app_utils.py

from functools import wraps
from typing import Any, Callable
import uuid
from werkzeug.contrib.cache import SimpleCache

from flask import abort, redirect, request

import config
# from authentication import Authentication
from authorization import Authorization
from calendar_data import CalendarData
from constants import SESSION_ID
from exporters.icalendar import ICalendar
from gregorian_calendar import GregorianCalendar


cache = SimpleCache()


def authenticated(decorated_function: Callable) -> Any:
    @wraps(decorated_function)
    def wrapper(*args: Any, **kwargs: Any) -> Any:
        session_id = request.cookies.get(SESSION_ID)
        if session_id is None or not is_session_valid(str(session_id)):
            if request.headers.get("Content-Type", "") == "application/json":
                abort(401)
            return redirect("/login")
        return decorated_function(*args, **kwargs)
    return wrapper


def authorized(decorated_function: Callable) -> Any:
    @wraps(decorated_function)
    def wrapper(*args: Any, **kwargs: Any) -> Any:
        username = get_session_username(str(request.cookies.get(SESSION_ID)))
        authorization = Authorization(calendar_data=CalendarData(data_folder=config.DATA_FOLTER))
        if "calendar_id" not in kwargs:
            raise ValueError("calendar_id")
        calendar_id = str(kwargs["calendar_id"])
        if not authorization.can_access(username=username, calendar_id=calendar_id):
            abort(403)
        return decorated_function(*args, **kwargs)
    return wrapper


def previous_month_link(year: int, month: int) -> str:
    month, year = GregorianCalendar.previous_month_and_year(year=year, month=month)
    return "" if year < config.MIN_YEAR or year > config.MAX_YEAR else "?y={}&m={}".format(year, month)


def next_month_link(year: int, month: int) -> str:
    month, year = GregorianCalendar.next_month_and_year(year=year, month=month)
    return "" if year < config.MIN_YEAR or year > config.MAX_YEAR else "?y={}&m={}".format(year, month)


def new_session_id() -> str:
    return str(uuid.uuid4())


def is_session_valid(session_id: str) -> bool:
    return cache.get(session_id) is not None


def add_session(session_id: str, username: str) -> None:
    cache.set(session_id, username, timeout=2678400)    # 1 month


def get_session_username(session_id: str) -> str:
    return str(cache.get(session_id))


def export_to_icalendar(calendar_data: CalendarData, calendar_id: str) -> bool:
    if not config.FEATURE_FLAG_ICAL_EXPORT:
        return True

    session_id = str(request.cookies.get(SESSION_ID))
    username = get_session_username(session_id)
    data = calendar_data.load_calendar(calendar_id)

    # TODO: set output folder from config, etc. and write the data. helper for filename format?
    # detect if ics_key key not present and throw exception to force configuration.

    # authentication = Authentication(
    #     data_folder=config.USERS_DATA_FOLDER, password_salt=config.PASSWORD_SALT,
    #     failed_login_delay_base=config.FAILED_LOGIN_DELAY_BASE
    # )
    # authentication.user_data(username=username)["ics_key"]

    ical_exporter = ICalendar(username=username,
                              timezone=config.TIMEZONE,
                              months_to_export=config.MONTHS_TO_EXPORT)  # type: ICalendar
    ical_exporter.write(calendar_data=calendar_data, data=data)
    return True