Book interviews for candidates you shortlist in Airtable

from datetime import datetime, timedelta, timezone
from clickruntime import on_trigger, credentials, http, report_fetched

AT = "https://api.airtable.com/v0/appXXXXXXXXXXXXXX/Candidates"
CAL = "https://www.googleapis.com/calendar/v3"

@on_trigger
def run(event):
    at = {"Authorization": f"Bearer {credentials.secret('AIRTABLE_API_KEY')}"}
    recs = http.get(AT, headers=at, params={"filterByFormula": "AND({Status} = 'Shortlisted', {Interview} = BLANK())"}).json()["records"]
    report_fetched(len(recs))
    if not recs:
        return {"new": 0}
    h = {"Authorization": f"Bearer {credentials.connection('google', 'work')}"}
    t = (datetime.now(timezone.utc) + timedelta(days=1)).replace(hour=9, minute=0, second=0, microsecond=0)
    busy = http.post(f"{CAL}/freeBusy", headers=h, json={"timeMin": t.isoformat(), "timeMax": (t + timedelta(days=10)).isoformat(),
                     "items": [{"id": "primary"}]}).json()["calendars"]["primary"]["busy"]
    taken = [(datetime.fromisoformat(b["start"]), datetime.fromisoformat(b["end"])) for b in busy]
    for r in recs:
        while t.weekday() > 4 or not 9 <= t.hour < 17 or any(t < e and t + timedelta(minutes=30) > s for s, e in taken):
            t += timedelta(minutes=30)
        f = r["fields"]
        http.post(f"{CAL}/calendars/primary/events", headers=h, params={"sendUpdates": "all"}, json={
            "summary": f"Interview: {f['Name']}", "attendees": [{"email": f["Email"]}],
            "start": {"dateTime": t.isoformat()}, "end": {"dateTime": (t + timedelta(minutes=30)).isoformat()}})
        http.patch(f"{AT}/{r['id']}", headers=at, json={"fields": {"Interview": t.isoformat()}})
        taken.append((t, t + timedelta(minutes=30)))
    return {"booked": len(recs)}