import os
import datetime
from collections import defaultdict
from django.db import models
from django.db.models import F, Q
from core.models import PlCoreBase,Site, DashboardView, DiffModelMixIn
from core.models.site import Deployment
from django.contrib.auth.models import AbstractBaseUser, BaseUserManager
from timezones.fields import TimeZoneField
from operator import itemgetter, attrgetter
from django.core.mail import EmailMultiAlternatives
from core.middleware import get_request
import model_policy
from django.core.exceptions import PermissionDenied

# Create your models here.
class UserManager(BaseUserManager):
    def create_user(self, email, firstname, lastname, password=None):
        """
        Creates and saves a User with the given email, date of
        birth and password.
        """
        if not email:
            raise ValueError('Users must have an email address')

        user = self.model(
            email=UserManager.normalize_email(email),
            firstname=firstname,
            lastname=lastname,
            password=password
        )
        #user.set_password(password)
        user.is_admin = True
        user.save(using=self._db)
        return user

    def create_superuser(self, email, firstname, lastname, password):
        """
        Creates and saves a superuser with the given email, date of
        birth and password.
        """
        user = self.create_user(email,
            password=password,
            firstname=firstname,
            lastname=lastname
        )
        user.is_admin = True
        user.save(using=self._db)
        return user

class DeletedUserManager(UserManager):
    def get_queryset(self):
        return super(UserManager, self).get_query_set().filter(deleted=True)

    # deprecated in django 1.7 in favor of get_queryset()
    def get_query_set(self):
        return self.get_queryset()

class User(AbstractBaseUser, DiffModelMixIn):

    class Meta:
        app_label = "core"

    email = models.EmailField(
        verbose_name='email address',
        max_length=255,
        unique=True,
        db_index=True,
    )

    username = models.CharField(max_length=255, default="Something" )

    firstname = models.CharField(help_text="person's given name", max_length=200)
    lastname = models.CharField(help_text="person's surname", max_length=200)

    phone = models.CharField(null=True, blank=True, help_text="phone number contact", max_length=100)
    user_url = models.URLField(null=True, blank=True)
    site = models.ForeignKey(Site, related_name='users', help_text="Site this user will be homed too", null=True)
    public_key = models.TextField(null=True, blank=True, max_length=1024, help_text="Public key string")

    is_active = models.BooleanField(default=True)
    is_admin = models.BooleanField(default=True)
    is_staff = models.BooleanField(default=True)
    is_readonly = models.BooleanField(default=False)

    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)
    enacted = models.DateTimeField(null=True, default=None)
    backend_status = models.CharField(max_length=140,
                                      default="Provisioning in progress")
    deleted = models.BooleanField(default=False)

    timezone = TimeZoneField()

    dashboards = models.ManyToManyField('DashboardView', through='UserDashboardView', blank=True)

    objects = UserManager()
    deleted_objects = DeletedUserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['firstname', 'lastname']

    def __init__(self, *args, **kwargs):
        super(User, self).__init__(*args, **kwargs)
        self._initial = self._dict # for DiffModelMixIn

    def isReadOnlyUser(self):
        return self.is_readonly

    def get_full_name(self):
        # The user is identified by their email address
        return self.email

    def get_short_name(self):
        # The user is identified by their email address
        return self.email

    def delete(self, *args, **kwds):
        # so we have something to give the observer
        purge = kwds.get('purge',False)
        try:
            purge = purge or observer_disabled
        except NameError:
            pass
            
        if (purge):
            super(User, self).delete(*args, **kwds)
        else:
            self.deleted = True
            self.enacted=None
            self.save(update_fields=['enacted','deleted'])

