From 0518499a4cfb8ec6e9334eb0776c8d37ea13d54c Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Fri, 10 Jan 2025 11:11:50 +0100
Subject: [PATCH] Initial set up for item use

---
 PkmnLib.Dataloader/CommonDataLoaderHelper.cs  | 21 ++++++++
 PkmnLib.Dataloader/ItemDataLoader.cs          | 16 +++---
 PkmnLib.Dataloader/Models/SerializedItem.cs   |  2 +
 PkmnLib.Dataloader/MoveDataLoader.cs          | 12 +----
 PkmnLib.Dynamic/Libraries/DynamicLibrary.cs   |  2 +-
 PkmnLib.Dynamic/Models/Battle.cs              |  3 +-
 .../Models/BattleFlow/MoveTurnExecutor.cs     |  4 +-
 .../Models/BattleFlow/TurnRunner.cs           | 36 ++++++++++++-
 PkmnLib.Dynamic/Models/Choices/ItemChoice.cs  | 23 +++++++-
 PkmnLib.Dynamic/Models/Choices/MoveChoice.cs  |  4 +-
 PkmnLib.Dynamic/Models/Pokemon.cs             |  8 +--
 PkmnLib.Dynamic/ScriptHandling/ItemScript.cs  | 54 +++++++++++++++++++
 .../Registry/ItemScriptAttribute.cs           | 20 +++++++
 .../ScriptHandling/Registry/ScriptRegistry.cs | 32 ++++++++++-
 PkmnLib.Dynamic/ScriptHandling/Script.cs      |  3 +-
 .../ScriptHandling/ScriptResolver.cs          | 38 ++++++++++---
 PkmnLib.Static/Item.cs                        | 14 ++++-
 PkmnLib.Tests/Data/Items.json                 | 16 +++---
 .../Scripts/Items/HealingItem.cs              | 40 ++++++++++++++
 .../Scripts/Moves/ChangeAllTargetStats.cs     |  3 +-
 .../Scripts/Moves/ChangeTargetStats.cs        |  3 +-
 .../Scripts/Moves/Drain.cs                    |  5 +-
 .../Scripts/Moves/HealEachEndOfTurn.cs        |  5 +-
 23 files changed, 305 insertions(+), 59 deletions(-)
 create mode 100644 PkmnLib.Dataloader/CommonDataLoaderHelper.cs
 create mode 100644 PkmnLib.Dynamic/ScriptHandling/ItemScript.cs
 create mode 100644 PkmnLib.Dynamic/ScriptHandling/Registry/ItemScriptAttribute.cs
 create mode 100644 Plugins/PkmnLib.Plugin.Gen7/Scripts/Items/HealingItem.cs

diff --git a/PkmnLib.Dataloader/CommonDataLoaderHelper.cs b/PkmnLib.Dataloader/CommonDataLoaderHelper.cs
new file mode 100644
index 0000000..86d09c4
--- /dev/null
+++ b/PkmnLib.Dataloader/CommonDataLoaderHelper.cs
@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+using System.Linq;
+using PkmnLib.Dataloader.Models;
+using PkmnLib.Static.Moves;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Dataloader;
+
+internal static class CommonDataLoaderHelper
+{
+    internal static ISecondaryEffect? ParseEffect(this SerializedMoveEffect? effect)
+    {
+        if (effect == null)
+            return null;
+        var name = effect.Name;
+        var chance = effect.Chance;
+        var parameters = effect.Parameters?.ToDictionary(x => (StringKey)x.Key, x => x.Value.ToParameter()) ??
+                         new Dictionary<StringKey, object?>();
+        return new SecondaryEffectImpl(chance, name, parameters);
+    }
+}
\ No newline at end of file
diff --git a/PkmnLib.Dataloader/ItemDataLoader.cs b/PkmnLib.Dataloader/ItemDataLoader.cs
index 8d2e864..6f9fed3 100644
--- a/PkmnLib.Dataloader/ItemDataLoader.cs
+++ b/PkmnLib.Dataloader/ItemDataLoader.cs
@@ -7,6 +7,7 @@ using System.Text.Json;
 using PkmnLib.Dataloader.Models;
 using PkmnLib.Static;
 using PkmnLib.Static.Libraries;
+using PkmnLib.Static.Moves;
 using PkmnLib.Static.Utils;
 
