# -*- coding: utf-8 -*- #
# Copyright 2020 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.
"""Local gcloud cache for Cloud Workflows."""


import os

from googlecloudsdk.core import config
from googlecloudsdk.core import exceptions
from googlecloudsdk.core import log
from googlecloudsdk.core import resources
from googlecloudsdk.core.util import files

EXECUTION_COLLECTION = (
    'workflowexecutions.projects.locations.workflows.executions')
WORKFLOW_CACHE_FILE = '.workflows-cached-execution-id.json'


def get_cached_execution_id():
  """Gets the cached execution object.

  Returns:
    execution: the execution resource name
  """
  cache_path = _get_cache_path()

  if not os.path.isfile(cache_path):
    raise exceptions.Error(_NO_CACHE_MESSAGE)
  try:
    cached_execution = files.ReadFileContents(cache_path)
    execution_ref = resources.REGISTRY.Parse(
        cached_execution, collection=EXECUTION_COLLECTION)
    log.status.Print('Using cached execution name: {}'.format(
        execution_ref.RelativeName()))
    return execution_ref
  except Exception:
    raise exceptions.Error(_NO_CACHE_MESSAGE)


def cache_execution_id(execution_name):
  """Saves the execution resource to a named cache file.

  Args:
    execution_name: the execution resource name
  """
  try:
    files.WriteFileContents(_get_cache_path(), execution_name)
  except files.Error:
    # Not outputting any error messages to the user as it might be
    # unclear what it means to not be able to cache the execution
    # and what the cache is used for when executing their workflow.
    pass


def delete_execution_cache():
  """Clears the execution cache.

  Returns:
    bool: True if the file was found and deleted, false otherwise.
  """
  try:
    os.remove(_get_cache_path())
  except OSError:
    return False
  return True


def _get_cache_path():
  config_dir = config.Paths().global_config_dir
  return os.path.join(config_dir, WORKFLOW_CACHE_FILE)

_NO_CACHE_MESSAGE = (
    '[NOT FOUND] There are no cached executions available. '
    'Use gcloud list and describe commands or '
    'https://console.developers.google.com/ to check resource state.')