#!/usr/bin/env python3
from PySide6.QtCore import QObject, Signal
from opcua import Client, ua
import time
from datetime import datetime

class OpcuaUiSignal(QObject):
    # 定义值变化信号：参数为(node_id, var_name, new_value)
    value_changed = Signal(str, str, object)

# Opcua回调处理器
class SubscriptionHandler:
    def __init__(self, opc_signal:OpcuaUiSignal):
        # 初始化nodeid→变量名映射表
        self.node_id_to_name = {}
        self.opc_signal = opc_signal

    def datachange_notification(self, node, val, data):
        """
        python-opcua标准的回调函数
        :param node: 变化的节点对象
        :param val: 节点新值
        :param data: 附加数据（包含时间戳等）
        """
        try:
            # 1. 解析时间戳
            # time_str = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
            # try:
            #     utc_time = data.monitored_item.Value.SourceTimestamp
            #     beijing_time = utc_time + datetime.timedelta(hours=8)
            #     time_str = beijing_time.strftime('%Y-%m-%d %H:%M:%S')
            # except:
            #     pass

            # 2. 获取nodeid并解析变量名
            node_id = node.nodeid.to_string()
            # 从映射表获取可读变量名
            var_name = self.node_id_to_name.get(node_id)

            # 3. 打印变化通知
            # print(f"\n 节点值发生变化！")
            # print(f"   节点ID: {node_id}")
            # print(f"   变量名称: {var_name}")
            # print(f"   时间: {time_str}")
            # print(f"   新值: {val}")

            self.opc_signal.value_changed.emit(node_id, var_name, val)
           
        except Exception as e:
            print(f"解析值变化事件失败: {e}")
            import traceback
            traceback.print_exc()

class OpcuaUiClient:
    def __init__(self, server_url="opc.tcp://localhost:4840/zjsh_feed/server/"):
        """初始化 OPC UA 客户端"""
        self.client = Client(server_url)

        self.connected = False
        self.subscription = None
        self.monitored_items = []

        # 创建Qt信号对象（用于跨线程传递数据）
        self.opc_signal = OpcuaUiSignal()
        self.handler = SubscriptionHandler(self.opc_signal)  # 回调处理器
        # 定义需要监控的变量路径（object_name + var_name）
        # 格式：(变量可读名称, [object路径, 变量路径])
        self.target_var_paths = [
            ("upper_weight", ["2:upper", "2:upper_weight"]),
            ("lower_weight", ["2:lower", "2:lower_weight"])
        ]
        self.node_id_mapping = {}  # 存储nodeid→变量名的映射表

    def connect(self):
        """连接到服务器"""
        try:
            self.client.connect()
            self.connected = True
            print(f"成功连接到 OPC UA 服务器: {self.client.server_url}")
            return True
        except Exception as e:
            print(f"连接服务器失败: {e}")
            return False

    def disconnect(self):
        """断开连接（包含取消订阅）"""
        if self.subscription:
            try:
                self.subscription.delete()
                print("已取消节点订阅")
            except:
                pass
        if self.connected:
            self.client.disconnect()
            self.connected = False
            print("已断开与 OPC UA 服务器的连接")

    def build_node_id_mapping(self):
        """
        根据object_name+var_name路径获取nodeid,建立映射表
        """
        if not self.connected:
            print("请先连接到服务器")
            return False
        
        try:
            print("\n 开始构建nodeid映射表...")
            objects_node = self.client.get_objects_node()  # 获取根Objects节点

            for var_name, path_list in self.target_var_paths:
                # 根据层级路径找到目标节点
                target_node = objects_node.get_child(path_list)
                # 提取nodeid字符串
                node_id = target_node.nodeid.to_string()
                # 存入映射表
                self.node_id_mapping[node_id] = var_name
                print(f"映射成功: {node_id} → {var_name}")
            
            # 将映射表传给回调处理器
            self.handler.node_id_to_name = self.node_id_mapping
            return True
        except Exception as e:
            print(f"构建映射表失败: {e}")
            import traceback
            traceback.print_exc()
            return False

    def create_multi_subscription(self, interval=500):
        """订阅多个变量(基于映射表的nodeid)"""
        if not self.connected:
            print("请先连接到服务器")
            return
        
        # 先构建映射表，失败则直接返回
        if not self.node_id_mapping:
            if not self.build_node_id_mapping():
                return
        
        try:
            interval = int(interval)
            # 1. 创建订阅
            self.subscription = self.client.create_subscription(interval, self.handler)
            print(f"\n订阅创建成功(间隔：{interval}ms)")

            # 2. 遍历映射表，为每个nodeid创建监控项
            for node_id, var_name in self.node_id_mapping.items():
                var_node = self.client.get_node(node_id)
                monitored_item = self.subscription.subscribe_data_change(var_node)
                self.monitored_items.append(monitored_item)
                print(f"已订阅变量: {var_name} (nodeid: {node_id})")

        except Exception as e:
            print(f"创建批量订阅失败: {e}")
            import traceback
            traceback.print_exc()

    def write_value_by_name(self, var_readable_name, value):
        """
        根据变量可读名称写入值(主要用于修改方量， 类型为 Double类型)
        :param var_readable_name: 变量可读名称（如"upper_weight"）
        :param value: 要写入的值
        """
        if not self.connected:
            print("请先连接到服务器")
            return
        
        # 反向查找：通过变量名找nodeid
        target_node_id = None
        for node_id, name in self.node_id_mapping.items():
            if name == var_readable_name:
                target_node_id = node_id
                break
        
        if not target_node_id:
            print(f"未找到变量名 {var_readable_name} 对应的nodeid")
            return
        
        try:
            target_node = self.client.get_node(target_node_id)
            # 明确指定值类型为Double，避免类型错误
            variant = ua.Variant(float(value), ua.VariantType.Double)
            target_node.set_value(variant)
        except Exception as e:
            print(f"写入值失败: {e}")