
             {
                 return MoveFailScore;
             }
             if (affectedTargets > 0)
                 score = (int)(score / (float)affectedTargets);
         }
-        if (ScoreMoves)
+        if (_skillFlags.ScoreMoves)
         {
             if (aiMove.Move.SecondaryEffect != null)
             {
-                _handlers.ApplyMoveEffectScore(aiMove.Move.SecondaryEffect.Name, new MoveOption(aiMove, battle, null),
-                    ref score);
-                _handlers.ApplyGenerateMoveScoreModifiers(new MoveOption(aiMove, battle, null), ref score);
+                _handlers.ApplyMoveEffectScore(this, aiMove.Move.SecondaryEffect.Name,
+                    new MoveOption(aiMove, battle, null), ref score);
+                _handlers.ApplyGenerateMoveScoreModifiers(this, new MoveOption(aiMove, battle, null), ref score);
             }
         }
         if (score < 0)
@@ -304,18 +355,18 @@ public class ExplicitAI : PokemonAI
 
     private int GetMoveScoreAgainstTarget(IPokemon user, AIMoveState aiMove, IPokemon target, IBattle battle)
     {
-        if (CanPredictMoveFailure && PredictMoveFailureAgainstTarget(user, aiMove, target, battle))
+        if (_skillFlags.CanPredictMoveFailure && PredictMoveFailureAgainstTarget(user, aiMove, target, battle))
         {
             AILogging.LogInformation($"{user} is considering {aiMove.Move.Name} against {target} but it will fail.");
             return -1;
         }
         var score = MoveBaseScore;
-        if (ScoreMoves && aiMove.Move.SecondaryEffect != null)
+        if (_skillFlags.ScoreMoves && aiMove.Move.SecondaryEffect != null)
         {
             var estimatedDamage = AIHelpers.CalculateDamageEstimation(aiMove.Move, user, target, battle.Library);
             var moveOption = new MoveOption(aiMove, battle, target, estimatedDamage);
-            _handlers.ApplyMoveEffectAgainstTargetScore(aiMove.Move.SecondaryEffect.Name, moveOption, ref score);
-            _handlers.ApplyGenerateMoveAgainstTargetScoreModifiers(moveOption, ref score);
+            _handlers.ApplyMoveEffectAgainstTargetScore(this, aiMove.Move.SecondaryEffect.Name, moveOption, ref score);
+            _handlers.ApplyGenerateMoveAgainstTargetScoreModifiers(this, moveOption, ref score);
         }
 
         if (aiMove.Move.Target.TargetsFoe() && target.BattleData?.SideIndex == user.BattleData?.SideIndex &&
@@ -343,4 +394,17 @@ public class ExplicitAI : PokemonAI
             return false;
         return true;
     }
+
+    private static bool CanAttack(IPokemon pokemon)
+    {
+        if (pokemon.Volatile.Contains("requires_recharge"))
+            return false;
+        if (pokemon.HasStatus("frozen") || pokemon.HasStatus("sleep"))
+            return false;
+        if (pokemon.ActiveAbility?.Name == "truant" && pokemon.Volatile.Contains("truant_effect"))
+            return false;
+        if (pokemon.Volatile.Contains("flinch_effect"))
+            return false;
+        return true;
+    }
 }

PkmnLib.Dynamic/AI/Explicit/ExplicitAIHandlers.cs

@@ -5,11 +5,14 @@ namespace PkmnLib.Dynamic.AI.Explicit;
 
 public record struct MoveOption(AIMoveState Move, IBattle Battle, IPokemon? Target, uint EstimatedDamage = 0);
 
-public delegate bool AIBoolHandler(MoveOption option);
+public delegate bool AIBoolHandler(IExplicitAI ai, MoveOption option);
 
-public delegate void AIMoveBasePowerHandler(MoveOption option, ref int score);
+public delegate bool AISwitchBoolHandler(IExplicitAI ai, IPokemon pokemon, IBattle battle,
+    IReadOnlyList<IPokemon> reserves);
 
-public delegate void AIScoreMoveHandler(MoveOption option, ref int score);
+public delegate void AIMoveBasePowerHandler(IExplicitAI ai, MoveOption option, ref int score);
+
+public delegate void AIScoreMoveHandler(IExplicitAI ai, MoveOption option, ref int score);
 
 public interface IReadOnlyExplicitAIHandlers
 {
@@ -21,7 +24,7 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Checks if a move will fail based on the provided function code and options.
     /// </summary>
-    bool MoveWillFail(StringKey functionCode, MoveOption option);
+    bool MoveWillFail(IExplicitAI ai, StringKey functionCode, MoveOption option);
 
     /// <summary>
     /// A list of checks to determine if a move will fail against a target.
@@ -31,7 +34,7 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Checks if a move will fail against a target based on the provided function code and options.
     /// </summary>
-    bool MoveWillFailAgainstTarget(StringKey functionCode, MoveOption option);
+    bool MoveWillFailAgainstTarget(IExplicitAI ai, StringKey functionCode, MoveOption option);
 
     /// <summary>
     /// A list of handlers to apply scores for move effects.
@@ -41,7 +44,7 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Applies the score for a move effect based on the provided name and options.
     /// </summary>
-    void ApplyMoveEffectScore(StringKey name, MoveOption option, ref int score);
+    void ApplyMoveEffectScore(IExplicitAI ai, StringKey name, MoveOption option, ref int score);
 
     /// <summary>
     /// A list of handlers to apply scores for move effects against a target.
@@ -51,7 +54,7 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Applies the score for a move effect against a target based on the provided name and options.
     /// </summary>
-    void ApplyMoveEffectAgainstTargetScore(StringKey name, MoveOption option, ref int score);
+    void ApplyMoveEffectAgainstTargetScore(IExplicitAI ai, StringKey name, MoveOption option, ref int score);
 
     /// <summary>
     /// A list of handlers to determine the base power of a move.
@@ -61,7 +64,7 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Applies the base power for a move based on the provided name and options.
     /// </summary>
-    void GetBasePower(StringKey name, MoveOption option, ref int power);
+    void GetBasePower(IExplicitAI ai, StringKey name, MoveOption option, ref int power);
 
     /// <summary>
     /// A list of handlers to apply scores for general move effectiveness.
@@ -71,10 +74,7 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Applies the score for a general move based on the provided option.
     /// </summary>
-    /// <param name="option"></param>
-    /// <param name="score"></param>
-    /// <returns></returns>
-    void ApplyGenerateMoveScoreModifiers(MoveOption option, ref int score);
+    void ApplyGenerateMoveScoreModifiers(IExplicitAI ai, MoveOption option, ref int score);
 
     /// <summary>
     /// A list of handlers to apply scores for general move effectiveness against a target.
@@ -84,10 +84,16 @@ public interface IReadOnlyExplicitAIHandlers
     /// <summary>
     /// Applies the score for a general move against a target based on the provided option.
     /// </summary>
-    void ApplyGenerateMoveAgainstTargetScoreModifiers(MoveOption option, ref int score);
+    void ApplyGenerateMoveAgainstTargetScoreModifiers(IExplicitAI ai, MoveOption option, ref int score);
+
+    IReadOnlyDictionary<StringKey, AISwitchBoolHandler> ShouldSwitchFunctions { get; }
+
+    bool ShouldSwitch(IExplicitAI ai, IPokemon pokemon, IBattle battle, IReadOnlyList<IPokemon> reserves);
+
+    IReadOnlyDictionary<StringKey, AISwitchBoolHandler> ShouldNotSwitchFunctions { get; }
+
+    bool ShouldNotSwitch(IExplicitAI ai, IPokemon pokemon, IBattle battle, IReadOnlyList<IPokemon> reserves);
 
