# -*- coding: utf-8 -*-

"""
Data models for the Deis API.
"""
import etcd
import importlib
import logging
import uuid

from django.conf import settings
from django.db import models
from django.db.models.signals import post_delete, post_save
from django.dispatch import receiver
from rest_framework.authtoken.models import Token
from api.utils import fingerprint

logger = logging.getLogger(__name__)


def log_event(app, msg, level=logging.INFO):
    # controller needs to know which app this log comes from
    logger.log(level, "{}: {}".format(app.id, msg))
    app.log(msg, level)


def get_etcd_client():
    if not hasattr(get_etcd_client, "client"):
        # wire up etcd publishing if we can connect
        try:
            get_etcd_client.client = etcd.Client(
                host=settings.ETCD_HOST,
                port=int(settings.ETCD_PORT))
            get_etcd_client.client.get('/deis')
        except etcd.EtcdException:
            logger.log(logging.WARNING, 'Cannot synchronize with etcd cluster')
            get_etcd_client.client = None
    return get_etcd_client.client


class AuditedModel(models.Model):
    """Add created and updated fields to a model."""

    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

    class Meta:
        """Mark :class:`AuditedModel` as abstract."""
        abstract = True

    @property
    def _scheduler(self):
        mod = importlib.import_module(settings.SCHEDULER_MODULE)
        return mod.SchedulerClient(settings.SCHEDULER_URL,
                                   settings.SCHEDULER_AUTH,
                                   settings.SCHEDULER_OPTIONS)


class UuidAuditedModel(AuditedModel):
    """Add a UUID primary key to an :class:`AuditedModel`."""

    uuid = models.UUIDField('UUID',
                            default=uuid.uuid4,
                            primary_key=True,
                            editable=False,
                            auto_created=True,
                            unique=True)

    class Meta:
        """Mark :class:`UuidAuditedModel` as abstract."""
        abstract = True


from .app import App, validate_id_is_docker_compatible, validate_reserved_names, validate_app_structure  # noqa
from .container import Container  # noqa
from .push import Push  # noqa
from .key import Key, validate_base64  # noqa
from .certificate import Certificate, validate_certificate  # noqa
from .domain import Domain  # noqa
from .release import Release  # noqa
from .config import Config  # noqa
from .build import Build  # noqa

# define update/delete callbacks for synchronizing
# models with the configuration management backend


def _log_build_created(**kwargs):
    if kwargs.get('created'):
        build = kwargs['instance']
        # log only to the controller; this event will be logged in the release summary
        logger.info("{}: build {} created".format(build.app, build))


def _log_release_created(**kwargs):
    if kwargs.get('created'):
        release = kwargs['instance']
        # log only to the controller; this event will be logged in the release summary
        logger.info("{}: release {} created".format(release.app, release))
        # append release lifecycle logs to the app
        release.app.log(release.summary)


def _log_config_updated(**kwargs):
    config = kwargs['instance']
    # log only to the controller; this event will be logged in the release summary
    logger.info("{}: config {} updated".format(config.app, config))


def _log_domain_added(**kwargs):
    if kwargs.get('created'):
        domain = kwargs['instance']
        msg = "domain {} added".format(domain)
        log_event(domain.app, msg)


def _log_domain_removed(**kwargs):
    domain = kwargs['instance']
    msg = "domain {} removed".format(domain)
    log_event(domain.app, msg)


def _log_cert_added(**kwargs):
    if kwargs.get('created'):
        cert = kwargs['instance']
        logger.info("cert {} added".format(cert))


def _log_cert_removed(**kwargs):
    cert = kwargs['instance']
    logger.info("cert {} removed".format(cert))


def _etcd_publish_key(**kwargs):
    key = kwargs['instance']
    _etcd_client.write('/deis/builder/users/{}/{}'.format(
        key.owner.username, fingerprint(key.public)), key.public)


def _etcd_purge_key(**kwargs):
    key = kwargs['instance']
    try:
        _etcd_client.delete('/deis/builder/users/{}/{}'.format(
            key.owner.username, fingerprint(key.public)))
    except KeyError:
        pass


def _etcd_purge_user(**kwargs):
    username = kwargs['instance'].username
    try:
        _etcd_client.delete(
            '/deis/builder/users/{}'.format(username), dir=True, recursive=True)
    except KeyError:
        # If _etcd_publish_key() wasn't called, there is no user dir to delete.
        pass


def _etcd_publish_app(**kwargs):
    appname = kwargs['instance']
    try:
        _etcd_client.write('/deis/services/{}'.format(appname), None, dir=True)
    except KeyError:
        # Ignore error when the directory already exists.
        pass


def _etcd_purge_app(**kwargs):
    appname = kwargs['instance']
    try:
        _etcd_client.delete('/deis/services/{}'.format(appname), dir=True, recursive=True)
    except KeyError:
        pass


def _etcd_publish_cert(**kwargs):
    cert = kwargs['instance']
    _etcd_client.write('/deis/certs/{}/cert'.format(cert), cert.certificate)
    _etcd_client.write('/deis/certs/{}/key'.format(cert), cert.key)


def _etcd_purge_cert(**kwargs):
    cert = kwargs['instance']
    try:
        _etcd_client.delete('/deis/certs/{}'.format(cert),
                            prevExist=True, dir=True, recursive=True)
    except KeyError:
        pass


# Log significant app-related events
post_save.connect(_log_build_created, sender=Build, dispatch_uid='api.models.log')
post_save.connect(_log_release_created, sender=Release, dispatch_uid='api.models.log')
post_save.connect(_log_config_updated, sender=Config, dispatch_uid='api.models.log')
post_save.connect(_log_domain_added, sender=Domain, dispatch_uid='api.models.log')
post_save.connect(_log_cert_added, sender=Certificate, dispatch_uid='api.models.log')
post_delete.connect(_log_domain_removed, sender=Domain, dispatch_uid='api.models.log')
post_delete.connect(_log_cert_removed, sender=Certificate, dispatch_uid='api.models.log')


# automatically generate a new token on creation
@receiver(post_save, sender=settings.AUTH_USER_MODEL)
def create_auth_token(sender, instance=None, created=False, **kwargs):
    if created:
        Token.objects.create(user=instance)


_etcd_client = get_etcd_client()


if _etcd_client:
    post_save.connect(_etcd_publish_key, sender=Key, dispatch_uid='api.models')
    post_delete.connect(_etcd_purge_key, sender=Key, dispatch_uid='api.models')
    post_delete.connect(_etcd_purge_user, sender=settings.AUTH_USER_MODEL, dispatch_uid='api.models')  # noqa
    post_save.connect(_etcd_publish_app, sender=App, dispatch_uid='api.models')
    post_delete.connect(_etcd_purge_app, sender=App, dispatch_uid='api.models')
    post_save.connect(_etcd_publish_cert, sender=Certificate, dispatch_uid='api.models')
    post_delete.connect(_etcd_purge_cert, sender=Certificate, dispatch_uid='api.models')