Initial support for item use scripts in angelscript.

CInterface/Library/Item.cpp

@@ -5,13 +5,20 @@ using namespace PkmnLib::Library;
 
 export Item* PkmnLib_Item_Construct(const char* name, CreatureLib::Library::ItemCategory category,
                                     CreatureLib::Library::BattleItemCategory battleCategory, int32_t price,
-                                    const char* flags[], size_t flagsCount, uint8_t flingPower) {
+                                    const char* effectName, CreatureLib::Library::EffectParameter* effectParameters[],
+                                    size_t effectParameterCount, const char* flags[], size_t flagsCount,
+                                    uint8_t flingPower) {
     std::unordered_set<uint32_t> conversedFlags(flagsCount);
     for (size_t i = 0; i < flagsCount; i++) {
         conversedFlags.insert(ArbUt::StringView::CalculateHash(flags[i]));
     }
 
-    return new Item(ArbUt::StringView(name), category, battleCategory, price, conversedFlags, flingPower);
+    return new Item(
+        ArbUt::StringView(name), category, battleCategory, price,
+        new CreatureLib::Library::SecondaryEffect(100, effectName,
+                                                  ArbUt::List<CreatureLib::Library::EffectParameter*>(
+                                                      effectParameters, effectParameters + effectParameterCount)),
+        conversedFlags, flingPower);
 };
 
 export void PkmnLib_Item_Destruct(const Item* p) { delete p; }

src/Library/Items/Item.hpp

@@ -9,8 +9,10 @@ namespace PkmnLib::Library {
     public:
         Item(const ArbUt::StringView& name, CreatureLib::Library::ItemCategory category,
              CreatureLib::Library::BattleItemCategory battleCategory, int32_t price,
-             const std::unordered_set<uint32_t>& flags, uint8_t flingPower) noexcept
-            : CreatureLib::Library::Item(name, category, battleCategory, price, flags), _flingPower(flingPower) {}
+             const CreatureLib::Library::SecondaryEffect* effect, const std::unordered_set<uint32_t>& flags,
+             uint8_t flingPower) noexcept
+            : CreatureLib::Library::Item(name, category, battleCategory, price, effect, flags),
+              _flingPower(flingPower) {}
 
         inline uint8_t GetFlingPower() const noexcept { return _flingPower; }
     };

src/ScriptResolving/AngelScript/AngelScriptFunctionCall.hpp

@@ -0,0 +1,52 @@
+#ifndef PKMNLIB_ANGELSCRIPTFUNCTIONCALL_HPP
+#define PKMNLIB_ANGELSCRIPTFUNCTIONCALL_HPP
+
+#include "ContextPool.hpp"
+
+class AngelScriptUtils {
+public:
+    static void AngelscriptFunctionCall(asIScriptFunction* func, ContextPool* ctxPool, asIScriptObject* obj,
+                                        const ArbUt::StringView& scriptName,
+                                        const std::function<void(asIScriptContext*)>& setup,
+                                        const std::function<void(asIScriptContext*)>& onEnd) {
+        auto ctx = asGetActiveContext();
+        bool newContext = false;
+        if (ctx == nullptr) {
+            ctx = ctxPool->RequestContext();
+            newContext = true;
+        } else {
+            ctx->PushState();
+        }
+        ctx->Prepare(func);
+        ctx->SetObject(obj);
+        setup(ctx);
+        auto scriptResult = ctx->Execute();
+        if (scriptResult != asEXECUTION_FINISHED) {
+            if (scriptResult == asEXECUTION_EXCEPTION) {
+                std::stringstream err;
+                err << "Script exception in script '" << scriptName.c_str() << "', line "
+                    << ctx->GetExceptionLineNumber() << ". Message: '" << ctx->GetExceptionString() << "'.";
+                if (newContext) {
+                    ctxPool->ReturnContextToPool(ctx);
+                } else {
+                    ctx->PopState();
+                }
+                throw ArbUt::Exception(err.str());
+            }
+            if (newContext) {
+                ctxPool->ReturnContextToPool(ctx);
+            } else {
+                ctx->PopState();
+            }
+            THROW("Script didn't finish properly; message " << scriptResult);
+        }
+        onEnd(ctx);
+        if (newContext) {
+            ctxPool->ReturnContextToPool(ctx);
+        } else {
+            ctx->PopState();
+        }
+    }
+};
+
+#endif

