import serial   #Using pyserial Library
from serial import SerialException
import serial.tools.list_ports
import time     #for loop timeout
import serial.tools.list_ports
import sys      #for sys.exit in while True loop
import logging as log
log.basicConfig(level=log.INFO, format='%(asctime)s - %(levelname)s - %(message)s')





def list_ports_matching_descr(dev_descr):
    ports_found = []
    ports = serial.tools.list_ports.comports()
    for p in ports:        
        log.info('Found device: %s, %s, %s', p.device, p.description, p.manufacturer)
        if dev_descr in str(p.manufacturer):
            ports_found.append(p.device)
    log.debug('Devices containing %s: %s', dev_descr, ports_found)
    return ports_found


def initialize_port(port_name):
    try:
        ser = serial.Serial(port_name, 19200, timeout=10)
        log.debug('Port: %s', ser.name)
    except SerialException:
        print port_name
        sys.exit('Error: cannot open port, quitting...')
    return ser
    
    
def Victron_HEX_call(ser, write_hex, expected_read):
    log.info('Sending %s to %s', write_hex, ser.name)

    timeout = time.time() + 3 #s of timeout
    while True:
        
        ser.write(write_hex)
            
        read_hex=ser.read_until('\n')       #Reading until "\n" symbol
        
        if read_hex[0:len(expected_read)] == expected_read:     #Exiting after receiving a correct answer
            log.info('Received HEX string: %s \n', read_hex)
            break
               
        elif time.time() > timeout:
            log.warning('Timeout reached, received HEX string: %s \n', read_hex)
            break
    
    return read_hex




#Find Victron devices
port_list = list_ports_matching_descr('Victron')


#Identyfying Victron devices
MPPT_port = []
BMV_port = []
for port in port_list:
    ser = initialize_port(port)
    read_hex = Victron_HEX_call(ser, ':451\n', ':1')
    ser.close()
    if read_hex[4:6] in ['A0', 'A1', '03']: #MPPT Product ID first byte
        MPPT_port.append(port)
        log.info('Found MPPT ID %s at port %s', read_hex[2:6], MPPT_port)
    if read_hex[4:6] in ['02', 'A3']:  #BMV Product ID first byte
        BMV_port.append(port)
        log.info('Found BMV ID %s at port %s', read_hex[2:6], BMV_port)
if not MPPT_port:
    log.critical('No MPPT port found, is the device connected and powered?')
if not BMV_port:
    log.critical('No BMV port found, is the device connected and powered?')
if (not MPPT_port) or (not BMV_port):
    sys.exit(log.critical('Quitting...'))