#!/usr/bin/env python

"""
particles "cannon" screen saver
written by Felix "Albert" Liard
"""

from graphics import *
from random import *
from time import *


class Particle:
    def __init__(self, window, colors, x=0, y=0):

        # position
        self.px = x
        self.py = y

        # direction
        self.dx = randint(5,25)
        self.dy = randint(-10,10)

        self.size = randint(4,25)
        self.color = colors[randint(0,len(colors)-1)]

        # once in a while... BIG & FAST particle
        if randint(1,100) == 42:  # 42 = answer to everything!
            self.size = 50
            self.dx = 25

        circle = Circle(Point(x,y),self.size)
        circle.setOutline(self.color)
        circle.setFill(self.color)
        circle.draw(window)
        self.circle = circle     # logical particle obj to physical circle


    def destroy(self, particles_list):
        del particles_list[self.circle]   # remove obj from dictionary
        self.circle.undraw()              # delete from screen
        del self.circle                   # remove physical object too!
        del self


def initialize_window(sizex,sizey,color='black'):
    w = GraphWin('Particles Cannon',sizex,sizey)
    w.setCoords(0,0,sizex,sizey)
    w.setBackground(color)
    seed()
    return w


def read_colors():
    colors = []
    with open('tclTK-colors.txt','r') as file:
        for line in file:
            (color,_) = line.strip().split(' ',1)
            colors.append(color)
    return colors


def main():
    particles_list = {}
    maxX = 1920
    maxY = 500
    Yorigin = 0
    Ydirection = 'UP'
    colors = read_colors()
    window = initialize_window(maxX,maxY)
    
    for _ in range(100):  # start with 100 objects
        particle = Particle(window, colors, 0, Yorigin)
        particles_list[particle.circle] = particle
    
    while True:
        # keep generating new particles as old ones leave screen
        particle = Particle(window, colors, 0, Yorigin)
        particles_list[particle.circle] = particle

        # origin of particle goes up/down along Y axis.. cool effect
        if Yorigin <= 0:
            Ydirection = 'UP'
        if Yorigin >= maxY:  # reverse when @top
            Ydirection = 'DOWN'
        Yorigin += 10 if Ydirection == 'UP' else -10

        # update position of all existing particles
        # c = phys circle, p = logical particle obj
        for c,p in particles_list.items():
            # EDGE detect, if not at edge keep moving
            if 0 < p.px+p.dx < maxX and 0 < p.py+p.dy < maxY: 
                p.px += p.dx
                p.py += p.dy
            # if at Y edge then alter course to "bounce"
            if p.py+p.dy >= maxY or p.py+p.dy <= 0:
                p.dy = -(p.dy)
                p.py += p.dy
            c.move(p.dx,p.dy)  #...finally, draw circle at next position

            # destroy when X edge reached (far left off-screen or far right)
            if p.px+p.dx >= maxX or p.px < -50:
                p.destroy(particles_list)


if __name__ == '__main__':
    main()