#!/usr/bin/env python
# encoding: utf-8
#
# SPDX-License-Identifier: LGPL-2.1-or-later

from __future__ import unicode_literals, absolute_import, division

import hmac
import hashlib
import time
import random
import string
from urllib.parse import urlparse, urlsplit, parse_qs, urlencode, quote, unquote
from .b64 import encode_base64, decode_base64
from .log import LOG

def generate_nonce(length=24):
    characters = string.ascii_lowercase + string.digits
    nonce = ''.join(random.choice(characters) for _ in range(length))
    return encode_base64(nonce)

def create_signature(method, url, token, scheme):
    consumer_key = 'web_1.0.0'
    consumer_secret = 'Rk1Qc2RaREJ0M1h1MkUwRWtJRmlxWGtpOVpOZFlGN3I='

    nonce = generate_nonce()
    #print('nonce', nonce)

    timestamp = int(time.time())

    parsed_url = urlsplit(url)
    path = parsed_url.netloc + parsed_url.path
    query = parse_qs(parsed_url.query, keep_blank_values=True)

    options = { scheme: token, 'consumer_key': consumer_key, 'nonce': nonce,
                'signature_method': 'HMAC-SHA1', 'version': '1.0', 'timestamp': timestamp}
    for k, v in query.items():
      options[k] = quote(v[0])

    query_string = "&".join("{}={}".format(key, value) for key, value in sorted(options.items()))
    #print(query_string)

    text = '{}&{}&{}'.format(method.upper(), quote(path, safe=''), quote(query_string, safe=''))
    #print(text)

    key = decode_base64(consumer_secret.encode('utf-8')).encode('utf-8')
    hashed = hmac.new(key, text.encode('utf-8'), hashlib.sha1).digest()
    signature = encode_base64(hashed)

    res = 'consumer_key="{}",nonce="{}",signature_method="HMAC-SHA1",signature="{}",timestamp="{}",version="1.0"'.format(consumer_key, nonce, signature, timestamp)
    return encode_base64(res)

def get_auth(method, url, token, scheme='Bearer'):
    signature = create_signature(method, url, token, scheme)
    return 'OPPlus {}={},Signature={}'.format(scheme, token, signature)