src/ScriptResolving/AngelScript/AngelScriptItemUseScript.cpp

@@ -0,0 +1,65 @@
+#include "AngelScriptItemUseScript.hpp"
+#include "AngelScriptResolver.hpp"
+
+bool AngelScriptItemUseScript::IsItemUsable() const {
+    if (!__IsItemUsable.Exists) {
+        return CreatureLib::Battling::ItemUseScript::IsItemUsable();
+    }
+    bool res = false;
+    AngelScriptUtils::AngelscriptFunctionCall(
+        __IsItemUsable.Function, _resolver->GetContextPool(), _scriptObject, ""_cnc,
+        [&]([[maybe_unused]] asIScriptContext* ctx) {},
+        [&]([[maybe_unused]] asIScriptContext* ctx) { res = ctx->GetReturnByte() == 1; });
+    return res;
+}
+
+bool AngelScriptItemUseScript::IsCreatureUseItem() const {
+    if (!__IsPokemonUseItem.Exists) {
+        return CreatureLib::Battling::ItemUseScript::IsCreatureUseItem();
+    }
+    bool res = false;
+    AngelScriptUtils::AngelscriptFunctionCall(
+        __IsPokemonUseItem.Function, _resolver->GetContextPool(), _scriptObject, ""_cnc,
+        [&]([[maybe_unused]] asIScriptContext* ctx) {},
+        [&]([[maybe_unused]] asIScriptContext* ctx) { res = ctx->GetReturnByte() == 1; });
+    return res;
+}
+bool AngelScriptItemUseScript::IsUseValidForCreature(CreatureLib::Battling::Creature* creature) const {
+    if (!__IsPokemonUseItem.Exists) {
+        return CreatureLib::Battling::ItemUseScript::IsUseValidForCreature(creature);
+    }
+    bool res = false;
+    AngelScriptUtils::AngelscriptFunctionCall(
+        __IsPokemonUseItem.Function, _resolver->GetContextPool(), _scriptObject, ""_cnc,
+        [&]([[maybe_unused]] asIScriptContext* ctx) { ctx->SetArgObject(0, (void*)creature); },
+        [&]([[maybe_unused]] asIScriptContext* ctx) { res = ctx->GetReturnByte() == 1; });
+    return res;
+}
+bool AngelScriptItemUseScript::IsHoldable() const {
+    if (!__IsHoldable.Exists) {
+        return CreatureLib::Battling::ItemUseScript::IsHoldable();
+    }
+    bool res = false;
+    AngelScriptUtils::AngelscriptFunctionCall(
+        __IsHoldable.Function, _resolver->GetContextPool(), _scriptObject, ""_cnc,
+        [&]([[maybe_unused]] asIScriptContext* ctx) {},
+        [&]([[maybe_unused]] asIScriptContext* ctx) { res = ctx->GetReturnByte() == 1; });
+    return res;
+}
+void AngelScriptItemUseScript::OnUse() const {
+    if (!__OnUse.Exists) {
+        CreatureLib::Battling::ItemUseScript::OnUse();
+    }
+    AngelScriptUtils::AngelscriptFunctionCall(
+        __OnUse.Function, _resolver->GetContextPool(), _scriptObject, ""_cnc,
+        [&]([[maybe_unused]] asIScriptContext* ctx) {}, [&]([[maybe_unused]] asIScriptContext* ctx) {});
+}
+void AngelScriptItemUseScript::OnCreatureUse(CreatureLib::Battling::Creature* creature) const {
+    if (!__OnPokemonUse.Exists) {
+        CreatureLib::Battling::ItemUseScript::OnUse();
+    }
+    AngelScriptUtils::AngelscriptFunctionCall(
+        __OnPokemonUse.Function, _resolver->GetContextPool(), _scriptObject, ""_cnc,
+        [&]([[maybe_unused]] asIScriptContext* ctx) { ctx->SetArgObject(0, (void*)creature); },
+        [&]([[maybe_unused]] asIScriptContext* ctx) {});
+}

