from authlib.integrations.base_client.errors import MissingTokenError, InvalidTokenError
from base64 import b64encode, b64decode
from fido2 import cbor
from fido2.webauthn import AttestationObject, AttestedCredentialData, AuthenticatorData
from flask import Blueprint, Response, redirect, request
from flask import current_app
from flask import jsonify, session, flash
from flask import render_template, url_for
from flask_login import login_user, logout_user, current_user
from http import HTTPStatus
from werkzeug.utils import redirect
import logging
from datetime import timedelta
from base64 import b64decode
from flask.typing import ResponseReturnValue 
from oauthlib.oauth2.rfc6749.errors import TokenExpiredError
from ory_hydra_client.api.admin import list_subject_consent_sessions, revoke_consent_sessions
from ory_hydra_client.models import GenericError
from urllib.parse import urlencode, parse_qs
from random import SystemRandom
import string
from collections.abc import Iterable
from typing import Optional

from ..model import db, User, SecurityUser, Totp, AppToken, WebauthnCredential
from ..form.frontend import ClientCertForm, TOTPForm, \
    TOTPDeleteForm, PasswordChangeForm, WebauthnRegisterForm, \
    AppTokenForm, AppTokenDeleteForm
from ..form.base import  ButtonForm
from ..auth_providers import PasswordAuthProvider
from .auth import webauthn
from .oauth2 import redirect_login, oauth2
from ..hydra import hydra_service
from ..pki import pki
from ..lenticular_services import lenticular_services

frontend_views = Blueprint('frontend', __name__, url_prefix='')
logger = logging.getLogger(__name__)


def before_request() -> Optional[ResponseReturnValue]:
    try:
        resp = oauth2.custom.get('/userinfo')
        if not current_user.is_authenticated or resp.status_code != 200:
            logger.info('user not logged in redirect')
            return redirect_login()
    except MissingTokenError:
        logger.info('MissingTokenError redirect user to login')
        return redirect_login()
    except InvalidTokenError:
        logger.info('InvalidTokenError redirect user to login')
        return redirect_login()

    return None


frontend_views.before_request(before_request)


@frontend_views.route('/logout')
def logout() -> ResponseReturnValue:
    logout_user()
    return redirect(
        f'{current_app.config["HYDRA_PUBLIC_URL"]}/oauth2/sessions/logout')


@frontend_views.route('/', methods=['GET'])
def index() -> ResponseReturnValue:
    if 'next_url' in session:
        next_url = session['next_url']
        del session['next_url']
        return redirect(next_url)
    return render_template('frontend/index.html.j2')


@frontend_views.route('/client_cert')
def client_cert() -> ResponseReturnValue:
    client_certs = {}
    for service in lenticular_services.values():
        client_certs[str(service.name)] = \
                pki.get_client_certs(current_user, service)

    return render_template(
            'frontend/client_cert.html.j2',
            services=lenticular_services,
            client_certs=client_certs)


@frontend_views.route('/client_cert/<service_name>/<serial_number>')
def get_client_cert(service_name, serial_number) -> ResponseReturnValue:
    service = lenticular_services[service_name]
    cert = pki.get_client_cert(
            current_user, service, serial_number)
    return jsonify({
        'data': {
            'pem': cert.pem()}
        })


@frontend_views.route(
        '/client_cert/<service_name>/<serial_number>', methods=['DELETE'])
def revoke_client_cert(service_name, serial_number) -> ResponseReturnValue:
    service = lenticular_services[service_name]
    cert = pki.get_client_cert(
            current_user, service, serial_number)
    pki.revoke_certificate(cert)
    return jsonify({})


