import re
from django.utils import timezone
from django.db import models
from django.db.models import Q


BAN_NAME_EMAIL = 0
BAN_NAME = 1
BAN_EMAIL = 2
BAN_IP = 3


class Ban(models.Model):
    type = models.PositiveIntegerField(default=BAN_NAME_EMAIL)
    ban = models.CharField(max_length=255)
    reason_user = models.TextField(null=True,blank=True)
    reason_admin = models.TextField(null=True,blank=True)
    expires = models.DateTimeField(null=True,blank=True,db_index=True)

    
def check_ban(ip=False, username=False, email=False):
    bans_model = Ban.objects.filter(Q(expires=None) | Q(expires__gt=timezone.now()))
    if not (ip and username and email):
        if ip:
            bans_model.filter(type=BAN_IP)
        if username:
            bans_model.filter(type=BAN_NAME_EMAIL)
            bans_model.filter(type=BAN_NAME)
        if email:
            bans_model.filter(type=BAN_NAME_EMAIL)
            bans_model.filter(type=BAN_EMAIL)
    for ban in bans_model.order_by('-expires').iterator():
        if (
            # Check user name
            ((username and (ban.type == BAN_NAME_EMAIL or ban.type == BAN_NAME))
            and re.search('^'+re.escape(ban.ban).replace('\*', '(.*?)')+'$', username, flags=re.IGNORECASE))
            or # Check user email
            ((email and (ban.type == BAN_NAME_EMAIL or ban.type == BAN_EMAIL))
            and re.search('^'+re.escape(ban.ban).replace('\*', '(.*?)')+'$', email, flags=re.IGNORECASE))
            or # Check IP address
            (ip and ban.type == BAN_IP
            and re.search('^'+re.escape(ban.ban).replace('\*', '(.*?)')+'$', ip, flags=re.IGNORECASE))):
                return ban
    return False


class BanCache(object):
    def __init__(self):
        self.banned = False
        self.type = None
        self.expires = None
        self.reason_user = None
        self.version = 0
        
    def check_for_updates(self, request):
        if (self.version < request.monitor['bans_version']
            or (self.expires != None and self.expires < timezone.now())):
            self.version = request.monitor['bans_version']
            
            # Check Ban
            if request.user.is_authenticated():
                ban = check_ban(
                                ip=request.session.get_ip(request),
                                username=request.user.username,
                                email=request.user.email
                                )
            else:
                ban = check_ban(ip=request.session.get_ip(request))
                
            # Update ban cache
            if ban:
                self.banned = True
                self.reason_user = ban.reason_user
                self.expires = ban.expires
                self.type = ban.type
            else:
                self.banned = False
                self.reason_user = None
                self.expires = None
                self.type = None
            return True
        return False    
    
    def is_banned(self):
        return self.banned