#!/usr/bin/env python3

'''
This script will perform a simple query to the DarkOwl Vision Search API.
By default, the query has just one API paramater: 'q', with the value 'test'
Query paramaters can be changed in the 'payload' variable in the main function

'''


import requests
import datetime
import hmac
import hashlib
import base64

publicKey = 'PUBLIC_KEY_HERE'
privateKey = 'PRIVATE_KEY_HERE'


def main():
    #API Parameters and values in for form of a list of tuples
    #('API_Param', 'Param_value')
    payload = [
        ('q', 'test')
            ]

    response = perform_query(payload)
    print_data(response)

def print_data(response):
    response = response.json()
    print(f'Total Results: {response["total"]}\n')

    #example, this just prints the document ID of each result from the query
    #modify as needed
    for result in response['results']:
        print(result['id'])


def perform_query(payload):
    host = 'api.darkowl.com'
    endpoint = '/api/v1/search'

    #Generate search string
    search = payloadToString(payload)
    url = f'https://{host}{endpoint}{search}'
    absPath = endpoint + search

    date = datetime.datetime.utcnow().strftime('%a, %d %b %Y %H:%M:%S GMT')

    auth = generate_auth_header(absPath, 'GET', privateKey, publicKey, date)
    headers = {'Authorization': auth, 'X-VISION-DATE': date, 'Accept': 'application/json'}
    r = requests.get(url, headers=headers)
    if r.status_code == 200:
        return r
    else:
        print(r.content)
        exit(1)

def generate_auth_header(abs_path,
                         http_method,
                         private_key,
                         public_key,
                         time_stamp):

    string2hash = http_method + abs_path + time_stamp
    bkey = bytes(source=private_key, encoding='UTF-8')
    bpayload = bytes(source=string2hash, encoding='UTF-8')
    hmacsha1 = hmac.new(bkey, bpayload, hashlib.sha1).digest()
    base64encoded = base64.b64encode(hmacsha1).decode('UTF-8')
    auth_header = f'OWL {public_key}:{base64encoded}'
    return auth_header

### Takes a payload (list of tuples) and generates a URL query string
def payloadToString(payload):
    search = ''
    count = 0
    for key, value in payload:
        if count == 0:
            search += f'?{key}={value}'
            count = 1
        else:
            search += f'&{key}={value}'
    return search

if __name__ == '__main__':
    main()