Weekly email of new members in a Telegram group

from clickruntime import on_trigger, credentials, http, state, notify

GROUP = -1001234567890

def tg(method, **params):
    r = http.post(f"https://api.telegram.org/bot{credentials.secret('TELEGRAM_BOT_TOKEN')}/{method}", json=params)
    r.raise_for_status()
    return r.json()["result"]

def who(u):
    name = " ".join(filter(None, [u.get("first_name"), u.get("last_name")]))
    return f"{name} (@{u['username']})" if u.get("username") else name

@on_trigger
def run(event):
    log = state.get("log") or {"joined": [], "left": []}
    cm = (event.get("json") or {}).get("chat_member")
    if cm:  # webhook update
        if cm["chat"]["id"] != GROUP:
            return {"skipped": True}
        old, new = cm["old_chat_member"]["status"], cm["new_chat_member"]["status"]
        member = ("member", "administrator", "creator", "restricted")
        if old not in member and new in member:
            log["joined"].append(who(cm["new_chat_member"]["user"]))
        elif old in member and new not in member:
            log["left"].append(who(cm["new_chat_member"]["user"]))
        state.set("log", log)
        return {"recorded": True}
    count = tg("getChatMemberCount", chat_id=GROUP)  # weekly report
    net = len(log["joined"]) - len(log["left"])
    body = (f"Joined ({len(log['joined'])}): " + (", ".join(log["joined"]) or "none") +
            f"\n\nLeft ({len(log['left'])}): " + (", ".join(log["left"]) or "none") +
            f"\n\nNet change: {net:+d} · Members now: {count:,}")
    notify.email_me(subject=f"Telegram group: {net:+d} this week", body=body)
    state.set("log", {"joined": [], "left": []})
    return {"net": net}