from django.contrib.auth import authenticate, get_user_model
from django.core.exceptions import ObjectDoesNotExist
from django.utils.translation import ugettext as _
from rest_framework import serializers
from rest_framework_jwt.serializers import JSONWebTokenSerializer
from rest_framework_jwt.settings import api_settings

import jwt

jwt_payload_handler = api_settings.JWT_PAYLOAD_HANDLER
jwt_encode_handler = api_settings.JWT_ENCODE_HANDLER
jwt_decode_handler = api_settings.JWT_DECODE_HANDLER
jwt_get_username_from_payload = api_settings.JWT_PAYLOAD_GET_USERNAME_HANDLER

class CustomJWTSerializer(JSONWebTokenSerializer):
    def validate(self, attrs):
        # get username and password
        username = attrs.get('username')
        password = attrs.get('password')

        # if both exist
        if username and password:

            #change username to all lowercase
            username = username.lower()

            # check if the user exists
            try:
                # rudimentary way to check if it's an email or username
                if '@' in username:
                    us = User.objects.get(email=username)
                else:
                    us = User.objects.get(username=username)
            except ObjectDoesNotExist:
                msg = _('no such user with such credentials.')
                raise serializers.ValidationError(msg)

            # check username/password combination
            user = authenticate(username=us.username, password=attrs.get('password'))

            if user:
                if not user.is_active:
                    msg = _('User account is disabled.')
                    raise serializers.ValidationError(msg)

                # generate jwt payload with token
                payload = jwt_payload_handler(user)

                return {
                    'token': jwt_encode_handler(payload),
                    'user': user,
                    'permissions':user.get_all_permissions(),
                }
            else:
                msg = _('Unable to log in with provided credentials.')
                print(user)
                raise serializers.ValidationError(msg)
        else:
            msg = _('Must include "{username_field}" and "password".')
            msg = msg.format(username_field=self.username_field)
            raise serializers.ValidationError(msg)