extends Node

# ============================================================================
# ApiClient.gd - 后端 JSON API 客户端
# ============================================================================
# 统一处理 WhaleTown 后端 HTTP JSON 请求、认证头和响应信封解析。
# ============================================================================

signal request_failed(endpoint: String, message: String)

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

const REQUEST_TIMEOUT: float = 12.0

var _activeRequests: Array[HTTPRequest] = []

func _exit_tree() -> void:
	for request in _activeRequests:
		if is_instance_valid(request):
			request.cancel_request()
			request.queue_free()
	_activeRequests.clear()

func get_json(endpoint: String, callback: Callable, authenticated: bool = true) -> void:
	request_json(endpoint, {}, callback, HTTPClient.METHOD_GET, authenticated)

func post_json(endpoint: String, payload: Dictionary, callback: Callable, authenticated: bool = true) -> void:
	request_json(endpoint, payload, callback, HTTPClient.METHOD_POST, authenticated)

func patch_json(endpoint: String, payload: Dictionary, callback: Callable, authenticated: bool = true) -> void:
	request_json(endpoint, payload, callback, HTTPClient.METHOD_PATCH, authenticated)

func put_json(endpoint: String, payload: Dictionary, callback: Callable, authenticated: bool = true) -> void:
	request_json(endpoint, payload, callback, HTTPClient.METHOD_PUT, authenticated)

func request_json(endpoint: String, payload: Dictionary, callback: Callable, method: int = HTTPClient.METHOD_GET, authenticated: bool = true) -> void:
	var request := HTTPRequest.new()
	request.timeout = REQUEST_TIMEOUT
	add_child(request)
	_activeRequests.append(request)

	request.request_completed.connect(func(result: int, responseCode: int, _headers: PackedStringArray, body: PackedByteArray) -> void:
		_activeRequests.erase(request)
		request.queue_free()
		_handle_response(endpoint, result, responseCode, body, callback)
	)

	var url := "%s%s" % [NetworkConfig.get_api_base_url(), endpoint]
	var body := "" if method == HTTPClient.METHOD_GET else JSON.stringify(payload)
	var err := request.request(url, _headers(authenticated), method, body)
	if err != OK:
		_activeRequests.erase(request)
		request.queue_free()
		var message := "网络请求发送失败: %s" % error_string(err)
		request_failed.emit(endpoint, message)
		callback.call(false, {}, {"message": message})

func _headers(authenticated: bool) -> PackedStringArray:
	var headers := PackedStringArray(["Content-Type: application/json"])
	if authenticated:
		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 ""
		if not accessToken.is_empty():
			headers.append("Authorization: Bearer %s" % accessToken)
	return headers

func _handle_response(endpoint: String, result: int, responseCode: int, body: PackedByteArray, callback: Callable) -> void:
	if result != HTTPRequest.RESULT_SUCCESS:
		var message := "网络请求失败: %s" % _http_result_to_string(result)
		request_failed.emit(endpoint, message)
		callback.call(false, {}, {"message": message})
		return

	var bodyText := body.get_string_from_utf8()
	var json := JSON.new()
	if json.parse(bodyText) != OK:
		var parseMessage := "服务器响应解析失败"
		request_failed.emit(endpoint, parseMessage)
		callback.call(false, {}, {"message": parseMessage, "response_code": responseCode})
		return

	var payloadVariant: Variant = json.data
	if not (payloadVariant is Dictionary):
		var formatMessage := "服务器响应格式错误"
		request_failed.emit(endpoint, formatMessage)
		callback.call(false, {}, {"message": formatMessage, "response_code": responseCode})
		return

	var response: Dictionary = payloadVariant
	var ok := responseCode >= 200 and responseCode < 300 and bool(response.get("success", true))
	if ok:
		callback.call(true, response, {})
		return

	var errorInfo := {
		"message": str(response.get("message", "请求失败")),
		"response_code": responseCode,
		"error_code": str(response.get("error_code", ""))
	}
	request_failed.emit(endpoint, str(errorInfo.get("message", "请求失败")))
	callback.call(false, response, errorInfo)

func _http_result_to_string(result: int) -> String:
	match result:
		HTTPRequest.RESULT_CHUNKED_BODY_SIZE_MISMATCH:
			return "响应分块大小不匹配"
		HTTPRequest.RESULT_CANT_CONNECT:
			return "无法连接服务器"
		HTTPRequest.RESULT_CANT_RESOLVE:
			return "无法解析服务器地址"
		HTTPRequest.RESULT_CONNECTION_ERROR:
			return "连接中断"
		HTTPRequest.RESULT_TLS_HANDSHAKE_ERROR:
			return "TLS握手失败"
		HTTPRequest.RESULT_NO_RESPONSE:
			return "服务器无响应"
		HTTPRequest.RESULT_BODY_SIZE_LIMIT_EXCEEDED:
			return "响应内容过大"
		HTTPRequest.RESULT_REQUEST_FAILED:
			return "请求失败"
		HTTPRequest.RESULT_DOWNLOAD_FILE_CANT_OPEN:
			return "下载文件无法打开"
		HTTPRequest.RESULT_DOWNLOAD_FILE_WRITE_ERROR:
			return "下载文件写入失败"
		HTTPRequest.RESULT_REDIRECT_LIMIT_REACHED:
			return "重定向次数过多"
		HTTPRequest.RESULT_TIMEOUT:
			return "请求超时"
		_:
			return "未知错误 %s" % result