-    IReadOnlyDictionary<StringKey, AIBoolHandler> ShouldSwitch { get; }
-    IReadOnlyDictionary<StringKey, AIBoolHandler> ShouldNotSwitch { get; }
     IReadOnlyDictionary<StringKey, AIScoreMoveHandler> AbilityRanking { get; }
 }
 
@@ -99,8 +105,8 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
     public FunctionHandlerDictionary<AIBoolHandler> MoveFailureCheck { get; } = new();
 
     /// <inheritdoc />
-    public bool MoveWillFail(StringKey functionCode, MoveOption option) =>
-        MoveFailureCheck.TryGetValue(functionCode, out var handler) && handler(option);
+    public bool MoveWillFail(IExplicitAI ai, StringKey functionCode, MoveOption option) =>
+        MoveFailureCheck.TryGetValue(functionCode, out var handler) && handler(ai, option);
 
     public FunctionHandlerDictionary<AIBoolHandler> MoveFailureAgainstTargetCheck { get; } = new();
 
@@ -109,8 +115,8 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
         MoveFailureAgainstTargetCheck;
 
     /// <inheritdoc />
-    public bool MoveWillFailAgainstTarget(StringKey functionCode, MoveOption option) =>
-        MoveFailureAgainstTargetCheck.TryGetValue(functionCode, out var handler) && handler(option);
+    public bool MoveWillFailAgainstTarget(IExplicitAI ai, StringKey functionCode, MoveOption option) =>
+        MoveFailureAgainstTargetCheck.TryGetValue(functionCode, out var handler) && handler(ai, option);
 
     public FunctionHandlerDictionary<AIScoreMoveHandler> MoveEffectScore { get; } = [];
 
@@ -121,10 +127,10 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
     public FunctionHandlerDictionary<AIScoreMoveHandler> MoveEffectAgainstTargetScore = [];
 
     /// <inheritdoc />
-    public void ApplyMoveEffectScore(StringKey name, MoveOption option, ref int score)
+    public void ApplyMoveEffectScore(IExplicitAI ai, StringKey name, MoveOption option, ref int score)
     {
         if (MoveEffectScore.TryGetValue(name, out var handler))
-            handler(option, ref score);
+            handler(ai, option, ref score);
     }
 
     /// <inheritdoc />
@@ -134,10 +140,10 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
     public FunctionHandlerDictionary<AIMoveBasePowerHandler> MoveBasePower = [];
 
     /// <inheritdoc />
-    public void ApplyMoveEffectAgainstTargetScore(StringKey name, MoveOption option, ref int score)
+    public void ApplyMoveEffectAgainstTargetScore(IExplicitAI ai, StringKey name, MoveOption option, ref int score)
     {
         if (MoveEffectAgainstTargetScore.TryGetValue(name, out var handler))
-            handler(option, ref score);
+            handler(ai, option, ref score);
     }
 
     /// <inheritdoc />
@@ -147,10 +153,10 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
     public FunctionHandlerDictionary<AIScoreMoveHandler> GeneralMoveScore = [];
 
     /// <inheritdoc />
-    public void GetBasePower(StringKey name, MoveOption option, ref int power)
+    public void GetBasePower(IExplicitAI ai, StringKey name, MoveOption option, ref int power)
     {
         if (MoveBasePower.TryGetValue(name, out var handler))
-            handler(option, ref power);
+            handler(ai, option, ref power);
     }
 
     /// <inheritdoc />
@@ -160,11 +166,11 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
     public FunctionHandlerDictionary<AIScoreMoveHandler> GeneralMoveAgainstTargetScore = [];
 
     /// <inheritdoc />
-    public void ApplyGenerateMoveScoreModifiers(MoveOption option, ref int score)
+    public void ApplyGenerateMoveScoreModifiers(IExplicitAI ai, MoveOption option, ref int score)
     {
         foreach (var (_, handler) in GeneralMoveScore)
         {
-            handler(option, ref score);
+            handler(ai, option, ref score);
         }
     }
 
@@ -172,27 +178,51 @@ public class ExplicitAIHandlers : IReadOnlyExplicitAIHandlers
     IReadOnlyDictionary<StringKey, AIScoreMoveHandler> IReadOnlyExplicitAIHandlers.GeneralMoveAgainstTargetScore =>
         GeneralMoveAgainstTargetScore;
 
-    public FunctionHandlerDictionary<AIBoolHandler> ShouldSwitch = [];
-
     /// <inheritdoc />
-    public void ApplyGenerateMoveAgainstTargetScoreModifiers(MoveOption option, ref int score)
+    public void ApplyGenerateMoveAgainstTargetScoreModifiers(IExplicitAI ai, MoveOption option, ref int score)
     {
         foreach (var (_, handler) in GeneralMoveAgainstTargetScore)
         {
-            handler(option, ref score);
+            handler(ai, option, ref score);
         }
     }
 
-    /// <inheritdoc />
-    IReadOnlyDictionary<StringKey, AIBoolHandler> IReadOnlyExplicitAIHandlers.ShouldSwitch => ShouldSwitch;
-
-    public FunctionHandlerDictionary<AIBoolHandler> ShouldNotSwitch = [];
+    public FunctionHandlerDictionary<AISwitchBoolHandler> ShouldSwitchFunctions = [];
 
     /// <inheritdoc />
-    IReadOnlyDictionary<StringKey, AIBoolHandler> IReadOnlyExplicitAIHandlers.ShouldNotSwitch => ShouldNotSwitch;
+    IReadOnlyDictionary<StringKey, AISwitchBoolHandler> IReadOnlyExplicitAIHandlers.ShouldSwitchFunctions =>
+        ShouldSwitchFunctions;
+
+    public bool ShouldSwitch(IExplicitAI ai, IPokemon pokemon, IBattle battle, IReadOnlyList<IPokemon> reserves)
+    {
+        var shouldSwitch = false;
+        foreach (var (_, handler) in ShouldSwitchFunctions)
+        {
+            shouldSwitch |= handler(ai, pokemon, battle, reserves);
+        }
+        return shouldSwitch;
+    }
+
+    public FunctionHandlerDictionary<AISwitchBoolHandler> ShouldNotSwitchFunctions = [];
+
+    /// <inheritdoc />
+    /// <inheritdoc />
+    IReadOnlyDictionary<StringKey, AISwitchBoolHandler> IReadOnlyExplicitAIHandlers.ShouldNotSwitchFunctions =>
+        ShouldNotSwitchFunctions;
 
     public FunctionHandlerDictionary<AIScoreMoveHandler> AbilityRanking = [];
 
+    /// <inheritdoc />
+    public bool ShouldNotSwitch(IExplicitAI ai, IPokemon pokemon, IBattle battle, IReadOnlyList<IPokemon> reserves)
+    {
+        var shouldNotSwitch = false;
+        foreach (var (_, handler) in ShouldNotSwitchFunctions)
+        {
+            shouldNotSwitch |= handler(ai, pokemon, battle, reserves);
+        }
+        return shouldNotSwitch;
+    }
+
     /// <inheritdoc />
     IReadOnlyDictionary<StringKey, AIScoreMoveHandler> IReadOnlyExplicitAIHandlers.AbilityRanking =>
         AbilityRanking;

