# -*- coding: utf-8 -*- #
# Copyright 2021 Google LLC. 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.

"""A library that is used to support Functions commands."""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import argparse
import functools
import json
import re

from apitools.base.py import base_api
from apitools.base.py import exceptions as apitools_exceptions
from apitools.base.py import list_pager
from googlecloudsdk.api_lib.functions.v1 import exceptions
from googlecloudsdk.api_lib.functions.v1 import operations
from googlecloudsdk.api_lib.functions.v2 import util as v2_util
from googlecloudsdk.api_lib.storage import storage_api as gcs_api
from googlecloudsdk.api_lib.storage import storage_util
from googlecloudsdk.api_lib.util import apis
from googlecloudsdk.api_lib.util import exceptions as exceptions_util
from googlecloudsdk.calliope import arg_parsers
from googlecloudsdk.calliope import base as calliope_base
from googlecloudsdk.calliope import exceptions as base_exceptions
from googlecloudsdk.command_lib.iam import iam_util
from googlecloudsdk.core import exceptions as core_exceptions
from googlecloudsdk.core import log
from googlecloudsdk.core import properties
from googlecloudsdk.core import resources
from googlecloudsdk.core.util import encoding
from googlecloudsdk.generated_clients.apis.cloudfunctions.v1 import cloudfunctions_v1_messages
import six.moves.http_client

_DEPLOY_WAIT_NOTICE = 'Deploying function (may take a while - up to 2 minutes)'

_FUNCTION_NAME_RE = re.compile(
    r'^(.*/)?[A-Za-z](?:[-_A-Za-z0-9]{0,61}[A-Za-z0-9])?$'
)
_FUNCTION_NAME_ERROR = (
    'Function name must contain only Latin letters, digits and a '
    'hyphen (-). It must start with letter, must not end with a hyphen, '
    'and must be at most 63 characters long.'
)

_TOPIC_NAME_RE = re.compile(r'^[a-zA-Z][\-\._~%\+a-zA-Z0-9]{2,254}$')
_TOPIC_NAME_ERROR = (
    'Topic must contain only Latin letters (lower- or upper-case), digits and '
    'the characters - + . _ ~ %. It must start with a letter and be from 3 to '
    '255 characters long.'
)

_BUCKET_RESOURCE_URI_RE = re.compile(r'^projects/_/buckets/.{3,222}$')

_API_NAME = 'cloudfunctions'
_API_VERSION = 'v1'

_V1_AUTOPUSH_REGIONS = ['asia-east1', 'europe-west6']
_V1_STAGING_REGIONS = [
    'southamerica-east1',
    'us-central1',
    'us-east1',
    'us-east4',
    'us-west1',
]

_DOCKER_REGISTRY_GCR = (
    cloudfunctions_v1_messages.CloudFunction.DockerRegistryValueValuesEnum.CONTAINER_REGISTRY
)


def _GetApiVersion(track=calliope_base.ReleaseTrack.GA):  # pylint: disable=unused-argument
  """Returns the current cloudfunctions Api Version configured in the sdk.

  NOTE: Currently the value is hard-coded to v1, and surface/functions/deploy.py
  assumes this to parse OperationMetadataV1 from the response.
  Please change the parsing if more versions should be supported.

  Args:
    track: The gcloud track.

  Returns:
    The current cloudfunctions Api Version.
  """
  return _API_VERSION


def GetApiClientInstance(track=calliope_base.ReleaseTrack.GA):
  # type: (calliope_base.ReleaseTrack) -> base_api.BaseApiClient
  """Returns the GCFv1 client instance."""
  endpoint_override = v2_util.GetApiEndpointOverride()

  if (
      not endpoint_override
      or 'autopush-cloudfunctions' not in endpoint_override
  ):
    return apis.GetClientInstance(_API_NAME, _GetApiVersion(track))

