Flag meetings on public holidays and post the on-call rota in Slack

from datetime import date, timedelta
from clickruntime import on_trigger, credentials, http, state, notify

CAL, COUNTRIES = "team@yourco.example", ["GB", "DE"]
ROTA = ["Alex", "Sam", "Priya", "Jonas"]

@on_trigger
def run(event):
    h = {"Authorization": f"Bearer {credentials.connection('google', 'work')}"}
    start = date.today()
    end = start + timedelta(days=14)
    events = http.get(f"https://www.googleapis.com/calendar/v3/calendars/{CAL}/events", headers=h, params={
        "timeMin": f"{start}T00:00:00Z", "timeMax": f"{end}T00:00:00Z", "singleEvents": True}).json().get("items", [])
    holidays = {}
    for c in COUNTRIES:
        for d in http.get(f"https://date.nager.at/api/v3/PublicHolidays/{start.year}/{c}").json():
            holidays.setdefault(d["date"], []).append(f"{d['localName']} ({c})")
    conflicts = [f"• {e.get('summary')} on {e['start']['dateTime'][:10]}: {', '.join(holidays[e['start']['dateTime'][:10]])}"
                 for e in events if "dateTime" in e["start"] and e["start"]["dateTime"][:10] in holidays]
    away = " ".join(e.get("summary", "") for e in events if "date" in e["start"] and e["start"]["date"] < str(start + timedelta(days=7)))
    i = state.get("next") or 0
    for _ in ROTA:
        person, i = ROTA[i % len(ROTA)], i + 1
        if person not in away:
            break
    state.set("next", i % len(ROTA))
    notify.slack(f"On call this week: *{person}*\n" + ("Holiday conflicts:\n" + "\n".join(conflicts) if conflicts else "No holiday conflicts."), channel="#team")
    return {"on_call": person, "conflicts": len(conflicts)}