# Copyright 2022 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.

import hashlib

from deepdiff import DeepDiff
from pathlib import Path

STAGES = Path(__file__).parents[4] / 'fast/stages'
STAGE_PEERING = STAGES / '2-networking-a-peering'
STAGE_VPN = STAGES / '2-networking-b-vpn'


def test_vpn_peering_parity(plan_summary):
  '''Ensure VPN- and peering-based networking stages are identical except
  for VPN and VPC peering resources'''
  summary_peering = plan_summary("fast/stages/2-networking-a-peering",
                                 tf_var_files=["common.tfvars"])
  summary_vpn = plan_summary("fast/stages/2-networking-b-vpn",
                             tf_var_files=["common.tfvars"])

  ddiff = DeepDiff(summary_vpn.values, summary_peering.values,
                   ignore_order=True)

  removed_types = {x.split('.')[-2] for x in ddiff['dictionary_item_removed']}
  added_types = {x.split('.')[-2] for x in ddiff['dictionary_item_added']}

  assert added_types == {'google_compute_network_peering'}
  assert removed_types == {
      'google_compute_ha_vpn_gateway', 'google_compute_router',
      'google_compute_router_interface', 'google_compute_router_peer',
      'google_compute_vpn_tunnel', 'random_id'
  }


def compute_md5(filename):
  with open(filename, "rb") as f:
    md5hash = hashlib.md5()
    while chunk := f.read(8192):
      md5hash.update(chunk)
  return md5hash.hexdigest()


def test_vpn_peering_checksums():
  '''Compare MD5 sums of common files in the vpn and peering
  networking stages'''
  peering_files = {
      x.name for x in STAGE_PEERING.glob("*.tf") if not x.is_symlink()
  }
  vpn_files = {x.name for x in STAGE_VPN.glob("*.tf") if not x.is_symlink()}
  common_files = peering_files & vpn_files

  for filename in common_files:
    md5_vpn = compute_md5(STAGE_VPN / filename)
    md5_peering = compute_md5(STAGE_PEERING / filename)
    assert md5_vpn == md5_peering, filename
