"""
Timezone Utilities

Centralized timezone handling for the Discord bot. The SBA league operates
in America/Chicago time, but the production container may have ambiguous
timezone config. These helpers ensure scheduling logic uses explicit timezones
rather than relying on the OS default.

- Internal storage/logging: UTC
- Scheduling checks (freeze/thaw): America/Chicago
"""

from datetime import datetime, timezone
from zoneinfo import ZoneInfo

# League timezone — all scheduling decisions use this
CHICAGO_TZ = ZoneInfo("America/Chicago")


def now_utc() -> datetime:
    """Return the current time as a timezone-aware UTC datetime."""
    return datetime.now(timezone.utc)


def now_chicago() -> datetime:
    """Return the current time as a timezone-aware America/Chicago datetime."""
    return datetime.now(CHICAGO_TZ)


def to_chicago(dt: datetime) -> datetime:
    """Convert a datetime to America/Chicago.

    If *dt* is naive (no tzinfo), it is assumed to be UTC.
    """
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=timezone.utc)
    return dt.astimezone(CHICAGO_TZ)


def to_discord_timestamp(dt: datetime, style: str = "f") -> str:
    """Format a datetime as a Discord dynamic timestamp.

    Args:
        dt: A datetime (naive datetimes are assumed UTC).
        style: Discord timestamp style letter.
            R = relative, f = long date/short time, F = long date/time,
            t = short time, T = long time, d = short date, D = long date.

    Returns:
        A string like ``<t:1234567890:f>``.
    """
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=timezone.utc)
    return f"<t:{int(dt.timestamp())}:{style}>"