# -*- coding: utf-8 -*-
from serpent.config import conf
from serpent import dataio, misc, rules
from datetime import datetime, timedelta
from os import path
from DNS import dnslookup
from operator import itemgetter
from smtplib import SMTP

class SmtpQueue(object):
    def __init__(self, store, local_delivery):
        self.stor = store
        self.local_delivery = local_delivery

    def add(self, data):
        '''Ставит письмо в очередь'''
        data['add_time'] = datetime.utcnow()
        data['state'] = misc.MSG_ACTIVE
        w = self.stor.write(data)
        if not w:
            return False
        return self.__process_(data['id'])
    
    def run(self):
        '''Запускает обработку очереди'''
        now = datetime.utcnow()
        check_delta = timedelta(minutes = conf.smtp_queue_check_period)
        expire_delta = timedelta(minutes = conf.smtp_queue_message_ttl)
        for mid in self.__list_messages_():
            info = self.stor.getinfo(mid)
            if (now - info['add_time']) >= expire_delta:
                self.stor.delete(mid)
                continue
            if (now - info['add_time']) >= check_delta:
                continue
            self.__process_(mid)
        return True
    
    def __local_deliver_(self, mid):
        message = self.stor.read(mid)
        user = rules.username_by_email(message['rcpt'])
        return self.local_delivery.deliver(user, message['message'])
    
    def __send_email_(self, mid):
        info = self.stor.getinfo(mid)
        try:
            mail_servers = dnslookup(info['rcpt'][1], 'mx')
        except:
            return False
        mail_servers = sorted(mail_servers, key=itemgetter(0))
        for _, mx in mail_servers:
            s = SMTP(local_hostname = conf.smtp_hostname)
            try:
                ret_code, banner = s.connect(mx, 25)
            except:
                s.quit()
                continue
            if ret_code != 220:
                s.quit()
                continue
            try:
                s.starttls()
            except:
                if conf.smtp_email_tls_required:
                    s.quit()
                    continue
            from_addr = conf.smtp_email_delim.join(info['from'])
            to_addr = conf.smtp_email_delim.join(info['rcpt'])
            message = self.stor.read(mid)
            try:
                s.sendmail(from_addr, [to_addr], message['message'])
            except:
                s.quit()
                continue
            s.quit()
            return True
        return False
            
    
    def __freeze_(self, mid):
        info = self.stor.getinfo(mid)
        if info:
            if info['state'] != misc.MSG_FROZEN :
                info['state'] = misc.MSG_FROZEN
                if self.stor.setinfo(info):
                    return True
            else:
                return True
        return False
    
    def __process_(self, mid):
        info = self.stor.getinfo(mid)
        if info:
            if info['rcpt'][1] in conf.local_domains:
                if self.__local_deliver_(mid):
                    self.__remove_message_(mid)
                    return True
                else:
                    return self.__freeze_(mid)
            else:
                if self.__send_email_(mid):
                    self.__remove_message_(mid)
                    return True
                else:
                    return self.__freeze_(mid)
        return False
    
    def __list_messages_(self):
        return self.stor.list()
    
    def __remove_message_(self, mid):
        self.stor.delete(mid)

mailstore = dataio.MailDirStore()
squeue = SmtpQueue(dataio.SmtpFileStore(path.join(conf.app_dir, conf.smtp_queue_dir)),
                   mailstore)