from Tkinter import *
import math
import random

class Vector:
    def __init__(self):
        r = range(1,5)
        self.x = random.choice(r)
        self.y = random.choice(r)
        self.Normalize()

    def Normalize(self):
        len = self.length()
        self.x /= len
        self.y /= len

    def length(self):
        return (math.sqrt(self.x*self.x + self.y*self.y))
        
class Circle(Frame):
    def __init__(self, parent):
        Frame.__init__(self)
        r = range(0,500)
        self.pack()
        self.center = (random.choice(r),random.choice(r))
        r = range(0,30)
        self.radius = random.choice(r)+2
        self.msecs = 1
        self.vec = Vector()
        self.canvas = parent
        canvas.pack()
        self.physical = self.canvas.create_oval((self.center[0]-self.radius),
                                           (self.center[1]-self.radius),
                                           (self.center[0]+self.radius),
                                           (self.center[1]+self.radius),
                                           width=1)
        self.Animate()
        
    def Animate(self):
        self.canvas.move(self.physical,self.vec.x*2,self.vec.y*2)
        self.center = ((self.center[0]+self.vec.x*2),(self.center[1]+self.vec.y*2))
        self.EdgeCollide()
        self.CirclesCollide()
        self.after(self.msecs,self.Animate)

    def CirclesCollide(self):
        global circles
        for c in circles:
            if c != self:
                #bounding box check
                if (abs(self.center[0]-c.center[0]) > (self.radius + c.radius)):
                    continue
                if (abs(self.center[1]-c.center[1]) > (self.radius + c.radius)):
                    continue

                #distance formula check
                if ((c.center[0]-self.center[0])*(c.center[0]-self.center[0]) +
                    (c.center[1]-self.center[1])*(c.center[1]-self.center[1]) < (self.radius+c.radius)*(self.radius+c.radius)):
                    #calculate new direction
                    self.vec.x = (-self.vec.x) + (self.center[0] - c.center[0])
                    self.vec.y = (-self.vec.y) + (self.center[1] - c.center[1])
                    self.vec.Normalize()
        
    def EdgeCollide(self):
        #left
        if ((self.center[0]-self.radius) <= 0):
            if (self.vec.x < 0):
                self.vec.x *= -1
           
        #right
        if ((self.center[0]+self.radius) >= 500):
            if (self.vec.x > 0):
                self.vec.x *= -1
                
        #top
        if ((self.center[1]-self.radius) <= 0):
            if (self.vec.y < 0):
                self.vec.y *= -1
                
        #bottom
        if ((self.center[1]+self.radius) >= 500):
            if (self.vec.y > 0):
                self.vec.y *= -1

#globals
bucketsOn=1
circles = []

###########################################################
# Name:     showBuckets
# Purpose:  toggle the display of the buckets on and off
###########################################################
def showBuckets():
    global bucketsOn
    if bucketsOn:
        bucketsOn=0
    else:
        bucketsOn=1

#code execution starts here
if __name__ == '__main__':     
    root = Tk()

    #create the canvas for the circles to exist in
    canvas = Canvas(root, width=500, height=500, bg='white')
    canvas.pack(expand=YES, fill=BOTH)

    #create the menu
    top = Menu(root)
    root.config(menu=top)
    file=Menu(top)                                                  #File menu
    file.add_command(label='Quit', command=root.quit, underline=0)
    top.add_cascade(label='File', menu=file, underline=0)
    options=Menu(top)
    options.add_command(label='Show Buckets', command=showBuckets, underline=0)
    top.add_cascade(label='Options', menu=options, underline=0)

    #create the circles
    r=range(0,30)
    for i in r:
        circles.append(Circle(canvas))

    root.mainloop()