Create a Xero invoice for each order and email it to the customer

import base64
from email.message import EmailMessage
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from clickruntime import on_event, credentials, http, ai
XERO = "https://api.xero.com/api.xro/2.0"
TENANT = "your-xero-tenant-id"

def xero(method, path, **kw):
    r = http.request(method, XERO + path, **kw, headers={"Accept": "application/json", "Xero-tenant-id": TENANT, "Authorization": "Bearer " + credentials.connection("xero", "company")})
    return r.raise_for_status() or r.json()

@on_event
def handle(event):
    order = event.json
    inv = xero("PUT", "/Invoices", json={"Invoices": [{"Type": "ACCREC", "Status": "AUTHORISED", "Reference": order.get("id", event.event_id),
               "Contact": {"Name": order["name"], "EmailAddress": order["email"]}, "DueDate": order.get("due"),
               "LineItems": [{"Description": i["name"], "Quantity": i["qty"], "UnitAmount": i["price"], "AccountCode": "200"} for i in order["items"]]}]})["Invoices"][0]
    r = http.get(f"{XERO}/Invoices/{inv['InvoiceID']}", headers={"Accept": "application/pdf", "Xero-tenant-id": TENANT,
                 "Authorization": "Bearer " + credentials.connection("xero", "company")})
    try:
        note = ai.generate(f"Write a two-sentence friendly thank-you for an order of {', '.join(i['name'] for i in order['items'])}.", max_output_tokens=80).text
    except ai.AIError:
        note = "Thank you for your order. Your invoice is attached."
    msg = EmailMessage()
    msg["To"], msg["Subject"] = order["email"], f"Invoice {inv['InvoiceNumber']} for your order"
    msg.set_content(f"Hi {order['name']},\n\n{note}\n\nTotal due: {inv['Total']:,.2f}")
    msg.add_attachment(r.content, maintype="application", subtype="pdf", filename=f"{inv['InvoiceNumber']}.pdf")
    gmail = build("gmail", "v1", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False)
    gmail.users().messages().send(userId="me", body={"raw": base64.urlsafe_b64encode(msg.as_bytes()).decode()}).execute()
    return {"invoice": inv["InvoiceNumber"]}