 namespace PkmnLib.Dataloader;
@@ -27,20 +28,23 @@ public static class ItemDataLoader
             library.Add(i);
         return library;
     }
-    
+
+    // ReSharper disable once MemberCanBePrivate.Global
     public static Func<SerializedItem, StringKey, ItemCategory, BattleItemCategory, int,
-        IEnumerable<StringKey>, IItem> ItemConstructor = (_, name, type, battleType, price, flags) =>
-    {
-        return new ItemImpl(name, type, battleType, price, flags);
-    };
+        IEnumerable<StringKey>, ISecondaryEffect?, ISecondaryEffect?,
+        // ReSharper disable once FieldCanBeMadeReadOnly.Global
+        IItem> ItemConstructor = (_, name, type, battleType, price, flags, effect, battleTriggerEffect) =>
+        new ItemImpl(name, type, battleType, price, flags, effect, battleTriggerEffect);
 
     private static IItem DeserializeItem(SerializedItem serialized)
     {
         if (!Enum.TryParse<ItemCategory>(serialized.ItemType, true, out var itemType))
             throw new InvalidDataException($"Item type {serialized.ItemType} is not valid for item {serialized.Name}.");
         Enum.TryParse(serialized.BattleType, true, out BattleItemCategory battleType);
+        var effect = serialized.Effect?.ParseEffect();
+        var battleTriggerEffect = serialized.BattleEffect?.ParseEffect();
 
         return ItemConstructor(serialized, serialized.Name, itemType, battleType, serialized.Price,
-            serialized.Flags.Select(x => (StringKey)x).ToImmutableHashSet());
+            serialized.Flags.Select(x => (StringKey)x).ToImmutableHashSet(), effect, battleTriggerEffect);
     }
 }
\ No newline at end of file
diff --git a/PkmnLib.Dataloader/Models/SerializedItem.cs b/PkmnLib.Dataloader/Models/SerializedItem.cs
index 4706a7e..fbbf53e 100644
--- a/PkmnLib.Dataloader/Models/SerializedItem.cs
+++ b/PkmnLib.Dataloader/Models/SerializedItem.cs
@@ -12,6 +12,8 @@ public class SerializedItem
     public string[] Flags { get; set; } = null!;
     public int Price { get; set; }
     public byte FlingPower { get; set; }
+    public SerializedMoveEffect? Effect { get; set; }
+    public SerializedMoveEffect? BattleEffect { get; set; }
     
     [JsonExtensionData]
     public Dictionary<string, JsonElement>? ExtensionData { get; set; }
diff --git a/PkmnLib.Dataloader/MoveDataLoader.cs b/PkmnLib.Dataloader/MoveDataLoader.cs
index 3ef1b87..7abd882 100644
--- a/PkmnLib.Dataloader/MoveDataLoader.cs
+++ b/PkmnLib.Dataloader/MoveDataLoader.cs
@@ -57,21 +57,11 @@ public static class MoveDataLoader
             throw new InvalidDataException($"Category {category} is not a valid category.");
         if (!Enum.TryParse<MoveTarget>(target, true, out var targetEnum))
             throw new InvalidDataException($"Target {target} is not a valid target.");
-        var secondaryEffect = ParseEffect(effect);
+        var secondaryEffect = effect.ParseEffect();
 
         var move = MoveConstructor(serialized, serialized.Name, typeIdentifier, categoryEnum, power, accuracy, pp, targetEnum,
             priority, secondaryEffect, flags.Select(x => (StringKey)x).ToImmutableHashSet());
         return move;
     }
 