  # GCFv1 autopush is actually behind the staging API endpoint so temporarily
  # override the endpoint so that a staging API client is returned.
  # The GCFv1 mixer routes to the appropriate autopush or staging manager job
  # based on region.
  # GFEs route autopush-cloudfunctions.sandbox.googleapis.com to the GCFv2
  # frontend.
  log.info(
      'Temporarily overriding cloudfunctions endpoint to'
      ' staging-cloudfunctions.sandbox.googleapis.com so that GCFv1 autopush'
      ' resources can be accessed.'
  )
  properties.VALUES.api_endpoint_overrides.Property('cloudfunctions').Set(
      'https://staging-cloudfunctions.sandbox.googleapis.com/'
  )
  client = apis.GetClientInstance(_API_NAME, _GetApiVersion(track))
  # Reset override in case a GCFv2 autopush client is created later.
  properties.VALUES.api_endpoint_overrides.Property('cloudfunctions').Set(
      'https://autopush-cloudfunctions.sandbox.googleapis.com/'
  )
  return client


def GetResourceManagerApiClientInstance():
  return apis.GetClientInstance('cloudresourcemanager', 'v1')


def GetApiMessagesModule(track=calliope_base.ReleaseTrack.GA):
  return apis.GetMessagesModule(_API_NAME, _GetApiVersion(track))


def GetFunctionRef(name):
  return resources.REGISTRY.Parse(
      name,
      params={
          'projectsId': properties.VALUES.core.project.Get(required=True),
          'locationsId': properties.VALUES.functions.region.Get(),
      },
      collection='cloudfunctions.projects.locations.functions',
  )


_ID_CHAR = '[a-zA-Z0-9_]'
_P_CHAR = "[][~@#$%&.,?:;+*='()-]"
# capture: '{' ID_CHAR+ ('=' '*''*'?)? '}'
# Named wildcards may be written in curly brackets (e.g. {variable}). The
# value that matched this parameter will be included  in the event
# parameters.
_CAPTURE = r'(\{' + _ID_CHAR + r'(=\*\*?)?})'
# segment: (ID_CHAR | P_CHAR)+
_SEGMENT = '((' + _ID_CHAR + '|' + _P_CHAR + ')+)'
# part: '/' segment | capture
_PART = '(/(' + _SEGMENT + '|' + _CAPTURE + '))'
# path: part+ (but first / is optional)
_PATH = '(/?(' + _SEGMENT + '|' + _CAPTURE + ')' + _PART + '*)'

_PATH_RE_ERROR = (
    'Path must be a slash-separated list of segments and '
    'captures. For example, [users/{userId}/profilePic].'
)


def GetHttpErrorMessage(error):
  # type: (apitools_exceptions.HttpError) -> str
  """Returns a human readable string representation from the http response.

  Args:
    error: HttpException representing the error response.

  Returns:
    A human readable string representation of the error.
  """
  status = error.response.status
  code = error.response.reason
  message = ''
  try:
    data = json.loads(error.content)
    if 'error' in data:
      error_info = data['error']
      if 'message' in error_info:
        message = error_info['message']
      violations = _GetViolationsFromError(error)
      if violations:
        message += '\nProblems:\n' + violations
      if status == 403:
        permission_issues = _GetPermissionErrorDetails(error_info)
        if permission_issues:
          message += '\nPermission Details:\n' + permission_issues
  except (ValueError, TypeError):
    message = error.content
  return 'ResponseError: status=[{0}], code=[{1}], message=[{2}]'.format(
      status, code, encoding.Decode(message)
  )


def _ValidateArgumentByRegexOrRaise(argument, regex, error_message):
  if isinstance(regex, str):
    match = re.match(regex, argument)
  else:
    match = regex.match(argument)
  if not match:
    raise arg_parsers.ArgumentTypeError(
        "Invalid value '{0}': {1}".format(argument, error_message)
    )
  return argument


def ValidateFunctionNameOrRaise(name):
  """Checks if a function name provided by user is valid.

  Args:
    name: Function name provided by user.

  Returns:
    Function name.
  Raises:
    ArgumentTypeError: If the name provided by user is not valid.
  """
  return _ValidateArgumentByRegexOrRaise(
      name, _FUNCTION_NAME_RE, _FUNCTION_NAME_ERROR
  )


def ValidateAndStandarizeBucketUriOrRaise(bucket):
  """Checks if a bucket uri provided by user is valid.

  If the Bucket uri is valid, converts it to a standard form.

  Args:
    bucket: Bucket uri provided by user.