src/ScriptResolving/AngelScript/AngelScriptItemUseScript.hpp

@@ -0,0 +1,50 @@
+#ifndef PKMNLIB_ANGELSCRIPTITEMUSESCRIPT_HPP
+#define PKMNLIB_ANGELSCRIPTITEMUSESCRIPT_HPP
+
+#include <CreatureLib/Battling/ScriptHandling/ItemUseScript.hpp>
+#include "AngelScriptFunctionCall.hpp"
+
+class AngelScriptResolver;
+
+class AngelScriptItemUseScript final : public CreatureLib::Battling::ItemUseScript {
+public:
+    AngelScriptItemUseScript(asIScriptObject* scriptObject, const AngelScriptResolver* resolver)
+        : _scriptObject(scriptObject), _resolver(resolver) {}
+
+    [[nodiscard]] bool IsItemUsable() const override;
+    [[nodiscard]] bool IsCreatureUseItem() const override;
+    bool IsUseValidForCreature(CreatureLib::Battling::Creature* creature) const override;
+
+    bool IsHoldable() const override;
+
+    void OnUse() const override;
+    void OnCreatureUse(CreatureLib::Battling::Creature* creature) const override;
+
+private:
+    asIScriptObject* _scriptObject;
+    const AngelScriptResolver* _resolver;
+
+    struct FunctionInfo {
+        bool Exists = false;
+        asIScriptFunction* Function = nullptr;
+    };
+
+    FunctionInfo Initialize(const std::string& decl) {
+        auto val = _scriptObject->GetObjectType()->GetMethodByDecl(decl.c_str(), false);
+        if (val == nullptr) {
+            return FunctionInfo{.Exists = false, .Function = nullptr};
+        }
+        return FunctionInfo{.Exists = true, .Function = val};
+    }
+
+#define ITEM_USE_SCRIPT_HOOK_FUNCTION(name, decl) FunctionInfo __##name = Initialize(decl);
+
+    ITEM_USE_SCRIPT_HOOK_FUNCTION(IsItemUsable, "bool IsItemUsable()");
+    ITEM_USE_SCRIPT_HOOK_FUNCTION(IsPokemonUseItem, "bool IsPokemonUseItem()");
+    ITEM_USE_SCRIPT_HOOK_FUNCTION(IsUseValidForPokemon, "bool IsUseValidForPokemon(Pokemon@ target)");
+    ITEM_USE_SCRIPT_HOOK_FUNCTION(IsHoldable, "bool IsHoldable()");
+    ITEM_USE_SCRIPT_HOOK_FUNCTION(OnUse, "void OnUse()");
+    ITEM_USE_SCRIPT_HOOK_FUNCTION(OnPokemonUse, "void OnPokemonUse(Pokemon@ target)");
+};
+
+#endif // PKMNLIB_ANGELSCRIPTITEMUSESCRIPT_HPP

src/ScriptResolving/AngelScript/AngelScriptResolver.cpp

@@ -127,7 +127,7 @@ void AngelScriptResolver::MessageCallback(const asSMessageInfo* msg, void*) {
 }
 
 CreatureLib::Battling::BattleScript* AngelScriptResolver::LoadScript(ScriptCategory category,
-                                                               const ArbUt::StringView& scriptName) {
+                                                                     const ArbUt::StringView& scriptName) {
     ArbUt::Dictionary<ArbUt::StringView, AngelScriptTypeInfo*> innerDb;
     auto v = _typeDatabase.TryGet(category);
     if (!v.has_value()) {
@@ -150,6 +150,36 @@ CreatureLib::Battling::BattleScript* AngelScriptResolver::LoadScript(ScriptCateg
     _contextPool->ReturnContextToPool(ctx);
     return new AngelScriptScript(this, t.value(), obj, _contextPool);
 }
+
+CreatureLib::Battling::ItemUseScript* AngelScriptResolver::LoadItemScript(const CreatureLib::Library::Item* item) {
+    auto v = this->_itemUseScripts.TryGet(item);
+    if (v.has_value()) {
+        return v.value();
+    }
+    if (!item->GetEffect().HasValue()) {
+        return nullptr;
+    }
+
+    auto typeInfoOption = _itemUseTypes.TryGet(item->GetEffect().GetValue()->GetEffectName());
+    if (!typeInfoOption.has_value()) {
+        return nullptr;
+    }
+
+    auto* ctx = _contextPool->RequestContext();
+    auto factory = typeInfoOption.value().get()->GetFactoryByIndex(0);
+    ctx->Prepare(factory);
+    auto result = ctx->Execute();
+    if (result != asEXECUTION_FINISHED) {
+        throw ArbUt::Exception("Instantiation failed.");
+    }
+    asIScriptObject* obj = *(asIScriptObject**)ctx->GetAddressOfReturnValue();
+    obj->AddRef();
+    auto scriptObject = new AngelScriptItemUseScript(obj, this);
+    _itemUseScripts.Insert(item, scriptObject);
+    _contextPool->ReturnContextToPool(ctx);
+    return scriptObject;
+}
+
 void AngelScriptResolver::FinalizeModule() {
     int r = _builder.BuildModule();
     if (r < 0)
@@ -159,62 +189,85 @@ void AngelScriptResolver::FinalizeModule() {
     std::regex variableMatcher(R"(\s*(\w+)=(\w+))", std::regex_constants::icase);
     std::smatch base_match;
 
