# 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.

"""Library for obtaining API clients and messages.

This should only be called by api_lib.util.apis, core.resources, gcloud meta
commands, and module tests.
"""

from __future__ import absolute_import
from __future__ import unicode_literals
from googlecloudsdk.api_lib.util import apis_util
from googlecloudsdk.api_lib.util import resource as resource_util
from googlecloudsdk.core import properties
from googlecloudsdk.third_party.apis import apis_map

import six


def _GetApiNameAndAlias(api_name):
  # pylint:disable=protected-access
  return (apis_util._API_NAME_ALIASES.get(api_name, api_name), api_name)


def _GetDefaultVersion(api_name):
  api_name, _ = _GetApiNameAndAlias(api_name)
  api_vers = apis_map.MAP.get(api_name, {})
  for ver, api_def in six.iteritems(api_vers):
    if api_def.default_version:
      return ver
  return None


def _GetApiNames():
  """Returns list of avaibleable apis, ignoring the version."""
  return sorted(apis_map.MAP.keys())


def _GetVersions(api_name):
  """Return available versions for given api.

  Args:
    api_name: str, The API name (or the command surface name, if different).

  Raises:
    apis_util.UnknownAPIError: If api_name does not exist in the APIs map.

  Returns:
    list, of version names.
  """
  api_name, _ = _GetApiNameAndAlias(api_name)
  version_map = apis_map.MAP.get(api_name, None)
  if version_map is None:
    raise apis_util.UnknownAPIError(api_name)
  return list(version_map.keys())


def _GetApiDef(api_name, api_version):
  """Returns the APIDef for the specified API and version.

  Args:
    api_name: str, The API name (or the command surface name, if different).
    api_version: str, The version of the API.

  Raises:
    apis_util.UnknownAPIError: If api_name does not exist in the APIs map.
    apis_util.UnknownVersionError: If api_version does not exist for given
      api_name in the APIs map.

  Returns:
    APIDef, The APIDef for the specified API and version.
  """
  api_name, api_name_alias = _GetApiNameAndAlias(api_name)
  if api_name not in apis_map.MAP:
    raise apis_util.UnknownAPIError(api_name)

  version_overrides = properties.VALUES.api_client_overrides.AllValues()
  version_override = version_overrides.get(api_name_alias, None)
  api_version = version_override or api_version

  api_versions = apis_map.MAP[api_name]
  if api_version is None or api_version not in api_versions:
    raise apis_util.UnknownVersionError(api_name, api_version)
  else:
    api_def = api_versions[api_version]

  return api_def


def _GetClientClass(api_name, api_version):
  """Returns the client class for the API specified in the args.

  Args:
    api_name: str, The API name (or the command surface name, if different).
    api_version: str, The version of the API.

  Returns:
    base_api.BaseApiClient, Client class for the specified API.
  """
  api_def = _GetApiDef(api_name, api_version)
  return _GetClientClassFromDef(api_def)


def _GetClientClassFromDef(api_def):
  """Returns the client class for the API definition specified in the args.

  Args:
    api_def: apis_map.APIDef, The definition of the API.

  Returns:
    base_api.BaseApiClient, Client class for the specified API.
  """
  module_path, client_class_name = api_def.client_full_classpath.rsplit('.', 1)
  module_obj = __import__(module_path, fromlist=[client_class_name])
  return getattr(module_obj, client_class_name)


def _GetClientInstance(api_name, api_version, no_http=False,
                       check_response_func=None, enable_resource_quota=True):
  """Returns an instance of the API client specified in the args.

  Args:
    api_name: str, The API name (or the command surface name, if different).
    api_version: str, The version of the API.
    no_http: bool, True to not create an http object for this client.
    check_response_func: error handling callback to give to apitools.
    enable_resource_quota: bool, By default, we are going to tell APIs to use
      the quota of the project being operated on. For some APIs we want to use
      gcloud's quota, so you can explicitly disable that behavior by passing
      False here.

  Returns:
    base_api.BaseApiClient, An instance of the specified API client.
  """
  # TODO(b/77278279): Decide whether we should always set this or not.
  encoding = None if six.PY2 else 'utf8'

  # pylint: disable=g-import-not-at-top
  if no_http:
    http_client = None
  else:
    # Import http only when needed, as it depends on credential infrastructure
    # which is not needed in all cases.
    from googlecloudsdk.core.credentials import http
    http_client = http.Http(enable_resource_quota=enable_resource_quota,
                            response_encoding=encoding)

  client_class = _GetClientClass(api_name, api_version)
  client_instance = client_class(
      url=_GetEffectiveApiEndpoint(api_name, api_version, client_class),
      get_credentials=False,
      http=http_client)
  if check_response_func is not None:
    client_instance.check_response_func = check_response_func
  api_key = properties.VALUES.core.api_key.Get()
  if api_key:
    client_instance.AddGlobalParam('key', api_key)
    header = 'X-Google-Project-Override'
    client_instance.additional_http_headers[header] = 'apikey'
  return client_instance


def _GetEffectiveApiEndpoint(api_name, api_version, client_class=None):
  """Returns effective endpoint for given api."""
  endpoint_overrides = properties.VALUES.api_endpoint_overrides.AllValues()
  endpoint_override = endpoint_overrides.get(api_name, '')
  if endpoint_override:
    return endpoint_override
  client_class = client_class or _GetClientClass(api_name, api_version)
  return client_class.BASE_URL


def _GetDefaultEndpointUrl(url):
  """Looks up default endpoint based on overridden endpoint value."""
  endpoint_overrides = properties.VALUES.api_endpoint_overrides.AllValues()
  for api_name, overridden_url in six.iteritems(endpoint_overrides):
    if url.startswith(overridden_url):
      api_version = _GetDefaultVersion(api_name)
      return (_GetClientClass(api_name, api_version).BASE_URL +
              url[len(overridden_url):])
  return url


def _GetMessagesModule(api_name, api_version):
  """Returns the messages module for the API specified in the args.

  Args:
    api_name: str, The API name (or the command surface name, if different).
    api_version: str, The version of the API.

  Returns:
    Module containing the definitions of messages for the specified API.
  """
  api_def = _GetApiDef(api_name, api_version)
  # fromlist below must not be empty, see:
  # http://stackoverflow.com/questions/2724260/why-does-pythons-import-require-fromlist.
  return __import__(api_def.messages_full_modulepath, fromlist=['something'])


def _GetResourceModule(api_name, api_version):
  """Imports and returns given api resources module."""

  api_def = _GetApiDef(api_name, api_version)
  # fromlist below must not be empty, see:
  # http://stackoverflow.com/questions/2724260/why-does-pythons-import-require-fromlist.
  return __import__(api_def.class_path + '.' + 'resources',
                    fromlist=['something'])


def _GetApiCollections(api_name, api_version):
  """Yields all collections for for given api."""

  try:
    resources_module = _GetResourceModule(api_name, api_version)
  except ImportError:
    pass
  else:
    for collection in resources_module.Collections:
      yield resource_util.CollectionInfo(
          api_name,
          api_version,
          resources_module.BASE_URL,
          resources_module.DOCS_URL,
          collection.collection_name,
          collection.path,
          collection.flat_paths,
          collection.params,
          collection.enable_uri_parsing,
      )
