Approve supplier invoices in Slack before they go into Xero

import json
from urllib.parse import parse_qs
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from slack_sdk import WebClient
from clickruntime import on_trigger, on_event, credentials, http, state, ai, report_fetched
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_trigger
def run(event):
    gmail, seen = build("gmail", "v1", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False), set(state.get("seen") or [])
    msgs = [m for m in gmail.users().messages().list(userId="me", q="label:Invoices newer_than:3d").execute().get("messages", []) if m["id"] not in seen]
    report_fetched(len(msgs))
    if not msgs:
        return {"summary": "Nothing new"}
    for m in msgs:
        snippet = gmail.users().messages().get(userId="me", id=m["id"]).execute()["snippet"]
        f = ai.generate(f"Return JSON supplier, reference, amount from:\n{snippet}", max_output_tokens=80, json_schema={"type": "object",
                        "properties": {"supplier": {"type": "string"}, "reference": {"type": "string"}, "amount": {"type": "number"}}}).json
        buttons = [{"type": "button", "text": {"type": "plain_text", "text": t}, "action_id": t.lower(), "value": json.dumps(f)} for t in ("Approve", "Reject")]
        WebClient(token=credentials.connection("slack", "work")).chat_postMessage(channel="#finance", text=f"{f['supplier']} {f['reference']}: {f['amount']:,.2f}",
            blocks=[{"type": "section", "text": {"type": "mrkdwn", "text": f"*{f['supplier']}* {f['reference']}: {f['amount']:,.2f}"}}, {"type": "actions", "elements": buttons}])
        seen.add(m["id"])
    state.set("seen", list(seen)[-500:])
    return {"posted": len(msgs)}

@on_event
def clicked(event):
    p = json.loads(parse_qs(event.body)["payload"][0])
    action, f = p["actions"][0]["action_id"], json.loads(p["actions"][0]["value"])
    if action == "approve":
        xero("PUT", "/Invoices", json={"Invoices": [{"Type": "ACCPAY", "Status": "AUTHORISED", "Contact": {"Name": f["supplier"]}, "InvoiceNumber": f["reference"],
             "LineItems": [{"Description": f["reference"], "Quantity": 1, "UnitAmount": f["amount"], "AccountCode": "400"}]}]})
    WebClient(token=credentials.connection("slack", "work")).chat_update(channel=p["channel"]["id"], ts=p["message"]["ts"], blocks=[],
        text=f"{f['supplier']} {f['reference']} {f['amount']:,.2f}: {action}d by <@{p['user']['id']}>")
    return {"action": action}