PkmnLib.Dynamic/BattleFlow/MoveTurnExecutor.cs

@@ -15,6 +15,7 @@ public static class MoveTurnExecutor
 {
     internal static void ExecuteMoveChoice(IBattle battle, IMoveChoice moveChoice)
     {
+        moveChoice.User.BattleData!.LastMoveChoice = moveChoice;
         var chosenMove = moveChoice.ChosenMove;
         var useMove = chosenMove.MoveData;
 

PkmnLib.Dynamic/Models/Battle.cs

@@ -252,7 +252,7 @@ public class BattleImpl : ScriptSource, IBattle
 
     /// <inheritdoc />
     public bool CanSlotBeFilled(byte side, byte position) => Parties.Any(x =>
-        x.IsResponsibleForIndex(new ResponsibleIndex(side, position)) && x.HasPokemonNotInField());
+        x.IsResponsibleForIndex(new ResponsibleIndex(side, position)) && x.HasUsablePokemonNotInField());
 
     /// <inheritdoc />
     public void ValidateBattleState()

PkmnLib.Dynamic/Models/BattleParty.cs

@@ -21,7 +21,12 @@ public interface IBattleParty : IDeepCloneable
     /// <summary>
     /// Whether the party has a living Pokemon left that is not in the field.
     /// </summary>
-    bool HasPokemonNotInField();
+    bool HasUsablePokemonNotInField();
+
+    /// <summary>
+    /// Gets all usable Pokemon that are not currently in the field.
+    /// </summary>
+    IEnumerable<IPokemon> GetUsablePokemonNotInField();
 }
 
 /// <summary>
@@ -49,6 +54,10 @@ public class BattlePartyImpl : IBattleParty
     public bool IsResponsibleForIndex(ResponsibleIndex index) => _responsibleIndices.Contains(index);
 
     /// <inheritdoc />
-    public bool HasPokemonNotInField() =>
+    public bool HasUsablePokemonNotInField() =>
         Party.WhereNotNull().Any(x => x.IsUsable && x.BattleData?.IsOnBattlefield != true);
+
+    /// <inheritdoc />
+    public IEnumerable<IPokemon> GetUsablePokemonNotInField() =>
+        Party.WhereNotNull().Where(x => x.IsUsable && x.BattleData?.IsOnBattlefield != true);
 }

PkmnLib.Dynamic/Models/Pokemon.cs

@@ -1,6 +1,7 @@
 using System.Diagnostics.CodeAnalysis;
 using PkmnLib.Dynamic.Events;
 using PkmnLib.Dynamic.Libraries;
+using PkmnLib.Dynamic.Models.Choices;
 using PkmnLib.Dynamic.Models.Serialized;
 using PkmnLib.Dynamic.ScriptHandling;
 using PkmnLib.Static;
@@ -489,6 +490,8 @@ public interface IPokemonBattleData : IDeepCloneable
     /// </summary>
     uint SwitchInTurn { get; internal set; }
 
+    uint TurnsOnField { get; }
+
     /// <summary>
     /// The side the Pokémon is on.
     /// </summary>
@@ -503,6 +506,11 @@ public interface IPokemonBattleData : IDeepCloneable
     /// The form of the Pokémon at the time it was sent out.
     /// </summary>
     IForm OriginalForm { get; }
+
+    /// <summary>
+    /// The last move choice executed by the Pokémon.
+    /// </summary>
+    IMoveChoice? LastMoveChoice { get; internal set; }
 }
 
 /// <inheritdoc cref="IPokemon"/>
@@ -1490,6 +1498,9 @@ public class PokemonBattleDataImpl : IPokemonBattleData
     /// <inheritdoc />
     public uint SwitchInTurn { get; set; }
 
+    /// <inheritdoc />
+    public uint TurnsOnField => Battle.CurrentTurnNumber - SwitchInTurn;
+
     /// <inheritdoc />
     public IBattleSide BattleSide => Battle.Sides[SideIndex];
 
@@ -1498,4 +1509,7 @@ public class PokemonBattleDataImpl : IPokemonBattleData
 
     /// <inheritdoc />
     public IForm OriginalForm { get; }
+
+    /// <inheritdoc />
+    public IMoveChoice? LastMoveChoice { get; set; }
 }

PkmnLib.Dynamic/PkmnLib.Dynamic.csproj

@@ -12,5 +12,10 @@
     <ItemGroup>
         <ProjectReference Include="..\PkmnLib.Static\PkmnLib.Static.csproj"/>
     </ItemGroup>
+    <ItemGroup>
+        <Compile Update="AI\Explicit\ExplicitAI.*.cs">
+            <DependentUpon>ExplicitAI.cs</DependentUpon>
+        </Compile>
+    </ItemGroup>
 
 </Project>

PkmnLib.Dynamic/ScriptHandling/ScriptAIInformationInterfaces.cs

@@ -26,4 +26,16 @@ public interface IAIInfoScriptExpectedEndOfTurnDamage
     /// have an end of turn effect, such as Poison or Burn.
     /// </summary>
     void ExpectedEndOfTurnDamage(IPokemon pokemon, ref int damage);
+}
+
+/// <summary>
+/// Script for getting the expected entry damage by the AI.
+/// </summary>
+public interface IAIInfoScriptExpectedEntryDamage
+{
+    /// <summary>
+    /// This function returns the expected entry damage for the script. This is used for scripts that have
+    /// an entry hazard effect, such as Spikes or Stealth Rock.
+    /// </summary>
+    void ExpectedEntryDamage(IPokemon pokemon, ref uint damage);
 }

Plugins/PkmnLib.Plugin.Gen7/AI/AIDamageFunctions.cs

@@ -0,0 +1,36 @@
+using PkmnLib.Dynamic.AI.Explicit;
+using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
+using PkmnLib.Static.Moves;
+
+namespace PkmnLib.Plugin.Gen7.AI;
+
+public static class AIDamageFunctions
+{
+    internal static void PredictedDamageScore(IExplicitAI ai, MoveOption option, ref int score)
+    {
+        var target = option.Target;
+        if (target == null)
+            return;
+        if (option.Move.Move.Category == MoveCategory.Status)
+            return;
+        var damage = option.EstimatedDamage;
+        if (target.Volatile.TryGet<SubstituteEffect>(out var substitute))
+        {
+            var health = substitute.Health;
+            score += (int)Math.Min(15.0f * damage / health, 20);
+            return;
+        }
+
+        score += (int)Math.Min(15.0f * damage / target.CurrentHealth, 30);
+
+        if (damage > target.CurrentHealth * 1.1f)
+        {
+            score += 10;
+            if ((option.Move.Move.HasFlag("multi_hit") && target.CurrentHealth == target.MaxHealth &&
+                 target.ActiveAbility?.Name == "sturdy") || target.HasHeldItem("focus_sash"))
+            {
+                score += 8;
+            }
+        }
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/AI/AIHelperFunctions.cs

@@ -1,6 +1,7 @@
 using PkmnLib.Dynamic.AI.Explicit;
 using PkmnLib.Plugin.Gen7.Libraries.Battling;
 using PkmnLib.Plugin.Gen7.Scripts.Side;
+using PkmnLib.Plugin.Gen7.Scripts.Status;
 using PkmnLib.Static.Moves;
 
 namespace PkmnLib.Plugin.Gen7.AI;
@@ -157,6 +158,8 @@ public static class AIHelperFunctions
         return true;
     }
 
