Initial commit: Item Interaction Ecosystem plugin (UE5.7)

Server-authoritative, data-driven item/inventory/interaction/carry/equipment/
world-slot/placement/crafting framework. 8 modules, compiles against UE 5.7.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Source/ItemWorld/Private/EquipmentComponent.cpp

@@ -0,0 +1,150 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#include "EquipmentComponent.h"
+#include "ItemWorldLog.h"
+#include "ItemDatabaseSubsystem.h"
+#include "ItemDefinitionRow.h"
+#include "InventoryComponent.h"
+#include "GameFramework/Character.h"
+#include "Components/SkeletalMeshComponent.h"
+#include "Net/UnrealNetwork.h"
+
+UEquipmentComponent::UEquipmentComponent()
+{
+	PrimaryComponentTick.bCanEverTick = false;
+	SetIsReplicatedByDefault(true);
+}
+
+void UEquipmentComponent::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const
+{
+	Super::GetLifetimeReplicatedProps(OutLifetimeProps);
+	DOREPLIFETIME(UEquipmentComponent, Equipped);
+}
+
+void UEquipmentComponent::OnUnregister()
+{
+	if (HasAuthority())
+	{
+		for (const FEquippedItemEntry& Entry : Equipped)
+		{
+			if (Entry.EquippedActor)
+			{
+				Entry.EquippedActor->Destroy();
+			}
+		}
+	}
+	Super::OnUnregister();
+}
+
+bool UEquipmentComponent::HasAuthority() const
+{
+	return GetOwner() && GetOwner()->HasAuthority();
+}
+
+USceneComponent* UEquipmentComponent::GetAttachTarget() const
+{
+	if (const ACharacter* Char = Cast<ACharacter>(GetOwner()))
+	{
+		return Char->GetMesh();
+	}
+	return GetOwner() ? GetOwner()->GetRootComponent() : nullptr;
+}
+
+FName UEquipmentComponent::ResolveSocket(const FGameplayTag& SlotTag) const
+{
+	if (const FName* Found = SlotSockets.Find(SlotTag))
+	{
+		return *Found;
+	}
+	return DefaultEquipSocket;
+}
+
+bool UEquipmentComponent::IsSlotEquipped(FGameplayTag SlotTag) const
+{
+	return Equipped.ContainsByPredicate([&SlotTag](const FEquippedItemEntry& E) { return E.SlotTag == SlotTag; });
+}
+
+bool UEquipmentComponent::ServerEquip(FGuid InstanceId, FGameplayTag SlotTag)
+{
+	if (!HasAuthority())
+	{
+		return false;
+	}
+
+	UInventoryComponent* Inv = GetOwner()->FindComponentByClass<UInventoryComponent>();
+	if (!Inv)
+	{
+		return false;
+	}
+	FItemInstanceData Item;
+	if (!Inv->FindItem(InstanceId, Item))
+	{
+		return false;
+	}
+
+	const UItemDatabaseSubsystem* DB = UItemDatabaseSubsystem::Get(this);
+	const FItemDefinitionRow* Def = DB ? DB->GetItemDefinition(Item.ItemId) : nullptr;
+	if (!Def || !Def->bCanEquip)
+	{
+		return false;
+	}
+	// Slot compatibility (if the item restricts equipment slots).
+	if (!Def->AllowedEquipmentSlots.IsEmpty() && !Def->AllowedEquipmentSlots.HasTag(SlotTag))
+	{
+		return false;
+	}
+
+	// Free the slot first.
+	ServerUnequip(SlotTag);
+
+	FEquippedItemEntry Entry;
+	Entry.SlotTag = SlotTag;
+	Entry.InstanceId = InstanceId;
+	Entry.ItemId = Item.ItemId;
+
+	if (!Def->EquippedActorClass.IsNull())
+	{
+		if (UClass* ActorClass = Def->EquippedActorClass.LoadSynchronous())
+		{
+			FActorSpawnParameters Params;
+			Params.Owner = GetOwner();
+			Params.Instigator = Cast<APawn>(GetOwner());
+			AActor* Spawned = GetWorld()->SpawnActor<AActor>(ActorClass, FTransform::Identity, Params);
+			if (Spawned)
+			{
+				Spawned->AttachToComponent(GetAttachTarget(), FAttachmentTransformRules::SnapToTargetIncludingScale, ResolveSocket(SlotTag));
+				Entry.EquippedActor = Spawned;
+			}
+		}
+	}
+
+	Equipped.Add(Entry);
+	OnEquipmentChanged.Broadcast();
+	UE_LOG(LogItemWorld, Log, TEXT("[Inventory] equipped %s in %s"), *Item.ItemId.ToString(), *SlotTag.ToString());
+	return true;
+}
+
+bool UEquipmentComponent::ServerUnequip(FGameplayTag SlotTag)
+{
+	if (!HasAuthority())
+	{
+		return false;
+	}
+	const int32 Index = Equipped.IndexOfByPredicate([&SlotTag](const FEquippedItemEntry& E) { return E.SlotTag == SlotTag; });
+	if (Index == INDEX_NONE)
+	{
+		return false;
+	}
+	if (Equipped[Index].EquippedActor)
+	{
+		Equipped[Index].EquippedActor->Destroy();
+	}
+	Equipped.RemoveAt(Index);
+	OnEquipmentChanged.Broadcast();
+	return true;
+}
+
+void UEquipmentComponent::OnRep_Equipped()
+{
+	OnEquipmentChanged.Broadcast();
+}