-    private static ISecondaryEffect? ParseEffect(SerializedMoveEffect? effect)
-    {
-        if (effect == null)
-            return null;
-        var name = effect.Name;
-        var chance = effect.Chance;
-        var parameters = effect.Parameters?.ToDictionary(x => (StringKey)x.Key, x => x.Value.ToParameter()) ??
-                         new Dictionary<StringKey, object?>();
-        return new SecondaryEffectImpl(chance, name, parameters);
-    }
 }
\ No newline at end of file
diff --git a/PkmnLib.Dynamic/Libraries/DynamicLibrary.cs b/PkmnLib.Dynamic/Libraries/DynamicLibrary.cs
index 3f282fd..0e1f1e0 100644
--- a/PkmnLib.Dynamic/Libraries/DynamicLibrary.cs
+++ b/PkmnLib.Dynamic/Libraries/DynamicLibrary.cs
@@ -58,7 +58,7 @@ public class DynamicLibraryImpl : IDynamicLibrary
             throw new InvalidOperationException("Stat calculator not found in plugins.");
         if (registry.MiscLibrary is null)
             throw new InvalidOperationException("Misc library not found in plugins.");
-        var scriptResolver = new ScriptResolver(registry.ScriptTypes);
+        var scriptResolver = new ScriptResolver(registry.ScriptTypes, registry.ItemScriptTypes);
         return new DynamicLibraryImpl(staticLibrary, registry.BattleStatCalculator,
             registry.DamageCalculator, registry.MiscLibrary, scriptResolver);
     }
diff --git a/PkmnLib.Dynamic/Models/Battle.cs b/PkmnLib.Dynamic/Models/Battle.cs
index a807983..3924d28 100644
--- a/PkmnLib.Dynamic/Models/Battle.cs
+++ b/PkmnLib.Dynamic/Models/Battle.cs
@@ -314,10 +314,9 @@ public class BattleImpl : ScriptSource, IBattle
     {
         if (weatherName.HasValue)
         {
-            if (!Library.ScriptResolver.TryResolve(ScriptCategory.Weather, weatherName.Value, out var script))
+            if (!Library.ScriptResolver.TryResolve(ScriptCategory.Weather, weatherName.Value, null, out var script))
                 throw new InvalidOperationException($"Weather script {weatherName} not found.");
             _weatherScript.Set(script);
-            script.OnInitialize(Library, null);
         }
         else
         {
diff --git a/PkmnLib.Dynamic/Models/BattleFlow/MoveTurnExecutor.cs b/PkmnLib.Dynamic/Models/BattleFlow/MoveTurnExecutor.cs
index caef755..d9921f2 100644
--- a/PkmnLib.Dynamic/Models/BattleFlow/MoveTurnExecutor.cs
+++ b/PkmnLib.Dynamic/Models/BattleFlow/MoveTurnExecutor.cs
@@ -25,10 +25,10 @@ internal static class MoveTurnExecutor
             var secondaryEffect = moveData.SecondaryEffect;
             if (secondaryEffect != null)
             {
-                if (moveChoice.User.Library.ScriptResolver.TryResolve(ScriptCategory.Move, secondaryEffect.Name, out var script))
+                if (moveChoice.User.Library.ScriptResolver.TryResolve(ScriptCategory.Move, secondaryEffect.Name,
+                        secondaryEffect.Parameters, out var script))
                 {
                     moveChoice.Script.Set(script);
-                    script.OnInitialize(moveChoice.User.Library, secondaryEffect.Parameters);
                 }
             }
 
diff --git a/PkmnLib.Dynamic/Models/BattleFlow/TurnRunner.cs b/PkmnLib.Dynamic/Models/BattleFlow/TurnRunner.cs
index b0d6290..acb1957 100644
--- a/PkmnLib.Dynamic/Models/BattleFlow/TurnRunner.cs
+++ b/PkmnLib.Dynamic/Models/BattleFlow/TurnRunner.cs
@@ -90,7 +90,9 @@ public static class TurnRunner
             case IFleeChoice fleeChoice:
                 ExecuteFleeChoice(battle, fleeChoice);
                 break;
-            // TODO: Implement item choice types
+            case IItemChoice itemChoice:
+                ExecuteItemChoice(battle, itemChoice);
+                break;
         }
     }
 
@@ -155,4 +157,36 @@ public static class TurnRunner
         battle.ValidateBattleState();
     }
 
+    private static void ExecuteItemChoice(IBattle battle, IItemChoice itemChoice)
+    {
+        var user = itemChoice.User;
+        var battleData = user.BattleData;
+        if (battleData == null)
+            return;
+        if (!battle.Library.ScriptResolver.TryResolveBattleItemScript(itemChoice.Item, out var itemScript))
+        {
+            return;
+        }
+        if (!itemScript.IsItemUsable)
+            return;
+        itemScript.OnInitialize(itemChoice.Item.BattleEffect!.Parameters);
+        IPokemon? target = null;
+        if (itemChoice is { TargetSide: not null, TargetPosition: not null })
+        {
+            var side = battle.Sides[itemChoice.TargetSide.Value];
+            target = side.Pokemon[itemChoice.TargetPosition.Value];
+        }
+
+        var requiresTarget = itemScript.RequiresTarget;
+        if (requiresTarget)
+        {
+            target ??= user;
+            itemScript.OnUseWithTarget(target);
+        }
+        else
+        {
+            itemScript.OnUse();
+        }
+    }
+
 }
\ No newline at end of file
diff --git a/PkmnLib.Dynamic/Models/Choices/ItemChoice.cs b/PkmnLib.Dynamic/Models/Choices/ItemChoice.cs
index 38535ec..80b6e72 100644
--- a/PkmnLib.Dynamic/Models/Choices/ItemChoice.cs
+++ b/PkmnLib.Dynamic/Models/Choices/ItemChoice.cs
@@ -8,19 +8,40 @@ namespace PkmnLib.Dynamic.Models.Choices;
 /// </summary>
 public interface IItemChoice : ITurnChoice
 {
+    /// <summary>
+    /// The item that is used.
+    /// </summary>
+    public IItem Item { get; }
     
