import json
import logging
import re
from base64 import b32encode
from getpass import getpass
from urllib.parse import urljoin
from uuid import uuid4

import requests
from pyotp import TOTP

from .appdata import AppData
from .jwe_handler import JWEHandler
from .utils import RequestFailure, hmac_sha256

logger = logging.getLogger(__name__)


class NotInitializedPIN(Exception):
    pass


class AuthError(Exception):
    pass


class SCA:
    LOGIN_URL = "https://posteid.poste.it/jod-securelogin-schema/"
    AUTH_URL = "https://posteid.poste.it/jod-login-schema/"
    SH_URL = ("https://sh2-web-posteid.poste.it/jod-secure-holder2-web"
              "/public/app/")

    def __init__(self, profile_name):
        self.appdata = AppData(profile_name)
        self.s = requests.Session()
        self.s.headers = {'Accept-Encoding': "gzip",
                          'User-Agent': "okhttp/3.12.1",
                          'Connection': "keep-alive"}
        self.jwe_handler = JWEHandler(self.appdata)
        self.reg_token = None
        self.profile_token = None
        self.access_token = None

    def _send_req(self, request):
        prepped = self.s.prepare_request(request)
        return self.s.send(prepped)

    def _parse_jwe_response(self, ans):
        if ans.status_code != 200:
            raise RequestFailure(f"Wrong status code: {ans.status_code}", ans)
        if not ans.headers.get('Content-Type').startswith("application/json"):
            raise RequestFailure("Response not JSON.", ans)
        ans_json = ans.json()
        if not ans_json.get('command-success'):
            raise RequestFailure(f"Command failed: {ans_json}", ans,
                                 error_code=ans_json.get('command-error-code'))
        if ans_json.get('command-result-type') not in ["JWE", "JSON"]:
            raise RequestFailure(f"Result is not JWE/JSON: {ans_json}", ans)
        return ans_json.get('command-result')

    def _parse_v4(self, ans):
        if ans.status_code != 200:
            raise RequestFailure(f"Wrong status code: {ans.status_code}", ans)
        if not ans.headers.get('Content-Type').startswith("application/json"):
            raise RequestFailure("Response not JSON.", ans)
        ans_json = ans.json()
        if (ans_json.get('status')
                not in ["v4_success", "v4_pending", "v4_signed"]):
            if ans_json.get('status') == "v4_error":
                reason = ans_json.get('reason')
                raise RequestFailure(f"Request v4 error: {reason}.", ans,
                                     error_code=reason)
            raise RequestFailure("Unknown v4 failure.", ans)
        return ans_json

    def _sign_challenge_v4(self, challenge, userpin):
        userpin = str(userpin)
        signature = {}
        key = self.appdata['sca_seed'] + userpin + challenge['randK']
        message = challenge['transaction-challenge']
        signature['jti'] = challenge['jti']
        signature['signature'] = hmac_sha256(key, message)
        signature['userpin'] = userpin
        signature['authzTool'] = "POSTEID"
        return json.dumps(signature)

    def _enrol_stage_basiclogin(self, username, password):
        url = urljoin(self.LOGIN_URL, "v4/xmobileauthjwt")
        data = {}
        data['password'] = password
        data['authLevel'] = "0"
        data['userid'] = username
        logger.debug("Enrol(basiclogin): sending username and password.")
        jwe_req = self.jwe_handler.req_jwe_bearer(url, 'login', data,
                                                  auth=True)
        ans = self._send_req(jwe_req)
        if ans.status_code == 401:
            raise AuthError("Wrong username or password!")
        if ans.status_code != 200:
            raise RequestFailure(f"Wrong status code: {ans.status_code}", ans)
        if 'X-PI' not in ans.headers:
            raise RequestFailure(f"Malformed request, missing 'X-PI'.", ans)
        uid = ans.headers.get('X-PI')
        logger.debug(f"Enrol(basiclogin): completed, uid='{uid}'.")

    def _enrol_stage_req_sms_otp(self, username):
        url = urljoin(self.LOGIN_URL, "v4/xmobileauthjwt")
        data = {}
        data['password'] = str(uuid4())
        data['authLevel'] = "3"
        data['userid'] = username
        logger.debug("Enrol(SMS-OTP-REQ): requesting SMS-OTP verification..")
        jwe_req = self.jwe_handler.req_jwe_bearer(url, 'login', data,
                                                  auth=True)
        ans = self._send_req(jwe_req)
        if ans.status_code != 200:
            raise RequestFailure(f"Wrong status code: {ans.status_code}", ans)
        if 'X-TEL' not in ans.headers:
            raise RequestFailure(f"Malformed request, missing 'X-TEL'.", ans)
        logger.debug("Enrol(SMS-OTP-REQ): SMS-OTP verification requested.")
        tel = ans.headers.get('X-TEL')
        logger.debug(f"Enrol(SMS-OTP-REQ): SMS-OTP sent to ***{tel}.")
        return tel