+    auto pkmnScriptType = _mainModule->GetTypeInfoByName("PkmnScript");
+    auto itemUseScriptType = _mainModule->GetTypeInfoByName("ItemUseScript");
     for (asUINT n = 0; n < count; n++) {
         auto typeInfo = _mainModule->GetObjectTypeByIndex(n);
-        auto metadata = _builder.GetMetadataForType(typeInfo->GetTypeId());
-        for (size_t m = 0; m < metadata.size(); m++) {
-            auto data = metadata[m];
-            if (std::regex_match(data, base_match, metadataMatcher)) {
-                auto mt = base_match[1].str();
-                auto metadataKind = ArbUt::StringView(mt.c_str(), mt.length());
-                auto metadataVariables = base_match[2].str();
-                if (!std::regex_match(metadataVariables, base_match, variableMatcher)) {
-                    continue;
-                }
-                ArbUt::StringView effectName;
-                for (size_t variableIndex = 1; variableIndex < base_match.size(); variableIndex += 2) {
-                    if (ArbUt::StringView::CalculateHash(base_match[variableIndex].str().c_str()) == "effect"_cnc) {
-                        auto val = base_match[variableIndex + 1].str();
-                        effectName = ArbUt::StringView(val.c_str(), val.length());
+        if (typeInfo->DerivesFrom(pkmnScriptType)) {
+            auto metadata = _builder.GetMetadataForType(typeInfo->GetTypeId());
+            for (size_t m = 0; m < metadata.size(); m++) {
+                auto data = metadata[m];
+                if (std::regex_match(data, base_match, metadataMatcher)) {
+                    auto mt = base_match[1].str();
+                    auto metadataKind = ArbUt::StringView(mt.c_str(), mt.length());
+                    auto metadataVariables = base_match[2].str();
+                    if (!std::regex_match(metadataVariables, base_match, variableMatcher)) {
+                        continue;
                     }
+                    ArbUt::StringView effectName;
+                    for (size_t variableIndex = 1; variableIndex < base_match.size(); variableIndex += 2) {
+                        if (ArbUt::StringView::CalculateHash(base_match[variableIndex].str().c_str()) == "effect"_cnc) {
+                            auto val = base_match[variableIndex + 1].str();
+                            effectName = ArbUt::StringView(val.c_str(), val.length());
+                        }
+                    }
+                    RegisterScriptType(typeInfo, metadataKind, effectName);
                 }
-                if (effectName.IsEmpty()) {
-                    continue;
-                }
-                switch (metadataKind) {
-                    case "Move"_cnc:
-                        _typeDatabase[ScriptCategory::Attack].Insert(effectName,
-                                                                     new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
-                    case "Pokemon"_cnc:
-                        _typeDatabase[ScriptCategory::Creature].Insert(effectName,
-                                                                       new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
-                    case "Ability"_cnc:
-                        _typeDatabase[ScriptCategory::Talent].Insert(effectName,
-                                                                     new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
-                    case "Status"_cnc:
-                        _typeDatabase[ScriptCategory::Status].Insert(effectName,
-                                                                     new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
-                    case "Battle"_cnc:
-                        _typeDatabase[ScriptCategory::Battle].Insert(effectName,
-                                                                     new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
-                    case "Side"_cnc:
-                        _typeDatabase[ScriptCategory::Side].Insert(effectName,
-                                                                   new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
-                    case "Weather"_cnc:
-                        _typeDatabase[static_cast<ScriptCategory>(PkmnScriptCategory::Weather)].Insert(
-                            effectName, new AngelScriptTypeInfo(effectName, typeInfo));
-                        break;
+            }
+        } else if (typeInfo->DerivesFrom(itemUseScriptType)) {
+            auto metadata = _builder.GetMetadataForType(typeInfo->GetTypeId());
+            for (size_t m = 0; m < metadata.size(); m++) {
+                auto data = metadata[m];
+                if (std::regex_match(data, base_match, metadataMatcher)) {
+                    auto mt = base_match[1].str();
+                    auto metadataKind = ArbUt::StringView(mt.c_str(), mt.length());
+                    auto metadataVariables = base_match[2].str();
+                    if (!std::regex_match(metadataVariables, base_match, variableMatcher)) {
+                        continue;
+                    }
+                    ArbUt::StringView effectName;
+                    for (size_t variableIndex = 1; variableIndex < base_match.size(); variableIndex += 2) {
+                        if (ArbUt::StringView::CalculateHash(base_match[variableIndex].str().c_str()) == "effect"_cnc) {
+                            auto val = base_match[variableIndex + 1].str();
+                            effectName = ArbUt::StringView(val.c_str(), val.length());
+                        }
+                    }
+                    _itemUseTypes.Insert(effectName, typeInfo);
                 }
             }
         }
     }
 }
+void AngelScriptResolver::RegisterScriptType(asITypeInfo* typeInfo, const ArbUt::StringView& metadataKind,
+                                             const ArbUt::StringView& effectName) {
+    if (effectName.IsEmpty()) {
+        return;
+    }
+    switch (metadataKind) {
+        case "Move"_cnc:
+            _typeDatabase[ScriptCategory::Attack].Insert(effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+        case "Pokemon"_cnc:
+            _typeDatabase[ScriptCategory::Creature].Insert(effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+        case "Ability"_cnc:
+            _typeDatabase[ScriptCategory::Talent].Insert(effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+        case "Status"_cnc:
+            _typeDatabase[ScriptCategory::Status].Insert(effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+        case "Battle"_cnc:
+            _typeDatabase[ScriptCategory::Battle].Insert(effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+        case "Side"_cnc:
+            _typeDatabase[ScriptCategory::Side].Insert(effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+        case "Weather"_cnc:
+            _typeDatabase[static_cast<ScriptCategory>(PkmnScriptCategory::Weather)].Insert(
+                effectName, new AngelScriptTypeInfo(effectName, typeInfo));
+            break;
+    }
+}
 void AngelScriptResolver::CreateScript(const char* name, const char* script) {
     _builder.AddSectionFromMemory(name, script);
 }