@frontend_views.route(
        '/client_cert/<service_name>/new',
        methods=['GET', 'POST'])
def client_cert_new(service_name) -> ResponseReturnValue:
    if service_name not in lenticular_services:
        return '', 404
    service = lenticular_services[service_name]
    form = ClientCertForm()
    if form.validate_on_submit():
        valid_time = int(form.data['valid_time']) * timedelta(1, 0, 0)
        cert = pki.signing_publickey(
                current_user,
                service,
                form.data['publickey'],
                valid_time=valid_time)
        return jsonify({
                'status': 'ok',
                'data': {
                    'cert': cert.pem(),
                    'ca_cert': pki.get_ca_cert_pem(service)
                }})
    elif form.is_submitted():
        return jsonify({
                'status': 'error',
                'errors': form.errors
            })

    return render_template(
            'frontend/client_cert_new.html.j2',
            service=service,
            form=form)

@frontend_views.route('/app_token')
def app_token() -> ResponseReturnValue:
    delete_form = AppTokenDeleteForm()
    form = ClientCertForm()
    return render_template('frontend/app_token.html.j2',
                           delete_form=delete_form,
                           services=lenticular_services)

@frontend_views.route('/app_token/<service_name>/new', methods=['GET','POST'])
def app_token_new(service_name: str) -> ResponseReturnValue:
    if service_name not in lenticular_services:
        return '', 404
    service = lenticular_services[service_name]
    form = AppTokenForm()

    if form.validate_on_submit():
        app_token = AppToken.new(service)
        form.populate_obj(app_token)
        # check for duplicate names
        for user_app_token in current_user.app_tokens:
            if user_app_token.name == app_token.name:
                return 'name already exist', 400
        current_user.app_tokens.append(app_token)
        db.session.commit()
        return render_template('frontend/app_token_new_show.html.j2', service=service, app_token=app_token)


    return render_template('frontend/app_token_new.html.j2',
                           form=form,
                           service=service)

@frontend_views.route('/app_token/<service_name>/<app_token_name>', methods=["POST"])
def app_token_delete(service_name: str, app_token_name: str) -> ResponseReturnValue:
    form = AppTokenDeleteForm()

    if service_name not in lenticular_services:
        return '', 404

    service = lenticular_services[service_name]
    if form.validate_on_submit():
        app_token = current_user.get_token(service, app_token_name)
        if app_token is None:
            return 'not found', 404
        db.session.delete(app_token)
        db.session.commit()

    return redirect(url_for('frontend.app_token'))

@frontend_views.route('/totp')
def totp() -> ResponseReturnValue:
    delete_form = TOTPDeleteForm()
    return render_template('frontend/totp.html.j2', delete_form=delete_form)


@frontend_views.route('/totp/new', methods=['GET', 'POST'])
def totp_new() -> ResponseReturnValue:
    form = TOTPForm()

    if form.validate_on_submit():
        totp = Totp(name=form.data['name'], secret=form.data['secret'])
        if totp.verify(form.data['token']):
            current_user.totps.append(totp)
            db.session.commit()
            return jsonify({
                    'status': 'ok'})
        else:
            return jsonify({
                'status': 'error',
                'errors': [
                    'TOTP Token invalid'
                    ]})
    return render_template('frontend/totp_new.html.j2', form=form)


@frontend_views.route('/totp/<totp_name>/delete', methods=['GET', 'POST'])
def totp_delete(totp_name) -> ResponseReturnValue:
    totp = Totp.query.filter(Totp.name == totp_name).first() # type: Optional[Totp]
    db.session.delete(totp)
    db.session.commit()

    return jsonify({
            'status': 'ok'})


@frontend_views.route('/webauthn/list', methods=['GET'])
def webauthn_list_route() -> ResponseReturnValue:
    """list registered credentials for current user"""

    creds = WebauthnCredential.query.all() # type: Iterable[WebauthnCredential] 
    return render_template('frontend/webauthn_list.html', creds=creds, button_form=ButtonForm())


