Get a morning count of new users and orders

from datetime import date, timedelta
from clickruntime import on_trigger, credentials, http, notify

PROJECT = "acme-prod"
FS = f"https://firestore.googleapis.com/v1/projects/{PROJECT}/databases/(default)/documents"

def fs_headers():
    return {"Authorization": f"Bearer {credentials.connection('google', 'work')}"}

def val(field):
    return next(iter(field.values())) if field else None

def count(collection, start, end):
    filters = [{"fieldFilter": {"field": {"fieldPath": "createdAt"}, "op": op, "value": {"timestampValue": f"{d}T00:00:00Z"}}}
               for op, d in (("GREATER_THAN_OR_EQUAL", start), ("LESS_THAN", end))]
    body = {"structuredAggregationQuery": {"aggregations": [{"alias": "n", "count": {}}], "structuredQuery": {
        "from": [{"collectionId": collection}], "where": {"compositeFilter": {"op": "AND", "filters": filters}}}}}
    result = http.post(f"{FS}:runAggregationQuery", json=body, headers=fs_headers()).json()[0]["result"]
    return int(result["aggregateFields"]["n"]["integerValue"])

@on_trigger
def run(event):
    today = date.today()
    y, d2 = today - timedelta(days=1), today - timedelta(days=2)
    lines = []
    for c in ("users", "orders"):
        now, before = count(c, y, today), count(c, d2, y)
        lines.append(f"{c}: {now} ({now - before:+d} vs the day before)")
    notify.email_me(f"Firestore new documents {y}", "\n".join(lines))
    return {"lines": lines}