src/ScriptResolving/AngelScript/AngelScriptResolver.hpp

@@ -6,7 +6,9 @@
 #include "../../Battling/Library/BattleLibrary.hpp"
 
 #define ANGELSCRIPT_DLL_LIBRARY_IMPORT
+#include <Arbutils/StringView.hpp>
 #include <angelscript.h>
+#include "AngelScriptItemUseScript.hpp"
 #include "AngelScriptScript.hpp"
 #include "AngelScriptTypeInfo.hpp"
 
@@ -21,10 +23,14 @@ private:
     static void Print(const std::string& str) { std::cout << str << std::endl; }
     ArbUt::Dictionary<ScriptCategory, ArbUt::Dictionary<ArbUt::StringView, AngelScriptTypeInfo*>> _typeDatabase;
     ArbUt::Dictionary<ArbUt::StringView, asITypeInfo*> _baseTypes;
+    ArbUt::Dictionary<ArbUt::StringView, asITypeInfo*> _itemUseTypes;
+    ArbUt::Dictionary<const CreatureLib::Library::Item*, AngelScriptItemUseScript*> _itemUseScripts;
 
     void RegisterTypes();
     void
     InitializeByteCode(const ArbUt::Dictionary<ScriptCategory, ArbUt::Dictionary<ArbUt::StringView, uint32_t>>& types);
+    void RegisterScriptType(asITypeInfo* typeInfo, const ArbUt::StringView& metadataKind,
+                            const ArbUt::StringView& effectName);
 
 public:
     ~AngelScriptResolver() override {
@@ -46,6 +52,7 @@ public:
 