  Returns:
    Sanitized bucket uri.
  Raises:
    ArgumentTypeError: If the name provided by user is not valid.
  """
  if _BUCKET_RESOURCE_URI_RE.match(bucket):
    bucket_ref = storage_util.BucketReference.FromUrl(bucket)
  else:
    try:
      bucket_ref = storage_util.BucketReference.FromArgument(
          bucket, require_prefix=False
      )
    except argparse.ArgumentTypeError as e:
      raise arg_parsers.ArgumentTypeError(
          "Invalid value '{}': {}".format(bucket, e)
      )

  # strip any extrenuous '/' and append single '/'
  bucket = bucket_ref.ToUrl().rstrip('/') + '/'
  return bucket


def ValidatePubsubTopicNameOrRaise(topic):
  """Checks if a Pub/Sub topic name provided by user is valid.

  Args:
    topic: Pub/Sub topic name provided by user.

  Returns:
    Topic name.
  Raises:
    ArgumentTypeError: If the name provided by user is not valid.
  """
  topic = _ValidateArgumentByRegexOrRaise(
      topic, _TOPIC_NAME_RE, _TOPIC_NAME_ERROR
  )
  return topic


def ValidateRuntimeOrRaise(client, runtime, region):
  """Checks if runtime is supported.

  Does not raise if the runtime list cannot be retrieved

  Args:
    client: v2 GCF client that supports ListRuntimes()
    runtime: str, the runtime.
    region: str, region code.

  Returns:
    warning: None|str, the warning if deprecated
  """
  response = client.ListRuntimes(
      region,
      query_filter='name={} AND environment={}'.format(
          runtime, client.messages.Runtime.EnvironmentValueValuesEnum.GEN_1
      ),
  )

  if not response or response.runtimes is None:
    return None

  if len(response.runtimes) < 1:
    raise exceptions.FunctionsError(
        'argument `--runtime`: {} is not a supported runtime on'
        ' GCF 1st gen. Use `gcloud functions runtimes list` to get a list'
        ' of available runtimes'.format(runtime)
    )
  runtime_info = response.runtimes[0]

  return (
      runtime_info.warnings[0]
      if runtime_info and runtime_info.warnings
      else None
  )


def ValidatePathOrRaise(path):
  """Check if path provided by user is valid.

  Args:
    path: A string: resource path

  Returns:
    The argument provided, if found valid.
  Raises:
    ArgumentTypeError: If the user provided a path which is not valid
  """
  path = _ValidateArgumentByRegexOrRaise(path, _PATH, _PATH_RE_ERROR)
  return path


def _GetViolationsFromError(error):
  """Looks for violations descriptions in error message.

  Args:
    error: HttpError containing error information.

  Returns:
    String of newline-separated violations descriptions.
  """
  error_payload = exceptions_util.HttpErrorPayload(error)
  errors = []
  errors.extend(
      ['{}:\n{}'.format(k, v) for k, v in error_payload.violations.items()]
  )
  errors.extend(
      [
          '{}:\n{}'.format(k, v)
          for k, v in error_payload.field_violations.items()
      ]
  )
  if errors:
    return '\n'.join(errors) + '\n'
  return ''


def _GetPermissionErrorDetails(error_info):
  """Looks for permission denied details in error message.

  Args:
    error_info: json containing error information.

  Returns:
    string containing details on permission issue and suggestions to correct.
  """
  try:
    if 'details' in error_info:
      details = error_info['details'][0]
      if 'detail' in details:
        return details['detail']

  except (ValueError, TypeError):
    pass
  return None


def CatchHTTPErrorRaiseHTTPException(func):
  """Decorator that catches HttpError and raises corresponding exception."""

  @functools.wraps(func)
  def CatchHTTPErrorRaiseHTTPExceptionFn(*args, **kwargs):
    try:
      return func(*args, **kwargs)
    except apitools_exceptions.HttpError as error:
      core_exceptions.reraise(
          base_exceptions.HttpException(GetHttpErrorMessage(error))
      )

  return CatchHTTPErrorRaiseHTTPExceptionFn


@CatchHTTPErrorRaiseHTTPException
def GetFunction(function_name):
  """Returns the Get method on function response, None if it doesn't exist."""
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  try:
    # We got response for a get request so a function exists.
    return client.projects_locations_functions.Get(
        messages.CloudfunctionsProjectsLocationsFunctionsGetRequest(
            name=function_name
        )
    )
  except apitools_exceptions.HttpError as error:
    if error.status_code == six.moves.http_client.NOT_FOUND:
      # The function has not been found.
      return None
    raise


