# -*- coding: utf-8 -*-
# Copyright 2017 Google Inc. All Rights Reserved.
#
# 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.
"""JSON gsutil Cloud API implementation for Google Cloud Storage."""

from __future__ import absolute_import

import json
import logging
import traceback

from apitools.base.py import exceptions as apitools_exceptions
from boto import config
from gslib.cloud_api import AccessDeniedException
from gslib.cloud_api import BadRequestException
from gslib.cloud_api import NotFoundException
from gslib.cloud_api import PreconditionException
from gslib.cloud_api import ServiceException
from gslib.gcs_json_credentials import SetUpJsonCredentialsAndCache
from gslib.no_op_credentials import NoOpCredentials
from gslib.third_party.pubsub_apitools import pubsub_v1_client as apitools_client
from gslib.third_party.pubsub_apitools import pubsub_v1_messages as apitools_messages
from gslib.utils import system_util
from gslib.utils.boto_util import GetCertsFile
from gslib.utils.boto_util import GetMaxRetryDelay
from gslib.utils.boto_util import GetNewHttp
from gslib.utils.boto_util import GetNumRetries


TRANSLATABLE_APITOOLS_EXCEPTIONS = (apitools_exceptions.HttpError)


if system_util.InvokedViaCloudSdk():
  _INSUFFICIENT_OAUTH2_SCOPE_MESSAGE = (
      'Insufficient OAuth2 scope to perform this operation. '
      'Please re-run `gcloud auth login`')
else:
  _INSUFFICIENT_OAUTH2_SCOPE_MESSAGE = (
      'Insufficient OAuth2 scope to perform this operation. '
      'Please re-run `gsutil config`')


class PubsubApi(object):
  """Wraps calls to the Cloud Pub/Sub v1 interface via apitools."""

  def __init__(self, logger=None, credentials=None, debug=0):
    """Performs necessary setup for interacting with Google Cloud Pub/Sub.

    Args:
      logger: logging.logger for outputting log messages.
      credentials: Credentials to be used for interacting with Google Cloud
          Pub/Sub
      debug: Debug level for the API implementation (0..3).
    """
    super(PubsubApi, self).__init__()
    self.logger = logger

    self.certs_file = GetCertsFile()
    self.http = GetNewHttp()
    self.http_base = 'https://'
    self.host_base = config.get('Credentials', 'gs_pubsub_host',
                                'pubsub.googleapis.com')
    gs_pubsub_port = config.get('Credentials', 'gs_pubsub_port', None)
    self.host_port = (':' + gs_pubsub_port) if gs_pubsub_port else ''
    self.url_base = (self.http_base + self.host_base + self.host_port)

    SetUpJsonCredentialsAndCache(self, logger, credentials=credentials)

    log_request = (debug >= 3)
    log_response = (debug >= 3)

    self.api_client = apitools_client.PubsubV1(
        url=self.url_base, http=self.http, log_request=log_request,
        log_response=log_response, credentials=self.credentials)

    self.num_retries = GetNumRetries()
    self.api_client.num_retries = self.num_retries

    self.max_retry_wait = GetMaxRetryDelay()
    self.api_client.max_retry_wait = self.max_retry_wait

    if isinstance(self.credentials, NoOpCredentials):
      # This API key is not secret and is used to identify gsutil during
      # anonymous requests.
      self.api_client.AddGlobalParam('key',
                                     u'AIzaSyDnacJHrKma0048b13sh8cgxNUwulubmJM')

  def GetTopic(self, topic_name):
    request = apitools_messages.PubsubProjectsTopicsGetRequest(topic=topic_name)
    try:
      return self.api_client.projects_topics.Get(request)
    except TRANSLATABLE_APITOOLS_EXCEPTIONS as e:
      self._TranslateExceptionAndRaise(e, topic_name=topic_name)

  def CreateTopic(self, topic_name):
    topic = apitools_messages.Topic(name=topic_name)
    try:
      return self.api_client.projects_topics.Create(topic)
    except TRANSLATABLE_APITOOLS_EXCEPTIONS as e:
      self._TranslateExceptionAndRaise(e, topic_name=topic_name)

  def DeleteTopic(self, topic_name):
    """Only used in system tests."""
    request = apitools_messages.PubsubProjectsTopicsDeleteRequest(
        topic=topic_name)
    try:
      return self.api_client.projects_topics.Delete(request)
    except TRANSLATABLE_APITOOLS_EXCEPTIONS as e:
      self._TranslateExceptionAndRaise(e, topic_name=topic_name)

  def GetTopicIamPolicy(self, topic_name):
    request = apitools_messages.PubsubProjectsTopicsGetIamPolicyRequest(
        resource=topic_name)
    try:
      return self.api_client.projects_topics.GetIamPolicy(request)
    except TRANSLATABLE_APITOOLS_EXCEPTIONS as e:
      self._TranslateExceptionAndRaise(e, topic_name=topic_name)

  def SetTopicIamPolicy(self, topic_name, policy):
    policy_request = apitools_messages.SetIamPolicyRequest(
        policy=policy)
    request = apitools_messages.PubsubProjectsTopicsSetIamPolicyRequest(
        resource=topic_name, setIamPolicyRequest=policy_request)
    try:
      return self.api_client.projects_topics.SetIamPolicy(request)
    except TRANSLATABLE_APITOOLS_EXCEPTIONS as e:
      self._TranslateExceptionAndRaise(e, topic_name=topic_name)

  def _TranslateExceptionAndRaise(self, e, topic_name=None):
    """Translates an HTTP exception and raises the translated or original value.

