# tools/julian.py

from datetime import datetime, timedelta
import math


def julian_date(date: datetime | None = None) -> float:
    """Given any date in the future or past, return julian date"""
    if date is None:
        date = datetime.now()

    time_ms = date.timestamp() * 1000
    return (time_ms / 86400000) + 2440587.5


def CJDN(date: datetime | None = None) -> int:
    return round(julian_date(date))


def current_julian_date() -> float:
    """Returns current julian date"""
    return julian_date()


def tomorrow_julian_date() -> float:
    """returns tomorrow's julian date"""
    date = datetime.now() + timedelta(days=1)
    return julian_date(date)


def future_julian_date(
    hoursadd: int = 0, minutesadd: int = 0, secondsadd: int = 0
) -> float:
    """defaults to current if no specifications made. HOURS, MINUTES, AND SECONDS CANNOT BE NEGATIVE"""
    date = datetime.now() + timedelta(
        hours=hoursadd, minutes=minutesadd, seconds=secondsadd
    )
    return julian_date(date)


def epoch_days(date: datetime | None = None) -> float:
    """returns days since Jan 1st, 2000. Negative if before this date"""
    return julian_date(date) - 2451545.0


def day_percent(date: datetime | None = None) -> float:
    """Returns decimal portion of Julian Date"""
    whole = julian_date(date)
    return whole - math.floor(whole)


def from_julian(j: float) -> datetime:
    """Returns datetime.datetime object given julian date J"""
    J1970 = 2440588.0
    dayMs = 24 * 60 * 60 * 1000
    return datetime.fromtimestamp((j + 0.5 - J1970) * dayMs / 1000.0)