Confirm appointments, remind clients and rebook no-shows

from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from twilio.rest import Client
import base64
from datetime import datetime, timedelta, timezone
from clickruntime import on_trigger, credentials, http, state

FEED = "https://bookings.example.com/api/appointments"
REBOOK = "https://bookings.example.com/book"
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)
gmail = lambda: build("gmail", "v1", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False).users()

def send_email(to, subject, text):
    gmail().messages().send(userId="me", body={"raw": base64.urlsafe_b64encode(f"To: {to}\r\nSubject: {subject}\r\n\r\n{text}".encode()).decode()}).execute()

@on_trigger
def run(event):
    done, now, sent = set(state.get("done") or []), datetime.now(timezone.utc), 0
    for a in http.get(FEED, headers={"Authorization": f"Bearer {credentials.secret('BOOKINGS_TOKEN')}"}).json():
        at = datetime.fromisoformat(a["start"]); when = at.strftime("%a %d %b %H:%M")
        if f"c{a['id']}" not in done:
            send_email(a["email"], "Your appointment is confirmed", f"Hi {a['name']}, see you on {when}.")
            sms(a["phone"], f"Confirmed: {when}. Reply C to cancel."); done.add(f"c{a['id']}"); sent += 1
        if f"r{a['id']}" not in done and now < at <= now + timedelta(hours=24):
            sms(a["phone"], f"Reminder: your appointment is tomorrow, {when}."); done.add(f"r{a['id']}"); sent += 1
        if a.get("status") == "no_show" and f"n{a['id']}" not in done:
            send_email(a["email"], "Sorry we missed you", f"Hi {a['name']}, no problem. Rebook here: {REBOOK}")
            sms(a["phone"], f"Sorry we missed you today. Rebook any time: {REBOOK}"); done.add(f"n{a['id']}"); sent += 1
    state.set("done", sorted(done)[-3000:])
    return {"sent": sent}