@frontend_views.route('/webauthn/delete/<webauthn_id>', methods=['POST'])
def webauthn_delete_route(webauthn_id: str) -> ResponseReturnValue:
    """delete registered credential"""

    form = ButtonForm()
    if form.validate_on_submit():
        cred = WebauthnCredential.query.filter(WebauthnCredential.id == webauthn_id).one() # type: WebauthnCredential
        db.session.delete(cred)
        db.session.commit()
        return redirect(url_for('app.webauthn_list_route'))

    return '', HTTPStatus.BAD_REQUEST



def webauthn_credentials(user: User) -> list[AttestedCredentialData]:
    """get and decode all credentials for given user"""
    return [AttestedCredentialData.create(**cbor.decode(cred.credential_data)) for cred in user.webauthn_credentials]


def random_string(length=32) -> str:
    """generates random string"""
    return ''.join([SystemRandom().choice(string.ascii_letters + string.digits) for i in range(length)])


@frontend_views.route('/webauthn/pkcco', methods=['POST'])
def webauthn_pkcco_route() -> ResponseReturnValue:
    """get publicKeyCredentialCreationOptions"""

    user = User.query.get(current_user.id) #type: Optional[User]
    if user is None:
        return 'internal error', 500
    user_handle = random_string()
    exclude_credentials = webauthn_credentials(user)
    pkcco, state = webauthn.register_begin(
        {'id': user_handle.encode('utf-8'), 'name': user.username, 'displayName': user.username},
        exclude_credentials)
    session['webauthn_register_user_handle'] = user_handle
    session['webauthn_register_state'] = state
    return Response(b64encode(cbor.encode(pkcco)).decode('utf-8'), mimetype='text/plain')


@frontend_views.route('/webauthn/register', methods=['GET', 'POST'])
def webauthn_register_route() -> ResponseReturnValue:
    """register credential for current user"""

    user = current_user # type: User 
    form = WebauthnRegisterForm()
    if form.validate_on_submit():
        try:
            attestation = cbor.decode(b64decode(form.attestation.data))
            auth_data = webauthn.register_complete(
                session.pop('webauthn_register_state'),
                ClientData(attestation['clientDataJSON']),
                AttestationObject(attestation['attestationObject']))

            db.session.add(WebauthnCredential(
                user_id=user.id,
                user_handle=session.pop('webauthn_register_user_handle'),
                credential_data=cbor.encode(auth_data.credential_data.__dict__),
                name=form.name.data))
            db.session.commit()

            return redirect(url_for('app.webauthn_list_route'))
        except (KeyError, ValueError) as e:
            logger.exception(e)
            flash('Error during registration.', 'error')

    return render_template('frontend/webauthn_register.html', form=form)


@frontend_views.route('/password_change')
def password_change() -> ResponseReturnValue:
    form = PasswordChangeForm()
    return render_template('frontend/password_change.html.j2', form=form)


@frontend_views.route('/password_change', methods=['POST'])
def password_change_post() -> ResponseReturnValue:
    form = PasswordChangeForm()
    if form.validate():
        password_old = str(form.data['password_old'])
        password_new = str(form.data['password_new'])
        if not PasswordAuthProvider.check_auth_internal(
                current_user, password_old):
            return jsonify(
                    {'errors': {'password_old': 'Old Password is invalid'}})

        current_user.change_password(password_new)
        logger.info(f"user {current_user.username} changed password")
        db.session.commit()
        return jsonify({})
    return jsonify({'errors': form.errors})


@frontend_views.route('/oauth2_token')
async def oauth2_tokens() -> ResponseReturnValue:

    subject = oauth2.custom.get('/userinfo').json()['sub']
    consent_sessions = await list_subject_consent_sessions.asyncio(subject=subject, _client=hydra_service.hydra_client)
    if consent_sessions is None or isinstance( consent_sessions, GenericError):
       return 'internal error, could not fetch sessions', 500
    return render_template(
            'frontend/oauth2_tokens.html.j2',
            consent_sessions=consent_sessions)


@frontend_views.route('/oauth2_token/<client_id>', methods=['DELETE'])
async def oauth2_token_revoke(client_id: str) -> ResponseReturnValue:
    subject = oauth2.session.get('/userinfo').json()['sub']
    await revoke_consent_sessions.asyncio( _client=hydra_service.hydra_client,
                                subject=subject,
                                client=client_id)

    return jsonify({})