import logging
from django.conf import settings
from django.core.mail import EmailMessage
from django.template.loader import get_template
from django.utils import translation

from pretix.base.models import User, Event

logger = logging.getLogger('pretix.base.mail')


def mail(user: User, subject: str, template: str, context: dict, event: Event=None):
    """
    Sends out an email to a user.

    :param user: The user this should be sent to.
    :param subject: The e-mail subject. Should be localized.
    :param template: The filename of a template to be used. It will
                     be rendered with the recipient's locale.
    :param context: The context for rendering the template.
    :param event: The event, used for determining the sender of the e-mail

    :return: ``False`` on obvious failures, like the user having to e-mail
    address, ``True`` otherwise. ``True`` does not necessarily mean that
    the email has been sent, just that it has been queued by the e-mail
    backend.
    """
    if not user.email:
        return False

    _lng = translation.get_language()
    translation.activate(user.locale or settings.LANGUAGE_CODE)

    tpl = get_template(template)
    body = tpl.render(context)

    sender = event.settings.get('mail_from') if event else settings.MAIL_FROM

    subject = str(subject)
    prefix = event.settings.get('mail_prefix')
    if prefix:
        subject = "[%s] %s" % (prefix, subject)

    email = EmailMessage(
        subject, body, sender,
        to=[user.email]
    )

    try:
        email.send(fail_silently=False)
        return True
    except Exception:
        logger.exception('Error sending e-mail')
        return False
    finally:
        translation.activate(_lng)