    def _enrol_stage_send_sms_otp(self, otp):
        url = urljoin(self.LOGIN_URL, "v4/xmobileauthjwt")
        data = {}
        data['otp'] = str(otp)
        data['authLevel'] = "2"
        data['nonce'] = str(uuid4())
        logger.debug("Enrol(SMS-OTP-AUTH): authenticating SMS-OTP.")
        jwe_req = self.jwe_handler.req_jwe_bearer(url, 'login', data,
                                                  auth=True)
        ans = self._send_req(jwe_req)
        if ans.status_code == 401:
            raise AuthError("Wrong SMS-OTP code!")
        if ans.status_code != 200:
            raise RequestFailure(f"Wrong status code: {ans.status_code}", ans)
        if 'X-RESULT' not in ans.headers:
            raise RequestFailure(
                f"Malformed request, missing 'X-RESULT'.", ans)
        logger.debug("Enrol(SMS-OTP-AUTH): decrypting response.")
        ans_json = self.jwe_handler.decrypt(ans.headers.get('X-RESULT'))
        logger.debug(f"Enrol(SMS-OTP-AUTH): decrypted response: {ans_json}")
        if 'data' not in ans_json:
            raise RequestFailure("Malformed request, missing 'data'.", ans)
        if 'token' not in ans_json['data']:
            raise RequestFailure("Malformed request, missing 'token'.", ans)
        reg_token = ans_json['data']['token']
        logger.debug(f"Enrol(SMS-OTP-AUTH): got reg token: {reg_token}.")
        self.reg_token = reg_token

    def _enrol_stage_finalize(self, userpin=""):
        url = urljoin(self.SH_URL, "v1/registerApp")
        data = {}
        data['userPIN'] = userpin
        data['idpAccessToken'] = ""
        data['registerToken'] = self.reg_token
        logger.debug("Enrol(REG-APP): encrypting request.")
        print(data)
        jwe_req = self.jwe_handler.req_jwe_post(
            url, 'registerApp', data, auth=True)
        logger.debug("Enrol(REG-APP): sending request.")
        ans = self._send_req(jwe_req)

        try:
            ans_jwe = self._parse_jwe_response(ans)
        except RequestFailure as e:
            if e.error_code == "PIN-ERR-1":
                raise NotInitializedPIN()
            raise e

        ans_json = self.jwe_handler.decrypt(ans_jwe)
        if 'data' not in ans_json:
            raise RequestFailure("Malformed request, missing 'data'.", ans)
        if 'appRegisterID' not in ans_json['data']:
            raise RequestFailure(
                "Malformed request, missing 'appRegisterID'.", ans)
        if 'secretAPP' not in ans_json['data']:
            raise RequestFailure(
                "Malformed request, missing 'secretAPP'.", ans)
        self.appdata['sca_app_regid'] = ans_json['data']['appRegisterID']
        self.appdata['sca_seed'] = ans_json['data']['secretAPP']
        logger.debug("Enrol(REG-APP): completed successfully!")

    def check_register(self):
        url = urljoin(self.SH_URL, "v1/checkRegisterApp")
        data = {'appRegisterID': self.appdata['sca_app_regid']}
        jwe_req = self.jwe_handler.req_jwe_post(url, "checkRegisterApp", data,
                                                auth=True)
        ans = self._send_req(jwe_req)
        result = self._parse_jwe_response(ans)
        if 'valid' not in result:
            raise RequestFailure(
                "Malformed request, missing 'valid'.", ans)
        return result["valid"]

    def enrol_sms_start(self, username, password):
        self._enrol_stage_basiclogin(username, password)
        tel = self._enrol_stage_req_sms_otp(username)
        return tel

    def enrol_sms_finish(self, otp, force_userpin=None):
        self._enrol_stage_send_sms_otp(otp)
        try:
            self._enrol_stage_finalize()
        except NotInitializedPIN as e:
            if force_userpin:
                logger.info('Enrol(REG-APP): Setting the new provided PIN.')
                self._enrol_stage_finalize(force_userpin)
                return
            raise e