+    /// <summary>
+    /// The side the move is targeted at.
+    /// </summary>
+    byte? TargetSide { get; }
+
+    /// <summary>
+    /// The position the move is targeted at.
+    /// </summary>
+    byte? TargetPosition { get; }
 }
 
 /// <inheritdoc cref="IItemChoice"/>
 public class ItemChoice : TurnChoice, IItemChoice
 {
-    public ItemChoice(IPokemon user, IItem item) : base(user)
+    public ItemChoice(IPokemon user, IItem item, byte? targetSide, byte? targetPosition) : base(user)
     {
         Item = item;
+        TargetSide = targetSide;
+        TargetPosition = targetPosition;
     }
 
     public IItem Item { get; }
 
+    /// <inheritdoc />
+    public byte? TargetSide { get; }
+
+    /// <inheritdoc />
+    public byte? TargetPosition { get; }
+
     /// <inheritdoc />
     public override int ScriptCount => User.ScriptCount;
 
diff --git a/PkmnLib.Dynamic/Models/Choices/MoveChoice.cs b/PkmnLib.Dynamic/Models/Choices/MoveChoice.cs
index b45c4f9..054c1a8 100644
--- a/PkmnLib.Dynamic/Models/Choices/MoveChoice.cs
+++ b/PkmnLib.Dynamic/Models/Choices/MoveChoice.cs
@@ -46,10 +46,10 @@ public class MoveChoice : TurnChoice, IMoveChoice
         var secondaryEffect = usedMove.MoveData.SecondaryEffect;
         if (secondaryEffect != null)
         {
-            if (user.Library.ScriptResolver.TryResolve(ScriptCategory.Move, secondaryEffect.Name, out var script))
+            if (user.Library.ScriptResolver.TryResolve(ScriptCategory.Move, secondaryEffect.Name,
+                    secondaryEffect.Parameters, out var script))
             {
                 Script.Set(script);
-                script.OnInitialize(user.Library, secondaryEffect.Parameters);
             }
         }
     }
diff --git a/PkmnLib.Dynamic/Models/Pokemon.cs b/PkmnLib.Dynamic/Models/Pokemon.cs
index 8d642b4..9780b5d 100644
--- a/PkmnLib.Dynamic/Models/Pokemon.cs
+++ b/PkmnLib.Dynamic/Models/Pokemon.cs
@@ -465,7 +465,7 @@ public class PokemonImpl : ScriptSource, IPokemon
 