+    private static readonly StringKey FoulPlayAbilityName = "foul_play";
+
     private static void GetTargetStatRaiseScoreOne(ref int score, IPokemon target, Statistic stat, sbyte increment,
         AIMoveState move, float desireMult = 1)
     {
@@ -200,7 +203,7 @@ public static class AIHelperFunctions
                 {
                     var hasPhysicalMoves = target.Moves.WhereNotNull().Any(x =>
                         x.MoveData.Category == MoveCategory.Physical &&
-                        x.MoveData.SecondaryEffect?.Name != "foul_play");
+                        x.MoveData.SecondaryEffect?.Name != FoulPlayAbilityName);
                     var inc = hasPhysicalMoves ? 8 : 12;
                     score += (int)(inc * incMult);
                 }
@@ -334,4 +337,55 @@ public static class AIHelperFunctions
 
     private static bool Opposes(this IPokemon pokemon, IPokemon target) =>
         pokemon.BattleData?.BattleSide != target.BattleData?.BattleSide;
+
+    public static bool WantsStatusProblem(IPokemon pokemon, StringKey? status)
+    {
+        if (status is null)
+            return true;
+        if (pokemon.ActiveAbility != null)
+        {
+            if (pokemon.ActiveAbility.Name == "guts" && status != ScriptUtils.ResolveName<Sleep>() &&
+                status != ScriptUtils.ResolveName<Frozen>() &&
+                IsStatRaiseWorthwhile(pokemon, Statistic.Attack, 1, true))
+            {
+                return true;
+            }
+            if (pokemon.ActiveAbility.Name == "marvel_scale" &&
+                IsStatRaiseWorthwhile(pokemon, Statistic.Defense, 1, true))
+            {
+                return true;
+            }
+            if (pokemon.ActiveAbility.Name == "quick_feet" && status != ScriptUtils.ResolveName<Sleep>() &&
+                status != ScriptUtils.ResolveName<Frozen>() && IsStatRaiseWorthwhile(pokemon, Statistic.Speed, 1, true))
+            {
+                return true;
+            }
+            if (pokemon.ActiveAbility.Name == "flare_boost" && status == ScriptUtils.ResolveName<Burned>() &&
+                IsStatRaiseWorthwhile(pokemon, Statistic.SpecialAttack, 1, true))
+            {
+                return true;
+            }
+            if (pokemon.ActiveAbility.Name == "toxic_boost" &&
+                (status == ScriptUtils.ResolveName<Poisoned>() || status == ScriptUtils.ResolveName<BadlyPoisoned>()) &&
+                IsStatRaiseWorthwhile(pokemon, Statistic.Attack, 1, true))
+            {
+                return true;
+            }
+            if (pokemon.ActiveAbility.Name == "poison_heal" && status == ScriptUtils.ResolveName<Poisoned>())
+            {
+                return true;
+            }
+            if (pokemon.ActiveAbility.Name == "magic_guard")
+            {
+                if (status != ScriptUtils.ResolveName<Poisoned>() &&
+                    status != ScriptUtils.ResolveName<BadlyPoisoned>() && status != ScriptUtils.ResolveName<Burned>())
+                    return false;
+                if (IsStatRaiseWorthwhile(pokemon, Statistic.Attack, 1, true))
+                {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
 }

