"""RFC 822 / HTTP date formatting.

Ported from net.i2p.util.RFC822Date.
"""

from __future__ import annotations

import time
from email.utils import formatdate, parsedate_to_datetime


def to_rfc822(timestamp_ms: int) -> str:
    """Convert millisecond timestamp to RFC 822 date string."""
    return formatdate(timeval=timestamp_ms / 1000.0, usegmt=True)


def parse_rfc822(date_str: str) -> int | None:
    """Parse an RFC 822 date string to millisecond timestamp.

    Returns None if parsing fails.
    """
    try:
        dt = parsedate_to_datetime(date_str)
        return int(dt.timestamp() * 1000)
    except Exception:
        return None