import os
from django.db import models
from django.core import exceptions
from core.models import PlCoreBase
from core.models import Image
from core.models import Slice
from core.models import Node
from core.models import Site
from core.models import Deployment
from core.models import User
from core.models import Tag
from core.models import Flavor
from django.contrib.contenttypes import generic

def get_default_flavor(deployment = None):
    # Find a default flavor that can be used for a sliver. This is particularly
    # useful in evolution. It's also intended this helper function can be used
    # for admin.py when users

    if deployment:
        flavors = deployment.flavors.all()
    else:
        flavors = Flavor.objects.all()

    if not flavors:
        return None

    for flavor in flavors:
        if flavor.default:
            return flavor

    return flavors[0]

# Create your models here.
class Sliver(PlCoreBase):
    instance_id = models.CharField(null=True, blank=True, max_length=200, help_text="Nova instance id")
    name = models.CharField(max_length=200, help_text="Sliver name")
    instance_name = models.CharField(blank=True, null=True, max_length=200, help_text="OpenStack generated name")
    ip = models.GenericIPAddressField(help_text="Sliver ip address", blank=True, null=True)
    image = models.ForeignKey(Image, related_name='slivers')
    #key = models.ForeignKey(Key, related_name='slivers')
    creator = models.ForeignKey(User, related_name='slivers', blank=True, null=True)
    slice = models.ForeignKey(Slice, related_name='slivers')
    node = models.ForeignKey(Node, related_name='slivers')
    deploymentNetwork = models.ForeignKey(Deployment, verbose_name='deployment', related_name='sliver_deploymentNetwork')
    numberCores = models.IntegerField(verbose_name="Number of Cores", help_text="Number of cores for sliver", default=0)
    flavor = models.ForeignKey(Flavor, help_text="Flavor of this instance", default=get_default_flavor)
    tags = generic.GenericRelation(Tag)
    userData = models.TextField(blank=True, null=True, help_text="user_data passed to instance during creation")

    def __unicode__(self):
        if self.instance_name:
            return u'%s' % (self.instance_name)
        elif self.id:
            return u'uninstantiated-%s' % str(self.id)
        elif self.slice:
            return u'unsaved-sliver on %s' % self.slice.name
        else:
            return u'unsaved-sliver'

    def save(self, *args, **kwds):
        self.name = self.slice.slicename
        if not self.creator and hasattr(self, 'caller'):
            self.creator = self.caller
        self.deploymentNetwork = self.node.deployment

# XXX smbaker - disabled for now, was causing fault in tenant view create slice
#        if not self.deploymentNetwork.test_acl(slice=self.slice):
#            raise exceptions.ValidationError("Deployment %s's ACL does not allow any of this slice %s's users" % (self.deploymentNetwork.name, self.slice.name))

        super(Sliver, self).save(*args, **kwds)

    def can_update(self, user):
        return self.slice.can_update(user)

    def all_ips(self):
        ips={}
        for ns in self.networksliver_set.all():
           ips[ns.network.name] = ns.ip
        return ips

    def all_ips_string(self):
        result = []
        ips = self.all_ips()
        for key in sorted(ips.keys()):
            #result.append("%s = %s" % (key, ips[key]))
            result.append(ips[key])
        return ", ".join(result)
    all_ips_string.short_description = "addresses"

    @staticmethod
    def select_by_user(user):
        if user.is_admin:
            qs = Sliver.objects.all()
        else:
            slices = Slice.select_by_user(user)
            qs = Sliver.objects.filter(slice__in=slices)
        return qs