Book interviews automatically when you shortlist a candidate

import base64
from datetime import datetime, timedelta, timezone
from email.message import EmailMessage
from clickruntime import on_event, credentials, http

CAL = "https://www.googleapis.com/calendar/v3"

@on_event
def handle(event):
    c = event.json or {}
    h = {"Authorization": f"Bearer {credentials.connection('google', 'work')}"}
    start = (datetime.now(timezone.utc) + timedelta(days=1)).replace(hour=10, minute=0, second=0, microsecond=0)
    busy = http.post(f"{CAL}/freeBusy", headers=h, json={"timeMin": start.isoformat(), "timeMax": (start + timedelta(days=7)).isoformat(),
                     "items": [{"id": "primary"}]}).json()["calendars"]["primary"]["busy"]
    def free(s):
        return s.weekday() < 5 and 10 <= s.hour < 16 and all(s + timedelta(minutes=45) <= datetime.fromisoformat(b["start"]) or
                                                               s >= datetime.fromisoformat(b["end"]) for b in busy)
    while not free(start):
        start += timedelta(minutes=15)
    end = start + timedelta(minutes=45)
    ev = http.post(f"{CAL}/calendars/primary/events", headers=h, params={"conferenceDataVersion": 1}, json={
        "summary": f"Interview: {c['name']} ({c['role']})", "start": {"dateTime": start.isoformat()}, "end": {"dateTime": end.isoformat()},
        "attendees": [{"email": c["email"]}], "conferenceData": {"createRequest": {"requestId": event.event_id}}}).json()
    m = EmailMessage(); m["To"] = c["email"]; m["Subject"] = f"Interview for {c['role']}"
    m.set_content(f"Hi {c['name']},\n\nWe'd love to talk. Your interview is on {start:%A %d %B at %H:%M} UTC.\nJoin: {ev.get('hangoutLink')}\n\nReply if the time doesn't work.")
    http.post("https://gmail.googleapis.com/gmail/v1/users/me/messages/send", headers=h, json={"raw": base64.urlsafe_b64encode(m.as_bytes()).decode()})
    return {"booked": start.isoformat()}