"""``geopy.units`` module provides utility functions for performing
angle and distance unit conversions.

Some shortly named aliases are provided for convenience (e.g.
:func:`.km` is an alias for :func:`.kilometers`).
"""

import math

# Angles


def degrees(radians=0, arcminutes=0, arcseconds=0):
    """
    Convert angle to degrees.
    """
    deg = 0.
    if radians:
        deg = math.degrees(radians)
    if arcminutes:
        deg += arcminutes / arcmin(degrees=1.)
    if arcseconds:
        deg += arcseconds / arcsec(degrees=1.)
    return deg


def radians(degrees=0, arcminutes=0, arcseconds=0):
    """
    Convert angle to radians.
    """
    if arcminutes:
        degrees += arcminutes / arcmin(degrees=1.)
    if arcseconds:
        degrees += arcseconds / arcsec(degrees=1.)
    return math.radians(degrees)


def arcminutes(degrees=0, radians=0, arcseconds=0):
    """
    Convert angle to arcminutes.
    """
    if radians:
        degrees += math.degrees(radians)
    if arcseconds:
        degrees += arcseconds / arcsec(degrees=1.)
    return degrees * 60.


def arcseconds(degrees=0, radians=0, arcminutes=0):
    """
    Convert angle to arcseconds.
    """
    if radians:
        degrees += math.degrees(radians)
    if arcminutes:
        degrees += arcminutes / arcmin(degrees=1.)
    return degrees * 3600.


# Lengths

def kilometers(meters=0, miles=0, feet=0, nautical=0):
    """
    Convert distance to kilometers.
    """
    ret = 0.
    if meters:
        ret += meters / 1000.
    if feet:
        ret += feet / ft(1.)
    if nautical:
        ret += nautical / nm(1.)
    ret += miles * 1.609344
    return ret


def meters(kilometers=0, miles=0, feet=0, nautical=0):
    """
    Convert distance to meters.
    """
    return (kilometers + km(nautical=nautical, miles=miles, feet=feet)) * 1000


def miles(kilometers=0, meters=0, feet=0, nautical=0):
    """
    Convert distance to miles.
    """
    ret = 0.
    if nautical:
        kilometers += nautical / nm(1.)
    if feet:
        kilometers += feet / ft(1.)
    if meters:
        kilometers += meters / 1000.
    ret += kilometers / 1.609344
    return ret


def feet(kilometers=0, meters=0, miles=0, nautical=0):
    """
    Convert distance to feet.
    """
    ret = 0.
    if nautical:
        kilometers += nautical / nm(1.)
    if meters:
        kilometers += meters / 1000.
    if kilometers:
        miles += mi(kilometers=kilometers)
    ret += miles * 5280
    return ret


def nautical(kilometers=0, meters=0, miles=0, feet=0):
    """
    Convert distance to nautical miles.
    """
    ret = 0.
    if feet:
        kilometers += feet / ft(1.)
    if miles:
        kilometers += km(miles=miles)
    if meters:
        kilometers += meters / 1000.
    ret += kilometers / 1.852
    return ret


# Compatible names

rad = radians
arcmin = arcminutes
arcsec = arcseconds
km = kilometers
m = meters
mi = miles
ft = feet
nm = nautical