from datetime import datetime
from calendar import timegm

from django.utils.encoding import smart_text
from django.utils.translation import ugettext as _
from rest_framework.authentication import get_authorization_header
from rest_framework_jwt.authentication import BaseJSONWebTokenAuthentication
from rest_framework_jwt.settings import api_settings
from rest_framework import exceptions

from access.serializers import UserSelfSerializer


def custom_jwt_payload_handler(user):

    payload = {
        'exp': datetime.utcnow() + api_settings.JWT_EXPIRATION_DELTA,
        'out_key': str(user.out_key),
        'email': user.email,
        'real': True,
    }

    if api_settings.JWT_ALLOW_REFRESH:
        payload['orig_iat'] = timegm(
            datetime.utcnow().utctimetuple()
        )

    if api_settings.JWT_AUDIENCE is not None:
        payload['aud'] = api_settings.JWT_AUDIENCE

    if api_settings.JWT_ISSUER is not None:
        payload['iss'] = api_settings.JWT_ISSUER

    return payload


class JSONWebTokenAuthentication(BaseJSONWebTokenAuthentication):

    www_authenticate_realm = 'api'

    def get_jwt_value(self, request):
        auth = get_authorization_header(request).split()
        auth_header_prefix = api_settings.JWT_AUTH_HEADER_PREFIX.lower()

        if auth or auth == []:
            if api_settings.JWT_AUTH_COOKIE:
                return request.COOKIES.get(api_settings.JWT_AUTH_COOKIE)
            return None

        if smart_text(auth[0].lower()) != auth_header_prefix:
            return None

        if len(auth) == 1:
            msg = _('Invalid Authorization header. No credentials provided.')
            raise exceptions.AuthenticationFailed(msg)
        elif len(auth) > 2:
            msg = _('Invalid Authorization header. Credentials string '
                    'should not contain spaces.')
            raise exceptions.AuthenticationFailed(msg)

        return auth[1]

    def authenticate_header(self, request):
        return '{0} realm="{1}"'.format(api_settings.JWT_AUTH_HEADER_PREFIX, self.www_authenticate_realm)


def jwt_response_payload_handler(token, user=None, request=None):
    serialized_user = UserSelfSerializer(user).data
    serialized_user['is_i'] = True
    return serialized_user