    def _pin_login(self, userpin):
        url_challenge = urljoin(self.LOGIN_URL,
                                "secureholder/v4/native/challenge")
        url_authorize = urljoin(self.LOGIN_URL,
                                "secureholder/v4/native/az")
        logger.debug("PINLogin: acquiring v4 challenge.")
        req = self.jwe_handler.req_jwe_post(url_challenge, "login", {},
                                            auth=True)
        ans = self._send_req(req)
        ans = self._parse_v4(ans)
        logger.debug(f"PINLogin: got v4 challenge: {ans}.")
        logger.debug(f"PINLogin: preparing challenge response.")
        data = {}
        data['signature'] = self._sign_challenge_v4(ans, userpin)
        data['appRegisterID'] = self.appdata['sca_app_regid']
        logger.debug(f"PINLogin: sending response {data}.")
        req = self.jwe_handler.req_jwe_post(url_authorize, "login", data,
                                            auth=True)
        ans = self._send_req(req)
        try:
            ans = self._parse_v4(ans)
        except RequestFailure as e:
            if e.error_code == "PIN-ERR-3":
                raise AuthError("Codice PosteID errato!")
            elif e.error_code == "CERT-ERR-2":
                raise AuthError("Codice PosteID bloccato per troppi errori!")
            raise(e)
        self.profile_token = ans['profile_token']
        self.access_token = ans['access_token']
        logger.debug(f"PINLogin: logged in, session token aquired.")

    def _unenrol(self):
        if not self.access_token:
            raise Exception(
                'Need to acquire an access token (pin_login) before.')
        logger.debug("Unenrol: unenrolling device.")
        url = urljoin(self.LOGIN_URL, "secureholder/v4/native/delete-posteid")
        jwe_req = self.jwe_handler.req_jwe_bearer(url, "delete_posteid", {},
                                                  auth=True)
        jwe_req.headers['Authorization'] = "Bearer " + self.access_token
        ans = self._send_req(jwe_req)
        ans = self._parse_v4(ans)
        logger.debug("Unenrol: device unenrolled.")

    def list_txs(self):
        if not self.access_token:
            raise Exception(
                "Need to acquire an access token (pin_login) before.")
        url = urljoin(self.LOGIN_URL,
                      "secureholder/v4/native/list-transaction")
        jwe_req = self.jwe_handler.req_jwe_post(url, "login", {}, auth=True)
        jwe_req.headers['Authorization'] = "Bearer " + self.access_token
        ans = self._send_req(jwe_req)
        ans_json = self._parse_v4(ans)
        if 'transaction' not in ans_json:
            raise RequestFailure(
                f"Malformed response, missing 'transaction'.", ans)
        return ans_json['transaction']

    def authorize_tx_start(self, tx_id):
        data = {}
        data['jti'] = tx_id
        data['appRegisterID']: self.appdata['sca_app_regid']
        url = urljoin(self.AUTH_URL, "secureholder/v4/challenge")
        jwe_req = self.jwe_handler.req_jwe_post(url, "login", data, auth=True)
        ans = self._send_req(jwe_req)
        ans_json = self._parse_v4(ans)
        if ans_json['status'] != "v4_pending":
            raise Exception(
                f"TX Status is '{ans_json['status']}', not pending.")
        if 'jti' not in ans_json:
            raise RequestFailure(f"Malformed response, missing 'jti'.", ans)
        if 'randK' not in ans_json:
            raise RequestFailure(f"Malformed response, missing 'randK'.", ans)
        if 'transaction-challenge' not in ans_json:
            raise RequestFailure(
                f"Malformed response, missing 'transaction-challenge'.", ans)
        return ans_json

    def authorize_tx_finish(self, challenge, userpin):
        signature = self._sign_challenge_v4(challenge, userpin)
        data = {}
        data['signature'] = signature
        data['appRegisterID'] = self.appdata['sca_app_regid']
        url = urljoin(self.AUTH_URL, "secureholder/v4/az")
        jwe_req = self.jwe_handler.req_jwe_post(url, "login", data, auth=True)
        ans = self._send_req(jwe_req)
        try:
            ans_json = self._parse_v4(ans)
        except RequestFailure as e:
            if e.error_code == "PIN-ERR-3":
                raise AuthError("Codice PosteID errato!")
            elif e.error_code == "CERT-ERR-2":
                raise AuthError("Codice PosteID bloccato per troppi errori!")
            raise(e)
        if ans_json['status'] != "v4_signed":
            raise Exception(
                f"TX Status is '{ans_json['status']}', not signed.")

    def unenrol(self, userpin):
        self._pin_login(userpin)
        self._unenrol()

    @property
    def totp(self):
        seed = self.appdata['sca_seed']
        seed = b32encode(seed.encode("utf-8") + b'\0' * 32)
        seed = seed.decode("utf-8").replace('=', '')
        totp = TOTP(seed, interval=120)
        return totp