import asyncio
import serial
import time



class CardReader():

    def __init__(self, dConfig):
        self.dConfig = dConfig
        self.dConfig['CR'] = self
        self.conn = serial.Serial(port=self.dConfig['ComPort'], baudrate=9600)
        self.new_key = False
        self.STX = b'\x02'
        self.ETX = b'\x03'
        self.DLE = b'\x10'
        self.NAK = b'\x15'
        self.telegram_length = b'\x07'
        self.read_eks = b'\x54\x4C'
        self.device_adress = b'\x01'
        self.data_start_adress = b'\x00\x00'
        self.data_length = b'\x7C'
        self.command = self.telegram_length + self.read_eks + self.device_adress + self.data_start_adress + self.data_length
        self.crc_sum = self.crc(self.command + self.DLE + self.ETX)
        print("CRC-Sum: " + str(self.crc_sum))
        dConfig['eLoop'].run_until_complete(self.callback())

        
    async def callback(self):
        while True:
            await self.key_detection()
            await self.read_key()
   
    async def key_detection(self):
        while True:
            if (self.conn.cts == True) and (self.new_key == False):
                self.new_key = True
                print("new Key detected")
                break
            if (self.conn.cts == False) and (self.new_key == True):
                self.new_key = False
                print("Key removed")
            
            await asyncio.sleep(1)         
            
    async def start_communikation(self):
        self.conn.write(self.STX)
        return self.conn.read()

    async def send_command_telegram(self):
        self.conn.write(self.command)
    
    async def end_communikation(self):
        self.conn.write(self.crc_sum)
        
    def crc (self,buffer):
        bcc= 0x00
        for c in buffer:
            #print (c)
            bcc ^= c
        return bytes([bcc])
        
    async def read_key(self):
        if await self.start_communikation() == self.DLE:
            await self.send_command_telegram()
            await self.end_communikation()
        response = self.conn.read()
        print("Response from EKS: " + str(response))