# Copyright 2017 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Firebase Instance ID module.

This module enables deleting instance IDs associated with Firebase projects.
"""

import requests

from firebase_admin import _http_client
from firebase_admin import _utils


_IID_SERVICE_URL = 'https://console.firebase.google.com/v1/'
_IID_ATTRIBUTE = '_iid'


def _get_iid_service(app):
    return _utils.get_app_service(app, _IID_ATTRIBUTE, _InstanceIdService)


def delete_instance_id(instance_id, app=None):
    """Deletes the specified instance ID and the associated data from Firebase.

    Note that Google Analytics for Firebase uses its own form of Instance ID to
    keep track of analytics data. Therefore deleting a regular Instance ID does
    not delete Analytics data. See `Delete an Instance ID`_ for more information.

    Args:
      instance_id: A non-empty instance ID string.
      app: An App instance (optional).

    Raises:
      InstanceIdError: If an error occurs while invoking the backend instance ID service.
      ValueError: If the specified instance ID or app is invalid.

    .. _Delete an Instance ID: https://firebase.google.com/support/privacy\
          /manage-iids#delete_an_instance_id
    """
    _get_iid_service(app).delete_instance_id(instance_id)


class _InstanceIdService:
    """Provides methods for interacting with the remote instance ID service."""

    error_codes = {
        400: 'Malformed instance ID argument.',
        401: 'Request not authorized.',
        403: 'Project does not match instance ID or the client does not have '
             'sufficient privileges.',
        404: 'Failed to find the instance ID.',
        409: 'Already deleted.',
        429: 'Request throttled out by the backend server.',
        500: 'Internal server error.',
        503: 'Backend servers are over capacity. Try again later.'
    }

    def __init__(self, app):
        project_id = app.project_id
        if not project_id:
            raise ValueError(
                'Project ID is required to access Instance ID service. Either set the projectId '
                'option, or use service account credentials. Alternatively, set the '
                'GOOGLE_CLOUD_PROJECT environment variable.')
        self._project_id = project_id
        self._client = _http_client.JsonHttpClient(
            credential=app.credential.get_credential(), base_url=_IID_SERVICE_URL)

    def delete_instance_id(self, instance_id):
        if not isinstance(instance_id, str) or not instance_id:
            raise ValueError('Instance ID must be a non-empty string.')
        path = 'project/{0}/instanceId/{1}'.format(self._project_id, instance_id)
        try:
            self._client.request('delete', path)
        except requests.exceptions.RequestException as error:
            msg = self._extract_message(instance_id, error)
            raise _utils.handle_requests_error(error, msg)

    def _extract_message(self, instance_id, error):
        if error.response is None:
            return None
        status = error.response.status_code
        msg = self.error_codes.get(status)
        if msg:
            return 'Instance ID "{0}": {1}'.format(instance_id, msg)

        return 'Instance ID "{0}": {1}'.format(instance_id, error)