@CatchHTTPErrorRaiseHTTPException
def ListRegions():
  """Returns the list of regions where GCF 1st Gen is supported."""
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  results = list_pager.YieldFromList(
      service=client.projects_locations,
      request=messages.CloudfunctionsProjectsLocationsListRequest(
          name='projects/' + properties.VALUES.core.project.Get(required=True)
      ),
      field='locations',
      batch_size_attribute='pageSize',
  )

  # We filter out v1 autopush and staging regions because they lie behind the
  # same staging API endpoint but they're not distinguishable by environment.
  if v2_util.GetCloudFunctionsApiEnv() is v2_util.ApiEnv.AUTOPUSH:
    log.info(
        'ListRegions: Autopush env detected. Filtering for v1 autopush regions.'
    )
    return [r for r in results if r.locationId in _V1_AUTOPUSH_REGIONS]
  elif v2_util.GetCloudFunctionsApiEnv() is v2_util.ApiEnv.STAGING:
    log.info(
        'ListRegions: Staging env detected. Filtering for v1 staging regions.'
    )
    return [r for r in results if r.locationId in _V1_STAGING_REGIONS]
  else:
    return results


# TODO(b/130604453): Remove try_set_invoker option
@CatchHTTPErrorRaiseHTTPException
def WaitForFunctionUpdateOperation(
    op, try_set_invoker=None, on_every_poll=None
):
  """Wait for the specied function update to complete.

  Args:
    op: Cloud operation to wait on.
    try_set_invoker: function to try setting invoker, see above TODO.
    on_every_poll: list of functions to execute every time we poll. Functions
      should take in Operation as an argument.
  """
  client = GetApiClientInstance()
  operations.Wait(
      op,
      client.MESSAGES_MODULE,
      client,
      _DEPLOY_WAIT_NOTICE,
      try_set_invoker=try_set_invoker,
      on_every_poll=on_every_poll,
  )


@CatchHTTPErrorRaiseHTTPException
def PatchFunction(function, fields_to_patch):
  """Call the api to patch a function based on updated fields.

  Args:
    function: the function to patch
    fields_to_patch: the fields to patch on the function

  Returns:
    The cloud operation for the Patch.
  """
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  fields_to_patch_str = ','.join(sorted(fields_to_patch))
  return client.projects_locations_functions.Patch(
      messages.CloudfunctionsProjectsLocationsFunctionsPatchRequest(
          cloudFunction=function,
          name=function.name,
          updateMask=fields_to_patch_str,
      )
  )


@CatchHTTPErrorRaiseHTTPException
def CreateFunction(function, location):
  """Call the api to create a function.

  Args:
    function: the function to create
    location: location for function

  Returns:
    Cloud operation for the create.
  """
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  return client.projects_locations_functions.Create(
      messages.CloudfunctionsProjectsLocationsFunctionsCreateRequest(
          location=location, cloudFunction=function
      )
  )


@CatchHTTPErrorRaiseHTTPException
def GetFunctionIamPolicy(function_resource_name):
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  return client.projects_locations_functions.GetIamPolicy(
      messages.CloudfunctionsProjectsLocationsFunctionsGetIamPolicyRequest(
          resource=function_resource_name
      )
  )


@CatchHTTPErrorRaiseHTTPException
def AddFunctionIamPolicyBinding(
    function_resource_name,
    member='allUsers',
    role='roles/cloudfunctions.invoker',
):
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  policy = GetFunctionIamPolicy(function_resource_name)
  iam_util.AddBindingToIamPolicy(messages.Binding, policy, member, role)
  return client.projects_locations_functions.SetIamPolicy(
      messages.CloudfunctionsProjectsLocationsFunctionsSetIamPolicyRequest(
          resource=function_resource_name,
          setIamPolicyRequest=messages.SetIamPolicyRequest(policy=policy),
      )
  )