         if (serializedPokemon.Status != null)
         {
-            if (!library.ScriptResolver.TryResolve(ScriptCategory.Status, serializedPokemon.Status,
+            if (!library.ScriptResolver.TryResolve(ScriptCategory.Status, serializedPokemon.Status, null,
                     out var statusScript))
                 throw new KeyNotFoundException($"Status script {serializedPokemon.Status} not found");
             StatusScript.Set(statusScript);
@@ -668,7 +668,7 @@ public class PokemonImpl : ScriptSource, IPokemon
     {
         if (HeldItem is null)
             return false;
-        if (!Library.ScriptResolver.TryResolveItemScript(HeldItem, out _))
+        if (!Library.ScriptResolver.TryResolveBattleItemScript(HeldItem, out _))
             return false;
         // TODO: actually consume the item
         throw new NotImplementedException();
@@ -777,10 +777,10 @@ public class PokemonImpl : ScriptSource, IPokemon
             AbilityScript.Clear();
             if (!Library.StaticLibrary.Abilities.TryGet(newAbility, out var ability))
                 throw new KeyNotFoundException($"Ability {newAbility} not found.");
-            if (Library.ScriptResolver.TryResolve(ScriptCategory.Ability, newAbility, out var abilityScript))
+            if (Library.ScriptResolver.TryResolve(ScriptCategory.Ability, newAbility, ability.Parameters,
+                    out var abilityScript))
             {
                 AbilityScript.Set(abilityScript);
-                abilityScript.OnInitialize(Library, ability.Parameters);
             }
             else
             {
diff --git a/PkmnLib.Dynamic/ScriptHandling/ItemScript.cs b/PkmnLib.Dynamic/ScriptHandling/ItemScript.cs
new file mode 100644
index 0000000..be0920d
--- /dev/null
+++ b/PkmnLib.Dynamic/ScriptHandling/ItemScript.cs
@@ -0,0 +1,54 @@
+using PkmnLib.Dynamic.Models;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Dynamic.ScriptHandling;
+
+public abstract class ItemScript : IDeepCloneable
+{
+    /// <summary>
+    /// Initializes the script with the given parameters for a specific item
+    /// </summary>
+    public virtual void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
+    {
+    }
+
+    /// <summary>
+    /// Returns whether the item is usable in the current context.
+    /// </summary>
+    public virtual bool IsItemUsable => false;
+
+    /// <summary>
+    /// Returns whether the item requires a target to be used.
+    /// </summary>
+    public virtual bool RequiresTarget => false;
+
+    /// <summary>
+    /// Returns whether the item is usable on the given target.
+    /// </summary>
+    public virtual bool IsTargetValid(IPokemon target) => false;
+
+    /// <summary>
+    /// Returns whether the item can be held by a Pokémon.
+    /// </summary>
+    public virtual bool IsHoldable => false;
+
+    /// <summary>
+    /// Returns whether the item can be held by the given target.
+    /// </summary>
+    public virtual bool CanTargetHold(IPokemon pokemon) => false;
+
+    /// <summary>
+    /// Handles the use of the item.
+    /// </summary>
+    public virtual void OnUse()
+    {
+    }
+
+    /// <summary>
+    /// Handles the use of the item on the given target.
+    /// </summary>
+    /// <param name="target"></param>
+    public virtual void OnUseWithTarget(IPokemon target)
+    {
+    }
+}
\ No newline at end of file
diff --git a/PkmnLib.Dynamic/ScriptHandling/Registry/ItemScriptAttribute.cs b/PkmnLib.Dynamic/ScriptHandling/Registry/ItemScriptAttribute.cs
new file mode 100644
index 0000000..e4e4d76
--- /dev/null
+++ b/PkmnLib.Dynamic/ScriptHandling/Registry/ItemScriptAttribute.cs
@@ -0,0 +1,20 @@
+using JetBrains.Annotations;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Dynamic.ScriptHandling.Registry;
+
+[AttributeUsage(AttributeTargets.Class)]
+[MeansImplicitUse]
+public class ItemScriptAttribute : Attribute
+{
+    /// <summary>
+    /// The name of the script.
+    /// </summary>
+    public StringKey Name { get; }
+
+    /// <inheritdoc cref="ItemScriptAttribute"/>
+    public ItemScriptAttribute(string name)
+    {
+        Name = name;
+    }
+}
\ No newline at end of file
diff --git a/PkmnLib.Dynamic/ScriptHandling/Registry/ScriptRegistry.cs b/PkmnLib.Dynamic/ScriptHandling/Registry/ScriptRegistry.cs
index 0df56c5..8c22b63 100644
--- a/PkmnLib.Dynamic/ScriptHandling/Registry/ScriptRegistry.cs
+++ b/PkmnLib.Dynamic/ScriptHandling/Registry/ScriptRegistry.cs
@@ -13,6 +13,7 @@ namespace PkmnLib.Dynamic.ScriptHandling.Registry;
 public class ScriptRegistry
 {
     private readonly Dictionary<(ScriptCategory category, StringKey name), Func<Script>> _scriptTypes = new();
+    private readonly Dictionary<StringKey, Func<ItemScript>> _itemScriptTypes = new();
     private IBattleStatCalculator? _battleStatCalculator;
     private IDamageCalculator? _damageCalculator;
     private IMiscLibrary? _miscLibrary;
@@ -32,6 +33,15 @@ public class ScriptRegistry
 
