More abilities, refactor stealing held items

PkmnLib.Dynamic/Models/Pokemon.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics.CodeAnalysis;
 using JetBrains.Annotations;
 using PkmnLib.Dynamic.Events;
 using PkmnLib.Dynamic.Libraries;
@@ -251,6 +252,12 @@ public interface IPokemon : IScriptSource, IDeepCloneable
     /// </remarks>
     IItem? RemoveHeldItemForBattle();
 
+    /// <summary>
+    /// Tries to steal the held item of the Pokémon. If successful, the item is removed from the Pokémon and returned.
+    /// If the Pokémon does not have a held item, or the item is a form changer, this will return false.
+    /// </summary>
+    bool TryStealHeldItem([NotNullWhen(true)] out IItem? item);
+
     /// <summary>
     /// Restores the held item of a Pokémon if it was temporarily removed.
     /// </summary>
@@ -812,6 +819,25 @@ public class PokemonImpl : ScriptSource, IPokemon
         return _stolenHeldItem = RemoveHeldItem();
     }
 
+    /// <inheritdoc />
+    public bool TryStealHeldItem([NotNullWhen(true)] out IItem? item)
+    {
+        if (HeldItem is null || HeldItem.Category == ItemCategory.FormChanger)
+        {
+            item = null;
+            return false;
+        }
+        var prevent = false;
+        this.RunScriptHook(script => script.PreventHeldItemSteal(this, HeldItem, ref prevent));
+        if (prevent)
+        {
+            item = null;
+            return false;
+        }
+        item = RemoveHeldItemForBattle();
+        return item is not null;
+    }
+
     /// <inheritdoc />
     public void RestoreStolenHeldItem()
     {

PkmnLib.Dynamic/ScriptHandling/Script.cs

@@ -812,6 +812,13 @@ public abstract class Script : IDeepCloneable
     {
     }
 
+    /// <summary>
+    /// This function allows a script to prevent a held item from being stolen by an effect such as Thief or Covet.
+    /// </summary>
+    public virtual void PreventHeldItemSteal(IPokemon pokemon, IItem heldItem, ref bool prevent)
+    {
+    }
+
     /// <summary>
     /// This function allows a script to run after a held item has changed. 
     /// </summary>

Plugins/PkmnLib.Plugin.Gen7/Data/Abilities.jsonc

@@ -594,18 +594,37 @@
   "speed_boost": {
     "effect": "speed_boost"
   },
-  "stakeout": {},
-  "stall": {},
-  "stamina": {},
+  "stakeout": {
+    "effect": "stakeout"
+  },
+  "stall": {
+    "effect": "stall"
+  },
+  "stamina": {
+    "effect": "stamina"
+  },
   "stance_change": {
+    "effect": "stance_change",
     "canBeChanged": false
   },
-  "static": {},
-  "steadfast": {},
-  "steelworker": {},
-  "stench": {},
-  "sticky_hold": {},
-  "storm_drain": {},
+  "static": {
+    "effect": "static"
+  },
+  "steadfast": {
+    "effect": "steadfast"
+  },
+  "steelworker": {
+    "effect": "steelworker"
+  },
+  "stench": {
+    "effect": "stench"
+  },
+  "sticky_hold": {
+    "effect": "sticky_hold"
+  },
+  "storm_drain": {
+    "effect": "storm_drain"
+  },
   "strong_jaw": {},
   "sturdy": {},
   "suction_cups": {},

Plugins/PkmnLib.Plugin.Gen7/Data/Pokemon.json

@@ -946,6 +946,7 @@
     "flags": [],
     "formes": {
       "blade": {
+        "isBattleOnly": true,
         "abilities": [
           "stance_change"
         ],

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Magician.cs

@@ -19,7 +19,10 @@ public class Magician : Script
         if (move.User.HeldItem is not null || target.HeldItem is null)
             return;
 
+        if (!move.User.TryStealHeldItem(out var item))
+            return;
+
         move.Battle.EventHook.Invoke(new AbilityTriggerEvent(move.User));
-        _ = move.User.SetHeldItem(target.RemoveHeldItemForBattle());
+        _ = move.User.SetHeldItem(item);
     }
 }

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Pickpocket.cs

@@ -11,10 +11,10 @@ public class Pickpocket : Script
     /// <inheritdoc />
     public override void OnIncomingHit(IExecutingMove move, IPokemon target, byte hit)
     {
-        if (move.GetHitData(target, hit).IsContact && target.HeldItem is null && move.User.HeldItem is not null)
-        {
+        if (!move.GetHitData(target, hit).IsContact || target.HeldItem is not null ||
+            !move.User.TryStealHeldItem(out var item))
+            return;
         move.Battle.EventHook.Invoke(new AbilityTriggerEvent(target));
-            _ = target.SetHeldItem(move.User.RemoveHeldItemForBattle());
-        }
+        _ = target.SetHeldItem(item);
     }
 }

