from oauth2_provider.oauth2_validators import OAuth2Validator

from django.contrib.auth import get_user_model
from oauth2_provider.settings import oauth2_settings

from apps.gooyal_oauth2.models import Resource

USER_MODEL = get_user_model()


class MultiGatewayOAuth2Validator(OAuth2Validator):  # pylint: disable=w0223
    def validate_user(self, username, password, client, request, *args, **kwargs):
        auth_fields = getattr(request, 'auth_fields', 'username:password').split(':')

        if len(auth_fields) != 2:
            return False

        user_field, pass_field = auth_fields

        if user_field not in ['phone_number', 'username', 'email']:
            return False

        if pass_field not in ['password', 'otp']:
            return False

        if not username or not password:
            return False

        user = USER_MODEL.objects.filter(**{user_field:username}).first()

        if not user:
            return False

        if not user.check_auth(pass_field, password):
            return False

        if user.is_active:
            request.user = user
            return True

        return False


class IntrospectOAuth2Validator(OAuth2Validator):
    def validate_bearer_token(self, token, scopes, request):
        """
        When users try to access resources, check that provided token is valid
        """
        if not token:
            return False

        introspection_url = oauth2_settings.RESOURCE_SERVER_INTROSPECTION_URL
        introspection_token = oauth2_settings.RESOURCE_SERVER_AUTH_TOKEN
        introspection_credentials = oauth2_settings.RESOURCE_SERVER_INTROSPECTION_CREDENTIALS

        try:
            access_token = Resource.objects.select_related("user").get(token=token)
        except Resource.DoesNotExist:
            access_token = None

        # if there is no token or it's invalid then introspect the token if there's an external OAuth server
        if not access_token or not access_token.is_valid(scopes):
            if introspection_url and (introspection_token or introspection_credentials):
                access_token = self._get_token_from_authentication_server(
                    token,
                    introspection_url,
                    introspection_token,
                    introspection_credentials
                )

        if access_token and access_token.is_valid(scopes):
            request.client = access_token.application
            request.user = access_token.user
            request.scopes = scopes

            # this is needed by django rest framework
            request.access_token = access_token
            return True
        else:
            self._set_oauth2_error_on_request(request, access_token, scopes)
            return False