from django.db import models
from django.contrib.auth.models import PermissionsMixin, Permission
from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
from django.contrib.contenttypes.models import ContentType
from django.utils.translation import ugettext_lazy as _


class UserManager(BaseUserManager):
    use_in_migrations = True

    def _create_user(self, user_id, password=None, **extra_fields):
        """
        Creates and saves a User with the given email and password.
        """
        if not user_id:
            raise ValueError('The user_id must be set')
        if not password:
            password = user_id
        if 'permissions' in extra_fields:
            p = extra_fields['permissions']
            del extra_fields['permissions']
        user = self.model(user_id=user_id, **extra_fields)
        user.set_password(password)
        user.save(using=self._db)
        user.user_permissions.add(*p)
        return user

    def create_superuser(self, user_id, password=None, **extra_fields):
        extra_fields['is_superuser'] = True
        extra_fields['is_staff'] = True
        extra_fields['user_role'] = 1  # ADMIN = 1
        extra_fields['permissions'] = Permission.objects.all()
        return self._create_user(user_id, password, **extra_fields)

    def create_student(self, user_id, password=None, **extra_fields):
        extra_fields['is_superuser'] = False
        extra_fields['is_staff'] = False
        extra_fields['user_role'] = 2  # STUDENT = 2
        return self._create_user(user_id, password, **extra_fields)

    def create_teacher(self, user_id, password=None, **extra_fields):
        extra_fields['is_superuser'] = False
        extra_fields['is_staff'] = False
        extra_fields['user_role'] = 3  # TEACHER = 3
        return self._create_user(user_id, password, **extra_fields)

    def create_controller(self, user_id, password=None, **extra_fields):
        extra_fields['is_superuser'] = False
        extra_fields['is_staff'] = True
        extra_fields['user_role'] = 4  # CONTROLLER = 4
        accounts_content_type = ContentType.objects.get(app_label='accounts')
        perms = Permission.objects.filter(content_type=accounts_content_type)
        extra_fields['permissions'] = perms
        return self._create_user(user_id, password, **extra_fields)


class User(AbstractBaseUser, PermissionsMixin):
    user_id = models.CharField(_('user id'), max_length=8, unique=True)
    email = models.EmailField(_('email address'), unique=True, 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(_('date joined'), auto_now_add=True)
    is_active = models.BooleanField(_('is active'), default=True)
    is_staff = models.BooleanField(_('is staff'), default=False)

    ADMIN = 1
    STUDENT = 2
    TEACHER = 3
    CONTROLLER = 4
    user_role = models.SmallIntegerField(_('user role'), choices=(
        (ADMIN, 'Admin'),
        (STUDENT, 'Student'),
        (TEACHER, 'Teacher'),
        (CONTROLLER, 'Controller'),
    ))

    USERNAME_FIELD = 'user_id'
    REQUIRED_FIELDS = []

    objects = UserManager()

    class Meta:
        verbose_name = _('user')
        verbose_name_plural = _('users')

    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 get_all_admins(self):
        return self.objects.filter(user_role=1)  # ADMIN = 1

    def get_all_students(self):
        return self.objects.filter(user_role=2)  # STUDENT = 2

    def get_all_teachers(self):
        return self.objects.filter(user_role=3)  # TEACHER = 3

    def get_all_controllers(self):
        return self.objects.filter(user_role=4)  # CONTROLLER = 4