# -*- coding: utf-8 -*-

# Copyright: (c) 2008, Jarek Zgoda <jarek.zgoda@gmail.com>

__revision__ = '$Id: models.py 28 2009-10-22 15:03:02Z jarek.zgoda $'

import re

from django.db import models
from django.core.urlresolvers import reverse
from django.conf import settings
from django.contrib.sites.models import Site
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes.fields import GenericForeignKey
from django.utils.timezone import now as timezone_now

from confirmation.util import get_status_field
from zerver.lib.send_email import send_email
from zerver.lib.utils import generate_random_token
from zerver.models import PreregistrationUser, EmailChangeStatus
from typing import Any, Dict, Optional, Text, Union

B16_RE = re.compile('^[a-f0-9]{40}$')

def check_key_is_valid(creation_key):
    # type: (Text) -> bool
    if not RealmCreationKey.objects.filter(creation_key=creation_key).exists():
        return False
    days_sofar = (timezone_now() - RealmCreationKey.objects.get(creation_key=creation_key).date_created).days
    # Realm creation link expires after settings.REALM_CREATION_LINK_VALIDITY_DAYS
    if days_sofar <= settings.REALM_CREATION_LINK_VALIDITY_DAYS:
        return True
    return False

def generate_key():
    # type: () -> Text
    return generate_random_token(40)

def generate_realm_creation_url():
    # type: () -> Text
    key = generate_key()
    RealmCreationKey.objects.create(creation_key=key, date_created=timezone_now())
    return u'%s%s%s' % (settings.EXTERNAL_URI_SCHEME,
                        settings.EXTERNAL_HOST,
                        reverse('zerver.views.create_realm',
                                kwargs={'creation_key': key}))

class ConfirmationManager(models.Manager):
    def confirm(self, confirmation_key):
        # type: (str) -> Union[bool, PreregistrationUser, EmailChangeStatus]
        if B16_RE.search(confirmation_key):
            try:
                confirmation = self.get(confirmation_key=confirmation_key)
            except self.model.DoesNotExist:
                return False

            max_days = self.get_link_validity_in_days()
            time_elapsed = timezone_now() - confirmation.date_sent
            if time_elapsed.total_seconds() > max_days * 24 * 3600:
                return False

            obj = confirmation.content_object
            status_field = get_status_field(obj._meta.app_label, obj._meta.model_name)
            setattr(obj, status_field, getattr(settings, 'STATUS_ACTIVE', 1))
            obj.save()
            return obj
        return False

    def get_link_for_object(self, obj, host=None):
        # type: (Union[ContentType, int], Optional[str]) -> Text
        key = generate_key()
        self.create(content_object=obj, date_sent=timezone_now(), confirmation_key=key)
        return self.get_activation_url(key, host=host)

    def get_activation_url(self, confirmation_key, host=None):
        # type: (Text, Optional[str]) -> Text
        if host is None:
            host = settings.EXTERNAL_HOST
        return u'%s%s%s' % (settings.EXTERNAL_URI_SCHEME,
                            host,
                            reverse('confirmation.views.confirm',
                                    kwargs={'confirmation_key': confirmation_key}))

    def get_link_validity_in_days(self):
        # type: () -> int
        return getattr(settings, 'EMAIL_CONFIRMATION_DAYS', 10)

class EmailChangeConfirmationManager(ConfirmationManager):
    def get_activation_url(self, key, host=None):
        # type: (Text, Optional[str]) -> Text
        if host is None:
            # This will raise exception if the key doesn't exist.
            host = self.get(confirmation_key=key).content_object.realm.host
        return u'%s%s%s' % (settings.EXTERNAL_URI_SCHEME,
                            host,
                            reverse('zerver.views.user_settings.confirm_email_change',
                                    kwargs={'confirmation_key': key}))

    def get_link_validity_in_days(self):
        # type: () -> int
        return settings.EMAIL_CHANGE_CONFIRMATION_DAYS

class Confirmation(models.Model):
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')
    date_sent = models.DateTimeField('sent')
    confirmation_key = models.CharField('activation key', max_length=40)

    objects = ConfirmationManager()

    class Meta(object):
        verbose_name = 'confirmation email'
        verbose_name_plural = 'confirmation emails'

    def __unicode__(self):
        # type: () -> Text
        return 'confirmation email for %s' % (self.content_object,)

class EmailChangeConfirmation(Confirmation):
    class Meta(object):
        proxy = True

    objects = EmailChangeConfirmationManager()

class RealmCreationKey(models.Model):
    creation_key = models.CharField('activation key', max_length=40)
    date_created = models.DateTimeField('created', default=timezone_now)