from datetime import datetime
import pytz


def format_absolute_datetime(date_time: datetime) -> str:
    """Generate a human-readable absolute time string."""
    now = datetime.now(tz=pytz.utc)
    format_str = ""
    if date_time.date() != now.date():
        format_str += "%Y-%m-%d"

        time_part = date_time.time()
        # Only add the relevant time parts
        if time_part.hour != 0 or time_part.minute != 0 or time_part.second != 0:
            if time_part.second != 0:
                format_str += " %H:%M:%S"
            else:
                format_str += " %H:%M"
    else:
        time_part = date_time.time()
        # Only add the relevant time parts
        if time_part.second != 0:
            format_str = "%H:%M:%S"
        else:
            format_str = "%H:%M"

    return date_time.strftime(format_str)