    Args:
      e: Any Exception.
      topic_name: Optional topic name in request that caused the exception.

    Raises:
      Translated CloudApi exception, or the original exception if it was not
      translatable.
    """
    if self.logger.isEnabledFor(logging.DEBUG):
      self.logger.debug(
          'TranslateExceptionAndRaise: %s', traceback.format_exc())
    translated_exception = self._TranslateApitoolsException(
        e, topic_name=topic_name)
    if translated_exception:
      raise translated_exception
    else:
      raise

  def _GetMessageFromHttpError(self, http_error):
    if isinstance(http_error, apitools_exceptions.HttpError):
      if getattr(http_error, 'content', None):
        try:
          json_obj = json.loads(http_error.content)
          if 'error' in json_obj and 'message' in json_obj['error']:
            return json_obj['error']['message']
        except Exception:  # pylint: disable=broad-except
          # If we couldn't decode anything, just leave the message as None.
          pass

  def _GetAcceptableScopesFromHttpError(self, http_error):
    try:
      www_authenticate = http_error.response['www-authenticate']
      # In the event of a scope error, the www-authenticate field of the HTTP
      # response should contain text of the form
      #
      # 'Bearer realm="https://oauth2.googleapis.com/",
      # error=insufficient_scope,
      # scope="${space separated list of acceptable scopes}"'
      #
      # Here we use a quick string search to find the scope list, just looking
      # for a substring with the form 'scope="${scopes}"'.
      scope_idx = www_authenticate.find('scope="')
      if scope_idx >= 0:
        scopes = www_authenticate[scope_idx:].split('"')[1]
        return 'Acceptable scopes: %s' % scopes
    except Exception:  # pylint: disable=broad-except
      # Return None if we have any trouble parsing out the acceptable scopes.
      pass

  def _TranslateApitoolsException(self, e, topic_name=None):
    """Translates apitools exceptions into their gsutil equivalents.

    Args:
      e: Any exception in TRANSLATABLE_APITOOLS_EXCEPTIONS.
      topic_name: Optional topic name in request that caused the exception.

    Returns:
      ServiceException for translatable exceptions, None
      otherwise.
    """

    if isinstance(e, apitools_exceptions.HttpError):
      message = self._GetMessageFromHttpError(e)
      if e.status_code == 400:
        # It is possible that the Project ID is incorrect.  Unfortunately the
        # JSON API does not give us much information about what part of the
        # request was bad.
        return BadRequestException(message or 'Bad Request',
                                   status=e.status_code)
      elif e.status_code == 401:
        if 'Login Required' in str(e):
          return AccessDeniedException(
              message or 'Access denied: login required.',
              status=e.status_code)
        elif 'insufficient_scope' in str(e):
          # If the service includes insufficient scope error detail in the
          # response body, this check can be removed.
          return AccessDeniedException(
              _INSUFFICIENT_OAUTH2_SCOPE_MESSAGE, status=e.status_code,
              body=self._GetAcceptableScopesFromHttpError(e))
      elif e.status_code == 403:
        if 'The account for the specified project has been disabled' in str(e):
          return AccessDeniedException(message or 'Account disabled.',
                                       status=e.status_code)
        elif 'Daily Limit for Unauthenticated Use Exceeded' in str(e):
          return AccessDeniedException(
              message or 'Access denied: quota exceeded. '
              'Is your project ID valid?',
              status=e.status_code)
        elif 'User Rate Limit Exceeded' in str(e):
          return AccessDeniedException('Rate limit exceeded. Please retry this '
                                       'request later.', status=e.status_code)
        elif 'Access Not Configured' in str(e):
          return AccessDeniedException(
              'Access Not Configured. Please go to the Google Cloud Platform '
              'Console (https://cloud.google.com/console#/project) for your '
              'project, select APIs and Auth and enable the '
              'Google Cloud Pub/Sub API.',
              status=e.status_code)
        elif 'insufficient_scope' in str(e):
          # If the service includes insufficient scope error detail in the
          # response body, this check can be removed.
          return AccessDeniedException(
              _INSUFFICIENT_OAUTH2_SCOPE_MESSAGE, status=e.status_code,
              body=self._GetAcceptableScopesFromHttpError(e))
        else:
          return AccessDeniedException(message or e.message,
                                       status=e.status_code)
      elif e.status_code == 404:
        return NotFoundException(e.message, status=e.status_code)

      elif e.status_code == 409 and topic_name:
        return ServiceException(
            'The topic %s already exists.' % topic_name, status=e.status_code)
      elif e.status_code == 412:
        return PreconditionException(message, status=e.status_code)
      return ServiceException(message, status=e.status_code)
