from datetime import datetime, timedelta


def _time_of_day_label(hour: int, *, for_today: bool) -> str:
    if 5 <= hour < 12:
        return "morning"
    if 12 <= hour < 17:
        return "afternoon"
    return "tonight" if for_today else "night"


def describe_relative_time(
    timestamp_str: str,
    reference_time: datetime,
    *,
    prefer_day_part_for_today: bool = False,
) -> str:
    try:
        timestamp = datetime.strptime(timestamp_str, "%Y-%m-%d %H:%M")
    except ValueError:
        return "a long time ago"

    delta = reference_time - timestamp
    seconds = delta.total_seconds()
    if seconds < 0:
        return "just now"

    if not prefer_day_part_for_today:
        if seconds < 120:
            return "just now"
        if seconds < 15 * 60:
            return "a few minutes ago"
        if seconds < 90 * 60:
            return "an hour ago"
        if seconds < 3 * 60 * 60:
            return "a couple hours ago"

    day_diff = (reference_time.date() - timestamp.date()).days
    if day_diff == 0:
        return f"today {_time_of_day_label(timestamp.hour, for_today=True)}"
    if day_diff == 1:
        return f"yesterday {_time_of_day_label(timestamp.hour, for_today=False)}"
    if day_diff == 2:
        return "2 days ago"
    if day_diff == 3:
        return "3 days ago"
    if day_diff <= 6:
        return "a couple days ago"
    if day_diff <= 10:
        return "a week ago"
    if day_diff <= 20:
        return "a couple weeks ago"
    if day_diff <= 45:
        return "a month ago"
    if day_diff <= 75:
        return "a couple months ago"
    if day_diff <= 420:
        return "a year ago"
    return "a long time ago"


class WorldClock:
    def __init__(self, start_year=1999, month=5, day=14, hour=18, minute=0):
        # We use a standard datetime object for easy math
        self.current_time = datetime(start_year, month, day, hour, minute)

    def advance_time(self, minutes=0, hours=0, days=0):
        self.current_time += timedelta(minutes=minutes, hours=hours, days=days)

    def get_time_str(self):
        # 1999-05-14 18:00
        return self.current_time.strftime("%Y-%m-%d %H:%M")

    def get_vibe(self):
        """Helper to tell the LLM the 'feel' of the time."""
        hour = self.current_time.hour
        if 5 <= hour < 12:
            return "Morning"
        if 12 <= hour < 17:
            return "Afternoon"
        if 17 <= hour < 21:
            return "Evening"
        return "Night"

    @classmethod
    def from_time_str(cls, time_str: str | None):
        if not time_str:
            return cls()
        parsed = datetime.strptime(time_str, "%Y-%m-%d %H:%M")
        return cls(
            start_year=parsed.year,
            month=parsed.month,
            day=parsed.day,
            hour=parsed.hour,
            minute=parsed.minute,
        )