#!/usr/bin/env python3

# Copyright 2022 Google Inc. 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.

"""Creates a VT Collection with indicators present in a given event."""

import base64
import json
import requests

misperrors = {
  'error': 'Error'
}

mispattributes = {
    'input': [
        'hostname',
        'domain',
        'ip-src',
        'ip-dst',
        'md5',
        'sha1',
        'sha256',
        'url'
    ],
    'format': 'misp_standard',
    'responseType': 'application/txt',
    'outputFileExtension': 'txt',
}

moduleinfo = {
    'version': '1.0',
    'author': 'VirusTotal',
    'description': 'Creates a VT Collection from an event iocs.',
    'module-type': ['export'],
    'name': 'VirusTotal Collections Export',
    'logo': 'virustotal.png',
    'requirements': ['An access to the VirusTotal API (apikey).'],
    'features': 'This export module which takes advantage of a new endpoint in VT APIv3 to create VT Collections from IOCs contained in a MISP event. With this module users will be able to create a collection just using the Download as... button.',
    'references': ['https://www.virustotal.com/', 'https://blog.virustotal.com/2021/11/introducing-virustotal-collections.html'],
    'input': 'A domain, hash (md5, sha1, sha256 or sha512), hostname, url or IP address attribute.',
    'output': 'A VirusTotal collection in VT.',
}

moduleconfig = [
    'vt_api_key',
    'proxy_host',
    'proxy_port',
    'proxy_username',
    'proxy_password'
]


class VTError(Exception):
  "Exception class to map vt api response errors."
  pass


def create_collection(api_key, event_data):
  headers = {
      'x-apikey': api_key,
      'content-type': 'application/json',
      'x-tool': 'MISPModuleVirusTotalCollectionExport',
  }

  response = requests.post('https://www.virustotal.com/api/v3/integrations/misp/collections',
                           headers=headers,
                           json=event_data)

  uuid = event_data['Event']['uuid']
  response_data = response.json()

  if response.status_code == 200:
    col_id = response_data['data']['id']
    return f'{uuid}: https://www.virustotal.com/gui/collection/{col_id}/iocs'

  error = response_data['error']['message']
  if response.status_code == 400:
    return f'{uuid}: {error}'
  else:
    misperrors['error'] = error
    raise VTError(error)


def normalize_misp_data(data):
  normalized_data = {'Event': data.pop('Event', {})}
  for attr_key in data:
    if isinstance(data[attr_key], list) or isinstance(data[attr_key], dict):
      if attr_key == 'EventTag':
        normalized_data['Event']['Tag'] = [tag['Tag'] for tag in data[attr_key]]
      else:
        normalized_data['Event'][attr_key] = data[attr_key]

  return normalized_data


def handler(q=False):
  request = json.loads(q)

  if not request.get('config') or not request['config'].get('vt_api_key'):
    misperrors['error'] = 'A VirusTotal api key is required for this module.'
    return misperrors

  config = request['config']
  data = request['data']
  responses = []

  try:
    for event_data in data:
      normalized_event = normalize_misp_data(event_data)
      responses.append(create_collection(config.get('vt_api_key'),
                                         normalized_event))

    output = '\n'.join(responses)
    return {
        "response": [],
        "data": str(base64.b64encode(bytes(output, 'utf-8')), 'utf-8'),
    }
  except VTError:
    return misperrors



def introspection():
    return mispattributes


def version():
    moduleinfo['config'] = moduleconfig
    return moduleinfo