             RegisterScriptType(attribute.Category, attribute.Name, type);
         }
+        var itemBaseType = typeof(ItemScript);
+        foreach (var type in assembly.GetTypes().Where(t => itemBaseType.IsAssignableFrom(t)))
+        {
+            var attribute = type.GetCustomAttribute<ItemScriptAttribute>();
+            if (attribute == null)
+                continue;
+
+            RegisterItemScriptType(attribute.Name, type);
+        }
     }
 
     /// <summary>
@@ -52,6 +62,25 @@ public class ScriptRegistry
         // This is more performant than using Activator.CreateInstance.
         _scriptTypes[(category, name)] = Expression.Lambda<Func<Script>>(Expression.New(constructor)).Compile();
     }
+    
+    /// <summary>
+    /// Register an item script type with the given name.
+    /// </summary>
+    [PublicAPI]
+    public void RegisterItemScriptType(StringKey name, Type type)
+    {
+        if (type == null)
+            throw new ArgumentNullException(nameof(type));
+
+        var constructor = type.GetConstructor(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
+            null, Type.EmptyTypes, null);
+        if (constructor == null)
+            throw new ArgumentException($"Type {type} does not have a parameterless constructor.");
+
+        // We create a lambda that creates a new instance of the script type.
+        // This is more performant than using Activator.CreateInstance.
+        _itemScriptTypes[name] = Expression.Lambda<Func<ItemScript>>(Expression.New(constructor)).Compile();
+    }
 
     /// <summary>
     /// Register a battle stat calculator.
@@ -71,7 +100,8 @@ public class ScriptRegistry
     public void RegisterMiscLibrary<T>(T miscLibrary) where T : IMiscLibrary
         => _miscLibrary = miscLibrary;
 
-    internal Dictionary<(ScriptCategory category, StringKey name), Func<Script>> ScriptTypes => _scriptTypes;
+    internal IReadOnlyDictionary<(ScriptCategory category, StringKey name), Func<Script>> ScriptTypes => _scriptTypes;
+    internal IReadOnlyDictionary<StringKey, Func<ItemScript>> ItemScriptTypes => _itemScriptTypes;
     internal IBattleStatCalculator? BattleStatCalculator => _battleStatCalculator;
     internal IDamageCalculator? DamageCalculator => _damageCalculator;
     internal IMiscLibrary? MiscLibrary => _miscLibrary;
diff --git a/PkmnLib.Dynamic/ScriptHandling/Script.cs b/PkmnLib.Dynamic/ScriptHandling/Script.cs
index c54569e..d4db686 100644
--- a/PkmnLib.Dynamic/ScriptHandling/Script.cs
+++ b/PkmnLib.Dynamic/ScriptHandling/Script.cs
@@ -1,4 +1,3 @@
-using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
 using PkmnLib.Dynamic.Models.Choices;
 using PkmnLib.Dynamic.ScriptHandling.Registry;
@@ -74,7 +73,7 @@ public abstract class Script : IDeepCloneable
     /// <summary>
     /// This function is ran when this script starts being in effect.
     /// </summary>
-    public virtual void OnInitialize(IDynamicLibrary library, IReadOnlyDictionary<StringKey, object?>? parameters)
+    public virtual void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
     {
     }
 
diff --git a/PkmnLib.Dynamic/ScriptHandling/ScriptResolver.cs b/PkmnLib.Dynamic/ScriptHandling/ScriptResolver.cs
index fd35909..9069eb9 100644
--- a/PkmnLib.Dynamic/ScriptHandling/ScriptResolver.cs
+++ b/PkmnLib.Dynamic/ScriptHandling/ScriptResolver.cs
@@ -9,33 +9,57 @@ namespace PkmnLib.Dynamic.ScriptHandling;
 /// </summary>
 public class ScriptResolver
 {
-    private Dictionary<(ScriptCategory, StringKey), Func<Script>> _scriptCtors;
+    private IReadOnlyDictionary<(ScriptCategory, StringKey), Func<Script>> _scriptCtors;
+    private IReadOnlyDictionary<StringKey, Func<ItemScript>> _itemScriptCtors;
 
