#  ============LICENSE_START===============================================
#  Copyright (C) 2021 Nordix Foundation. 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.
#  ============LICENSE_END=================================================
#

import copy
import datetime
import json
import logging
import collections
import time

from connexion import NoContent
from flask import Flask, request, Response
from var_declaration import policy_instances, policy_status, callbacks, forced_settings, policy_fingerprint, hosts_set
from utils import calcFingerprint
from maincommon import check_apipath, apipath, get_supported_interfaces_response, extract_host_name, is_duplicate_check

#Constsants
APPL_JSON='application/json'
APPL_PROB_JSON='application/problem+json'

# API Function: Get all policy ids
def get_all_policy_identities():

  extract_host_name(hosts_set, request)

  if ((r := check_modified_response()) is not None):
    return r

  res = list(policy_instances.keys())
  return Response(json.dumps(res), 200, mimetype=APPL_JSON)
  
# API Function: Create or update a policy
def put_policy(policyId):

  extract_host_name(hosts_set, request)

  if ((r := check_modified_response()) is not None):
    return r

  try:
    data = request.data
    data = json.loads(data)
  except Exception:
    pjson=create_problem_json(None, "The policy is corrupt or missing.", 400, None, policyId)
    return Response(json.dumps(pjson), 400, mimetype=APPL_PROB_JSON)

  fp_previous=None
  retcode=201
  if policyId in policy_instances.keys():
    retcode=200
    if (is_duplicate_check()):
      fp_previous=calcFingerprint(policy_instances[policyId])
    else:
      fp_previous=policyId

  if (is_duplicate_check()):
    fp=calcFingerprint(data)
  else:
    fp=policyId

  if (fp in policy_fingerprint.keys()):
    p_id=policy_fingerprint[fp]
    if (p_id != policyId):
      pjson=create_problem_json(None, "The policy json already exists.", 400, None, policyId)
      return Response(json.dumps(pjson), 400, mimetype=APPL_PROB_JSON)

  if (fp_previous is not None):
    del policy_fingerprint[fp_previous]

  policy_fingerprint[fp]=policyId

  noti=request.args.get('notificationDestination')
  callbacks[policyId]=noti

  policy_instances[policyId]=data
  ps={}
  ps["enforceStatus"] = "UNDEFINED"
  policy_status[policyId]=ps

  if (retcode == 200):
    return Response(json.dumps(data), 200, mimetype=APPL_JSON)
  else:
    headers={}
    headers['Location']='/A1-P/v1/policies/' + policyId
    return Response(json.dumps(data), 201, headers=headers, mimetype=APPL_JSON)

# API Function: Get a policy
def get_policy(policyId):

  extract_host_name(hosts_set, request)

  if ((r := check_modified_response()) is not None):
    return r

  if policyId in policy_instances.keys():
    return Response(json.dumps(policy_instances[policyId]), 200, mimetype=APPL_JSON)

  pjson=create_problem_json(None, "The requested policy does not exist.", 404, None, policyId)
  return Response(json.dumps(pjson), 404, mimetype=APPL_PROB_JSON)

# API Function: Delete a policy
def delete_policy(policyId):

  extract_host_name(hosts_set, request)

  if ((r := check_modified_response()) is not None):
    return r

  if policyId in policy_instances.keys():
    if (is_duplicate_check()):
      fp_previous=calcFingerprint(policy_instances[policyId])
    else:
      fp_previous=policyId

    policy_fingerprint.pop(fp_previous)
    policy_instances.pop(policyId)
    policy_status.pop(policyId)
    callbacks.pop(policyId)
    return Response('', 204, mimetype=APPL_JSON)

  pjson=create_problem_json(None, "The policy identity does not exist.", 404, "No policy instance has been deleted.", policyId)
  return Response(json.dumps(pjson), 404, mimetype=APPL_PROB_JSON)

# API Function: Get status for a policy
def get_policy_status(policyId):

  extract_host_name(hosts_set, request)

  if ((r := check_modified_response()) is not None):
    return r

  if policyId in policy_instances.keys():
    return Response(json.dumps(policy_status[policyId]), status=200, mimetype=APPL_JSON)

  pjson=create_problem_json(None, "The policy identity does not exist.", 404, "There is no existing policy instance with the identity: " + policyId, policyId)
  return Response(json.dumps(pjson), 404, mimetype=APPL_PROB_JSON)

# Helper: Create a response object if forced http response code is set
def get_forced_response():
  if (forced_settings['code'] is not None):
    pjson=create_error_response(forced_settings['code'])
    forced_settings['code']=None
    return Response(json.dumps(pjson), pjson['status'], mimetype=APPL_PROB_JSON)
  return None

# Helper: Delay if delayed response code is set
def do_delay():
  if (forced_settings['delay'] is not None):
    try:
      val=int(forced_settings['delay'])
      time.sleep(val)
    except Exception:
      return

# Helper: Check if response shall be delayed or a forced response shall be sent
def check_modified_response():
  do_delay()
  return get_forced_response()

# Helper: Create a problem json object
def create_problem_json(type_of, title, status, detail, instance):

  error = {}
  if type_of is not None:
    error["type"] = type_of
  if title is not None:
    error["title"] = title
  if status is not None:
    error["status"] = status
  if detail is not None:
    error["detail"] = detail
  if instance is not None:
    error["instance"] = instance
  return error

# Helper: Create a problem json based on a generic http response code
def create_error_response(code):

    if code == '400':
      return(create_problem_json(None, "Bad request", 400, "Object in payload not properly formulated or not related to the method", None))
    elif code == '404':
      return(create_problem_json(None, "Not found", 404, "No resource found at the URI", None))
    elif code == '405':
      return(create_problem_json(None, "Method not allowed", 405, "Method not allowed for the URI", None))
    elif code == '409':
      return(create_problem_json(None, "Conflict", 409, "Request could not be processed in the current state of the resource", None))
    elif code == '429':
      return(create_problem_json(None, "Too many requests", 429, "Too many requests have been sent in a given amount of time", None))
    elif code == '507':
      return(create_problem_json(None, "Insufficient storage", 507, "The method could not be performed on the resource because the provider is unable to store the representation needed to successfully complete the request", None))
    elif code == '503':
      return(create_problem_json(None, "Service unavailable", 503, "The provider is currently unable to handle the request due to a temporary overload", None))
    else:
      return(create_problem_json(None, "Unknown", code, "Not implemented response code", None))