     CreatureLib::Battling::BattleScript* LoadScript(ScriptCategory category,
                                                     const ArbUt::StringView& scriptName) override;
+    CreatureLib::Battling::ItemUseScript* LoadItemScript(const CreatureLib::Library::Item* item) override;
 
     void WriteByteCodeToFile(const char* file, bool stripDebugInfo = false);
     void LoadByteCodeFromFile(const char* file);
@@ -81,5 +88,7 @@ public:
         }
         return t;
     }
+
+    inline ContextPool* GetContextPool() const noexcept { return _contextPool; }
 };
 #endif // PKMNLIB_ANGELSCRIPRESOLVER_HPP

src/ScriptResolving/AngelScript/AngelScriptScript.cpp

@@ -1,46 +1,14 @@
 #include "AngelScriptScript.hpp"
+#include "AngelScriptFunctionCall.hpp"
 #include "AngelScriptResolver.hpp"
 
 #define CALL_HOOK(name, setup)                                                                                         \
     auto s = _type->Get##name();                                                                                       \
     if (!s.Exists)                                                                                                     \
         return;                                                                                                        \
-    auto ctx = asGetActiveContext();                                                                                   \
-    bool newContext = false;                                                                                           \
-    if (ctx == nullptr) {                                                                                              \
-        ctx = _ctxPool->RequestContext();                                                                              \
-        newContext = true;                                                                                             \
-    } else {                                                                                                           \
-        ctx->PushState();                                                                                              \
-    }                                                                                                                  \
-    ctx->Prepare(s.Function);                                                                                          \
-    ctx->SetObject(_obj);                                                                                              \
-    setup;                                                                                                             \
-    auto scriptResult = ctx->Execute();                                                                                \
-    if (scriptResult != asEXECUTION_FINISHED) {                                                                        \
-        if (scriptResult == asEXECUTION_EXCEPTION) {                                                                   \
-            std::stringstream err;                                                                                     \
-            err << "Script exception in script '" << GetName().c_str() << "', line " << ctx->GetExceptionLineNumber()  \
-                << ". Message: '" << ctx->GetExceptionString() << "'.";                                                \
-            if (newContext) {                                                                                          \
-                _ctxPool->ReturnContextToPool(ctx);                                                                    \
-            } else {                                                                                                   \
-                ctx->PopState();                                                                                       \
-            }                                                                                                          \
-            throw ArbUt::Exception(err.str());                                                                         \
-        }                                                                                                              \
-        if (newContext) {                                                                                              \
-            _ctxPool->ReturnContextToPool(ctx);                                                                        \
-        } else {                                                                                                       \
-            ctx->PopState();                                                                                           \
-        }                                                                                                              \
-        THROW("Script didn't finish properly; message " << scriptResult);                                              \
-    }                                                                                                                  \
-    if (newContext) {                                                                                                  \
-        _ctxPool->ReturnContextToPool(ctx);                                                                            \
-    } else {                                                                                                           \
-        ctx->PopState();                                                                                               \
-    }
+    AngelScriptUtils::AngelscriptFunctionCall(                                                                         \
+        s.Function, _ctxPool, _obj, GetName(), [&]([[maybe_unused]] asIScriptContext* ctx) { setup },                  \
+        [&]([[maybe_unused]] asIScriptContext* ctx) {});
 
 CScriptArray* AngelScriptScript::GetEffectParameters(const ArbUt::List<CreatureLib::Library::EffectParameter*>& ls) {
     asITypeInfo* t = _resolver->GetBaseType("array<EffectParameter@>"_cnc);

src/ScriptResolving/AngelScript/TypeRegistry/BasicScriptClass.cpp

@@ -3,7 +3,7 @@
 void BasicScriptClass::Register(asIScriptEngine* engine) {
     // As far as I am aware at the moment you can't create an abstract class with virtual members through the
     // application registry interface. As such, we just create it from string.
-    [[maybe_unused]] int r = engine->GetModuleByIndex(0)->AddScriptSection("PkmnScript", R"(
+    int r = engine->GetModuleByIndex(0)->AddScriptSection("PkmnScript", R"(
 shared abstract class PkmnScript {
   // CreatureLib methods
     void OnInitialize(const array<EffectParameter@> &in parameters){};
@@ -46,4 +46,18 @@ shared abstract class PkmnScript {
 }
 )");
     Ensure(r >= 0);
+    r = engine->GetModuleByIndex(0)->AddScriptSection("ItemUseScript", R"(
+shared abstract class ItemUseScript {
+    bool IsItemUsable() { return false; };
+    bool IsPokemonUseItem() { return false; };
+    bool IsUseValidForPokemon(Pokemon@ target) { return false; };
+
+    bool IsHoldable() { return false; }
+
+    void OnUse() { };
+    void OnPokemonUse(Pokemon@ target) { };
+}
+)");
+    Ensure(r >= 0);
+
 }