     /// <inheritdoc cref="ScriptResolver"/>
-    public ScriptResolver(Dictionary<(ScriptCategory, StringKey), Func<Script>> scriptCtors)
+    public ScriptResolver(IReadOnlyDictionary<(ScriptCategory, StringKey), Func<Script>> scriptCtors,
+        IReadOnlyDictionary<StringKey, Func<ItemScript>> itemScriptCtors)
     {
         _scriptCtors = scriptCtors;
+        _itemScriptCtors = itemScriptCtors;
     }
-    
+
     /// <summary>
     /// Try and create a new script for the given category and key. If the script does not exist, return false.
     /// </summary>
-    public bool TryResolve(ScriptCategory category, StringKey key, [MaybeNullWhen(false)] out Script script)
+    public bool TryResolve(ScriptCategory category, StringKey key, IReadOnlyDictionary<StringKey, object?>? parameters,
+        [MaybeNullWhen(false)] out Script script)
     {
         if (!_scriptCtors.TryGetValue((category, key), out var scriptCtor))
         {
             script = null;
             return false;
         }
+
         script = scriptCtor();
+        if (parameters != null)
+        {
+            script.OnInitialize(parameters);
+        }
+        
         return true;
     }
-    
+
     /// <summary>
     /// Try and resolve an item script for the given item. If the item does not have a script, return false.
     /// </summary>
-    public bool TryResolveItemScript(IItem item, [MaybeNullWhen(false)] out Script script)
+    public bool TryResolveBattleItemScript(IItem item, [MaybeNullWhen(false)] out ItemScript script)
     {
-        throw new NotImplementedException();
+        var effect = item.BattleEffect;
+        if (effect == null)
+        {
+            script = null;
+            return false;
+        }
+        if (!_itemScriptCtors.TryGetValue(effect.Name, out var scriptCtor))
+        {
+            script = null;
+            return false;
+        }
+
+        script = scriptCtor();
+        script.OnInitialize(effect.Parameters);
+        return true;
     }
 }
\ No newline at end of file
diff --git a/PkmnLib.Static/Item.cs b/PkmnLib.Static/Item.cs
index e4e21fe..d43f783 100644
--- a/PkmnLib.Static/Item.cs
+++ b/PkmnLib.Static/Item.cs
@@ -1,4 +1,5 @@
 using System.Collections.Immutable;
+using PkmnLib.Static.Moves;
 using PkmnLib.Static.Utils;
 
 namespace PkmnLib.Static;
@@ -104,6 +105,9 @@ public interface IItem : INamedValue
     /// A set of arbitrary flags that can be set on the item.
     /// </summary>
     ImmutableHashSet<StringKey> Flags { get; }
+    
+    ISecondaryEffect? Effect { get; }
+    ISecondaryEffect? BattleEffect { get; }
 
     /// <summary>
     /// Checks whether the item has a specific flag.
@@ -118,12 +122,14 @@ public class ItemImpl : IItem
 {
     /// <inheritdoc cref="ItemImpl"/>
     public ItemImpl(StringKey name, ItemCategory category, BattleItemCategory battleCategory, int price,
-        IEnumerable<StringKey> flags)
+        IEnumerable<StringKey> flags, ISecondaryEffect? effect, ISecondaryEffect? battleTriggerEffect)
     {
         Name = name;
         Category = category;
         BattleCategory = battleCategory;
         Price = price;
+        Effect = effect;
+        BattleEffect = battleTriggerEffect;
         Flags = [..flags];
     }
 
@@ -142,6 +148,12 @@ public class ItemImpl : IItem
     /// <inheritdoc />
     public ImmutableHashSet<StringKey> Flags { get; }
 