Plugins/PkmnLib.Plugin.Gen7/AI/AISwitchFunctions.cs

@@ -0,0 +1,208 @@
+using PkmnLib.Dynamic.AI.Explicit;
+using PkmnLib.Plugin.Gen7.Scripts.Moves;
+using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
+using PkmnLib.Plugin.Gen7.Scripts.Side;
+using PkmnLib.Plugin.Gen7.Scripts.Status;
+using PkmnLib.Static.Moves;
+
+namespace PkmnLib.Plugin.Gen7.AI;
+
+public static class AISwitchFunctions
+{
+    internal static void RegisterAISwitchFunctions(ExplicitAIHandlers handlers)
+    {
+        handlers.ShouldSwitchFunctions.Add("perish_song", PerishSong);
+        handlers.ShouldSwitchFunctions.Add("significant_end_of_turn_damage", SignificantEndOfTurnDamage);
+        handlers.ShouldSwitchFunctions.Add("high_damage_from_foe", HighDamageFromFoe);
+        handlers.ShouldSwitchFunctions.Add("cure_status_problem_by_switching_out", CureStatusProblemBySwitchingOut);
+    }
+
+    /// <summary>
+    /// Switch out if the Perish Song effect is about to cause the Pokémon to faint.
+    /// </summary>
+    private static bool PerishSong(IExplicitAI ai, IPokemon pokemon, IBattle battle, IReadOnlyList<IPokemon> reserves)
+    {
+        if (!pokemon.Volatile.TryGet<PerishSongEffect>(out var effect))
+            return false;
+        return effect.Turns <= 1;
+    }
+
+    private static readonly StringKey PoisonHealAbilityName = "poison_heal";
+
+    /// <summary>
+    /// Switch out if the Pokémon is expected to take significant end-of-turn damage.
+    /// </summary>
+    private static bool SignificantEndOfTurnDamage(IExplicitAI ai, IPokemon pokemon, IBattle battle,
+        IReadOnlyList<IPokemon> reserves)
+    {
+        var eorDamage = 0;
+        pokemon.RunScriptHook<IAIInfoScriptExpectedEndOfTurnDamage>(x =>
+            x.ExpectedEndOfTurnDamage(pokemon, ref eorDamage));
+        if (eorDamage >= pokemon.CurrentHealth / 2 || eorDamage >= pokemon.MaxHealth / 4)
+            return true;
+        if (!ai.TrainerHighSkill || eorDamage <= 0)
+            return false;
+
+        if (pokemon.Volatile.Contains<LeechSeedEffect>() && ai.Random.GetBool())
+            return true;
+        if (pokemon.Volatile.Contains<NightmareEffect>())
+            return true;
+        if (pokemon.Volatile.Contains<GhostCurseEffect>())
+            return true;
+        var statusScript = pokemon.StatusScript.Script;
+        if (statusScript is BadlyPoisoned { Turns: > 0 } badlyPoisoned &&
+            pokemon.ActiveAbility?.Name != PoisonHealAbilityName)
+        {
+            var poisonDamage = pokemon.MaxHealth / 8;
+            var nextToxicDamage = pokemon.MaxHealth * badlyPoisoned.GetPoisonMultiplier();
+            if ((pokemon.CurrentHealth <= nextToxicDamage && pokemon.CurrentHealth > poisonDamage) ||
+                nextToxicDamage > poisonDamage * 2)
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static bool HighDamageFromFoe(IExplicitAI ai, IPokemon pokemon, IBattle battle,
+        IReadOnlyList<IPokemon> reserves)
+    {
+        if (!ai.TrainerHighSkill)
+            return false;
+        if (pokemon.CurrentHealth >= pokemon.MaxHealth / 2)
+            return false;
+        var bigThreat = false;
+        var opponents = battle.Sides.Where(x => x != pokemon.BattleData?.BattleSide)
+            .SelectMany(x => x.Pokemon.WhereNotNull());
+        foreach (var opponent in opponents)
+        {
+            if (Math.Abs(opponent.Level - pokemon.Level) > 5)
+                continue;
+            var lastMoveUsed = opponent.BattleData?.LastMoveChoice;
+            if (lastMoveUsed is null)
+                continue;
+            var moveData = lastMoveUsed.ChosenMove.MoveData;
+            if (moveData.Category == MoveCategory.Status)
+                continue;
+            var effectiveness = pokemon.Library.StaticLibrary.Types.GetEffectiveness(moveData.MoveType, pokemon.Types);
+            if (effectiveness <= 1 || moveData.BasePower < 70)
+                continue;
+            var switchChange = moveData.BasePower > 90 ? 50 : 25;
+            bigThreat = ai.Random.GetInt(100) < switchChange;
+        }
+        return bigThreat;
+    }
+
+    private static readonly StringKey ImmunityAbilityName = "immunity";
+    private static readonly StringKey InsomniaAbilityName = "insomnia";
+    private static readonly StringKey LimberAbilityName = "limber";
+    private static readonly StringKey MagmaArmorAbilityName = "magma_armor";
+    private static readonly StringKey VitalSpiritAbilityName = "vital_spirit";
+    private static readonly StringKey WaterBubbleAbilityName = "water_bubble";
+    private static readonly StringKey WaterVeilAbilityName = "water_veil";
+    private static readonly StringKey NaturalCureAbilityName = "natural_cure";
+    private static readonly StringKey RegeneratorAbilityName = "regenerator";
+
+    private static readonly Dictionary<StringKey, List<StringKey>> StatusCureAbilities = new()
+    {
+        {
+            ImmunityAbilityName,
+            [ScriptUtils.ResolveName<Poisoned>(), ScriptUtils.ResolveName<BadlyPoisoned>()]
+        },
+        { InsomniaAbilityName, [ScriptUtils.ResolveName<Sleep>()] },
+        { LimberAbilityName, [ScriptUtils.ResolveName<Paralyzed>()] },
+        { MagmaArmorAbilityName, [ScriptUtils.ResolveName<Frozen>()] },
+        { VitalSpiritAbilityName, [ScriptUtils.ResolveName<Sleep>()] },
+        { WaterBubbleAbilityName, [ScriptUtils.ResolveName<Burned>()] },
+        { WaterVeilAbilityName, [ScriptUtils.ResolveName<Burned>()] },
+    };
+
+    /// <summary>
+    /// Switch out to cure a status problem or heal HP with abilities like Natural Cure or Regenerator.
+    /// </summary>
+    private static bool CureStatusProblemBySwitchingOut(IExplicitAI ai, IPokemon pokemon, IBattle battle,
+        IReadOnlyList<IPokemon> reserves)
+    {
+        if (pokemon.ActiveAbility == null)
+            return false;
+
+        // Don't try to cure a status problem/heal a bit of HP if entry hazards will
+        // KO the battler if it switches back in
+        var entryHazardDamage = ExplicitAI.CalculateEntryHazardDamage(pokemon, pokemon.BattleData!.BattleSide);
+        if (entryHazardDamage >= pokemon.CurrentHealth)
+            return false;
+        if (pokemon.StatusScript.Script is null)
+            return false;
+
+        var abilityName = pokemon.ActiveAbility.Name;
+        var statusName = pokemon.StatusScript.Script.Name;
+
+        // Check abilities that cure specific status conditions
+        var canCureStatus = false;
+        if (abilityName == NaturalCureAbilityName)
+        {
+            canCureStatus = true;
+        }
+        else if (StatusCureAbilities.TryGetValue(abilityName, out var statusList))
+        {
+            canCureStatus = statusList.Any(status => status == statusName);
+        }
+
+        if (canCureStatus)
+        {
+            if (AIHelperFunctions.WantsStatusProblem(pokemon, statusName))
+                return false;
+
+            // Don't bother if the status will cure itself soon
+            if (pokemon.StatusScript.Script is Sleep { Turns: 1 })
+                return false;
+
+            if (entryHazardDamage >= pokemon.MaxHealth / 4)
+                return false;
+
+            // Don't bother curing a poisoning if Toxic Spikes will just re-poison
+            if (pokemon.StatusScript.Script is Poisoned or BadlyPoisoned &&
+                !reserves.Any(p => p.Types.Any(t => t.Name == "poison")))
+            {
+                if (pokemon.BattleData!.BattleSide.VolatileScripts.TryGet<ToxicSpikesEffect>(out _))
+                {
+                    return false;
+                }
+            }
+
+            // Not worth curing status problems that still allow actions if at high HP
+            var isImmobilizing = pokemon.StatusScript.Script is Sleep or Frozen;
+            if (pokemon.CurrentHealth >= pokemon.MaxHealth / 2 && !isImmobilizing)
+                return false;
+
+            if (ai.Random.GetInt(100) < 70)
+                return true;
+        }
+        else if (abilityName == RegeneratorAbilityName)
+        {
+            // Not worth healing if battler would lose more HP from switching back in later
+            if (entryHazardDamage >= pokemon.MaxHealth / 3)
+                return false;
+
+            // Not worth healing HP if already at high HP
+            if (pokemon.CurrentHealth >= pokemon.MaxHealth / 2)
+                return false;
+
+            // Don't bother if a foe is at low HP and could be knocked out instead
+            var hasDamagingMove = pokemon.Moves.Any(m => m?.MoveData.Category != MoveCategory.Status);
+            if (hasDamagingMove)
+            {
+                var opponents = battle.Sides.Where(x => x != pokemon.BattleData?.BattleSide)
+                    .SelectMany(x => x.Pokemon.WhereNotNull());
+                var weakFoe = opponents.Any(opponent => opponent.CurrentHealth < opponent.MaxHealth / 3);
+                if (weakFoe)
+                    return false;
+            }
+
+            if (ai.Random.GetInt(100) < 70)
+                return true;
+        }
+
+        return false;
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/AI/ExplicitAIFunctionRegistration.cs

