import os
from django.db import models
from core.models import PlCoreBase
from core.models import Site
from core.models import User
from core.models import Role
from core.models import Deployment
from core.models import ServiceClass
from core.models import Tag
from django.contrib.contenttypes import generic
from core.models import Service

# Create your models here.

class Slice(PlCoreBase):
    tenant_id = models.CharField(max_length=200, help_text="Keystone tenant id")
    name = models.CharField(unique=True, help_text="The Name of the Slice", max_length=80)
    enabled = models.BooleanField(default=True, help_text="Status for this Slice")
    omf_friendly = models.BooleanField()
    description=models.TextField(blank=True,help_text="High level description of the slice and expected activities", max_length=1024)
    slice_url = models.URLField(blank=True, max_length=512)
    site = models.ForeignKey(Site, related_name='slices', help_text="The Site this Slice belongs to")
    network_id = models.CharField(null=True, blank=True, max_length=256, help_text="Quantum network")
    router_id = models.CharField(null=True, blank=True, max_length=256, help_text="Quantum router id")
    subnet_id = models.CharField(null=True, blank=True, max_length=256, help_text="Quantum subnet id")
    service = models.ForeignKey(Service, related_name='service', null=True, blank=True)

    tags = generic.GenericRelation(Tag)

    serviceClass = models.ForeignKey(ServiceClass, related_name = "slices", null=True, default=ServiceClass.get_default)
    creator = models.ForeignKey(User, related_name='slices', blank=True, null=True)

    def __unicode__(self):  return u'%s' % (self.name)

    def save(self, *args, **kwds):
        if self.serviceClass is None:
            # We allowed None=True for serviceClass because Django evolution
            # will fail unless it is allowed. But, we we really don't want it to
            # ever save None, so fix it up here.
            self.serviceClass = ServiceClass.get_default()
        if not self.creator and hasattr(self, 'caller'):
            self.creator = self.caller
        super(Slice, self).save(*args, **kwds)

    def can_update(self, user):
        if user.is_readonly:
            return False
        if user.is_admin:
            return True
        slice_privs = SlicePrivilege.objects.filter(user=user, slice=self)
        for slice_priv in slice_privs:
            if slice_priv.role.role == 'admin':
                return True
        return False

    @staticmethod
    def select_by_user(user):
        if user.is_admin:
            qs = Slice.objects.all()
        else:
            slice_ids = [sp.slice.id for sp in SlicePrivilege.objects.filter(user=user)]
            qs = Slice.objects.filter(id__in=slice_ids)
        return qs

class SliceRole(PlCoreBase):
    ROLE_CHOICES = (('admin','Admin'),('default','Default'))

    role = models.CharField(choices=ROLE_CHOICES, unique=True, max_length=30)

    def __unicode__(self):  return u'%s' % (self.role)

class SlicePrivilege(PlCoreBase):
    user = models.ForeignKey('User', related_name='slice_privileges')
    slice = models.ForeignKey('Slice', related_name='slice_privileges')
    role = models.ForeignKey('SliceRole')

    def __unicode__(self):  return u'%s %s %s' % (self.slice, self.user, self.role)

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

    @staticmethod
    def select_by_user(user):
        if user.is_admin:
            qs = SlicePrivilege.objects.all()
        else:
            sp_ids = [sp.id for sp in SlicePrivilege.objects.filter(user=user)]
            qs = SlicePrivilege.objects.filter(id__in=sp_ids)
        return qs