import serial
import time

def calculate_crc(data):
    """计算Modbus RTU CRC16校验码"""
    crc = 0xFFFF
    for byte in data:
        crc ^= byte
        for _ in range(8):
            if crc & 0x0001:
                crc >>= 1
                crc ^= 0xA001
            else:
                crc >>= 1
    return crc.to_bytes(2, byteorder='little')


def create_modbus_frame(slave_address, function_code=0x03, start_address=0x0000, num_registers=1):
    """创建Modbus RTU请求帧"""
    frame = bytes([
        slave_address,  # 设备地址
        function_code,  # 功能码
        (start_address >> 8) & 0xFF,  # 起始地址高字节
        start_address & 0xFF,  # 起始地址低字节
        (num_registers >> 8) & 0xFF,  # 寄存器数量高字节
        num_registers & 0xFF  # 寄存器数量低字节
    ])
    crc = calculate_crc(frame)
    return frame + crc


def bytes_to_hex(data):
    """将字节数据转换为十六进制字符串"""
    return ' '.join([f"{b:02X}" for b in data]) if data else ""


def validate_response(response, slave_address, function_code):
    """验证Modbus响应有效性"""
    if len(response) < 5:
        return False

    # 检查地址和功能码
    if response[0] != slave_address or response[1] != function_code:
        # 检查是否是错误响应
        if response[0] == slave_address and response[1] == function_code + 0x80:
            error_code = response[2]
            print(f"  Modbus错误响应 (异常码: {error_code:02X})")
        return False

    # 检查数据长度
    data_length = response[2]
    if len(response) != 5 + data_length:
        return False

    # 验证CRC校验
    received_crc = response[-2:]
    calculated_crc = calculate_crc(response[:-2])
    return received_crc == calculated_crc


def get_stopbits(stopbits_str):
    """将字符串表示的停止位转换为serial库常量"""
    if stopbits_str == '1.5':
        return serial.STOPBITS_ONE_POINT_FIVE
    elif stopbits_str == '2':
        return serial.STOPBITS_TWO
    else:
        return serial.STOPBITS_ONE


def get_function_code(func_str):
    """将字符串表示的功能码转换为整数"""
    try:
        # 尝试解析十六进制
        if func_str.lower().startswith('0x'):
            return int(func_str, 16)
        # 尝试解析十进制
        return int(func_str)
    except ValueError:
        # 解析失败，返回默认值
        return 0x03


def scan(port_temp,baudrate_temp,timeout_temp,retries_temp,send_interval_temp,register_address_temp,func_input_temp,bytesize_input_temp,parity_input_temp,stopbits_input_temp):
    port = port_temp.strip()
    baudrate = baudrate_temp.strip()
    timeout = float(timeout_temp.strip())
    retries = int(retries_temp.strip())
    send_interval = float(send_interval_temp.strip())
    register_address = int(register_address_temp.strip())

    func_input = func_input_temp.strip()
    function_code = get_function_code(func_input) if func_input else 0x03

    # 数据位配置
    bytesize_input = bytesize_input_temp.strip()
    if bytesize_input == '5':
        bytesize = serial.FIVEBITS
    elif bytesize_input == '6':
        bytesize = serial.SIXBITS
    elif bytesize_input == '7':
        bytesize = serial.SEVENBITS
    else:
        bytesize = serial.EIGHTBITS  # 默认

    # 校验位配置
    parity_input = parity_input_temp.strip().upper()
    if parity_input == 'E':
        parity = serial.PARITY_EVEN
    elif parity_input == 'O':
        parity = serial.PARITY_ODD
    elif parity_input == 'M':
        parity = serial.PARITY_MARK
    elif parity_input == 'S':
        parity = serial.PARITY_SPACE
    else:
        parity = serial.PARITY_NONE  # 默认

    # 停止位配置
    stopbits_input = stopbits_input_temp.strip()
    if stopbits_input == '1.5':
        stopbits = serial.STOPBITS_ONE_POINT_FIVE
    elif stopbits_input == '2':
        stopbits = serial.STOPBITS_TWO
    else:
        stopbits = serial.STOPBITS_ONE  # 默认

    # 停止位描述转换
    stopbits_desc = {
        serial.STOPBITS_ONE: "1位",
        serial.STOPBITS_ONE_POINT_FIVE: "1.5位",
        serial.STOPBITS_TWO: "2位"
    }





def scan_modbus_devices(port='COM3', baudrate=9600, addr=1,
                        timeout=0.2, retries=1, send_interval=0.05, register_address=0,
                        bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
                        function_code=0x03):
    try:
        # 配置串口参数
        ser = serial.Serial(
            port=port,
            baudrate=baudrate,
            bytesize=bytesize,
            parity=parity,
            stopbits=stopbits,
            timeout=timeout
        )
        # 使用用户设置的寄存器地址和功能码创建请求帧
        frame = create_modbus_frame(addr, function_code=function_code, start_address=register_address)

        # 打印发送的发码
        # print(f"地址 {addr:3d}: 发送 -> {bytes_to_hex(frame)}")
        sendding_frame=f"地址 {addr:3d}: 发送 -> {bytes_to_hex(frame)}"
        for attempt in range(retries):
            try:
                ser.write(frame)
                time.sleep(send_interval)  # 发送间隔时间
                response = ser.read_all()
                recvied_frame=''
                register_value=''
                if response:
                    # 打印接收的收码
                    # print(f"地址 {addr:3d}: 接收 <- {bytes_to_hex(response)}")
                    recvied_frame=f"地址 {addr:3d}: 接收 <- {bytes_to_hex(response)}"
                if response and validate_response(response, addr, function_code):
                    # 解析寄存器值
                    data_length = response[2]
                    if data_length >= 2:  # 至少2字节数据
                        # 提取第一个寄存器的值
                        reg_value = (response[3] << 8) | response[4]
                        # print(f"地址 {addr:3d} - 设备响应有效 | 寄存器 {register_address} 值: {reg_value}")
                        register_value=f"地址 {addr:3d} - 设备响应有效 | 寄存器 {register_address} 值: {reg_value}"
                    else:
                        # print(f"地址 {addr:3d} - 设备响应有效 | 无效数据长度")
                        register_value =f"地址 {addr:3d} - 设备响应有效 | 无效数据长度"
                    break
                elif attempt == retries - 1:
                    # print(f"地址 {addr:3d} - 无响应")
                    recvied_frame =f"地址 {addr:3d} - 无响应"
            except Exception as e:
                print(f"\n地址 {addr} 通信错误: {str(e)}")

        ser.close()
        status={
            'status':200,
            'sending_code':f"发码:{sendding_frame}",
            'receving_code':f"回码:{recvied_frame}",
            'register_value':f"寄存器值: {register_value}"
        }
    except serial.SerialException as e:
        print(f"\n串口错误: {str(e)}")
        status={
            'status':403,
            'error':f"\n串口错误: {str(e)}"
        }
        return status
    print(status)
    return status