tests/ScriptTests/ItemUseScriptTests.cpp

@@ -0,0 +1,88 @@
+#ifdef TESTS_BUILD
+#include "../../extern/doctest.hpp"
+#include "../../src/Battling/Pokemon/CreatePokemon.hpp"
+#include "../../src/ScriptResolving/AngelScript/AngelScriptResolver.hpp"
+#include "../TestLibrary/TestLibrary.hpp"
+
+#define AS_CLASS(name, contents)                                                                                       \
+    { #name, "namespace Pokemon{ [ItemUse effect=" #name "] class " #name " : ItemUseScript { " contents "}}" }
+
+static std::unordered_map<const char*, const char*> _scripts = std::unordered_map<const char*, const char*>{
+    AS_CLASS(blankClass, R"(
+)"),
+
+    AS_CLASS(isItemUsable, R"(
+bool IsItemUsable() override {
+    return true;
+}
+)"),
+
+    AS_CLASS(isPokemonUseItem, R"(
+bool IsPokemonUseItem() override {
+    return true;
+}
+)"),
+};
+
+static AngelScriptResolver* _resolverCache = nullptr;
+static AngelScriptResolver* GetScriptResolver(PkmnLib::Battling::BattleLibrary* mainLib) {
+    _resolverCache = dynamic_cast<AngelScriptResolver*>(PkmnLib::Battling::BattleLibrary::CreateScriptResolver());
+    _resolverCache->Initialize(mainLib);
+    for (auto kv : _scripts) {
+        _resolverCache->CreateScript(kv.first, kv.second);
+    }
+    _resolverCache->FinalizeModule();
+    return _resolverCache;
+}
+
+static AngelScriptItemUseScript* GetScript(PkmnLib::Battling::BattleLibrary* mainLib, const ArbUt::StringView& name) {
+    auto lib = GetScriptResolver(mainLib);
+    auto item = CreatureLib::Library::Item(name, CreatureLib::Library::ItemCategory::MiscItem,
+                                           CreatureLib::Library::BattleItemCategory::None, 0,
+                                           new CreatureLib::Library::SecondaryEffect(100, name, {}), {});
+
+    auto s = lib->LoadItemScript(&item);
+    auto script = dynamic_cast<AngelScriptItemUseScript*>(s);
+    REQUIRE(script != nullptr);
+    return script;
+}
+
+TEST_CASE("Invoke isItemUsable item use script function on empty class") {
+    auto mainLib = TestLibrary::GetLibrary();
+
+    auto script = GetScript(mainLib, "blankClass"_cnc);
+    REQUIRE(script != nullptr);
+    REQUIRE_FALSE(script->IsItemUsable());
+
+    delete script;
+}
+TEST_CASE("Invoke isItemUsable item use script function") {
+    auto mainLib = TestLibrary::GetLibrary();
+
+    auto script = GetScript(mainLib, "isItemUsable"_cnc);
+    REQUIRE(script != nullptr);
+    REQUIRE(script->IsItemUsable());
+
+    delete script;
+}
+
+TEST_CASE("Invoke isPokemonUseItem item use script function on empty class") {
+    auto mainLib = TestLibrary::GetLibrary();
+
+    auto script = GetScript(mainLib, "blankClass"_cnc);
+    REQUIRE(script != nullptr);
+    REQUIRE_FALSE(script->IsCreatureUseItem());
+
+    delete script;
+}
+TEST_CASE("Invoke isPokemonUseItem item use script function") {
+    auto mainLib = TestLibrary::GetLibrary();
+
+    auto script = GetScript(mainLib, "isPokemonUseItem"_cnc);
+    REQUIRE(script != nullptr);
+    REQUIRE(script->IsCreatureUseItem());
+
+    delete script;
+}
+
+#endif

tests/ScriptTests/ScriptTypeTests/Battle/PokemonTests.cpp

@@ -8,7 +8,7 @@ static std::unordered_map<const char*, const char*> _scripts =
     std::unordered_map<const char*, const char*>{{"testScript1", R"(
 namespace Pokemon{
 [Pokemon effect=testScript1]
-class testScript1 {
+class testScript1 : PkmnScript {
     bool testSpecies(Pokemon@ p, const Species@ species){ return p.Species is species; }
     bool testForme(Pokemon@ p, const Forme@ forme){ return p.Forme is forme; }
     bool testLevel(Pokemon@ p, uint8 level){ return p.Level == level; }

