#!/usr/bin/env python

from datetime import datetime
from flask import Flask
from caldav import DAVClient, Calendar, Principal, Todo
import re
import configparser


def parseConfig() -> tuple[str, str, str, str]:
    def passwordFromFile() -> str:
        calDavPasswordFile = config.get("calDAV", "passwordFile")
        with open(calDavPasswordFile, "r") as file:
            return file.readline().strip()

    config = configparser.ConfigParser()
    # config.read("/etc/calDAVtoCSV/config.ini")
    config.read("/etc/calDAVtoCSV/config.ini")

    calDavAddress = config.get("calDAV", "address")
    calDavUsername = config.get("calDAV", "username")
    caldavpwd = config.get("calDAV", "password", fallback=None)
    caldavpwd = caldavpwd if caldavpwd is not None else passwordFromFile()
    calDavCalendarName = config.get("calDAV", "calendarName")
    return calDavAddress, calDavUsername, caldavpwd, calDavCalendarName


def fetch_10_next_todos_as_csv() -> str:
    def auth(add: str, user: str, pwd: str) -> Principal:
        # TODO: on the final version, fetch it locally
        client = DAVClient(url=add, username=user, password=pwd)
        principal = client.principal()
        return principal

    def get_calendar(principal: Principal, name: str) -> Calendar:
        calendar = principal.calendar(name=name)
        return calendar

    def filter_todos(todos: list[Todo]) -> list[Todo]:
        today = datetime.today().date()
        return [
            todo
            for todo in todos
            if (
                match := re.search(
                    r"\d{4}-\d{2}-\d{2}", todo.icalendar_component["due"]
                )
            )
            and datetime.strptime(match.group(), "%Y-%m-%d").date() > today
        ]

    def todos_to_csv(todos: list[Todo]) -> str:
        result = "".join(
            f"{todo.icalendar_component['uid']},{todo.icalendar_component['summary']}\n"
            for todo in todos
        )
        return result

    add, user, pwd, name = parseConfig()
    principal = auth(add, user, pwd)
    calendar = get_calendar(principal, name)

    sorted_todos = calendar.todos(sort_keys=("due"))
    cut_todos = sorted_todos[:10]
    filtered_todos = filter_todos(cut_todos)
    csv = todos_to_csv(filtered_todos)
    return csv


app = Flask(__name__)


@app.route("/")
def send_events():
    return fetch_10_next_todos_as_csv()


# not suitable for production apparently, just for testing
if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8000)