import json
from random import randint
from time import time
from uuid import uuid4

from jwcrypto.jwe import JWE
from pyotp import HOTP
from requests import Request

from .utils import sha256_base64, hmac_sha256


class JWEHandler:
    def __init__(self, appdata):
        self.appdata = appdata

    def new_otp_specs(self):
        generator = HOTP(self.appdata['xkey_seed'], 8, "SHA1")
        counter = randint(0, 99999999)
        otp_specs = {}
        otp_specs['movingFactor'] = counter
        otp_specs['otp'] = generator.generate_otp(counter)
        otp_specs['type'] = "HMAC-SHA1"
        return otp_specs

    def encrypt(self, sub, data, auth=False):
        now = int(time())
        claims = {'data': data}
        claims['sub'] = sub
        claims['jti'] = str(uuid4())
        claims['iat'] = now
        claims['nbf'] = now
        claims['exp'] = now + 60
        claims['iss'] = "app-posteid-v3"
        headers = {}
        headers['cty'] = "JWE"
        headers['typ'] = "JWT"
        headers['alg'] = "RSA-OAEP-256"
        headers['enc'] = "A256CBC-HS512"
        if auth:
            app_uuid = self.appdata['xkey_appuuid']
            headers['kid'] = app_uuid
            claims['kid-sha256'] = sha256_base64(app_uuid)
            claims['otp-specs'] = self.new_otp_specs()
        jwe_token = JWE(json.dumps(claims),
                        protected=headers,
                        recipient=self.appdata.serv_pubkey.jwk)
        return jwe_token.serialize(compact=True)

    def req_jwe_post(self, url, sub, data, auth=False):
        jwe_token = self.encrypt(sub, data, auth)
        headers = {'Content-Type': "application/json; charset=UTF-8"}
        req = Request('POST', url, headers, data=jwe_token)
        return req

    def req_jwe_bearer(self, url, sub, data, auth=False):
        jwe_token = self.encrypt(sub, data, auth)
        headers = {'Content-Type': "",
                   'Authorization': "Bearer " + jwe_token}
        req = Request('GET', url, headers)
        return req

    def decrypt(self, serialized_jwe_token):
        if isinstance(serialized_jwe_token, bytes):
            serialized_jwe_token = serialized_jwe_token.decode('utf-8')
        jwe_token = JWE()
        jwe_token.deserialize(serialized_jwe_token)
        jwe_token.decrypt(self.appdata.app_privkey.jwk)
        return json.loads(jwe_token.payload)