#!/usr/bin/env python3

# ~ Empresa Libre
# ~ Copyright (C) 2016-2019  Mauricio Baeza Servin (public@elmau.net)
# ~
# ~ This program is free software: you can redistribute it and/or modify
# ~ it under the terms of the GNU General Public License as published by
# ~ the Free Software Foundation, either version 3 of the License, or
# ~ (at your option) any later version.
# ~
# ~ This program is distributed in the hope that it will be useful,
# ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
# ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# ~ GNU General Public License for more details.
# ~
# ~ You should have received a copy of the GNU General Public License
# ~ along with this program.  If not, see <http://www.gnu.org/licenses/>.

import base64
import math
import smtplib

from email.mime.multipart import MIMEMultipart
from email.mime.base import MIMEBase
from email.mime.text import MIMEText
from email import encoders
from email.utils import formatdate

import requests
from cryptography.fernet import Fernet
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes


TIMEOUT = 10


class SendMail(object):

    def __init__(self, config):
        self._config = config
        self._server = None
        self._error = ''
        self._is_connect = self._login()

    @property
    def is_connect(self):
        return self._is_connect

    @property
    def error(self):
        return self._error

    def _login(self):
        hosts = ('gmail' in self._config['server'] or
                'outlook' in self._config['server'])
        try:
            if self._config['ssl'] and hosts:
                self._server = smtplib.SMTP(
                    self._config['server'],
                    self._config['port'], timeout=TIMEOUT)
                self._server.ehlo()
                self._server.starttls()
                self._server.ehlo()
            elif self._config['ssl']:
                self._server = smtplib.SMTP_SSL(
                    self._config['server'],
                    self._config['port'], timeout=TIMEOUT)
                self._server.ehlo()
            else:
                self._server = smtplib.SMTP(
                    self._config['server'],
                    self._config['port'], timeout=TIMEOUT)
            self._server.login(self._config['user'], self._config['pass'])
            return True
        except smtplib.SMTPAuthenticationError as e:
            if '535' in str(e):
                self._error = 'Nombre de usuario o contraseña inválidos'
                return False
            # ~ print (e)
            if '534' in str(e) and 'gmail' in self._config['server']:
                self._error = 'Necesitas activar el acceso a otras ' \
                    'aplicaciones en tu cuenta de GMail'
                return False
        except smtplib.SMTPException as e:
            self._error = str(e)
            return False
        except Exception as e:
            self._error = str(e)
            return False
        return

    def send(self, options):
        try:
            message = MIMEMultipart()
            message['From'] = self._config['user']
            message['To'] = options['to']
            message['CC'] = options.get('copy', '')
            message['Subject'] = options['subject']
            message['Date'] = formatdate(localtime=True)
            if options.get('confirm', False):
                message['Disposition-Notification-To'] = message['From']
            message.attach(MIMEText(options['message'], 'html'))
            for f in options.get('files', ()):
                part = MIMEBase('application', 'octet-stream')
                if isinstance(f[0], str):
                    part.set_payload(f[0].encode('utf-8'))
                else:
                    part.set_payload(f[0])
                encoders.encode_base64(part)
                part.add_header(
                    'Content-Disposition',
                    "attachment; filename={}".format(f[1]))
                message.attach(part)

            receivers = options['to'].split(',') + message['CC'].split(',')
            self._server.sendmail(
                self._config['user'], receivers, message.as_string())
            return ''
        except Exception as e:
            return str(e)

    def close(self):
        try:
            self._server.quit()
        except:
            pass
        return


def send_mail(data):
    msg = ''
    ok = True
    server = SendMail(data['server'])
    if server.is_connect:
        msg = server.send(data['mail'])
    else:
        msg = server.error
        ok = False
    server.close()

    return {'ok': ok, 'msg': msg}


def round_up(value):
    return int(math.ceil(value))


def _get_key(password):
    digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
    digest.update(password.encode())
    key = base64.urlsafe_b64encode(digest.finalize())
    return key


def encrypt(data, password):
    f = Fernet(_get_key(password))
    return f.encrypt(data.encode()).decode()


def decrypt(data, password):
    f = Fernet(_get_key(password))
    return f.decrypt(data.encode()).decode()


def to_bool(value):
    return bool(int(value))


def get_url(url):
    r = requests.get(url).text
    return r