import logging
import os
import time
from pydbus import SystemBus
from gi.repository import GLib


# Setup logging
logfile = "/opt/sms/sms.log"
FORMAT = '%(asctime)-15s %(message)s'
logging.basicConfig(format=FORMAT,filename=logfile,level=10)
logger = logging.getLogger('observiumsms')

class ModemManagerError(Exception):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)
		
class SIMError(ModemManagerError):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)


def get_modem_pin():

    def read_modem_pin(path):
        with open(path, 'r') as mp:
            return mp.readline().rstrip('\n')
    
    # Check multiple paths
    paths = [
        os.path.join(
            os.getcwd(),
            'modem_pin.txt'
        ),
        os.path.join(
            os.path.dirname(os.path.abspath(__file__)),
            'modem_pin.txt'
        ),
        '/etc/modem_pin.txt'
        ]

    for p in paths:
        if os.path.isfile(p):
            return read_modem_pin(p)

    raise Exception('modem_pin.txt not found in any directory')

def get_modem():
        # Retry for 5 seconds and give the modems time
        retries = 0
        while retries < 5:
            retries += 1
            # Contact ModemManager, unlock SIM and send SMS to emergency numbers
            with SystemBus() as bus:
                mm = bus.get('.ModemManager1')
                modems = mm.GetManagedObjects()
                if not modems or len(modems) == 0:
                    time.sleep(5)
                else:
                    break
        
        if not modems or len(modems) == 0:
            raise ModemManagerError('No modems found') 
        modem_path = list(modems.keys())[0]
    
        logger.info("Going with %s", modem_path)
        modem = bus.get(".ModemManager1", modem_path)
        return modem

def unlock_sim(modem):
    sim_path = modem.Sim
    if not sim_path:
        raise SIMError('No SIM card found') 
            
    # unlock SIM, if not alreadY
    props = modem.GetStatus()
    logger.debug("Modem status: {}".format(props))
    if props and props['state'] == 2:
        # check if the modem_pin.txt file exists
        mypin = get_modem_pin()
        logger.info("Trying to unlock %s", sim_path)
        with SystemBus() as bus:
            sim = bus.get('.ModemManager1', sim_path)
            try:
                sim.SendPin(mypin, timeout=10000)
            except GLib.Error as exc:
                remaining_attempts = modem.UnlockRetries
                raise SIMError('Failed to unlock PIN, remaining attempts: {}'.format(remaining_attempts)) from exc

def unlock_and_enable_modem():

    retries = 0
    # Retry the whole block, because once pydbus fetches the properties
    # it does not really refresh them, including modems
    while True:
        try:
            # enable the modem
            # Get modem, unlock SIM
            modem = get_modem()
            
            logger.debug("Unlocking SIM (if needed)")
            unlock_sim(modem)
            
            logger.debug("Enabling modem")
            modem.Enable(True)
            return modem

        except SIMError:
            # cannot continue with this one (could be a wrong PIN
            # and then we waste our attempts)
            raise

        except:
            retries += 1
            time.sleep(1)
            if retries > 15:
                raise

def send_sms(recipients, smsstring):
    
    # Assemble SMS
    logger.info("Sending SMS: %s", smsstring)
    
    modem = unlock_and_enable_modem()
    
    # test sending SMS
    modem_msg = modem['org.freedesktop.ModemManager1.Modem.Messaging']
    smses = modem_msg.List()

    while not modem.GetStatus().get('signal-quality', None) or not modem.GetStatus()['signal-quality'][1]:
        modem = get_modem()
        print(modem.GetStatus().get('signal-quality', None))
        time.sleep(2)

    for line in recipients:
        line = line.strip()
        if not line:
                continue

        logger.info("Creating new SMS for %s", line)
        smstext = GLib.Variant('s', smsstring)
        smsnumber = GLib.Variant('s', line)
        
        dictsms = { 'text': smstext, 'number': smsnumber }

        msgpath = modem_msg.Create(dictsms)
        logger.info("Created new SMS %s", msgpath)

        logger.info("Sending SMS %s", msgpath)
        with SystemBus() as bus:
            sms = bus.get(".ModemManager1", msgpath)
            sms.Send(timeout=30000)
            
            logger.info("SMS %s state %s", msgpath, sms.State)