"""Django signal handlers for relaydomains."""

from django.db.models import signals
from django.dispatch import receiver
from django.utils.translation import ugettext as _

from modoboa.admin import models as admin_models, signals as admin_signals
from modoboa.core import signals as core_signals
from modoboa.lib.email_utils import split_mailbox
from modoboa.transport import models as tr_models
from . import forms, lib, models, postfix_maps


@receiver(admin_signals.use_external_recipients)
def check_relaydomain_alias(sender, recipients, **kwargs):
    """Allow the creation of an alias on a relaydomain."""
    localpart, domain = split_mailbox(recipients)
    qset = admin_models.Domain.objects.filter(name=domain, type="relaydomain")
    if not qset.exists():
        return False
    qset = admin_models.Mailbox.objects.select_related("domain").filter(
        domain__name=domain, address=localpart)
    if qset.exists():
        return False
    return True


@receiver(signals.post_save, sender=admin_models.Domain)
def clean_domain(sender, instance, **kwargs):
    """Remove or create Transport record if needed."""
    if kwargs.get("created") or instance.type == "relaydomain":
        return
    tr_models.Transport.objects.filter(pattern=instance.name).delete()


@receiver(signals.post_delete, sender=admin_models.Domain)
def delete_transport(sender, instance, **kwargs):
    """Delete Transport instance if any."""
    tr_models.Transport.objects.filter(pattern=instance.name).delete()


@receiver(core_signals.register_postfix_maps)
def register_postfix_maps(sender, **kwargs):
    """Register postfix maps."""
    return [
        postfix_maps.RelayDomainsMap,
        postfix_maps.SplitedDomainsTransportMap,
        postfix_maps.RelayRecipientVerification
    ]


@receiver(admin_signals.extra_domain_forms)
def extra_domain_form(sender, user, **kwargs):
    """Return relay settings for domain edition."""
    if not user.has_perm("relaydomains.change_relaydomain"):
        return []
    domain = kwargs.get("domain")
    if not domain or domain.type != "relaydomain":
        return []
    return [{
        "id": "relaydomain", "title": _("Transport settings"),
        "cls": forms.RelayDomainFormGeneral,
        "formtpl": "transport/_transport_form.html"
    }]


@receiver(admin_signals.get_domain_form_instances)
def fill_domain_instances(sender, user, domain, **kwargs):
    """Fill the relaydomain form with the right instance."""
    condition = (
        not user.has_perm("transport.change_transport") or
        domain.type != "relaydomain"
    )
    if condition:
        return {}
    return {
        "relaydomain": domain.transport
    }


@receiver(admin_signals.extra_domain_wizard_steps)
def extra_wizard_step(sender, **kwargs):
    """Return a step to configure the relay settings."""
    return [forms.RelayDomainWizardStep(
        "relay", forms.RelayDomainFormGeneral, _("Transport"),
        "transport/_transport_form.html"
    )]


@receiver(admin_signals.import_object)
def get_import_func(sender, objtype, **kwargs):
    """Return function used to import objtype."""
    if objtype == "relaydomain":
        return lib.import_relaydomain
    return None


@receiver(signals.post_save, sender=tr_models.Transport)
def update_recipient_access(sender, instance, **kwargs):
    """Create or delete recipient access rule."""
    if instance.service != "relay":
        return
    if instance._settings.get("relay_verify_recipients", False):
        models.RecipientAccess.objects.get_or_create(
            pattern=instance.pattern,
            defaults={"action": "reject_unverified_recipient"}
        )
    else:
        models.RecipientAccess.objects.filter(
            pattern=instance.pattern).delete()


@receiver(signals.post_delete, sender=tr_models.Transport)
def delete_recipient_access(sender, instance, **kwargs):
    """Delete recipient access rule."""
    if instance.service != "relay":
        return
    models.RecipientAccess.objects.filter(pattern=instance.pattern).delete()