"""Outgoing mail for 2FA codes, using the Mail* settings in patchbay.conf."""

import smtplib
import ssl
import sys
from email.message import EmailMessage


class MailError(Exception):
    pass


def send(conf, to, subject, body):
    host = conf.get("mailhost")
    if not host:
        raise MailError("mail server is not configured")
    if host == "log":
        # Development only: MailHost = log prints mails to the server log.
        print(f"[mail to {to}] {subject}\n{body}", file=sys.stderr, flush=True)
        return

    msg = EmailMessage()
    msg["From"] = conf.get("mailfrom") or conf.get("mailuser")
    msg["To"] = to
    msg["Subject"] = subject
    msg.set_content(body)

    port = conf.getint("mailport", 587)
    security = (conf.get("mailsecurity") or "starttls").lower()
    ctx = ssl.create_default_context()
    try:
        if security == "ssl":
            server = smtplib.SMTP_SSL(host, port, context=ctx, timeout=20)
        else:
            server = smtplib.SMTP(host, port, timeout=20)
        with server:
            if security == "starttls":
                server.starttls(context=ctx)
            if conf.get("mailuser"):
                server.login(conf.get("mailuser"), conf.get("mailpassword"))
            server.send_message(msg)
    except (OSError, smtplib.SMTPException) as e:
        raise MailError(str(e)) from e