Win back failed payments with a friendly email

import base64, time
from email.message import EmailMessage
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
import stripe
from clickruntime import on_event, on_trigger, credentials, verify, state, ai

def send(to, subject, text):
    msg = EmailMessage(); msg["To"], msg["Subject"] = to, subject; msg.set_content(text)
    g = build("gmail", "v1", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False)
    g.users().messages().send(userId="me", body={"raw": base64.urlsafe_b64encode(msg.as_bytes()).decode()}).execute()

@on_event
def handle(event):
    if not verify.stripe(event.body, event.header("Stripe-Signature"), credentials.secret("STRIPE_WEBHOOK_SECRET")):
        return {"ignored": "bad signature"}
    inv = event.json["data"]["object"]
    send(inv["customer_email"], "Your payment didn't go through", ai.generate(f"Write a short, friendly email asking the customer to update "
         f"their card. Amount: {inv['amount_due'] / 100:.2f} {inv['currency'].upper()}. Link: {inv['hosted_invoice_url']}", max_output_tokens=250).text)
    state.set("pending", {**(state.get("pending") or {}), inv["id"]: time.time() + 3 * 86400})
    return {"emailed": inv["id"]}
@on_trigger
def remind(event):
    stripe.api_key, pending = credentials.secret("STRIPE_API_KEY"), state.get("pending") or {}
    for inv_id in [i for i, due in pending.items() if due <= time.time()]:
        inv = stripe.Invoice.retrieve(inv_id); pending.pop(inv_id)
        if inv.status == "open":
            send(inv.customer_email, "Reminder: payment still due", f"A quick reminder that your invoice is still open: {inv.hosted_invoice_url}")
    state.set("pending", pending)
    return {"waiting": len(pending)}