from __future__ import absolute_import

from django import forms
from django.core.exceptions import ValidationError
from django.utils.safestring import mark_safe
from django.contrib.auth.forms import SetPasswordForm, AuthenticationForm
from django.conf import settings

from zerver.models import Realm, get_user_profile_by_email, UserProfile, \
    completely_open, resolve_email_to_domain, get_realm
from zerver.lib.actions import do_change_password, is_inactive
from zproject.backends import password_auth_enabled
import DNS

SIGNUP_STRING = '<a href="https://zulip.com/signup">Sign up</a> to find out when Zulip is ready for you.'

def has_valid_realm(value):
    try:
        realm = Realm.objects.get(domain=resolve_email_to_domain(value))
    except Realm.DoesNotExist:
        return False
    if settings.ENTERPRISE:
        return True
    return realm.deployment.name in ["mit.edu", "zulip.com"]

def not_mit_mailing_list(value):
    # I don't want ec-discuss signed up for Zulip
    if "@mit.edu" in value:
        username = value.rsplit("@", 1)[0]
        # Check whether the user exists and can get mail.
        try:
            DNS.dnslookup("%s.pobox.ns.athena.mit.edu" % username, DNS.Type.TXT)
            return True
        except DNS.Base.ServerError, e:
            if e.rcode == DNS.Status.NXDOMAIN:
                raise ValidationError(mark_safe(u'That user does not exist at MIT or is a <a href="https://ist.mit.edu/email-lists">mailing list</a>. If you want to sign up an alias for Zulip, <a href="mailto:support@zulip.com">contact us</a>.'))
            else:
                raise
    return True

class RegistrationForm(forms.Form):
    full_name = forms.CharField(max_length=100)
    if password_auth_enabled():
        password = forms.CharField(widget=forms.PasswordInput, max_length=100)
    if not settings.ENTERPRISE:
        terms = forms.BooleanField(required=True)

class ToSForm(forms.Form):
    full_name = forms.CharField(max_length=100)
    terms = forms.BooleanField(required=True)

class HomepageForm(forms.Form):
    # This form is important because it determines whether users can
    # register for our product. Be careful when modifying the
    # validators.
    email = forms.EmailField(validators=[is_inactive,])

    def __init__(self, *args, **kwargs):
        self.domain = kwargs.get("domain")
        if kwargs.has_key("domain"):
            del kwargs["domain"]
        super(HomepageForm, self).__init__(*args, **kwargs)

    def clean_email(self):
        data = self.cleaned_data['email']
        if completely_open(self.domain) or has_valid_realm(data) and not_mit_mailing_list(data):
            return data
        raise ValidationError(mark_safe(
                u'Registration is not currently available for your domain. ' \
                    + SIGNUP_STRING))

class LoggingSetPasswordForm(SetPasswordForm):
    def save(self, commit=True):
        do_change_password(self.user, self.cleaned_data['new_password1'],
                           log=True, commit=commit)
        return self.user

class CreateUserForm(forms.Form):
    full_name = forms.CharField(max_length=100)
    email = forms.EmailField()

class OurAuthenticationForm(AuthenticationForm):
    def clean_username(self):
        email = self.cleaned_data['username']
        try:
            user_profile = get_user_profile_by_email(email)
        except UserProfile.DoesNotExist:
            return email

        if user_profile.realm.deactivated:
            error_msg = u"""Sorry for the trouble, but %s has been deactivated.

Please contact support@zulip.com to reactivate this group.""" % (
                user_profile.realm.name,)
            raise ValidationError(mark_safe(error_msg))

        return email