from turtle import *
from math import sqrt
from geometry.validation import expect_type
from geometry.point import Point
from geometry.vector import Vector
from simulation import Simulation
from simulation.ball import Ball

def get_ball_positions(origin, spacing, columns=5):
    """Returns a list of Points in a triangle, growing to the right of position.
    spacing is the distance between each point,
    columns is the number of columns in the triangle, and
    jiggle is the amount of randomness to add to each ball's position.
    """
    expect_type(origin, Point)
    positions = []
    col_spacing = spacing * sqrt(3) / 2
    for col in range(columns):
        offset_x = col_spacing * col
        for row in range(col + 1):
            offset_y = spacing * (row - col / 2)
            offset = Vector((offset_x, offset_y))
            positions.append(origin + offset)
    return positions

r = 10
positions = get_ball_positions(Point((100, 0)), 2 * r + 2)
rack = [Ball(p, radius=r, color="red") for p in positions]
cue_ball = Ball(
    Point((-250, 0)), 
    radius=r, 
    velocity=Vector((9, 0)), 
    mass=1,
    color="white"
)

sim = Simulation(rack + [cue_ball], e=1, boundary=250)
sim.run(1000)