UCrimsonInventoryManagerComponent

The central authority component. Add it to a PlayerState, Pawn, PlayerController, or a world container actor. All mutating functions are BlueprintAuthorityOnly. The inventory list replicates via FFastArraySerializer; the layout asset replicates COND_InitialOnly; ActiveConstraints replicates as a subobject array; tag-stack constraints are COND_OwnerOnly.

Initialization & layout

cpp

// Layout (set before init; replicated COND_InitialOnly)
UCrimsonInventoryLayout* GetLayout() const;
void SetLayout(UCrimsonInventoryLayout* InLayout);                 // authority-only
const FCrimsonLayoutRuntimeState& GetLayoutRuntime() const;
FCrimsonPlacementContext MakePlacementContext(int32 LayoutGroupId = 0) const;
void RebuildLayoutRuntime();

// Init: tag-stack caps + currency tables
void InitializeInventory(
    const TArray<UDataTable*>& ConstraintDataTables,
    const TArray<FCrimsonTagStack>&      DefaultIntConstraints,
    const TArray<FCrimsonFloatTagStack>& DefaultFloatConstraints,
    const TArray<UDataTable*>& CurrencyDataTables);

DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnInventoryInitialized);
UPROPERTY(BlueprintAssignable) FOnInventoryInitialized OnInventoryInitialized;

Item operations (authority-only, EntryId-based)

Method	Description
`CanAddItemDefinition(ItemDef, Count)`	Returns false (and broadcasts failure) if adding would violate any constraint
`AddItemDefinition(ItemDef, Count, Policy, ExplicitTarget)`	Adds items via the layout's `FindPlacement`. Policy = `MergeFirst` / `FirstFree` / `LastFree` / `MergeOnly` / `ExplicitTarget`
`AddItemInstance(Instance, Count, Policy, ExplicitTarget)`	Adds a pre-existing instance (e.g. from inventory transfer)
`RemoveItemsByDefinition(ItemDef, Count)`	Removes N items by definition; -1 removes all
`RemoveItemInstance(Instance)`	Removes a specific instance entirely
`MoveItemByEntry(SourceEntryId, Target)`	Moves an entry; layout decides Move/Swap/Merge. Returns FCrimsonMoveResult.
`DropItemByEntry(EntryId, Qty, Location)`	Removes items and broadcasts `FCrimsonInventory_Message_ItemDropped`; spawns one pickup actor if the item has `PickupActorClass`
`DropItemsByDefinition(ItemDef, Count, Location)`	Same but finds items by definition; spawns one pickup actor per consumed instance
`DropEntriesAsBag(EntryIds, Location, BagActorClass)`	Server-only: packs every supplied entry's full stack into a single `ACrimsonPickupActorBase` bag actor. Preserves per-instance state.
`SplitStackByEntry(SourceEntryId, Amount)`	Creates a new entry with the split portion via the layout
`MergeStacksByEntry(SourceEntryId, TargetEntryId)`	Merges source into target up to MaxStackSize
`MergeStack(Instance)`	Finds compatible stacks and merges into them
`LockEntry(EntryId, bLocked)`	Lock/unlock an entry. Locked entries are skipped by sort / consume / quick-merge
`ConsumeItemsByDefinition(ItemDef, Count, OutConsumed)`	Removes N items and populates `OutConsumed`; skips locked entries

Read operations

Method	Description
`GetAllItems()`	All item instances
`FindFirstItemStackByDefinition(ItemDef)`	First instance matching definition
`FindEntryByEntryId(EntryId)`	Entry by stable id
`FindEntryAtTarget(Target)`	Entry at a layout target
`GetSlottedEntries()`	Raw entry array
`GetFilteredItems(Filter)` / `PartitionItemsByFilter(...)`	Filter-based queries
`GetTotalItemCountByInstance / ByDefinition`	Aggregate stack counts
`HasRoomFor(ItemDef, Count)`	Convenience: would `Count` items fit?
`CalculateAddableQuantity(ItemDef, Requested, OutReason)`	Max that can actually be added given current constraints

Constraint stack

cpp

// Runtime mutation (authority-only)
void AddConstraint(UCrimsonInventoryConstraint* Constraint);
bool RemoveConstraint(UCrimsonInventoryConstraint* Constraint);

// Read
TArray<UCrimsonInventoryConstraint*> GetActiveConstraints() const;
TArray<UCrimsonInventoryConstraint*> GetConstraintsByTag(FGameplayTag Tag) const;

// Tag-stack caps (replicated FastArray)
int32 GetCurrentIntConstraintValue(FGameplayTag Tag) const;
int32 GetMaxIntConstraintValue(FGameplayTag Tag) const;
float GetCurrentFloatConstraintValue(FGameplayTag Tag) const;
float GetMaxFloatConstraintValue(FGameplayTag Tag) const;
void  ModifyIntConstraintValue(FGameplayTag Tag, int32 Delta);    // authority-only
void  ModifyFloatConstraintValue(FGameplayTag Tag, float Delta);  // authority-only

Async sort

cpp

FCrimsonInventorySortRequest Request;
Request.bMergeAfterSort = true;
Request.Rules = {
    { TAG_Crimson_Inventory_Sort_ByItemType, true },
    { TAG_Crimson_Inventory_Sort_ByName,     true }
};
InventoryComponent->RequestAsyncSort(Request);  // locked entries are excluded

Currency API

cpp

InventoryComponent->AddCurrency(GoldRowHandle, 100);
bool bOk = InventoryComponent->RemoveCurrency(GoldRowHandle, 50);
int64 Amount = InventoryComponent->GetCurrencyAmount(GoldRowHandle);

TArray<UCrimsonInventoryCurrency*> AllGold = InventoryComponent->FindAllCurrencyByTag(TAG_Currency_Gold);
UCrimsonInventoryCurrency* Coins = InventoryComponent->FindCurrencyByName(TEXT("Gold"));

InventoryComponent->DropCurrency(GoldRowHandle, 10, DropLocation);
InventoryComponent->RemoveCurrencyByTag(TAG_Currency_Gold, 25);

Save / Load

cpp

FCrimsonInventorySaveData SaveData = InventoryComponent->GetSaveData();
// ... serialize
InventoryComponent->ApplySaveData(SaveData);  // authority-only

Replication notes

- FCrimsonInventoryList uses FFastArraySerializer. Every mutation calls MarkItemDirty (per entry) or MarkArrayDirty (bulk).
- LayoutAsset is Replicated, COND_InitialOnly - set during init, immutable thereafter.
- ActiveConstraints replicates as a subobject array (AddReplicatedSubObject / RemoveReplicatedSubObject on add/remove).
- LayoutRuntime is Transient, NotReplicated. Rebuilt from entries in OnRep_InventoryList and FastArray PostReplicatedAdd/Change/Remove.
- ConstraintTags (int) and ConstraintFloatTags (float) are COND_OwnerOnly.
- Currencies are replicated subobjects.
- Constraint-change notifications use Client Reliable RPCs, re-broadcast via UCrimsonMessageSubsystem so UI can subscribe without seeing the RPC plumbing.