@CatchHTTPErrorRaiseHTTPException
def RemoveFunctionIamPolicyBindingIfFound(
    function_resource_name,
    member='allUsers',
    role='roles/cloudfunctions.invoker',
):
  """Removes the specified policy binding if it is found."""
  client = GetApiClientInstance()
  messages = client.MESSAGES_MODULE
  policy = GetFunctionIamPolicy(function_resource_name)
  if not iam_util.BindingInPolicy(policy, member, role):
    return policy
  iam_util.RemoveBindingFromIamPolicy(policy, member, role)
  return client.projects_locations_functions.SetIamPolicy(
      messages.CloudfunctionsProjectsLocationsFunctionsSetIamPolicyRequest(
          resource=function_resource_name,
          setIamPolicyRequest=messages.SetIamPolicyRequest(policy=policy),
      )
  )


@CatchHTTPErrorRaiseHTTPException
def CanAddFunctionIamPolicyBinding(project):
  """Returns True iff the caller can add policy bindings for project."""
  client = GetResourceManagerApiClientInstance()
  messages = client.MESSAGES_MODULE
  needed_permissions = [
      'resourcemanager.projects.getIamPolicy',
      'resourcemanager.projects.setIamPolicy',
  ]
  iam_request = messages.CloudresourcemanagerProjectsTestIamPermissionsRequest(
      resource=project,
      testIamPermissionsRequest=messages.TestIamPermissionsRequest(
          permissions=needed_permissions
      ),
  )
  iam_response = client.projects.TestIamPermissions(iam_request)
  can_add = True
  for needed_permission in needed_permissions:
    if needed_permission not in iam_response.permissions:
      can_add = False
  return can_add


def ValidateSecureImageRepositoryOrWarn(region_name, project_id):
  """Validates image repository. Yields security and deprecation warnings.

  Args:
    region_name: String name of the region to which the function is deployed.
    project_id: String ID of the Cloud project.
  """
  _AddGcrDeprecationWarning()
  gcr_bucket_url = GetStorageBucketForGcrRepository(region_name, project_id)
  try:
    gcr_host_policy = gcs_api.StorageClient().GetIamPolicy(
        storage_util.BucketReference.FromUrl(gcr_bucket_url)
    )
    if gcr_host_policy and iam_util.BindingInPolicy(
        gcr_host_policy, 'allUsers', 'roles/storage.objectViewer'
    ):
      log.warning(
          "The Container Registry repository that stores this function's "
          'image is public. This could pose the risk of disclosing '
          'sensitive data. To mitigate this, either use Artifact Registry '
          "('--docker-registry=artifact-registry' flag) or change this "
          'setting in Google Container Registry.\n'
      )
  except apitools_exceptions.HttpError:
    log.warning(
        'Secuirty check for Container Registry repository that stores this '
        "function's image has not succeeded. To mitigate risks of disclosing "
        'sensitive data, it is recommended to keep your repositories '
        'private. This setting can be verified in Google Container Registry.\n'
    )


def GetStorageBucketForGcrRepository(region_name, project_id):
  """Retrieves the GCS bucket that backs the GCR repository in specified region.

  Args:
    region_name: String name of the region to which the function is deployed.
    project_id: String ID of the Cloud project.

  Returns:
    String representing the URL of the GCS bucket that backs the GCR repo.
  """
  return 'gs://{multiregion}.artifacts.{project_id}.appspot.com'.format(
      multiregion=_GetGcrMultiregion(region_name),
      project_id=project_id,
  )


def _GetGcrMultiregion(region_name):
  """Returns String name of the GCR multiregion for the given region."""
  # Corresponds to the mapping outlined in go/gcf-regions-to-gcr-domains-map.
  if region_name.startswith('europe'):
    return 'eu'
  elif region_name.startswith('asia') or region_name.startswith('australia'):
    return 'asia'
  else:
    return 'us'


def IsGcrRepository(function):
  return function.dockerRegistry == _DOCKER_REGISTRY_GCR


def _AddGcrDeprecationWarning():
  """Adds warning on deprecation of Container Registry."""
  log.warning(
      'Due to the general transition from Container Registry to Artifact'
      ' Registry, `--docker-registry=container-registry` will no longer be'
      ' available as an option when deploying a function.'
      ' All container image storage and management will automatically'
      ' transition to Artifact Registry.'
      ' For more information, please visit:'
      ' https://cloud.google.com/artifact-registry/docs/transition/transition-from-gcr'
  )