@@ -0,0 +1,77 @@
+using System.Linq.Expressions;
+using System.Reflection;
+using PkmnLib.Dynamic.AI.Explicit;
+
+namespace PkmnLib.Plugin.Gen7.AI;
+
+public static class ExplicitAIFunctionRegistration
+{
+    public static void RegisterAIFunctions(ExplicitAIHandlers handlers)
+    {
+        var baseType = typeof(Script);
+        foreach (var type in typeof(ExplicitAIFunctionRegistration).Assembly.GetTypes()
+                     .Where(t => baseType.IsAssignableFrom(t)))
+        {
+            var attribute = type.GetCustomAttribute<ScriptAttribute>();
+            if (attribute == null)
+                continue;
+
+            if (attribute.Category == ScriptCategory.Move)
+            {
+                InitializeMoveFailFunction(handlers, type, attribute);
+                InitializeMoveScoreFunction(handlers, type, attribute);
+            }
+        }
+
+        handlers.GeneralMoveAgainstTargetScore.Add("predicted_damage", AIDamageFunctions.PredictedDamageScore);
+
+        AISwitchFunctions.RegisterAISwitchFunctions(handlers);
+    }
+
+    #region Reflection based function initialization
+
+    private static void InitializeMoveFailFunction(ExplicitAIHandlers handlers, Type type, ScriptAttribute attribute)
+    {
+        var failureMethod = type.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault(m =>
+            m.GetCustomAttribute<AIMoveFailureFunctionAttribute>() != null);
+        if (failureMethod == null)
+            return;
+        if (failureMethod.ReturnType != typeof(bool) || failureMethod.GetParameters().Length != 2 ||
+            failureMethod.GetParameters()[0].ParameterType != typeof(IExplicitAI) ||
+            failureMethod.GetParameters()[1].ParameterType != typeof(MoveOption))
+        {
+            throw new InvalidOperationException(
+                $"Method {failureMethod.Name} in {type.Name} must return bool and take an IExplicitAI and a MoveOption as parameters.");
+        }
+        var aiParam = Expression.Parameter(typeof(IExplicitAI), "ai");
+        var optionParam = Expression.Parameter(typeof(MoveOption), "option");
+        var functionExpression = Expression.Lambda<AIBoolHandler>(
+            Expression.Call(null, failureMethod, aiParam, optionParam), aiParam, optionParam).Compile();
+        handlers.MoveFailureCheck.Add(attribute.Name, functionExpression);
+    }
+
+    private static void InitializeMoveScoreFunction(ExplicitAIHandlers handlers, Type type, ScriptAttribute attribute)
+    {
+        var scoreMethod = type.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault(m =>
+            m.GetCustomAttribute<AIMoveScoreFunctionAttribute>() != null);
+        if (scoreMethod == null)
+            return;
+        if (scoreMethod.ReturnType != typeof(void) || scoreMethod.GetParameters().Length != 3 ||
+            scoreMethod.GetParameters()[0].ParameterType != typeof(IExplicitAI) ||
+            scoreMethod.GetParameters()[1].ParameterType != typeof(MoveOption) ||
+            scoreMethod.GetParameters()[2].ParameterType != typeof(int).MakeByRefType())
+        {
+            throw new InvalidOperationException(
+                $"Method {scoreMethod.Name} in {type.Name} must return void and take an IExplicitAI, a MoveOption, and a ref int as parameters.");
+        }
+        var aiParam = Expression.Parameter(typeof(IExplicitAI), "ai");
+        var optionParam = Expression.Parameter(typeof(MoveOption), "option");
+        var scoreParam = Expression.Parameter(typeof(int).MakeByRefType(), "score");
+        var functionExpression = Expression.Lambda<AIScoreMoveHandler>(
+                Expression.Call(null, scoreMethod, aiParam, optionParam, scoreParam), aiParam, optionParam, scoreParam)
+            .Compile();
+        handlers.MoveEffectScore.Add(attribute.Name, functionExpression);
+    }
+
+    #endregion
+}

Plugins/PkmnLib.Plugin.Gen7/AI/ExplicitAIFunctions.cs

@@ -1,89 +0,0 @@
-using System.Linq.Expressions;
-using System.Reflection;
-using PkmnLib.Dynamic.AI.Explicit;
-using PkmnLib.Plugin.Gen7.Scripts.Moves;
-using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
-using PkmnLib.Static.Moves;
-
-namespace PkmnLib.Plugin.Gen7.AI;
-
-public static class ExplicitAIFunctions
-{
-    public static void RegisterAIFunctions(ExplicitAIHandlers handlers)
-    {
-        var baseType = typeof(Script);
-        foreach (var type in typeof(ExplicitAIFunctions).Assembly.GetTypes().Where(t => baseType.IsAssignableFrom(t)))
-        {
-            var attribute = type.GetCustomAttribute<ScriptAttribute>();
-            if (attribute == null)
-                continue;
-
-            if (attribute.Category == ScriptCategory.Move)
-            {
-                var failureMethod = type.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault(m =>
-                    m.GetCustomAttribute<AIMoveFailureFunctionAttribute>() != null);
-                if (failureMethod != null)
-                {
-                    if (failureMethod.ReturnType != typeof(bool) || failureMethod.GetParameters().Length != 1 ||
-                        failureMethod.GetParameters()[0].ParameterType != typeof(MoveOption))
-                    {
-                        throw new InvalidOperationException(
-                            $"Method {failureMethod.Name} in {type.Name} must return bool and take a single MoveOption parameter.");
-                    }
-                    var optionParam = Expression.Parameter(typeof(MoveOption), "option");
-                    var functionExpression = Expression.Lambda<AIBoolHandler>(
-                        Expression.Call(null, failureMethod, optionParam), optionParam).Compile();
-                    handlers.MoveFailureCheck.Add(attribute.Name, functionExpression);
-                }
-
-                var scoreMethod = type.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault(m =>
-                    m.GetCustomAttribute<AIMoveScoreFunctionAttribute>() != null);
-                if (scoreMethod != null)
-                {
-                    if (scoreMethod.ReturnType != typeof(void) || scoreMethod.GetParameters().Length != 2 ||
-                        scoreMethod.GetParameters()[0].ParameterType != typeof(MoveOption) ||
-                        scoreMethod.GetParameters()[1].ParameterType != typeof(int).MakeByRefType())
-                    {
-                        throw new InvalidOperationException(
-                            $"Method {scoreMethod.Name} in {type.Name} must return void and take a MoveOption and an int by reference parameter.");
-                    }
-                    var optionParam = Expression.Parameter(typeof(MoveOption), "option");
-                    var scoreParam = Expression.Parameter(typeof(int).MakeByRefType(), "score");
-                    var functionExpression = Expression.Lambda<AIScoreMoveHandler>(
-                        Expression.Call(null, scoreMethod, optionParam, scoreParam), optionParam, scoreParam).Compile();
-                    handlers.MoveEffectScore.Add(attribute.Name, functionExpression);
-                }
-            }
-        }
-
-        handlers.GeneralMoveAgainstTargetScore.Add("predicated_damage", PredictedDamageScore);
-    }
-
-    private static void PredictedDamageScore(MoveOption option, ref int score)
-    {
-        var target = option.Target;
-        if (target == null)
-            return;
-        if (option.Move.Move.Category == MoveCategory.Status)
-            return;
-        var damage = option.EstimatedDamage;
-        if (target.Volatile.TryGet<SubstituteEffect>(out var substitute))
-        {
-            var health = substitute.Health;
-            score += (int)Math.Min(15.0f * damage / health, 20);
-            return;
-        }
-
-        score += (int)Math.Min(15.0f * damage / target.CurrentHealth, 30);
-
-        if (damage > target.CurrentHealth * 1.1f)
-        {
-            score += 10;
-            if ((option.Move.Move.HasFlag("multi_hit") && target.CurrentHealth == target.MaxHealth &&
-                 target.ActiveAbility?.Name == "sturdy") || target.HasHeldItem("focus_sash"))
-            {
-                score += 8;
-            }
-        }
-    }
-}

Plugins/PkmnLib.Plugin.Gen7/Gen7Plugin.cs

@@ -50,7 +50,7 @@ public class Gen7Plugin : Plugin<Gen7PluginConfiguration>, IResourceProvider
         registry.RegisterMiscLibrary(new Gen7MiscLibrary());
         registry.RegisterCaptureLibrary(new Gen7CaptureLibrary(Configuration));
 
-        ExplicitAIFunctions.RegisterAIFunctions(registry.ExplicitAIHandlers);
+        ExplicitAIFunctionRegistration.RegisterAIFunctions(registry.ExplicitAIHandlers);
     }
 
     /// <inheritdoc />

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

@@ -60,10 +60,10 @@ public class ChangeUserAttack : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.Attack);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) => WouldMoveFail(option, Statistic.Attack);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.Attack, ref score);
 }
 
@@ -75,10 +75,10 @@ public class ChangeUserDefense : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.Defense);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) => WouldMoveFail(option, Statistic.Defense);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.Defense, ref score);
 }
 
@@ -90,10 +90,11 @@ public class ChangeUserSpecialAttack : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.SpecialAttack);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) =>
+        WouldMoveFail(option, Statistic.SpecialAttack);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.SpecialAttack, ref score);
 }
 
