class_name PlayerHotbar
extends Node

const SLOT_COUNT: int = 9
const ItemCatalogType = preload("res://items/item_catalog.gd")
const ItemDataType = preload("res://items/item_data.gd")
const PlayerBagType = preload("res://inventory/player_bag.gd")

signal slots_changed
signal selected_slot_changed(slot_index: int, item_id: StringName)

var _bag: PlayerBagType
var _catalog: ItemCatalogType
var _slots: Array[StringName] = []
var _selected_slot: int = 0


func _init() -> void:
	_slots.resize(SLOT_COUNT)
	_slots.fill(StringName())


func setup(bag: PlayerBagType, catalog: ItemCatalogType) -> void:
	_bag = bag
	_catalog = catalog
	if _bag != null and not _bag.contents_changed.is_connected(
		_on_bag_contents_changed
	):
		_bag.contents_changed.connect(_on_bag_contents_changed)
	_validate_assignments()


func assign_item(slot_index: int, item_id: StringName) -> bool:
	if not _is_slot_valid(slot_index) or not _can_assign(item_id):
		return false
	if _slots[slot_index] == item_id:
		return true
	for index: int in range(SLOT_COUNT):
		if index != slot_index and _slots[index] == item_id:
			_slots[index] = StringName()
	_slots[slot_index] = item_id
	slots_changed.emit()
	if slot_index == _selected_slot:
		selected_slot_changed.emit(_selected_slot, item_id)
	return true


func clear_slot(slot_index: int) -> bool:
	if not _is_slot_valid(slot_index) or _slots[slot_index].is_empty():
		return false
	_slots[slot_index] = StringName()
	slots_changed.emit()
	if slot_index == _selected_slot:
		selected_slot_changed.emit(_selected_slot, StringName())
	return true


func swap_slots(from_index: int, to_index: int) -> bool:
	if (
		not _is_slot_valid(from_index)
		or not _is_slot_valid(to_index)
		or from_index == to_index
	):
		return false
	var temporary: StringName = _slots[from_index]
	_slots[from_index] = _slots[to_index]
	_slots[to_index] = temporary
	slots_changed.emit()
	if from_index == _selected_slot or to_index == _selected_slot:
		selected_slot_changed.emit(
			_selected_slot,
			_slots[_selected_slot]
		)
	return true


func select_slot(slot_index: int) -> bool:
	if not _is_slot_valid(slot_index):
		return false
	if _selected_slot == slot_index:
		return true
	_selected_slot = slot_index
	selected_slot_changed.emit(_selected_slot, _slots[_selected_slot])
	return true


func cycle_selection(direction: int) -> bool:
	if direction == 0:
		return false
	return select_slot(
		posmod(_selected_slot + signi(direction), SLOT_COUNT)
	)


func get_selected_slot() -> int:
	return _selected_slot


func get_selected_item_id() -> StringName:
	return _slots[_selected_slot]


func get_item_id(slot_index: int) -> StringName:
	return _slots[slot_index] if _is_slot_valid(slot_index) else StringName()


func get_slots() -> Array[StringName]:
	return _slots.duplicate()


func replace_state(
	slots: Array[StringName],
	selected_slot: int,
) -> bool:
	var normalized: Array[StringName] = []
	normalized.resize(SLOT_COUNT)
	normalized.fill(StringName())
	var seen_assignments: Dictionary[StringName, bool] = {}
	for index: int in range(mini(slots.size(), SLOT_COUNT)):
		var item_id: StringName = slots[index]
		if item_id.is_empty():
			continue
		if _can_assign(item_id) and not seen_assignments.has(item_id):
			normalized[index] = item_id
			seen_assignments[item_id] = true
	_slots = normalized
	_selected_slot = clampi(selected_slot, 0, SLOT_COUNT - 1)
	slots_changed.emit()
	selected_slot_changed.emit(
		_selected_slot,
		_slots[_selected_slot]
	)
	return true


func has_any_assignment() -> bool:
	for item_id: StringName in _slots:
		if not item_id.is_empty():
			return true
	return false


func _can_assign(item_id: StringName) -> bool:
	if item_id.is_empty() or _bag == null or not _bag.owns_item(item_id):
		return false
	if _catalog == null:
		return false
	var item: ItemDataType = _catalog.get_item_by_id(item_id)
	return item != null and item.is_valid() and item.hotbar_allowed


func _validate_assignments() -> void:
	var changed: bool = false
	for index: int in range(SLOT_COUNT):
		if not _slots[index].is_empty() and not _can_assign(_slots[index]):
			_slots[index] = StringName()
			changed = true
	if changed:
		slots_changed.emit()
		selected_slot_changed.emit(
			_selected_slot,
			_slots[_selected_slot]
		)


func _on_bag_contents_changed() -> void:
	_validate_assignments()


func _is_slot_valid(slot_index: int) -> bool:
	return slot_index >= 0 and slot_index < SLOT_COUNT