import time
from datetime import datetime

recvData = bytearray() #接收的数据存放此数组
startTime = time.time() 

# 将bytearray以字为单位转换成16进制字符串，方便显示
def wordData2HexStr(data):
    ret = ' '.join(data[i:i+2].hex() for i in range(0, len(data), 2))
    return ret.upper()

# 获取当前时间字符串
def nowStr():
    now = datetime.now()
    ret = now.strftime('%H:%M:%S.') + f"{now.microsecond // 1000:03d}"
    return ret
    
def checkValue(data: bytes) -> int:
    # 初始化crc为0xFFFF
    crc = 0xFFFF

    length = len(data)
    if length % 2 != 0:
        return 0
    
    for i in range(0, length, 2):
        val = data[i] * 256 + data[i + 1]
        crc = crc ^ val

    # 返回最终的crc值
    return crc

# 启动函数，命令开始会调用此函数
def start():

    log_i('----------------- ' + cmdInfo['name'] + ' ----------------')
    #log(f"[{devInfo['name']}]{cmdInfo['name']}")
    
    startTime = time.time() #记录启动时间
    
    recvData = bytearray() #清空接收数组

    attr = cmdInfo['attr']
    cmdStr = attr['cmd'] + attr['data'] #组合要发送的报文，十六进制字符串
            
    data = bytearray().fromhex(cmdStr) #将十六进制字符串转成字节数据发送
    
    if attr['req_is_check'] == True:
        crc = checkValue(data)
        data = data + bytearray(crc.to_bytes(2, 'big'))
    send(data)

    log_d(f"[{nowStr()}] Sent:{wordData2HexStr(data)}")
        
    return True

# 接收数据处理函数，当收到数据会调用此函数
def recvDataHandler(data):
    global recvData
    recvData = recvData + data
    attr = cmdInfo['attr']
    rsp_len = int(attr['rsp_len']) * 2
    if len(recvData) >= rsp_len: #TBUS指令rsp_len以字为单位        
        log_d(f"[{nowStr()}] Echo:{wordData2HexStr(recvData)}")
        if attr['rsp_is_check'] == True:
            # 校验数据正确性
            crc = int.from_bytes(recvData[rsp_len - 2:rsp_len], byteorder='big')
            calc_value = checkValue(recvData[0:rsp_len - 2])
            if crc != calc_value:
                log_w("CRC error:" +
                    "should be " + '{:04X}'.format(calc_value) + 
                    ",got " + '{:04X}'.format(crc))
                finish()
                return
        log_i("success")    
        finish()
        
# 此函数会被重复调用，间隔10毫秒，直到finish()        
def loop():
    global recvData
    if time.time() > startTime + int(cmdInfo['attr']['rsp_timeout']) / 1000.0:
        if len(recvData) > 0:
            log_w(f"[{nowStr()}]RX timeout:{wordData2HexStr(recvData)}")
        else:
            log_w(f"[{nowStr()}]RX timeout")
        log_e(f"[{devInfo['name']}]{cmdInfo['name']} fail.")
        finish()