extends Node

signal decor_save_succeeded(item: Dictionary)
signal decor_save_failed(item: Dictionary, message: String)

const NetworkConfig = preload("res://_Core/utils/NetworkConfig.gd")

const REQUEST_TIMEOUT: float = 12.0
const MAX_SAVE_RETRIES: int = 3
const RETRY_BASE_DELAY: float = 0.75

var _request: HTTPRequest
var _retryTimer: Timer
var _queue: Array[Dictionary] = []
var _inFlight: Dictionary = {}
var _requestGeneration: int = -1
var _accountGeneration: int = -1

func _ready() -> void:
	_request = HTTPRequest.new()
	_request.name = "roomDecorSaveRequest"
	_request.timeout = REQUEST_TIMEOUT
	_request.request_completed.connect(_on_request_completed)
	add_child(_request)

	_retryTimer = Timer.new()
	_retryTimer.name = "roomDecorSaveRetryTimer"
	_retryTimer.one_shot = true
	_retryTimer.timeout.connect(_process_next_save)
	add_child(_retryTimer)

	var authManager := get_node_or_null("/root/AuthManager")
	if authManager != null and authManager.has_signal("auth_state_changed"):
		_accountGeneration = _current_account_generation()
		authManager.auth_state_changed.connect(_on_auth_state_changed)

func enqueue_save(item: Dictionary) -> bool:
	if not _is_authenticated():
		decor_save_failed.emit(item.duplicate(true), "请先登录后保存摆放")
		return false
	var decorId := str(item.get("decor_id", "")).strip_edges()
	if decorId.is_empty():
		decor_save_failed.emit(item.duplicate(true), "家具数据缺少 decor_id")
		return false

	# Only the newest queued placement for a decor matters.
	for index in range(_queue.size() - 1, -1, -1):
		var queuedItem: Dictionary = _queue[index].get("item", {})
		if str(queuedItem.get("decor_id", "")) == decorId:
			_queue.remove_at(index)
	_queue.append({"item": item.duplicate(true), "retry_count": 0})
	_process_next_save()
	return true

func has_pending_saves() -> bool:
	return not _inFlight.is_empty() or not _queue.is_empty() or (_retryTimer != null and not _retryTimer.is_stopped())

func _process_next_save() -> void:
	if not _inFlight.is_empty() or _queue.is_empty() or not _is_authenticated():
		return
	if _retryTimer != null and not _retryTimer.is_stopped():
		return
	_inFlight = _queue.pop_front()
	_requestGeneration = _current_account_generation()
	var item: Dictionary = _inFlight.get("item", {})
	var payload := {
		"decor_id": str(item.get("decor_id", "")),
		"placed": bool(item.get("placed", false)),
		"position_x": float(item.get("position_x", 0.0)),
		"position_y": float(item.get("position_y", 0.0)),
		"scale": float(item.get("scale", item.get("default_scale", 1.0))),
		"rotation_degrees": int(item.get("rotation_degrees", item.get("default_rotation_degrees", 0))),
		"z_index": int(item.get("z_index", item.get("default_z_index", 0))),
	}
	var decorId := str(item.get("decor_id", "")).uri_encode()
	var err := _request.request(
		"%s/rooms/me/decor-placements/%s" % [NetworkConfig.get_api_base_url(), decorId],
		_auth_headers(),
		HTTPClient.METHOD_PUT,
		JSON.stringify(payload)
	)
	if err != OK:
		_retry_or_fail("家具位置保存请求发送失败")

func _on_request_completed(result: int, responseCode: int, _headers: PackedStringArray, body: PackedByteArray) -> void:
	if _inFlight.is_empty():
		return
	if _requestGeneration != _current_account_generation():
		_inFlight.clear()
		_requestGeneration = -1
		_process_next_save()
		return
	if result != HTTPRequest.RESULT_SUCCESS or responseCode < 200 or responseCode >= 300:
		_retry_or_fail(_read_error_message(body, "家具位置保存失败"))
		return

	var savedItem: Dictionary = (_inFlight.get("item", {}) as Dictionary).duplicate(true)
	var json := JSON.new()
	if json.parse(body.get_string_from_utf8()) == OK and json.data is Dictionary:
		var response: Dictionary = json.data
		if not bool(response.get("success", true)):
			_retry_or_fail(str(response.get("message", "家具位置保存失败")))
			return
		var dataVariant: Variant = response.get("data", {})
		if dataVariant is Dictionary:
			savedItem = (dataVariant as Dictionary).duplicate(true)

	_inFlight.clear()
	_requestGeneration = -1
	decor_save_succeeded.emit(savedItem)
	_process_next_save()

func _retry_or_fail(message: String) -> void:
	if _inFlight.is_empty():
		return
	var failedEntry := _inFlight.duplicate(true)
	var failedItem: Dictionary = failedEntry.get("item", {})
	var decorId := str(failedItem.get("decor_id", ""))
	_inFlight.clear()
	_requestGeneration = -1

	if _queue_has_decor(decorId):
		_process_next_save()
		return
	var retryCount := int(failedEntry.get("retry_count", 0)) + 1
	if retryCount <= MAX_SAVE_RETRIES and _is_authenticated():
		failedEntry["retry_count"] = retryCount
		_queue.push_front(failedEntry)
		_retryTimer.start(RETRY_BASE_DELAY * pow(2.0, retryCount - 1))
		return

	decor_save_failed.emit(failedItem.duplicate(true), message)
	_process_next_save()

func _queue_has_decor(decorId: String) -> bool:
	for entryVariant in _queue:
		if entryVariant is Dictionary:
			var item: Dictionary = (entryVariant as Dictionary).get("item", {})
			if str(item.get("decor_id", "")) == decorId:
				return true
	return false

func _on_auth_state_changed(_isAuthenticated: bool, _user: Dictionary) -> void:
	var currentGeneration := _current_account_generation()
	if currentGeneration == _accountGeneration:
		return
	_accountGeneration = currentGeneration
	if is_instance_valid(_request):
		_request.cancel_request()
	if is_instance_valid(_retryTimer):
		_retryTimer.stop()
	_queue.clear()
	_inFlight.clear()
	_requestGeneration = -1

func _auth_headers() -> PackedStringArray:
	var authManager := get_node_or_null("/root/AuthManager")
	var accessToken := str(authManager.call("get_access_token")).strip_edges() if authManager != null and authManager.has_method("get_access_token") else ""
	return PackedStringArray([
		"Content-Type: application/json",
		"Authorization: Bearer %s" % accessToken,
	])

func _is_authenticated() -> bool:
	var authManager := get_node_or_null("/root/AuthManager")
	return authManager != null and authManager.has_method("is_authenticated") and bool(authManager.call("is_authenticated"))

func _current_account_generation() -> int:
	var authManager := get_node_or_null("/root/AuthManager")
	return int(authManager.call("get_account_generation")) if authManager != null and authManager.has_method("get_account_generation") else -1

func _read_error_message(body: PackedByteArray, fallback: String) -> String:
	var json := JSON.new()
	if json.parse(body.get_string_from_utf8()) != OK or not (json.data is Dictionary):
		return fallback
	var response: Dictionary = json.data
	var messageVariant: Variant = response.get("message", fallback)
	if messageVariant is Array:
		var parts: Array[String] = []
		for part in messageVariant:
			parts.append(str(part))
		return "; ".join(parts) if not parts.is_empty() else fallback
	var message := str(messageVariant).strip_edges()
	return message if not message.is_empty() else fallback