#!/usr/bin/python3

import os
import subprocess
import confparser
import imapclient
import contextlib
import backports.ssl
import socket

def conf_boolean_postprocess(src):
    src = src.lower().strip()
    if src == 'true' or src == 'on' or src == '1':
        return True
    return False

def conf_postprocess(conf):
    d = {
            'imap.tls':                     conf_boolean_postprocess,
            'imap.start_tls':               conf_boolean_postprocess,
            'imap.tls_nocheck_hostname':    conf_boolean_postprocess,
            'imap.tls_nocheck_ca':          conf_boolean_postprocess,
    }
    return {key: d[key](value) if key in d else value
            for key, value in conf.items()}

@contextlib.contextmanager
def connect_to_imap(conf, password):

    cafile = conf.get('imap.tls_ca', None)

    if cafile:
        cafile = os.path.expanduser(cafile)

    ssl_context = imapclient.create_default_context(cafile=cafile)

    if conf.get('imap.tls_nocheck_hostname', False):
        # don't check if certificate hostname doesn't match target hostname
        ssl_context.check_hostname = False

    if conf.get('imap.tls_nocheck_ca', False):
        # don't check if the certificate is trusted by a certificate authority
        ssl_context.verify_mode = backports.ssl.CERT_NONE

    connection = imapclient.IMAPClient(host=conf.get('imap.server'),
            ssl=conf.get('imap.tls', True),
            ssl_context=ssl_context)
    if conf.get('imap.start_tls', False):
        connection.start_tls(ssl_context=ssl_context)
    print('connection succeed')
    connection.login(username=conf.get('imap.username'), password=password)
    print('successfuly logged')

    # TODO: replace shutdown by logouts when it will not timeout through ssl
    try:
        yield connection
        #connection.logout()
    except (connection.AbortError, socket.error, socket.timeout,
            backports.ssl.SSLError, backports.ssl.CertificateError):
        raise
    else:
        pass
        #connection.logout()
    finally:
        connection.shutdown()

def main():
    confpath = os.path.expanduser('~/temp/conf.cfg')
    conf = conf_postprocess(confparser.read_conf(confpath))
    print('Read conf:', conf)
    password_command = conf.get('imap.password_command', None)
    if password_command:
        password = subprocess.check_output(password_command, shell=True)
        password = password.rstrip().decode('utf8')
        print('got pasword:', password)

    #connection = connect_to_imap(conf, password)
    with connect_to_imap(conf, password) as connection:
        print('selecting folder')
        connection.select_folder(conf.get('imap.mailbox'))
        print('entering idle mode')
        connection.idle()
        print('waiting for an event')
        while True:
            try:
                result = connection.idle_check(timeout=10)
            except KeyboardInterrupt:
                break
            print('result:', result)
    print('end of connection')


main() # dev mode for now