import modbus_tk
import modbus_tk.defines as cst
import modbus_tk.modbus_tcp as modbus_tcp
import socket

class ModbusClient:
    def __init__(self):
        self.master = None

    def connect(self, ip, port):
        if self.master:
            self.master.close()
            self.master = None
        try:
            self.master = modbus_tcp.TcpMaster(host=ip, port=port)
            self.master.set_timeout(5.0)
            self.master.set_verbose(False)
            # Test connection
            self.master.execute(1, cst.READ_HOLDING_REGISTERS, 0, 1)
            return {'success': True, 'msg': f"Modbus连接成功\nIP: {ip}\n端口: {port}"}
        except modbus_tk.modbus.ModbusError as e:
            self.master = None
            return {'success': False, 'msg': f"Modbus协议错误: {e}\n从站地址: {e.slave}\n功能码: {e.function_code}"}
        except socket.error as e:
            self.master = None
            return {'success': False, 'msg': f"网络连接失败: {e}"}
        except Exception as e:
            self.master = None
            return {'success': False, 'msg': f"连接失败: {str(e)}"}

    def disconnect(self):
        if self.master:
            self.master.close()
            self.master = None

    def read_holding_registers(self, slave_id, address, count):
        if not self.master:
            return {'success': False, 'data': None, 'msg': "Modbus未初始化，请先连接"}
        try:
            result = self.master.execute(
                slave=slave_id,
                function_code=cst.READ_HOLDING_REGISTERS,
                starting_address=address,
                quantity_of_x=count
            )
            if result:
                return {'success': True, 'data': list(result), 'msg': "读取成功"}
            else:
                return {'success': False, 'data': None, 'msg': "读取结果为空"}
        except Exception as e:
            return {'success': False, 'data': None, 'msg': f"读取失败：{e}"}

    def write_single_register(self, slave_id, address, value):
        if not self.master:
            return {'success': False, 'msg': "Modbus未连接，请先初始化连接"}
        if value is None:
            return {'success': False, 'msg': "未指定要写入的值"}
        try:
            write_value = int(value)
            if not (0 <= write_value <= 65535):
                return {'success': False, 'msg': "值必须在0-65535范围内(16位无符号整数)"}
        except ValueError:
            return {'success': False, 'msg': "写入值必须为整数"}
        try:
            self.master.execute(
                slave=slave_id,
                function_code=cst.WRITE_SINGLE_REGISTER,
                starting_address=address,
                output_value=write_value
            )
            return {'success': True, 'msg': f"写入成功: 从机ID={slave_id}，地址={address}，值={write_value}"}
        except Exception as e:
            return {'success': False, 'msg': f"写入失败: 从机ID={slave_id}，地址={address}，错误：{e}"}