#!/usr/bin/env python3

import smtplib
import ssl
from config import config
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication
from email.mime.multipart import MIMEMultipart


class Mailer(object):
    """
    Maintains the connection to the mailserver and sends text to users.
    """

    def __init__(self):
        """
        Creates an SMTP client to send a mail. Is called only once
        when you actually want to send a mail. After you sent the
        mail, the SMTP client is shut down again.

        """
        # This generates the From address by stripping the part until the first
        # period from the mail server address and won't work always.
        self.fromaddr = config["mail"]["user"] + "@" + config["mail"]["mailserver"].partition(".")[2]

        # starts a client session with the SMTP server
        self.s = smtplib.SMTP(config["mail"]["mailserver"])
        context = ssl.create_default_context()
        self.s.starttls(context=context)
        self.s.login(config["mail"]["user"], config["mail"]["passphrase"])

    def send(self, text, recipient, subject, attachment=None):
        """

        :param text: (string) the content of the mail
        :param recipient: (string) the recipient of the mail
        :param subject: (string) the subject of the mail
        :param attachment: (string) the path to the logfile
        :return: string for logging purposes, contains recipient & subject
        """
        msg = MIMEMultipart()
        msg.attach(MIMEText(text))

        msg["From"] = self.fromaddr
        msg["To"] = recipient
        msg["Subject"] = subject

        # attach logfile
        if attachment:
            with open(attachment, "rb") as fil:
                part = MIMEApplication(
                    fil.read(),
                    Name="logfile"
                )
            # After the file is closed
            part['Content-Disposition'] = 'attachment; filename="logfile"'
            msg.attach(part)

        self.s.send_message(msg)
        self.s.close()

        return "Sent mail to " + recipient + ": " + subject


# For testing:
if __name__ == '__main__':
    m = Mailer()
    print(m.send("This is a test mail.", m.fromaddr, "Test"))