# tools/julian.py

from datetime import datetime, timedelta
import math


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

    time = date.timestamp() * 1000

    offset = date.utcoffset()
    tzoffset = offset.total_seconds() // 60 if offset is not None else 0

    return (time / 86400000) - (tzoffset / 1440) + 2440587.5


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


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


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


def future_julian_date(hoursadd=0, minutesadd=0, secondsadd=0):
    """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):
    """returns days since Jan 1st, 2000. Negative if before this date"""
    return julian_date(date) - 2451545


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


def from_julian(j):
    """Returns datetime.datetime object given julian date J"""
    J1970 = 2440588
    dayMs = 24 * 60 * 60 * 1000
    return datetime.fromtimestamp((j + 0.5 - J1970) * dayMs / 1000.0)