import struct
import serial

ser = serial.Serial('/dev/ttyACM0' , 115200)


def lecture_Detection():
    ser.write(b'\xFF\xFF\x05dP\x80\x21\x00')
    nb_read = ser.in_waiting
    data = ser.read(nb_read)
    # print("nb_read={}".format(nb_read))
    list_message = data.split(b"\xff\xffP")
    # print("nb_read={}, list_message={}".format(nb_read, len(list_message)))
    if len(list_message)>1:
        if len(list_message[1])>33:
                struct_value = struct.unpack('ffffffffB',list_message[1][1:34])
                return (struct_value[0],struct_value[1],struct_value[2], struct_value[3], struct_value[4], struct_value[5], struct_value[6], struct_value[7], struct_value[8])
        
def check_message(message, offset):
    offset = offset + 2 # on saut '\xFF\xFF'
    if(len(message) > 0 + offset):
        taille_message = message[0+offset]
        print("taille_message + " + str(taille_message))
        if(len(message) > taille_message + offset):
            if(message[taille_message+offset] == 0):
                print("message valide")
                return message[0+offset:taille_message+offset]
    return None



if __name__ == "__main__":
    data = b''
    while(1):
        nb_read = ser.in_waiting
        offset = 0
        valid_offset = 0
        if nb_read > 0:
            data+= ser.read(nb_read)
            while offset > -1:
                offset = data.find(b'\xFF\xFF', offset)
                if(offset > -1):
                    message_brut = data[offset:]
                    message = check_message(data, offset)
                    if message is not None:
                        print(message)
                        valid_offset = offset
                    offset = offset + 1
            data = data[valid_offset:]