from datetime import datetime, time
import pytz
import logging


logger = logging.getLogger(__name__)


class MarketHours:
    """
    Utility class for determining NYSE market hours.
    Market is open 9:30 AM - 4:00 PM ET, Monday-Friday (excluding holidays).
    """

    NYSE_TIMEZONE = pytz.timezone('America/New_York')
    MARKET_OPEN = time(9, 30)
    MARKET_CLOSE = time(16, 0)

    # Major NYSE holidays (this is a simplified list - production systems would use a holiday calendar API)
    HOLIDAYS_2024 = [
        datetime(2024, 1, 1),   # New Year's Day
        datetime(2024, 1, 15),  # MLK Day
        datetime(2024, 2, 19),  # Presidents Day
        datetime(2024, 3, 29),  # Good Friday
        datetime(2024, 5, 27),  # Memorial Day
        datetime(2024, 6, 19),  # Juneteenth
        datetime(2024, 7, 4),   # Independence Day
        datetime(2024, 9, 2),   # Labor Day
        datetime(2024, 11, 28), # Thanksgiving
        datetime(2024, 12, 25), # Christmas
    ]

    HOLIDAYS_2025 = [
        datetime(2025, 1, 1),   # New Year's Day
        datetime(2025, 1, 20),  # MLK Day
        datetime(2025, 2, 17),  # Presidents Day
        datetime(2025, 4, 18),  # Good Friday
        datetime(2025, 5, 26),  # Memorial Day
        datetime(2025, 6, 19),  # Juneteenth
        datetime(2025, 7, 4),   # Independence Day
        datetime(2025, 9, 1),   # Labor Day
        datetime(2025, 11, 27), # Thanksgiving
        datetime(2025, 12, 25), # Christmas
    ]

    @classmethod
    def is_market_open(cls, check_time: datetime = None) -> bool:
        """
        Determine if the NYSE is currently open.

        Args:
            check_time: Datetime to check (defaults to now)

        Returns:
            True if market is open, False otherwise
        """
        if check_time is None:
            check_time = datetime.now(cls.NYSE_TIMEZONE)
        else:
            check_time = check_time.astimezone(cls.NYSE_TIMEZONE)

        # Check if weekend
        if check_time.weekday() >= 5:  # Saturday = 5, Sunday = 6
            logger.debug("Market closed: Weekend")
            return False

        # Check if holiday
        check_date = check_time.date()
        all_holidays = cls.HOLIDAYS_2024 + cls.HOLIDAYS_2025
        if any(holiday.date() == check_date for holiday in all_holidays):
            logger.debug(f"Market closed: Holiday ({check_date})")
            return False

        # Check if within market hours
        current_time = check_time.time()
        if cls.MARKET_OPEN <= current_time < cls.MARKET_CLOSE:
            return True
        else:
            logger.debug(f"Market closed: Outside trading hours ({current_time})")
            return False

    @classmethod
    def get_next_market_open(cls, from_time: datetime = None) -> datetime:
        """
        Calculate the next time the market will open.

        Args:
            from_time: Starting datetime (defaults to now)

        Returns:
            Datetime of next market open
        """
        if from_time is None:
            from_time = datetime.now(cls.NYSE_TIMEZONE)
        else:
            from_time = from_time.astimezone(cls.NYSE_TIMEZONE)

        # Start checking from the next day at market open
        next_day = from_time.replace(hour=cls.MARKET_OPEN.hour,
                                       minute=cls.MARKET_OPEN.minute,
                                       second=0,
                                       microsecond=0)

        # If we have not passed today's open time, check today first
        if from_time.time() < cls.MARKET_OPEN:
            next_day = next_day
        else:
            # Otherwise start from tomorrow
            next_day = next_day.replace(day=next_day.day + 1)

        # Find the next valid market day
        max_iterations = 14  # Search up to 2 weeks ahead
        for _ in range(max_iterations):
            if cls.is_market_open(next_day):
                return next_day
            # Move to next day
            next_day = next_day.replace(day=next_day.day + 1)

        # Fallback (should not reach here under normal circumstances)
        logger.warning("Could not determine next market open within 2 weeks")
        return next_day