from datetime import datetime, time
from zoneinfo import ZoneInfo

from app.api.schemas import MarketState


def get_market_state(now: datetime | None = None) -> MarketState:
    current = now or datetime.now(ZoneInfo("Asia/Shanghai"))
    current_time = current.time()

    if current_time < time(9, 30):
        return "pre_open"
    if time(9, 30) <= current_time < time(12, 0):
        return "trading_am"
    if time(12, 0) <= current_time < time(13, 0):
        return "midday_break"
    if time(13, 0) <= current_time < time(16, 0):
        return "trading_pm"
    if time(16, 0) <= current_time < time(16, 10):
        return "finalizing"
    return "closed"