from django.contrib.auth.models import AbstractUser, Group
from django.db import models
from django.conf import settings
from django.dispatch import receiver
from rest_framework.authtoken.models import Token
from django.db.models.signals import post_save
from datetime import datetime


class User(AbstractUser):
    TYPE_CHOICES = (
            ('apiclient', 'API-Client'),
            ('oidcuser', 'OIDC User'),
            ('admin', 'Admin'),
            )
    user_type = models.CharField(
            max_length=20,
            choices=TYPE_CHOICES,
            default='oidcuser',
            )
    sub = models.CharField(max_length=150, blank=True, null=True)
    password = models.CharField(max_length=150, blank=True, null=True)


@receiver(post_save, sender=settings.AUTH_USER_MODEL)
def create_auth_token(sender, instance=None, created=False, **kwargs):
    if created:
        if instance.user_type == 'apiclient':
            Token.objects.create(user=instance)


def construct_user(user_info):
    return User(
            sub=user_info['sub'],
            name=user_info['name'],
            first_name=user_info['given_name'],
            last_name=user_info['family_name'],
            email=user_info['email'],
            username=user_info['email'],
            )


class Site(models.Model):
    client = models.OneToOneField(
            User,
            related_name='site',
            blank=True,
            null=True)
    name = models.CharField(max_length=150, unique=True)
    description = models.TextField(max_length=300, blank=True)
    last_fetch = models.DateTimeField(default=datetime.utcfromtimestamp(0))

    def __str__(self):
        return self.name

    def clientapi_get_deployments(self, all=False):
        services = {}

        for service in self.services.all():
            ds = (
                    service.deployments
                    .filter(user__user_type='oidcuser')
                    .exclude(ssh_keys=None)
                    )
            if not all:
                ds = ds.filter(last_change__gt=self.last_fetch)

            # deployments with ssh keys
            services[service.name] = ds

        self.last_fetch = datetime.now()
        self.save()
        return services


class Service(models.Model):
    name = models.CharField(max_length=150, unique=True)
    description = models.TextField(max_length=300, blank=True)
    site = models.ForeignKey(
            Site,
            related_name='services')
    groups = models.ManyToManyField(
            Group,
            related_name='services',
            blank=True)

    def __str__(self):
        return self.name + '@' + self.site.name


class SSHPublicKey(models.Model):
    name = models.CharField(max_length=150, unique=True)
    key = models.TextField(max_length=1000)
    user = models.ForeignKey(
            User,
            related_name='ssh_keys')

    def __str__(self):
        return self.name


class Deployment(models.Model):
    user = models.ForeignKey(
            User,
            related_name='deployments',
            on_delete=models.CASCADE,
            )
    service = models.ForeignKey(
            Service,
            related_name='deployments',
            on_delete=models.CASCADE,
            )
    # SET_NULL: we allow credentials to be deleted after deployment
    ssh_keys = models.ManyToManyField(
            SSHPublicKey,
            related_name='deployments',
            blank=True,
            )
    last_change = models.DateTimeField(
            auto_now=True
            )

    def __str__(self):
        return str(self.user) + '@' + str(self.service)