@@ -105,10 +106,11 @@ public class ChangeUserSpecialDefense : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.SpecialDefense);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) =>
+        WouldMoveFail(option, Statistic.SpecialDefense);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.SpecialDefense, ref score);
 }
 
@@ -120,10 +122,10 @@ public class ChangeUserSpeed : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.Speed);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) => WouldMoveFail(option, Statistic.Speed);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.Speed, ref score);
 }
 
@@ -135,10 +137,10 @@ public class ChangeUserAccuracy : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.Accuracy);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) => WouldMoveFail(option, Statistic.Accuracy);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.Accuracy, ref score);
 }
 
@@ -150,9 +152,9 @@ public class ChangeUserEvasion : ChangeUserStats
     }
 
     [AIMoveFailureFunction]
-    public static bool AIMoveWillFail(MoveOption option) => WouldMoveFail(option, Statistic.Evasion);
+    public static bool AIMoveWillFail(IExplicitAI ai, MoveOption option) => WouldMoveFail(option, Statistic.Evasion);
 
     [AIMoveScoreFunction]
-    public static void AIMoveEffectScore(MoveOption option, ref int score) =>
+    public static void AIMoveEffectScore(IExplicitAI ai, MoveOption option, ref int score) =>
         GetMoveEffectScore(option, Statistic.Evasion, ref score);
 }

Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Conversion2.cs

@@ -8,25 +8,7 @@ public class Conversion2 : Script, IScriptOnSecondaryEffect
     {
         var previousTurnChoices = target.BattleData?.Battle.PreviousTurnChoices;
         var nextExecutingChoice = target.BattleData?.Battle.ChoiceQueue?.Peek();
-        var lastMoveByTarget = previousTurnChoices?
-            // The previous turn choices include the choices of the current turn, so we need to have special handling for
-            // the current turn
-            .Select((x, index) =>
-            {
-                // All choices before the current turn are valid
-                if (index < previousTurnChoices.Count - 1)
-                    return x;
-                // If there is no next choice, we're at the end of the list, so we can just return the whole list
-                if (nextExecutingChoice == null)
-                    return x;
-                // Otherwise we determine where the next choice is and return everything before that
-                var indexOfNext = x.IndexOf(nextExecutingChoice);
-                if (indexOfNext == -1)
-                    return x;
-                return x.Take(indexOfNext);
-            }).SelectMany(x => x)
-            // We only want the last move choice by the target
-            .OfType<IMoveChoice>().FirstOrDefault(x => x.User == target);
+        var lastMoveByTarget = target.BattleData?.LastMoveChoice;
         if (lastMoveByTarget == null)
         {
             move.GetHitData(target, hit).Fail();

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

@@ -8,8 +8,7 @@ public class Copycat : Script, IScriptChangeMove
     /// <inheritdoc />
     public void ChangeMove(IMoveChoice choice, ref StringKey moveName)
     {
-        var lastMove = choice.User.BattleData?.Battle.PreviousTurnChoices.SelectMany(x => x).OfType<IMoveChoice>()
-            .LastOrDefault();
+        var lastMove = choice.User.BattleData?.LastMoveChoice;
         if (lastMove == null || !lastMove.ChosenMove.MoveData.CanCopyMove())
         {
             choice.Fail();

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

@@ -11,8 +11,7 @@ public class Disable : Script, IScriptOnSecondaryEffect
         var battleData = move.User.BattleData;
         if (battleData == null)
             return;
-        var choiceQueue = battleData.Battle.PreviousTurnChoices;
-        var lastMove = choiceQueue.SelectMany(x => x).OfType<IMoveChoice>().LastOrDefault(x => x.User == target);
+        var lastMove = target.BattleData?.LastMoveChoice;
         if (lastMove == null)
         {
             move.GetHitData(target, hit).Fail();

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

@@ -12,9 +12,7 @@ public class Encore : Script, IScriptOnSecondaryEffect
         if (battle == null)
             return;
 
-        var currentTurn = battle.ChoiceQueue!.LastRanChoice;
-        var lastMove = battle.PreviousTurnChoices.SelectMany(x => x).OfType<IMoveChoice>()
-            .TakeWhile(x => !Equals(x, currentTurn)).LastOrDefault(x => x.User == target);
+        var lastMove = target.BattleData?.LastMoveChoice;
         if (lastMove == null || battle.Library.MiscLibrary.IsReplacementChoice(lastMove))
         {
             move.GetHitData(target, hit).Fail();

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

@@ -11,7 +11,7 @@ public class FusionBolt : Script, IScriptChangeDamageModifier
             return;
 
         // Grab the choices for the current turn, that have been executed before this move.
-        var choice = battleData.Battle.PreviousTurnChoices.Last().TakeWhile(x => x != move.MoveChoice)
+        var choice = battleData.Battle.PreviousTurnChoices.Last().TakeWhile(x => !Equals(x, move.MoveChoice))
             // Of these, find the move choice that used Fusion Flare.
             .OfType<MoveChoice>().FirstOrDefault(x => x.ChosenMove.MoveData.Name == "fusion_flare");
 

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

@@ -11,7 +11,7 @@ public class FusionFlare : Script, IScriptChangeDamageModifier
             return;
 
         // Grab the choices for the current turn, that have been executed before this move.
-        var choice = battleData.Battle.PreviousTurnChoices.Last().TakeWhile(x => x != move.MoveChoice)
+        var choice = battleData.Battle.PreviousTurnChoices.Last().TakeWhile(x => !Equals(x, move.MoveChoice))
             // Of these, find the move choice that used Fusion Bolt.
             .OfType<MoveChoice>().FirstOrDefault(x => x.ChosenMove.MoveData.Name == "fusion_bolt");
 

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

@@ -14,8 +14,7 @@ public class Instruct : Script, IScriptOnSecondaryEffect
         if (battleData == null)
             return;
 
-        var lastMoveChoiceByTarget = battleData.Battle.PreviousTurnChoices.SelectMany(x => x).Reverse()
-            .SkipWhile(x => x != move.MoveChoice).OfType<MoveChoice>().FirstOrDefault(x => x.User == target);
+        var lastMoveChoiceByTarget = target.BattleData?.LastMoveChoice;
 
         if (lastMoveChoiceByTarget == null || !battleData.Battle.CanUse(lastMoveChoiceByTarget))
         {

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

@@ -21,8 +21,7 @@ public class Sketch : Script, IScriptOnSecondaryEffect
             return;
         }
 
-        var choiceQueue = move.Battle.PreviousTurnChoices;
-        var lastMove = choiceQueue.SelectMany(x => x).OfType<IMoveChoice>().LastOrDefault(x => x.User == target);
+        var lastMove = target.BattleData?.LastMoveChoice;
         if (lastMove == null || lastMove.ChosenMove.MoveData.HasFlag("not_sketchable"))
         {
             move.GetHitData(target, hit).Fail();

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

@@ -6,8 +6,7 @@ public class Spite : Script, IScriptOnSecondaryEffect
     /// <inheritdoc />
     public void OnSecondaryEffect(IExecutingMove move, IPokemon target, byte hit)
     {
-        var lastMoveChoiceByTarget = move.Battle.PreviousTurnChoices.SelectMany(x => x).Reverse()
-            .SkipWhile(x => x != move.MoveChoice).OfType<MoveChoice>().FirstOrDefault(x => x.User == target);
+        var lastMoveChoiceByTarget = target.BattleData?.LastMoveChoice;
         if (lastMoveChoiceByTarget == null || lastMoveChoiceByTarget.HasFailed)
         {
             move.GetHitData(target, hit).Fail();