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Stakeout.cs

@@ -0,0 +1,17 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Stakeout is an ability that doubles the damage dealt to Pokémon that have switched in this turn.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Stakeout_(Ability)">Bulbapedia - Stakeout</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "stakeout")]
+public class Stakeout : Script
+{
+    /// <inheritdoc />
+    public override void ChangeBasePower(IExecutingMove move, IPokemon target, byte hit, ref ushort basePower)
+    {
+        if (target.BattleData?.SwitchInTurn == move.Battle.CurrentTurnNumber)
+            basePower = basePower.MultiplyOrMax(2);
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Stall.cs

@@ -0,0 +1,16 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Stall is an ability that makes the Pokémon move last in its priority bracket.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Stall_(Ability)">Bulbapedia - Stall</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "stall")]
+public class Stall : Script
+{
+    /// <inheritdoc />
+    public override void ChangeSpeed(ITurnChoice choice, ref uint speed)
+    {
+        speed = 0;
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Stamina.cs

@@ -0,0 +1,23 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Stamina is an ability that raises the user's Defense by one stage when hit by an attack.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Stamina_(Ability)">Bulbapedia - Stamina</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "stamina")]
+public class Stamina : Script
+{
+    /// <inheritdoc />
+    public override void OnIncomingHit(IExecutingMove move, IPokemon target, byte hit)
+    {
+        EventBatchId batchId = new();
+        if (target.ChangeStatBoost(Statistic.Defense, 1, true, false, batchId))
+        {
+            move.Battle.EventHook.Invoke(new AbilityTriggerEvent(target)
+            {
+                BatchId = batchId,
+            });
+        }
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/StanceChange.cs

@@ -0,0 +1,30 @@
+using PkmnLib.Static.Moves;
+
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Stance Change is an ability that changes Aegislash's form depending on the move used.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Stance_Change_(Ability)">Bulbapedia - Stance Change</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "stance_change")]
+public class StanceChange : Script
+{
+    /// <inheritdoc />
+    public override void OnBeforeMove(IExecutingMove move)
+    {
+        if (move.User.Species.Name != "aegislash")
+            return;
+
+        if (move.UseMove.Category is not (MoveCategory.Physical or MoveCategory.Special) ||
+            move.User.Form.Name == "blade" || !move.User.Species.TryGetForm("blade", out var bladeForm))
+            return;
+        EventBatchId batchId = new();
+        move.Battle.EventHook.Invoke(new AbilityTriggerEvent(move.User)
+        {
+            BatchId = batchId,
+        });
+        move.User.ChangeForm(bladeForm, batchId);
+        // Kings shield is handled in the move script.
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Static.cs

@@ -0,0 +1,31 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Static is an ability that may paralyze attackers using contact moves.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Static_(Ability)">Bulbapedia - Static</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "static")]
+public class Static : Script
+{
+    private const int ChanceToParalyze = 30;
+
+    /// <inheritdoc />
+    public override void OnIncomingHit(IExecutingMove move, IPokemon target, byte hit)
+    {
+        if (!move.GetHitData(target, hit).IsContact)
+            return;
+
+        if (move.Battle.Random.GetInt(0, 100) < ChanceToParalyze)
+        {
+            EventBatchId batchId = new();
+            if (target.SetStatus(ScriptUtils.ResolveName<Status.Paralyzed>(), false, batchId))
+            {
+                move.Battle.EventHook.Invoke(new AbilityTriggerEvent(target)
+                {
+                    BatchId = batchId,
+                });
+            }
+        }
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Steadfast.cs

@@ -0,0 +1,26 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Steadfast is an ability that raises the user's Speed each time it flinches.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Steadfast_(Ability)">Bulbapedia - Steadfast</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "steadfast")]
+public class Steadfast : Script
+{
+    /// <inheritdoc />
+    public override void CustomTrigger(StringKey eventName, ICustomTriggerArgs args)
+    {
+        if (eventName != CustomTriggers.OnFlinch)
+            return;
+        if (args is not CustomTriggers.OnFlinchArgs flinchArgs)
+            return;
+
+        EventBatchId batchId = new();
+        flinchArgs.Move.Battle.EventHook.Invoke(new AbilityTriggerEvent(flinchArgs.Move.User)
+        {
+            BatchId = batchId,
+        });
+        flinchArgs.Move.User.ChangeStatBoost(Statistic.Speed, 1, true, false, batchId);
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Steelworker.cs

@@ -0,0 +1,20 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Steelworker is an ability that boosts the power of Steel-type moves.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Steelworker_(Ability)">Bulbapedia - Steelworker</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "steelworker")]
+public class Steelworker : Script
+{
+    /// <inheritdoc />
+    public override void ChangeOffensiveStatValue(IExecutingMove move, IPokemon target, byte hit, uint defensiveStat,
+        ImmutableStatisticSet<uint> targetStats, Statistic stat, ref uint value)
+    {
+        if (move.GetHitData(target, hit).Type?.Name == "steel")
+        {
+            value = value.MultiplyOrMax(1.5f);
+        }
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Stench.cs

