send_at("ATE0")
send_at("AT")
# reboot and wait
send_at("AT+CREBOOT")
print("rebooting... please wait")
failed = True
for i in range(1,10):
    if send_at("ATE0", "OK", timeout=3):
        failed = False
        break
    send_at("AT")
if failed:
    print("failed to reboot")
    exit()
# set as verbose
send_at("AT+CMEE=2")
# sim and rf status check
send_at("AT+CPIN?")
send_at("AT+CSQ")
# manual APN conf
send_at("AT+CFUN=0")
send_at("AT+CGDCONT=1,\"IP\",\"m2m.public.cz\"")
send_at("AT+CFUN=1")
send_at("AT+CGATT?")
send_at("AT+CGNAPN")
send_at("AT+CNCFG=0,1,\"m2m.public.cz\"")
# APN check
send_at("AT+CGNAPN")
# activate apn/pdp#
send_at("AT+CNACT=0,1")
send_at("AT+CNACT?")
# synch UTC
send_at(f'AT+CNTP="{NTP_SERVER}",2,0,2')
time.sleep(12)
send_at("AT+CNTP")
send_at("AT+CCLK?")
# file system init
send_at("AT+CFSINIT")
# upload ca certificate
with open(CA_LOCAL_PATH, "rb") as f:
    data = f.read()
cert_len = len(data)
send_at(f'AT+CFSWFILE=1,"{CA_FILENAME}",0,{cert_len},10000', "DOWNLOAD")
time.sleep(1)
print(ser.read_all().decode())
ser.write(data)
send_at("AT+CFSTERM")
# setup mqtt with ssl
send_at(f'AT+SMCONF="URL","{EMQX_HOST}","{EMQX_PORT}"')
send_at("AT+SMCONF=\"KEEPTIME\",60")
send_at("AT+SMCONF=\"CLEANSS\",1")
send_at(f'AT+SMCONF="CLIENTID","{MQTT_CLIENT_ID}"')
send_at('AT+SMCONF="QOS",1')
send_at("AT+SMCONF?")
# set tls version to 1.2, ignore rtc time and set cipher. then check it
send_at('AT+CSSLCFG="sslversion",1,3')
send_at('AT+CSSLCFG="IGNORERTCTIME",1,1')
send_at('AT+CSSLCFG=“CIPHERSUITE”,1,0,0x0035')
send_at('AT+CSSLCFG=“CIPHERSUITE”,1,1,0x002F')
send_at("AT+CSSLCFG?")
time.sleep(10)
# convert and use uploaded certificate
send_at(f'AT+CSSLCFG="CONVERT",2,"{CA_FILENAME}"')
send_at(f'AT+SMSSL=2,"{CA_FILENAME}",""') # no idea how to CHOOSE the certificte
send_at("AT+SMSSL?")
# try to connect
if not send_at("AT+SMCONN", "OK", timeout=20):
    print(" - FAILED to connect")
# disconnect/clean-up
send_at("AT+SMDISC")
send_at("AT+CNACT=0,0")
 
ser.close()