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

@@ -6,8 +6,7 @@ public class StompingTantrum : Script, IScriptChangeBasePower
     /// <inheritdoc />
     public void ChangeBasePower(IExecutingMove move, IPokemon target, byte hit, ref ushort basePower)
     {
-        var lastMoveChoice = move.Battle.PreviousTurnChoices.Reverse().Skip(1).SelectMany(x => x.Reverse())
-            .OfType<IMoveChoice>().FirstOrDefault(x => x.User == move.User);
+        var lastMoveChoice = move.User.BattleData?.LastMoveChoice;
         if (lastMoveChoice is { HasFailed: true })
         {
             basePower = basePower.MultiplyOrMax(2);

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

@@ -6,8 +6,7 @@ public class Torment : Script, IScriptOnSecondaryEffect
     /// <inheritdoc />
     public void OnSecondaryEffect(IExecutingMove move, IPokemon target, byte hit)
     {
-        var lastTargetChoice = move.Battle.PreviousTurnChoices.SelectMany(x => x).Reverse().OfType<IMoveChoice>()
-            .FirstOrDefault(x => x.User == target);
+        var lastTargetChoice = target.BattleData?.LastMoveChoice;
         target.Volatile.Add(new Pokemon.TormentEffect(lastTargetChoice));
     }
 }

Plugins/PkmnLib.Plugin.Gen7/Scripts/Pokemon/PerishSongEffect.cs

@@ -3,20 +3,20 @@ namespace PkmnLib.Plugin.Gen7.Scripts.Pokemon;
 [Script(ScriptCategory.Pokemon, "perish_song")]
 public class PerishSongEffect : Script, IScriptOnEndTurn
 {
-    private int _turns;
+    internal int Turns { get; private set; }
     private IPokemon _owner;
 
     public PerishSongEffect(IPokemon owner, int turns = 3)
     {
         _owner = owner;
-        _turns = turns;
+        Turns = turns;
     }
 
     /// <inheritdoc />
     public void OnEndTurn(IScriptSource owner, IBattle battle)
     {
-        _turns--;
-        if (_turns <= 0)
+        Turns--;
+        if (Turns <= 0)
         {
             RemoveSelf();
             _owner.Faint(DamageSource.Misc);

Plugins/PkmnLib.Plugin.Gen7/Scripts/Side/SpikesEffect.cs

@@ -1,7 +1,7 @@
 namespace PkmnLib.Plugin.Gen7.Scripts.Side;
 
 [Script(ScriptCategory.Side, "spikes")]
-public class SpikesEffect : Script, IScriptOnSwitchIn, IScriptStack
+public class SpikesEffect : Script, IScriptOnSwitchIn, IScriptStack, IAIInfoScriptExpectedEntryDamage
 {
     private int _layers = 1;
 
@@ -18,14 +18,7 @@ public class SpikesEffect : Script, IScriptOnSwitchIn, IScriptStack
         if (pokemon.IsFloating)
             return;
 
-        var modifier = _layers switch
-        {
-            1 => 1 / 16f,
-            2 => 3 / 16f,
-            3 => 1 / 4f,
-            _ => throw new ArgumentOutOfRangeException(),
-        };
-        var damage = (uint)(pokemon.MaxHealth * modifier);
+        var damage = CalculateDamage(pokemon);
 
         EventBatchId eventBatch = new();
         pokemon.Damage(damage, DamageSource.Misc, eventBatch);
@@ -37,4 +30,26 @@ public class SpikesEffect : Script, IScriptOnSwitchIn, IScriptStack
             BatchId = eventBatch,
         });
     }
+
+    private uint CalculateDamage(IPokemon pokemon)
+    {
+        var modifier = _layers switch
+        {
+            1 => 1 / 16f,
+            2 => 3 / 16f,
+            3 => 1 / 4f,
+            _ => throw new ArgumentOutOfRangeException(),
+        };
+        var damage = (uint)(pokemon.MaxHealth * modifier);
+        return damage;
+    }
+
+    /// <inheritdoc />
+    public void ExpectedEntryDamage(IPokemon pokemon, ref uint damage)
+    {
+        if (pokemon.IsFloating)
+            return;
+
+        damage += CalculateDamage(pokemon);
+    }
 }

Plugins/PkmnLib.Plugin.Gen7/Scripts/Side/StealthRockEffect.cs

@@ -1,18 +1,12 @@
 namespace PkmnLib.Plugin.Gen7.Scripts.Side;
 
 [Script(ScriptCategory.Side, "stealth_rock")]
-public class StealthRockEffect : Script, IScriptOnSwitchIn
+public class StealthRockEffect : Script, IScriptOnSwitchIn, IAIInfoScriptExpectedEntryDamage
 {
     /// <inheritdoc />
     public void OnSwitchIn(IPokemon pokemon, byte position)
     {
-        var typeLibrary = pokemon.Library.StaticLibrary.Types;
-        var effectiveness = 1.0f;
-        if (typeLibrary.TryGetTypeIdentifier("rock", out var rockType))
-        {
-            effectiveness = typeLibrary.GetEffectiveness(rockType, pokemon.Types);
-        }
-        var damage = (uint)(pokemon.MaxHealth / 8f * effectiveness);
+        var damage = CalculateStealthRockDamage(pokemon);
         EventBatchId batchId = new();
         pokemon.Damage(damage, DamageSource.Misc, batchId);
         pokemon.BattleData?.Battle.EventHook.Invoke(new DialogEvent("stealth_rock_damage",
@@ -21,4 +15,21 @@ public class StealthRockEffect : Script, IScriptOnSwitchIn
                 { "pokemon", pokemon },
             }));
     }
+
+    private static uint CalculateStealthRockDamage(IPokemon pokemon)
+    {
+        var typeLibrary = pokemon.Library.StaticLibrary.Types;
+        var effectiveness = 1.0f;
+        if (typeLibrary.TryGetTypeIdentifier("rock", out var rockType))
+        {
+            effectiveness = typeLibrary.GetEffectiveness(rockType, pokemon.Types);
+        }
+        return (uint)(pokemon.MaxHealth / 8f * effectiveness);
+    }
+
+    /// <inheritdoc />
+    public void ExpectedEntryDamage(IPokemon pokemon, ref uint damage)
+    {
+        damage += CalculateStealthRockDamage(pokemon);
+    }
 }

Plugins/PkmnLib.Plugin.Gen7/Scripts/Status/BadlyPoisoned.cs

@@ -3,15 +3,15 @@ namespace PkmnLib.Plugin.Gen7.Scripts.Status;
 [Script(ScriptCategory.Status, "badly_poisoned")]
 public class BadlyPoisoned : Poisoned
 {
-    private int _turns = 1;
+    internal int Turns { get; private set; } = 1;
 
     /// <inheritdoc />
-    public override float GetPoisonMultiplier() => 1f / (16f * _turns);
+    public override float GetPoisonMultiplier() => 1f / (16f * Turns);
 
     /// <inheritdoc />
     public override void OnEndTurn(IScriptSource owner, IBattle battle)
     {
         base.OnEndTurn(owner, battle);
-        _turns = Math.Min(_turns + 1, 15);
+        Turns = Math.Min(Turns + 1, 15);
     }
 }