Get alerted when a Stripe refund is issued

from clickruntime import on_event, credentials, notify, verify

@on_event
def handle(event):
    if not verify.stripe(event.body, event.header("Stripe-Signature"), credentials.secret("STRIPE_WEBHOOK_SECRET")):
        return {"ignored": "bad signature"}
    if event.json["type"] != "charge.refunded":
        return {"ignored": event.json["type"]}
    charge = event.json["data"]["object"]
    refund = charge["refunds"]["data"][0] if charge.get("refunds", {}).get("data") else None
    amount = (refund["amount"] if refund else charge["amount_refunded"]) / 100
    reason = (refund or {}).get("reason") or "no reason given"
    who = (charge.get("billing_details") or {}).get("email") or charge.get("receipt_email") or charge.get("customer") or "unknown"
    full = "fully refunded" if charge["refunded"] else f"{charge['amount_refunded'] / 100:,.2f} refunded so far"
    notify.slack(f":leftwards_arrow_with_hook: Refund of {amount:,.2f} {charge['currency'].upper()} to {who} ({reason})\n"
                 f"Original payment: {charge['amount'] / 100:,.2f} {charge['currency'].upper()}, "
                 f"{charge.get('description') or 'no description'} · {full}\n"
                 f"https://dashboard.stripe.com/payments/{charge['payment_intent']}", channel="#billing")
    return {"charge": charge["id"]}