#!/usr/bin/env python
'''
Simulates gravitational movement of a solar system.

Takes one argument: integer number of planets.
'''
import visual, time, sys
from system import SolarSystem

class SolarSim(object):
    def __init__(self, nPlanets):
        self.ss = SolarSystem(nPlanets)
        visual.scene.scale = (0.1, 0.1, 0.1)
    def go(self):
        while True:
            self.ss.move()
            time.sleep(0.02)

if __name__ == '__main__':
    try:
        nPlanets = int(sys.argv[1])
    except IndexError:
        nPlanets = 6
    except:
        print __doc__
        sys.exit()
    sim = SolarSim(nPlanets)
    sim.go()