import datetime
import json
import os

import emails
from dateutil.tz import tzutc
from rcal.db import Session
from rcal.model import MailQueue

BASEPATH = os.path.join(
    os.environ['PYTHONPATH'],
    '..',
    '..')


def get_config(section, filename='config/mailer.json'):
    config = json.load(open(os.path.join(BASEPATH, filename)))
    return config[section]


def get_queue(session, queue_config):
    return session.query(MailQueue).filter(
        MailQueue.is_sent.is_(False),
        MailQueue.send_attempts <= queue_config['retry']
    ).order_by(
        MailQueue.send_attempts.desc(),
        MailQueue.last_attempt_time
    ).limit(queue_config['batch']).all()


def prepare_message(item, sender):
    msg = emails.Message(html=item.html_body,
                         text=item.text_body.strip(),
                         subject=item.subject.strip(),
                         mail_from=(sender['name'], sender['from']))
    if sender['send_copies']:
        msg.set_bcc((sender['name'], sender['from']))
    return msg


def dump_error(item, retry_limit):
    print ('Message #%d to %s reached maximum failed send attepmts (%d), dropping from queue.'
           'Message created: %s'
           'Last error message: %s') % (
               item.id, item.recipient_mail, retry_limit,
               item.create_time,
               item.last_error_info)


def main():
    session = Session.create()

    queue_config = get_config('queue')
    sender = get_config('mail')
    smtp_conf = get_config('smtp')

    for item in get_queue(session, queue_config):
        item.send_attempts += 1
        item.last_attempt_time = datetime.datetime.now(tzutc())

        msg = prepare_message(item, sender)
        msg_response = msg.send(to=(item.recipient_name, item.recipient_mail),
                                smtp={'host': smtp_conf['host'],
                                      'port': smtp_conf['port'],
                                      'ssl': smtp_conf['tls'],
                                      'user': smtp_conf['user'],
                                      'password': smtp_conf['pass']})
        if msg_response.status_code in [250, ]:
            item.is_sent = True
        else:
            item.last_error_info = msg_response.status_text
            if item.send_attempts >= queue_config['retry']:
                dump_error(item, queue_config['retry'])

    session.commit()

if __name__ == '__main__':
    main()