ticketfrei3/kibicara/platforms/email/webapi.py

# Copyright (C) 2020 by Maike <maike@systemli.org>
#
# SPDX-License-Identifier: 0BSD

from fastapi import APIRouter, Depends, HTTPException, status
from kibicara.platforms.email.bot import spawner
from kibicara.platforms.email.model import Email, EmailSubscribers
from kibicara.platformapi import Message
from kibicara.config import config
from kibicara.email import send_email
from kibicara.webapi.hoods import get_hood, get_hood_unauthorized
from pydantic import BaseModel
from ormantic.exceptions import NoMatch, MultipleMatches
from sqlite3 import IntegrityError
from kibicara.webapi.admin import from_token, to_token
from os import urandom
from smtplib import SMTPException
from logging import getLogger


logger = getLogger(__name__)


class BodyMessage(BaseModel):
    """ This model shows which values are supplied by the MDA listener script. """

    text: str
    author: str
    secret: str


class Subscriber(BaseModel):
    """ This model holds the email address of a fresh subscriber. """

    email: str


async def get_email(hood, email_id=None):
    try:
        return await Email.objects.get(hood=hood)
    except NoMatch:
        return HTTPException(status_code=status.HTTP_404_NOT_FOUND)
    except MultipleMatches:
        # Email rows *should* be unique - the unique constraint doesn't work yet though.
        if email_id is None:
            email_id = hood.id
        return await Email.objects.get(hood=hood, id=email_id)


router = APIRouter()


@router.post('/', status_code=status.HTTP_201_CREATED)
async def email_create(hood=Depends(get_hood)):
    """ Create an Email bot. Call this when creating a hood.

    :param hood: Hood.id of the hood the Email bot is supposed to belong to.
    :return: Email row of the new email bot.
    """
    try:
        email_row = await Email.objects.create(hood=hood, secret=urandom(32).hex())
        spawner.start(email_row)
        return email_row
    except IntegrityError:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT)


@router.delete('/{email_id}', status_code=status.HTTP_200_OK)
async def email_delete(email_id, hood=Depends(get_hood)):
    """ Delete an Email bot. Call this when deleting a hood.
    Stops and deletes the Email bot as well as all subscribers.

    :param hood: Hood the Email bot belongs to.
    """
    email_row = await get_email(hood, email_id=email_id)
    spawner.stop(email_row)
    await EmailSubscribers.objects.delete_many(hood=hood.id)
    await email_row.delete()


@router.post('/subscribe/', status_code=status.HTTP_200_OK)
async def email_subscribe(subscriber: Subscriber, hood=Depends(get_hood_unauthorized)):
    """ Send a confirmation mail to subscribe to messages via email.

    :param subscriber: Subscriber object, holds the email address.
    :param hood: Hood the Email bot belongs to.
    :return: Returns status code 200 after sending confirmation email.
    """
    token = to_token(email=subscriber.email)
    confirm_link = (
        config['root_url'] + "api/" + str(hood.id) + "/email/subscribe/confirm/" + token
    )
    try:
        send_email(
            subscriber.email,
            "Subscribe to Kibicara " + hood.name,
            sender=hood.name,
            body="To confirm your subscription, follow this link: " + confirm_link,
        )
    except ConnectionRefusedError:
        logger.info(token)
        logger.error("Sending subscription confirmation email failed.", exc_info=True)
        raise HTTPException(status_code=status.HTTP_502_BAD_GATEWAY)
    except SMTPException:
        logger.info(token)
        logger.error("Sending subscription confirmation email failed.", exc_info=True)
        raise HTTPException(status_code=status.HTTP_502_BAD_GATEWAY)


@router.get('/subscribe/confirm/{token}', status_code=status.HTTP_201_CREATED)
async def email_subscribe_confirm(token, hood=Depends(get_hood_unauthorized)):
    """ Confirm a new subscriber and add them to the database.

    :param token: encrypted JSON token, holds the email of the subscriber.
    :param hood: Hood the Email bot belongs to.
    :return: Returns status code 200 after adding the subscriber to the database.
    """
    payload = from_token(token)
    try:
        await EmailSubscribers.objects.create(hood=hood.id, email=payload['email'])
    except IntegrityError:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT)


@router.get('/unsubscribe/{token}', status_code=status.HTTP_200_OK)
async def email_unsubscribe(token, hood=Depends(get_hood_unauthorized)):
    """ Remove a subscriber from the database when they click on an unsubscribe link.

    :param token: encrypted JSON token, holds subscriber email + hood.id.
    :param hood: Hood the Email bot belongs to.
    """
    logger.warning("token is: " + token)
    payload = from_token(token)
    # If token.hood and url.hood are different, raise an error:
    if hood.id is not payload['hood']:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST)
    await EmailSubscribers.objects.delete_many(
        hood=payload['hood'], email=payload['email']
    )


@router.post('/messages/{email_id}', status_code=status.HTTP_201_CREATED)
async def email_message_create(
    email_id, message: BodyMessage, hood=Depends(get_hood_unauthorized)
):
    """ Receive a message from the MDA and pass it to the censor.

    :param message: BodyMessage object, holds the message.
    :param hood: Hood the Email bot belongs to.
    :return: returns status code 201 if the message is accepted by the censor.
    """
    # get bot via "To:" header
    try:
        email_row = await get_email(hood, email_id=email_id)
    except HTTPException as exc:
        raise exc
    # check API secret
    logger.warning(str(message))
    logger.warning(str(email_row))
    if message.secret != email_row.secret:
        logger.warning(
            "Someone is trying to submit an email without the correct API secret"
        )
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)
    # pass message.text to bot.py
    if await spawner.get(email_row).publish(Message(message.text)):
        pass
    else:
        raise HTTPException(status_code=status.HTTP_451_UNAVAILABLE_FOR_LEGAL_REASONS)