from django.contrib.auth.models import AbstractBaseUser, BaseUserManager, PermissionsMixin

from django.db import models

from django.core import validators

from django.utils.translation import ugettext_lazy as _

from django.utils import timezone

import uuid

class UserManager(BaseUserManager):

    def create_user(self, external_id, username, password=None, **extra_fields):

        """

        Creates and saves a User with the given username, email and password.

        """

        now = timezone.now()

        user = self.model(external_id=external_id, username=username,

                          is_staff=False, is_active=True, is_superuser=False,

                          date_joined=now, **extra_fields)

        user.set_password(password)

        user.save(using=self._db)

        return user

    def create_superuser(self, external_id, username, password=None, **extra_fields):

        superuser = self.create_user(external_id, username, password, **extra_fields)

        superuser.is_staff = True

        superuser.is_active = True

        superuser.is_superuser = True

        superuser.save(using=self._db)

        return superuser

class User(AbstractBaseUser, PermissionsMixin):

    external_id = models.CharField(max_length=256, unique=True, default=uuid.uuid4)

    uai = models.CharField(max_length=40, blank=True)

    first_name = models.CharField(_('first name'), max_length=30, blank=True)

    last_name = models.CharField(_('last name'), max_length=30, blank=True)

    date_joined = models.DateTimeField(default=timezone.now)

    is_active = models.BooleanField(default=True)

    is_staff = models.BooleanField(default=False)

    objects = UserManager()

    USERNAME_FIELD = 'external_id'

    REQUIRED_FIELDS = ['username']

    def get_full_name(self):

        """

        Returns the first_name plus the last_name, with a space in between.

        """

        full_name = '%s %s' % (self.first_name, self.last_name)

        return full_name.strip()

    def get_short_name(self):

        return self.first_name

    def __unicode__(self):

        return self.external_id