from authlib.integrations.base_client.errors import MissingTokenError, InvalidTokenError
from base64 import b64encode, b64decode
from fido2 import cbor
from fido2.client import ClientData
from fido2.ctap2 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({})