tests/ScriptTests/ScriptTypeTests/Library/FormesTests.cpp

@@ -7,7 +7,7 @@ static std::unordered_map<const char*, const char*> _scripts =
     std::unordered_map<const char*, const char*>{{"testScript1", R"(
 namespace Pokemon{
 [Pokemon effect=testScript1]
-class testScript1 {
+class testScript1 : PkmnScript {
     bool testName(const Forme@ s, const constString &in name){ return s.Name == name; }
     bool testWeight(const Forme@ s, float weight){ return s.Weight == weight; }
     bool testHeight(const Forme@ s, float height){ return s.Height == height; }

tests/ScriptTests/ScriptTypeTests/Library/ItemDataTests.cpp

@@ -7,7 +7,7 @@ static std::unordered_map<const char*, const char*> _scripts =
     std::unordered_map<const char*, const char*>{{"testScript1", R"(
 namespace Pokemon{
 [Pokemon effect=testScript1]
-class testScript1 {
+class testScript1 : PkmnScript {
     bool testName(const Item@ i, const constString &in name){ return i.Name == name; }
     bool testCategory(const Item@ i, ItemCategory category){ return i.Category == category; }
     bool testBattleCategory(const Item@ i, BattleItemCategory category){ return i.BattleCategory == category; }

tests/ScriptTests/ScriptTypeTests/Library/MoveTests.cpp

@@ -7,7 +7,7 @@ static std::unordered_map<const char*, const char*> _scripts =
     std::unordered_map<const char*, const char*>{{"testScript1", R"(
 namespace Pokemon{
 [Pokemon effect=testScript1]
-class testScript1 {
+class testScript1 : PkmnScript {
     bool testName(const MoveData@ s, const constString &in name){ return s.Name == name; }
     bool testType(const MoveData@ s, uint8 type){ return s.Type == type; }
     bool testCategory(const MoveData@ s, MoveCategory category){ return s.Category == category; }

tests/ScriptTests/ScriptTypeTests/Library/SpeciesTests.cpp

@@ -7,7 +7,7 @@ static std::unordered_map<const char*, const char*> _scripts =
     std::unordered_map<const char*, const char*>{{"testScript1", R"(
 namespace Pokemon{
 [Pokemon effect=testScript1]
-class testScript1 {
+class testScript1 : PkmnScript {
     bool testName(const Species@ s, const constString &in name){ return s.Name == name; }
     bool testId(const Species@ s, uint16 id){ return s.Id == id; }
     bool testGenderRate(const Species@ s, float rate){ return s.GenderRate == rate; }

tests/ScriptTests/ScriptTypeTests/Library/StaticLibraryTests.cpp

@@ -7,7 +7,7 @@ static std::unordered_map<const char*, const char*> _scripts =
     std::unordered_map<const char*, const char*>{{"testScript1", R"(
 namespace Pokemon{
 [Pokemon effect=testScript1]
-class testScript1 {
+class testScript1 : PkmnScript {
     bool testMaximumLevel(const StaticLibrary@ s, uint8 level){ return s.Settings.MaximalLevel == level; }
     bool testMaximumMoves(const StaticLibrary@ s, uint8 moveCount){ return s.Settings.MaximalMoves == moveCount; }
     bool testSpeciesLibrary(const StaticLibrary@ s, const SpeciesLibrary@ speciesLib){ return s.SpeciesLibrary is speciesLib; }

tests/TestLibrary/TestLibrary.cpp

@@ -55,6 +55,6 @@ PkmnLib::Library::ItemLibrary* TestLibrary::BuildItemLibrary() {
     auto lib = new PkmnLib::Library::ItemLibrary();
     lib->Insert("testItem"_cnc.GetHash(),
                 new PkmnLib::Library::Item("testItem"_cnc, CreatureLib::Library::ItemCategory::MiscItem,
-                                           CreatureLib::Library::BattleItemCategory::None, 0, {}, 0));
+                                           CreatureLib::Library::BattleItemCategory::None, 0, nullptr, {}, 0));
     return lib;
 }