class_name Inventory

enum ItemSortType {
	NAME,
	TYPE
};

class ItemStackNameComparator:
	static func _sort(a, b):
		return ITEM.getItemName(a).to_lower() < ITEM.getItemName(b).to_lower()

class ItemStackTypeComparator:
	static func _sort(a, b):
		return a.item.getCategory() < b.item.getCategory()

const ITEM_STACK_SIZE_MAX = 99;

var contents:Array[ItemStack] = [];
signal inventoryUpdated()

func isPlayerInventory() -> bool:
	return self == ITEM.PLAYER_INVENTORY

func addItem(type:Item.Type, quantity: int = 1) -> void:
	if !ITEM.isStackable(type):
		# Item cannot be stacked, add each item to inv
		for i in range(quantity):
			contents.append(ItemStack.new(type, 1))
		_contentsUpdated()
		return
		
	# Check for existing stacks
	for stack in contents:
		if stack.type != type or stack.quantity >= ITEM_STACK_SIZE_MAX:
			continue
			
		var spaceAvailable = ITEM_STACK_SIZE_MAX - stack.quantity
		
		if quantity <= spaceAvailable:
			stack.quantity += quantity;
			_contentsUpdated()
			return
			
		stack.quantity = ITEM_STACK_SIZE_MAX;
		quantity -= spaceAvailable;
	
	# Add any remaining inventory as new stack.
	while quantity > 0:
		var newStackQuantity = min(quantity, ITEM_STACK_SIZE_MAX);
		contents.append(ItemStack.new(type, newStackQuantity));
		quantity -= newStackQuantity;
	_contentsUpdated()

func removeItem(type:Item.Type, quantity:int) -> void:
	var totalQuantity = 0
	
	# Calculate total quantity of the item in the inventory
	for stack in contents:
		if stack.type != type:
			continue
		totalQuantity += stack.quantity
	
	if totalQuantity < quantity:
		push_error("Not enough quantity to remove");
		return
	
	# Remove the quantity from the stacks
	for stack in contents:
		if stack.type != type:
			continue

		if stack.quantity < quantity:
			quantity -= stack.quantity
			contents.erase(stack)

		stack.quantity -= quantity
		if stack.quantity == 0:
			contents.erase(stack)

		if quantity == 0:
			self._contentsUpdated()
			return

func removeStack(stack: ItemStack) -> void:
	self.removeItem(stack.item, stack.quantity);

func hasItem(type:Item.Type, quantity: int = 1) -> bool:
	var totalQuantity = 0
	
	for stack in contents:
		if stack.type != type:
			continue
		
		totalQuantity += stack.quantity

		if totalQuantity >= quantity:
			return true
	
	return false

func sortBy(by:ItemSortType) -> void:
	match by:
		ItemSortType.NAME:
			contents.sort_custom(ItemStackNameComparator._sort)
		ItemSortType.TYPE:
			contents.sort_custom(ItemStackTypeComparator._sort)
		_:
			assert(false, "Invalid sort type: %s" % by)

func _contentsUpdated() -> void:
	inventoryUpdated.emit()
	if isPlayerInventory():
		QUEST.playerInventoryUpdated.emit()