# Copyright 2021 Google LLC
#
# 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.

""" Compilations of all disks tasks related. """

from typing import Dict
import logging
from threading import Thread

import googleapiclient.errors

from gce_rescue.tasks.keeper import wait_for_operation
from gce_rescue.tasks.backup import create_snapshot
from gce_rescue.utils import ThreadHandler as Handler
from googleapiclient.errors import HttpError

_logger = logging.getLogger(__name__)
snapshot_thread = None

def _create_rescue_disk(vm, source_disk: str) -> Dict:
  """ Create new temporary rescue disk based on source_disk.
  https://cloud.google.com/compute/docs/reference/rest/v1/disks/insert
  Returns:
    operation-result: Dict
  """

  chk_disk_exist = {}
  try:
    chk_disk_exist = vm.compute.disks().get(
      **vm.project_data,
      disk = vm.rescue_disk).execute()
  except googleapiclient.errors.HttpError as e:
    if e.status_code == 404:
      _logger.info(f'Creating rescue disk {vm.rescue_disk}...')
    else:
      raise Exception(e) from e

  if 'name' in chk_disk_exist.keys():
    if 'users' in chk_disk_exist.keys():
      disk_users = chk_disk_exist['users']
      raise Exception(
        f'Disk {vm.rescue_disk} is currently in use: {disk_users}'
      )
    _logger.info(f'Disk {vm.rescue_disk} already exist. Skipping...')
    return {}

  disk_body = {
    'name': vm.rescue_disk,
    'sourceImage': source_disk,
    'type': f'projects/{vm.project}/zones/{vm.zone}/diskTypes/pd-balanced'
  }
  operation = vm.compute.disks().insert(
    **vm.project_data,
    body = disk_body).execute()

  result = wait_for_operation(vm, oper=operation)
  return result


def _set_disk_label(vm, disk_name = str) -> Dict:
  """ Set labels.rescue=TS to be able to idenfied the boot disk when restore
  the VM to the normal configuration.
  https://cloud.google.com/compute/docs/reference/rest/v1/disks/setLabels
  Return:
    operation-result: Dict
  """

  name_filter = f'name={disk_name}'
  response = list_disk(
    vm,
    project_data=vm.project_data,
    label_filter=name_filter
  )
  label_fingerprint = response[0]['labelFingerprint']
  request_body = {
    'labels': {
        'rescue': vm.ts
    },
    'labelFingerprint': label_fingerprint
  }
  operation = vm.compute.disks().setLabels(
    **vm.project_data,
    resource = disk_name,
    body = request_body).execute()

  return operation

def _delete_rescue_disk(vm, disk_name: str) -> Dict:
  """
  Delete rescue disk after resetting the instance to the original configuration.
  https://cloud.google.com/compute/docs/reference/rest/v1/disks/delete
  Param:
    disk_name: str, Name of the disk to be deleted.
  Returns:
    operation-result: Dict
  """
  _logger.info(f'Deleting disk {disk_name}...')
  operation = vm.compute.disks().delete(
    **vm.project_data,
    disk = disk_name).execute()

  result = wait_for_operation(vm, oper=operation)
  return result


def list_disk(vm, project_data: Dict, label_filter: str) -> Dict:
  """Filter existing disks with labels.rescue=TS
  https://cloud.google.com/compute/docs/reference/rest/v1/disks/list
  Returns:
    result: Dict
  """
  result = vm.compute.disks().list(
    **project_data,
    filter=label_filter).execute()

  #TODO: Add validation and throw exception if response has more than 1 disk:
  #  len(response['items'])
  #For test phase - remember to fix that
  return result['items']


def attach_disk(
  vm,
  disk_name: str,
  device_name: str,
  boot: bool = False
) -> Dict:
  """
  Attach disk on the instance. By default it will attach as secundary
  https://cloud.google.com/compute/docs/reference/rest/v1/instances/attachDisk
  Returns:
      operation-result: Dict
  """
  if not boot:
    request = _set_disk_label(vm, disk_name)
    if request['status'] != 'DONE':
      _logger.error(f'Unable to set label to disk {disk_name}.')
      raise Exception(request)
    else:
      _logger.info(f'Label configured successfully disk {disk_name}.')
  attach_disk_body = {
    'boot': boot,
    'name': disk_name,
    'deviceName': device_name,
    'type': 'PERSISTENT',
    'source': f'projects/{vm.project}/zones/{vm.zone}/disks/{disk_name}'
  }
  _logger.info(f'Attaching disk {disk_name}...')
  operation = vm.compute.instances().attachDisk(
    **vm.project_data,
    instance = vm.name,
    body = attach_disk_body).execute()

  result = wait_for_operation(vm, oper=operation)
  return result


def _detach_disk(vm, disk: str) -> Dict:
  """ Detach disk from the instance.
  https://cloud.google.com/compute/docs/reference/rest/v1/instances/detachDisk
  """

  _logger.info(f'Detaching disk {disk} from {vm.name}...')
  operation = vm.compute.instances().detachDisk(
      **vm.project_data,
      instance = vm.name,
      deviceName = disk).execute()
  result = wait_for_operation(vm, oper=operation)
  return result


def take_snapshot(vm, join_snapshot=None) -> None:
  global snapshot_thread
  if not join_snapshot:
    snapshot_thread = Thread(target=create_snapshot, args=(vm,), daemon=True)
    snapshot_thread.start()
  else:
    snapshot_thread.join()


def create_rescue_disk(vm) -> None:
  device_name = vm.disks['device_name']
  # task1 = multitasks.Handler(
  #     target = backup,
  #     kwargs={'vm' : vm}
  #     )
  # task1.start()
  task2 = Handler(
    target = _create_rescue_disk,
    kwargs={'vm': vm, 'source_disk': vm.rescue_source_disk}
    )
  task2.start()
  task2.join()
  _detach_disk(vm, disk=device_name)
  attach_disk(
    vm,
    disk_name=vm.rescue_disk,
    device_name=vm.rescue_disk,
    boot=True
  )

def list_snapshot(vm) -> str:
  snapshot_name = f"{vm.disks['disk_name']}-{vm.ts}"
  try:
    result = vm.compute.snapshots().get(
      snapshot=snapshot_name,
      project=vm.project
    ).execute()
  except HttpError:
    _logger.info('Snapshot was not found for VM in active rescue mode')
    return ''
  return snapshot_name

def restore_original_disk(vm) -> None:
  """ Restore tasks to the original disk """
  device_name = vm.disks['device_name']

  _detach_disk(vm, disk=vm.rescue_disk)
  _detach_disk(vm, disk=device_name)
  _delete_rescue_disk(vm, disk_name=vm.rescue_disk)
  attach_disk(vm, **vm.disks, boot=True)