import urllib.error
from urllib.request import urlretrieve

import asyncio

import httpx
import icalendar
import json
import recurring_ical_events

from init import scheduler, app


async def fetchPlan(session, url):
    return await session.get(url=url)


def writeToFile(filename, data):
    with open(filename, 'w+') as f:
        f.write(data.text)
        f.close()


def parseURL(url: str):
    """
    Konvertiert URLs ins korrekte Format. \n
    Konvertiert werden: http, www.; page=calendar \n
    In: https; page=ical
    :param url:
    :return str:
    """
    rapla = url.find("rapla.")
    if rapla == -1:
        return 0
    elif len(url[:rapla]) == 4 or len(url[:rapla]) > 6:
        url = url[rapla:]
    http = url.find(":")
    if url[:http] == "http":
        url = "https" + url[http:]
    elif http == -1:
        url = "https://" + url
    p = url.find("page=")
    u = url.find("&")
    if (url[p + 5:u]).lower() == "ical":
        return url
    elif p != -1:
        return url[:p + 5] + "ical" + url[u:]
    else:
        return 0


async def getNewRapla(url: str):
    """
    Speichert den iCal eines Raplas auf dem Server. \n
    Gibt Namen der Datei zurück. \n
    TODO: Standort zu Dateibezeichner hinzufügen, um Konflikte zu vermeiden.
    :param url:
    :return str:
    """
    url = parseURL(url)
    if url == 0:
        return 0
    urlfile = url.find("file=")
    kurs = url[urlfile + 5:].upper()

    try:
        urlretrieve(url, "calendars/rapla" + kurs + ".ical")
        async with httpx.AsyncClient() as s:
            response = await fetchPlan(s, url)
            writeToFile(f"calendars/rapla{kurs}.ical", response)
    except urllib.error.URLError:
        return -1
    file = open("calendars/list.json", "r+")
    jsoncal = json.load(file)
    jsoncal.update({kurs: [f"rapla{kurs}.ical", url]})
    file.close()
    file = open("calendars/list.json", "w")
    json.dump(jsoncal, file, indent=4)
    return f"rapla{kurs}.ical"


def getIcal(kurs: str):
    """
    Liefert den Namen der Datei des mitgegebenen Kurses.
    :param kurs:
    :return str:
    """
    file = open("calendars/list.json", "r")
    jf = json.load(file)
    try:
        return jf[kurs][0]
    except KeyError:
        return None


def getRaplas():
    """
    Liefert alle auf dem Server gespeicherten Raplas.
    :return (Kursliste, Dateiliste, URL-Liste):
    """
    file = open("calendars/list.json", "r")
    jsonf = json.load(file)
    kursl = []
    filel = []
    urll = []
    for i in jsonf:
        kursl += [i]
        filel += [jsonf[i][0]]
        urll += [jsonf[i][1]]
    return sorted(kursl), sorted(filel), sorted(urll)


async def refreshRapla():
    """
    Aktualisiert alle 5 Minuten alle gespeicherten Raplas.
    """
    filel = getRaplas()[1]
    urll = getRaplas()[2]
    jobl = []
    async with httpx.AsyncClient() as s:
        for i in range(len(filel)):
            print(f"Update Rapla: {filel[i][:-5]}")
            jobl += [fetchPlan(s, urll[i])]
        callist = await asyncio.gather(*jobl, return_exceptions=True)
        for cal in range(len(callist)):
            writeToFile(f"calendars/{filel[cal]}", callist[cal])


@scheduler.task('cron', id="raplaschedule", hour='*', day_of_week='*', minute='*/15', week='*')
def raplaschedule():
    with app.app_context():
        asyncio.run(refreshRapla())