Track your spending from receipt emails

import re
from datetime import date
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from clickruntime import on_trigger, credentials, state, notify, report_fetched

@on_trigger
def run(event):
    gmail = build("gmail", "v1", credentials=Credentials(credentials.connection("google", "work")), cache_discovery=False)
    seen = set(state.get("seen") or [])
    msgs = gmail.users().messages().list(userId="me", maxResults=20,
                                         q="from:(uber.com OR deliveroo.co.uk) subject:(receipt OR order) newer_than:2d").execute().get("messages", [])
    new = [m for m in msgs if m["id"] not in seen]
    report_fetched(len(new))
    if not new:
        return {"new": 0}
    month = date.today().strftime("%Y-%m")
    total = state.get(f"total:{month}") or 0.0
    for m in new:
        msg = gmail.users().messages().get(userId="me", id=m["id"], format="metadata", metadataHeaders=["Subject"]).execute()
        subject = msg["payload"]["headers"][0]["value"]
        amount = float((re.search(r"£\s?(\d+[.,]\d{2})", msg["snippet"]) or re.search(r"(\d+\.\d{2})", msg["snippet"]) or [0, "0"])[1].replace(",", "."))
        place = re.sub(r"^(Your|Order|Receipt).*?(from|for)\s+", "", subject, flags=re.I)
        total += amount
        notify.slack(f"🍔 {place}: £{amount:.2f} (month so far £{total:.2f})", channel="#spending")
    state.set(f"total:{month}", total)
    state.set("seen", [m["id"] for m in msgs])
    return {"new": len(new), "month_total": total}