from django.contrib.sites.models import Site
from django.conf import settings
from django_cas.backends import CASBackend, _verify as CASverify
from django_cas.models import User
from django.db import models, connection

from gestioncof.models import CofProfile

class COFCASBackend(CASBackend):
    def authenticate_cas(self, ticket, service, request):
        """Verifies CAS ticket and gets or creates User object"""

        username, attributes = CASverify(ticket, service)
        if attributes:
            request.session['attributes'] = attributes
        if not username:
            return None
        profiles = CofProfile.objects.filter(login_clipper = username)
        if len(profiles) > 0:
            profile = profiles.order_by('-is_cof')[0]
            user = profile.user
            return user
        try:
            user = User.objects.get(username=username)
        except User.DoesNotExist:
            # user will have an "unusable" password
            user = User.objects.create_user(username, '')
            user.save()
        return user

    def authenticate(self, ticket, service, request):
        """Authenticates CAS ticket and retrieves user data"""
        user = self.authenticate_cas(ticket, service, request)
        if user is None:
            return user
        try:
            profile = user.get_profile()
        except CofProfile.DoesNotExist:
            profile, created = CofProfile.objects.get_or_create(user = user)
            profile.save()
        if not profile.login_clipper:
            profile.login_clipper = user.username
            profile.save()
        if not user.email:
            user.email = settings.CAS_EMAIL_FORMAT % profile.login_clipper
            user.save()
        if profile.is_buro and not user.is_superuser:
            user.is_superuser = True
            user.is_staff = True
            user.save()
        return user

def context_processor (request):
    '''Append extra data to the context of the given request'''
    data = {
            "user": request.user,
            "site": Site.objects.get_current(),
           }
    return data

def lock_table(*models):
    query = "LOCK TABLES "
    for i, model in enumerate(models):
        table = model._meta.db_table
        if i > 0: query += ", "
        query += "%s WRITE" % table
    cursor = connection.cursor()
    cursor.execute(query)
    row = cursor.fetchone()
    return row

def unlock_tables(*models):
    cursor = connection.cursor()
    cursor.execute("UNLOCK TABLES")
    row = cursor.fetchone()
    return row

unlock_table = unlock_tables