from datetime import datetime
from zoneinfo import ZoneInfo

ET_TZ = ZoneInfo('America/New_York')
UTC_TZ = ZoneInfo('UTC')

def now_et():
    return datetime.now(ET_TZ)

def now_utc():
    return datetime.now(UTC_TZ)

def fmt_et(dt: datetime | None = None, with_date: bool = True) -> str:
    if dt is None:
        dt = now_et()
    return dt.strftime('%Y-%m-%d %H:%M:%S' if with_date else '%H:%M:%S')

def fmt_et_hm(dt: datetime | None = None) -> str:
    if dt is None:
        dt = now_et()
    return dt.strftime('%H:%M:%S')

def fmt_utc(dt: datetime | None = None) -> str:
    if dt is None:
        dt = now_utc()
    return dt.strftime('%Y-%m-%d %H:%M:%S')