import threading
import time
from opcua import Client, ua
from opcua.ua.uaerrors import UaError
import json


class OPCClient:
    def __init__(self, url='opc.tcp://127.0.0.1:4840'):
        self.url = url
        self.client = None
        self.is_connected = False
        self.reconnect_interval = 5  # 重连间隔(秒)
        self.is_running = False
        self.namespace_idx = None
        self.data_node = None

    def connect(self):
        """连接到OPC UA服务端"""
        try:
            if self.client:
                self.client.disconnect()
                
            self.client = Client(self.url)
            self.client.set_security_string("None")
            self.client.connect()
            
            # 获取命名空间索引
            self.namespace_idx = self.client.get_namespace_index("urn:python-opcua")
            
            # 获取数据节点
            self.data_node = self.client.get_node(f"ns={self.namespace_idx};i=2001")  # 默认数据节点
            
            self.is_connected = True
            print(f"已连接到 OPC UA 服务端 {self.url}")
            return True
        except UaError as e:
            print(f"OPC UA 连接错误: {e}")
            self.is_connected = False
            return False
        except Exception as e:
            print(f"连接到 OPC UA 服务端失败: {e}")
            self.is_connected = False
            return False

    def start(self):
        """启动客户端并维持连接"""
        self.is_running = True
        reconnect_thread = threading.Thread(target=self._reconnect_worker, daemon=True)
        reconnect_thread.start()

    def _reconnect_worker(self):
        """重连工作线程"""
        while self.is_running:
            if not self.is_connected:
                print(f"尝试重新连接到 {self.url}...")
                self.connect()
            time.sleep(self.reconnect_interval)

    def send_data(self, data):
        """通过OPC UA发送数据到服务端"""
        if not self.is_connected or not self.client:
            print("OPC UA 客户端未连接到服务端")
            return False

        try:
            # 将数据转换为JSON字符串
            json_data = json.dumps(data, ensure_ascii=False)
            
            # 写入数据到OPC UA节点
            if self.data_node:
                variant = ua.Variant(json_data, ua.VariantType.String)
                self.data_node.set_value(variant)
                print(f"已通过 OPC UA 发送数据: {json_data}")
                return True
            else:
                print("数据节点未初始化")
                return False
        except UaError as e:
            print(f"OPC UA 发送数据时出错: {e}")
            self.is_connected = False
            return False
        except Exception as e:
            print(f"发送数据时出错: {e}")
            self.is_connected = False
            return False

    def stop(self):
        """停止客户端"""
        self.is_running = False
        self.is_connected = False
        if self.client:
            try:
                self.client.disconnect()
            except Exception as e:
                print(f"断开 OPC UA 客户端时出错: {e}")
        print("OPC UA 客户端已停止")