Offer cancelled appointments to your waitlist by text

from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from twilio.rest import Client
from datetime import datetime, timezone
from clickruntime import on_trigger, on_event, credentials, http, state, report_fetched

WAITLIST = {"+447700900111": "Ali", "+447700900222": "Bo"}
FROM = "+15005550006"

def sms(to, body):
    return Client(credentials.secret("TWILIO_ACCOUNT_SID"), credentials.secret("TWILIO_AUTH_TOKEN")).messages.create(to=to, from_=FROM, body=body)
cal = lambda: build("calendar", "v3", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False).events()

@on_trigger
def run(event):
    now = datetime.now(timezone.utc).isoformat()
    since = state.get("since") or now
    state.set("since", now)
    items = cal().list(calendarId="primary", updatedMin=since, showDeleted=True, singleEvents=True).execute()["items"]
    gone = [e for e in items if e["status"] == "cancelled" and e.get("start", {}).get("dateTime", "") > now]
    report_fetched(len(gone))
    if not gone:
        return {"summary": "No cancellations"}
    state.set("open", {"start": gone[0]["start"], "end": gone[0]["end"]})
    for phone in WAITLIST:
        sms(phone, f"A slot opened: {gone[0]['start']['dateTime'][:16].replace('T', ' ')}. Reply YES to take it.")
    return {"offered": gone[0]["start"]["dateTime"]}

@on_event
def handle(event):
    f, slot = event.json or {}, state.get("open")
    if (f.get("Body") or "").strip().upper() != "YES" or f.get("From") not in WAITLIST:
        return {"skipped": True}
    if slot:
        cal().insert(calendarId="primary", body={"summary": f"Appointment – {WAITLIST[f['From']]}", "description": f["From"], **slot}).execute()
        state.delete("open")
    sms(f["From"], "You're booked! See you then." if slot else "Sorry, that slot has already been filled.")
    return {"booked": bool(slot)}