+    /// <inheritdoc />
+    public ISecondaryEffect? Effect { get; }
+
+    /// <inheritdoc />
+    public ISecondaryEffect? BattleEffect { get; }
+
     /// <inheritdoc />
     public bool HasFlag(string key)
     {
diff --git a/PkmnLib.Tests/Data/Items.json b/PkmnLib.Tests/Data/Items.json
index 38a3e1e..db06cf7 100755
--- a/PkmnLib.Tests/Data/Items.json
+++ b/PkmnLib.Tests/Data/Items.json
@@ -3326,10 +3326,10 @@
     "price": 200,
     "flingPower": 0,
     "battleEffect": {
-      "name": "Pokeball",
-      "parameters": [
-        1.0
-      ]
+      "name": "pokeball",
+      "parameters": {
+        "catchRate": 1
+      }
     }
   },
   {
@@ -3388,10 +3388,10 @@
     "price": 200,
     "flingPower": 30,
     "effect": {
-      "name": "heal",
-      "parameters": [
-        20
-      ]
+      "name": "healing_item",
+      "parameters": {
+        "heal_amount": 20
+      }
     }
   },
   {
diff --git a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Items/HealingItem.cs b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Items/HealingItem.cs
new file mode 100644
index 0000000..5a7e51a
--- /dev/null
+++ b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Items/HealingItem.cs
@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using PkmnLib.Dynamic.Models;
+using PkmnLib.Dynamic.ScriptHandling;
+using PkmnLib.Dynamic.ScriptHandling.Registry;
+using PkmnLib.Static.Utils;
+
+namespace PkmnLib.Plugin.Gen7.Scripts.Items;
+
+[ItemScript("healing_item")]
+public class HealingItem : ItemScript
+{
+    private uint _healAmount;
+
+    /// <inheritdoc />
+    public override bool IsItemUsable => true;
+
+    /// <inheritdoc />
+    public override bool RequiresTarget => true;
+
+    /// <inheritdoc />
+    public override void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
+    {
+        if (parameters == null || !parameters.TryGetValue("heal_amount", out var healAmountObj) ||
+            healAmountObj is not int healAmount)
+        {
+            healAmount = 20;
+        }
+
+        _healAmount = (uint)healAmount;
+    }
+
+    /// <inheritdoc />
+    public override bool IsTargetValid(IPokemon target) => !target.IsFainted;
+
+    /// <inheritdoc />
+    public override void OnUseWithTarget(IPokemon target)
+    {
+        target.Heal(_healAmount);
+    }
+}
\ No newline at end of file
diff --git a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeAllTargetStats.cs b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeAllTargetStats.cs
index ebc63b6..043b8a2 100644
--- a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeAllTargetStats.cs
+++ b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeAllTargetStats.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
 using PkmnLib.Dynamic.ScriptHandling;
 using PkmnLib.Dynamic.ScriptHandling.Registry;
@@ -15,7 +14,7 @@ public class ChangeAllTargetStats : Script
     private sbyte _amount;
     
     /// <inheritdoc />
-    public override void OnInitialize(IDynamicLibrary library, IReadOnlyDictionary<StringKey, object?>? parameters)
+    public override void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
     {
         if (parameters == null)
         {
diff --git a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeTargetStats.cs b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeTargetStats.cs
index b91373e..85e083f 100644
--- a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeTargetStats.cs
+++ b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/ChangeTargetStats.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
 using PkmnLib.Dynamic.ScriptHandling;
 using PkmnLib.Dynamic.ScriptHandling.Registry;
@@ -20,7 +19,7 @@ public abstract class ChangeTargetStats : Script
     }
 
     /// <inheritdoc />
-    public override void OnInitialize(IDynamicLibrary library, IReadOnlyDictionary<StringKey, object?>? parameters)
+    public override void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
     {
         if (parameters == null)
         {
diff --git a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Drain.cs b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Drain.cs
index 603a7ae..01092c9 100644
--- a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Drain.cs
+++ b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Drain.cs
@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
 using PkmnLib.Dynamic.ScriptHandling;
 using PkmnLib.Dynamic.ScriptHandling.Registry;
@@ -13,9 +12,9 @@ public class Drain : Script
     public float DrainModifier { get; set; } = 0.5f;
     
     /// <inheritdoc />
-    public override void OnInitialize(IDynamicLibrary library, IReadOnlyDictionary<StringKey, object?>? parameters)
+    public override void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
     {
-        base.OnInitialize(library, parameters);
+        base.OnInitialize(parameters);
         if (parameters == null)
             return;
         DrainModifier = parameters.GetValueOrDefault("drain_modifier") as float? ?? DrainModifier;
diff --git a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/HealEachEndOfTurn.cs b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/HealEachEndOfTurn.cs
index 2c1b718..063bf2f 100644
--- a/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/HealEachEndOfTurn.cs
+++ b/Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/HealEachEndOfTurn.cs
@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
 using PkmnLib.Dynamic.ScriptHandling;
 using PkmnLib.Dynamic.ScriptHandling.Registry;
@@ -14,9 +13,9 @@ public class HealEachEndOfTurn : Script
     private float _healPercentage;
 
     /// <inheritdoc />
-    public override void OnInitialize(IDynamicLibrary library, IReadOnlyDictionary<StringKey, object?>? parameters)
+    public override void OnInitialize(IReadOnlyDictionary<StringKey, object?>? parameters)
     {
-        base.OnInitialize(library, parameters);
+        base.OnInitialize(parameters);
         if (parameters == null || !parameters.TryGetValue("percent", out var healPercentageObj) ||
             healPercentageObj is not float healPercentage)
         {