@@ -0,0 +1,21 @@
+using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
+
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Stench is an ability that may cause the target to flinch when hit by a damaging move.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Stench_(Ability)">Bulbapedia - Stench</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "stench")]
+public class Stench : Script
+{
+    /// <inheritdoc />
+    public override void OnSecondaryEffect(IExecutingMove move, IPokemon target, byte hit)
+    {
+        if (move.Battle.Random.GetInt(100) >= 10)
+            return;
+        move.Battle.EventHook.Invoke(new AbilityTriggerEvent(move.User));
+        target.Volatile.Add(new FlinchEffect());
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/StickyHold.cs

@@ -0,0 +1,16 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Sticky Hold is an ability that prevents the Pokémon's held item from being taken.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Sticky_Hold_(Ability)">Bulbapedia - Sticky Hold</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "sticky_hold")]
+public class StickyHold : Script
+{
+    /// <inheritdoc />
+    public override void PreventHeldItemSteal(IPokemon pokemon, IItem heldItem, ref bool prevent)
+    {
+        prevent = true;
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/StormDrain.cs

@@ -0,0 +1,34 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Storm Drain is an ability that draws in all Water-type moves to up its Special Attack.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Storm_Drain_(Ability)">Bulbapedia - Storm Drain</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "storm_drain")]
+public class StormDrain : Script
+{
+    /// <inheritdoc />
+    public override void ChangeIncomingTargets(IMoveChoice moveChoice, ref IReadOnlyList<IPokemon?> targets)
+    {
+        if (moveChoice.ChosenMove.MoveData.MoveType.Name == "water" && targets.Count == 1)
+        {
+            targets = [moveChoice.User];
+        }
+    }
+
+    /// <inheritdoc />
+    public override void ChangeEffectiveness(IExecutingMove move, IPokemon target, byte hit, ref float effectiveness)
+    {
+        if (move.GetHitData(target, hit).Type?.Name != "water")
+            return;
+
+        effectiveness = 0f;
+        EventBatchId batchId = new();
+        move.Battle.EventHook.Invoke(new AbilityTriggerEvent(move.User)
+        {
+            BatchId = batchId,
+        });
+        move.User.ChangeStatBoost(Statistic.SpecialAttack, 1, true, true, batchId);
+    }
+}

Plugins/PkmnLib.Plugin.Gen7/Scripts/CustomTriggers.cs

@@ -132,4 +132,11 @@ public static class CustomTriggers
     {
         public byte NumberOfHits { get; set; } = NumberOfHits;
     }
+
+    public static readonly StringKey OnFlinch = "on_flinch";
+
+    public record OnFlinchArgs(IExecutingMove Move) : ICustomTriggerArgs
+    {
+        public bool Prevent { get; set; } = false;
+    }
 }

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

@@ -13,11 +13,12 @@ public class BugBite : Script
 
         var targetHeldItem = target.HeldItem;
 
-        if (targetHeldItem is not { Category: ItemCategory.Berry })
+        if (targetHeldItem is not { Category: ItemCategory.Berry } || !target.TryStealHeldItem(out targetHeldItem))
         {
             move.GetHitData(target, hit).Fail();
             return;
         }
+
         _ = target.SetHeldItem(null);
         targetHeldItem.RunItemScript(battleData.Battle.Library.ScriptResolver, user);
     }

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

@@ -8,8 +8,8 @@ public class Covet : Script
     {
         if (target.HeldItem == null)
             return;
-        if (move.User.HeldItem != null)
+        if (!move.User.TryStealHeldItem(out var item))
             return;
-        _ = move.User.SetHeldItem(target.RemoveHeldItemForBattle());
+        _ = move.User.SetHeldItem(item);
     }
 }

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

@@ -6,9 +6,11 @@ public class Incinerate : Script
     /// <inheritdoc />
     public override void OnSecondaryEffect(IExecutingMove move, IPokemon target, byte hit)
     {
-        if (target.HeldItem is { Category: ItemCategory.Berry })
+        if (target.HeldItem is not { Category: ItemCategory.Berry } || !target.TryStealHeldItem(out _))
         {
-            target.RemoveHeldItemForBattle();
+            move.GetHitData(target, hit).Fail();
+            return;
         }
+        // TODO: Add message for item incineration
     }
 }

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

@@ -6,7 +6,7 @@ public class KnockOff : Script
     /// <inheritdoc />
     public override void OnSecondaryEffect(IExecutingMove move, IPokemon target, byte hit)
     {
-        if (target.RemoveHeldItemForBattle() is null)
+        if (!target.TryStealHeldItem(out var item))
         {
             move.GetHitData(target, hit).Fail();
         }

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

@@ -7,6 +7,11 @@ public class FlinchEffect : Script
     public override void PreventMove(IExecutingMove move, ref bool prevent)
     {
         prevent = true;
+        var args = new CustomTriggers.OnFlinchArgs(move);
+        move.RunScriptHook(x => x.CustomTrigger(CustomTriggers.OnFlinch, args));
+        if (args.Prevent)
+            return;
+
         RemoveSelf();
     }
 }