## AvatarLoadout - Serializable loadout model + validation.
##
## Represents a complete avatar composition: a base body plus equipped items
## per slot. Validates slot exclusivity and references against a catalog.
##
## See docs/architecture/avatar.md §5 for the loadout JSON format.

extends RefCounted


## Maximum number of accessories allowed in the accessory slot.
const MAX_ACCESSORIES: int = 8

## The base body asset ID.
var base_body: String = ""

## Equipped items per slot. Keys are slot IDs from AvatarSlotRegistry.
## Exclusive slots hold a single asset ID (or null).
## The "accessory" slot holds an array of asset IDs.
var slots: Dictionary = {}

## Validation errors found during the last validate() call.
var validation_errors: Array[String] = []


func _init() -> void:
	validation_errors = []


## Create a loadout from a JSON string.
static func from_json(json_string: String) -> AvatarLoadout:
	var loadout := AvatarLoadout.new()
	var data: Variant = JSON.parse_string(json_string)
	if data is not Dictionary:
		loadout.validation_errors.append("Loadout JSON root is not an object")
		return loadout

	var root: Dictionary = data as Dictionary

	# Parse base_body
	if root.has("base_body"):
		var bb = root["base_body"]
		if typeof(bb) == TYPE_STRING:
			loadout.base_body = bb as String
		else:
			loadout.validation_errors.append("base_body must be a string")

	# Parse slots
	if root.has("slots"):
		var slots_data = root["slots"]
		if typeof(slots_data) == TYPE_DICTIONARY:
			loadout.slots = slots_data as Dictionary
		else:
			loadout.validation_errors.append("slots must be an object")
	else:
		loadout.validation_errors.append("Missing 'slots' in loadout JSON")

	return loadout


## Serialize this loadout to a JSON string.
func to_json() -> String:
	var data := {
		"base_body": base_body,
		"slots": {}
	}

	for slot_id in AvatarSlotRegistry.SLOT_IDS:
		if slot_id == "accessory":
			data.slots[slot_id] = slots.get(slot_id, [])
		else:
			data.slots[slot_id] = slots.get(slot_id, null)

	return JSON.stringify(data, "  ")


## Validate this loadout against the slot registry.
## Returns true if valid; populates validation_errors if not.
func validate() -> bool:
	validation_errors.clear()

	# Check base_body
	if base_body.is_empty():
		validation_errors.append("base_body is required")

	# Check each slot
	for slot_id in AvatarSlotRegistry.SLOT_IDS:
		var slot_def = AvatarSlotRegistry.get_slot(slot_id)
		if slot_def == null:
			validation_errors.append("Unknown slot: %s" % slot_id)
			continue

		var value = slots.get(slot_id)

		if slot_def.exclusive:
			# Exclusive slots: must be null or a string
			if value != null and typeof(value) != TYPE_STRING:
				validation_errors.append(
					"Slot '%s' must be null or a string, got %s" % [
						slot_id, typeof(value)
					]
				)
		else:
			# Non-exclusive (accessory): must be null or an array
			if value != null and typeof(value) != TYPE_ARRAY:
				validation_errors.append(
					"Slot '%s' must be null or an array, got %s" % [
						slot_id, typeof(value)
					]
				)
			elif value is Array:
				if slot_id == "accessory":
					if value.size() > MAX_ACCESSORIES:
						validation_errors.append(
							"Accessory count (%d) exceeds maximum (%d)" % [
								value.size(), MAX_ACCESSORIES
							]
						)

	# Check for duplicate accessories
	if slots.has("accessory") and slots["accessory"] is Array:
		var accessories = slots["accessory"] as Array
		var seen := {}
		for item in accessories:
			if item is String:
				if seen.has(item):
					validation_errors.append(
						"Duplicate accessory: %s" % item
					)
				seen[item] = true

	return validation_errors.is_empty()


## Check if a specific slot is equipped with a non-null item.
func is_equipped(slot_id: String) -> bool:
	if not AvatarSlotRegistry.has_slot(slot_id):
		return false

	var value = slots.get(slot_id)
	if value == null:
		return false

	if typeof(value) == TYPE_STRING:
		return not (value as String).is_empty()
	elif typeof(value) == TYPE_ARRAY:
		return (value as Array).size() > 0

	return false


## Get the equipped asset ID for an exclusive slot.
## Returns empty string if not equipped or slot is not exclusive.
func get_equipment(slot_id: String) -> String:
	var value = slots.get(slot_id)
	if value is String:
		return value
	return ""


## Set equipment for an exclusive slot.
func set_equipment(slot_id: String, asset_id: String) -> void:
	if not AvatarSlotRegistry.has_slot(slot_id):
		push_error("Unknown slot: %s" % slot_id)
		return

	var slot_def = AvatarSlotRegistry.get_slot(slot_id)
	if slot_def and not slot_def.exclusive:
		push_error("Slot '%s' is not exclusive" % slot_id)
		return

	if slots.has(slot_id):
		var current = slots[slot_id]
		if current is Array:
			# Convert array to single value
			slots[slot_id] = asset_id if asset_id.is_empty() else null
		else:
			slots[slot_id] = asset_id if not asset_id.is_empty() else null
	else:
		slots[slot_id] = asset_id if not asset_id.is_empty() else null


## Add an accessory to the accessory slot.
func add_accessory(asset_id: String) -> bool:
	var accessories = slots.get("accessory", []) as Array
	if accessories.size() >= MAX_ACCESSORIES:
		return false
	if asset_id.is_empty():
		return false
	if accessories.has(asset_id):
		return false
	accessories.append(asset_id)
	slots["accessory"] = accessories
	return true


## Remove an accessory from the accessory slot.
func remove_accessory(asset_id: String) -> bool:
	var accessories = slots.get("accessory", []) as Array
	if accessories.has(asset_id):
		accessories.erase(asset_id)
		slots["accessory"] = accessories
		return true
	return false


## Compute a hash of this loadout for change detection.
## Mirrors the server's loadout_hash concept.
func compute_hash() -> int:
	var hasher := HashingContext.new()
	hasher.start(HashingContext.HASH_SHA256)
	hasher.update(base_body.to_utf8_buffer())
	for slot_id in AvatarSlotRegistry.SLOT_IDS:
		hasher.update(slot_id.to_utf8_buffer())
		var value = slots.get(slot_id)
		if value is String:
			hasher.update(value.to_utf8_buffer())
		elif value is Array:
			var arr_str = JSON.stringify(value)
			hasher.update(arr_str.to_utf8_buffer())
		else:
			hasher.update("null".to_utf8_buffer())
	var digest = hasher.finish()
	# Return first 4 bytes as int for compact storage
	return digest[0] | (digest[1] << 8) | (digest[2] << 16) | (digest[3] << 24)