    @property
    def keyname(self):
        return self.email[:self.email.find('@')]

    def __unicode__(self):
        return self.email

    def has_perm(self, perm, obj=None):
        "Does the user have a specific permission?"
        # Simplest possible answer: Yes, always
        return True

    def has_module_perms(self, app_label):
        "Does the user have permissions to view the app `app_label`?"
        # Simplest possible answer: Yes, always
        return True

    def is_superuser(self):
        return False

    def get_dashboards(self):
        DEFAULT_DASHBOARDS=["Tenant"]

        dashboards = sorted(list(self.dashboardViews.all()), key=attrgetter('order'))
        dashboards = [x.dashboardView for x in dashboards]

        if not dashboards:
            for dashboardName in DEFAULT_DASHBOARDS:
                dbv = DashboardView.objects.filter(name=dashboardName)
                if dbv:
                    dashboards.append(dbv[0])

        return dashboards

#    def get_roles(self):
#        from core.models.site import SitePrivilege
#        from core.models.slice import SliceMembership
#
#        site_privileges = SitePrivilege.objects.filter(user=self)
#        slice_memberships = SliceMembership.objects.filter(user=self)
#        roles = defaultdict(list)
#        for site_privilege in site_privileges:
#            roles[site_privilege.role.role_type].append(site_privilege.site.login_base)
#        for slice_membership in slice_memberships:
#            roles[slice_membership.role.role_type].append(slice_membership.slice.name)
#        return roles   

    def save(self, *args, **kwds):
        if not self.id:
            self.set_password(self.password)
        if self.is_active:
            if self.password=="!":
                self.send_temporary_password()

        self.username = self.email
        super(User, self).save(*args, **kwds)

        self._initial = self._dict

    def send_temporary_password(self):
        password = User.objects.make_random_password()
        self.set_password(password)
        subject, from_email, to = 'OpenCloud Account Credentials', 'support@opencloud.us', str(self.email)
        text_content = 'This is an important message.'
        userUrl="http://%s/" % get_request().get_host()
        html_content = """<p>Your account has been created on OpenCloud. Please log in <a href="""+userUrl+""">here</a> to activate your account<br><br>Username: """+self.email+"""<br>Temporary Password: """+password+"""<br>Please change your password once you successully login into the site.</p>"""
        msg = EmailMultiAlternatives(subject,text_content, from_email, [to])
        msg.attach_alternative(html_content, "text/html")
        msg.send()

    def can_update_field(self, user, fieldName):
        from core.models import SitePrivilege
        if (user.is_admin):
            # admin can update anything
            return True

        # fields that a site PI can update
        if fieldName in ["is_active", "is_readonly"]:
            site_privs = SitePrivilege.objects.filter(user=user, site=self.site)
            for site_priv in site_privs:
                if site_priv.role.role == 'pi':
                    return True

        # fields that a user cannot update in his/her own record
        if fieldName in ["is_admin", "is_active", "site", "is_staff", "is_readonly"]:
            return False

        return True

    def can_update(self, user):
        from core.models import SitePrivilege
        if user.is_readonly:
            return False
        if user.is_admin:
            return True
        if (user.id == self.id):
            return True
        # site pis can update
        site_privs = SitePrivilege.objects.filter(user=user, site=self.site)
        for site_priv in site_privs:
            if site_priv.role.role == 'pi':
                return True

        return False

    @staticmethod
    def select_by_user(user):
        if user.is_admin:
            qs = User.objects.all()
        else:
            # can see all users at any site where this user has pi role
            from core.models.site import SitePrivilege
            site_privs = SitePrivilege.objects.filter(user=user)
            sites = [sp.site for sp in site_privs if sp.role.role == 'pi']
            # get site privs of users at these sites
            site_privs = SitePrivilege.objects.filter(site__in=sites)
            user_ids = [sp.user.id for sp in site_privs] + [user.id]
            qs = User.objects.filter(Q(site__in=sites) | Q(id__in=user_ids))
        return qs

    def save_by_user(self, user, *args, **kwds):
        if not self.can_update(user):
            raise PermissionDenied("You do not have permission to update %s objects" % self.__class__.__name__)

        for fieldName in self.changed_fields:
            if not self.can_update_field(user, fieldName):
                raise PermissionDenied("You do not have permission to update field %s in object %s" % (fieldName, self.__class__.__name__))

        self.save(*args, **kwds)

    def delete_by_user(self, user, *args, **kwds):
        if not self.can_update(user):
            raise PermissionDenied("You do not have permission to delete %s objects" % self.__class__.__name__)
        self.delete(*args, **kwds)

class UserDashboardView(PlCoreBase):
     user = models.ForeignKey(User, related_name="dashboardViews")
     dashboardView = models.ForeignKey(DashboardView, related_name="dashboardViews")
     order = models.IntegerField(default=0)