#! /usr/bin/python
# File: bsc.py
#       Makes 7 transmit switches and 7 noise switches and 7 received switches

from Tkinter import *
from random import *

def flipnoise(k=0):
    transmit()
    pass

def transmit():
    for n in range(N):
        r[n].set( (e[n].get() + t[n].get())%2 )
    pass

def makenoise():
    for n in range(N): ## get a random bit
        print n
        e[n].set( ( random()<f.get() ) )
    transmit()    
    pass

## Hint 2:   random()<f.get()

root = Tk() ## create a Tk root widget. This is an ordinary window
N = 7 ## number of switches

trow=2 ; erow=trow+1 ; rrow = trow+2

## Hint: how to make a noise level 'scale'
f = DoubleVar()
fscale = Scale( root, label="Noise level", variable=f, \
                 from_=0.0, to=1.0,resolution=0.01, orient="horizontal",sliderlength=25, length=250)
fscale.grid( row=rrow + 1 , column=0 , columnspan=N+1  )
## Endhint
f.set(0.2)

tlabel = Label(root, text="transmitted bits")
tlabel.grid(row=trow,column=0)
elabel = Label(root, text="noise flips")
elabel.grid(row=erow,column=0)
rlabel = Label(root, text="received bits")
rlabel.grid(row=rrow,column=0)

## make the switches
t =[] ; e=[] ; r=[] 
tswitches = []
eswitches = []
rswitches = []
for n in range(N) :
    t.append( IntVar() ) ## this makes the integer variable t[n]
    ## this makes tswitches[n]
    tswitches.append( Checkbutton( root , text=n , command=flipnoise , variable=t[n] ) )
    tswitches[n].grid(row=trow,column=n+1)
    e.append( IntVar() ) 
    eswitches.append( Checkbutton( root , text=n , command=flipnoise , variable=e[n] , selectcolor="red") )
    eswitches[n].grid(row=erow,column=n+1)
    r.append( IntVar() ) 
    rswitches.append( Checkbutton( root , text=n , variable=r[n] , selectcolor="yellow") )
    rswitches[n].grid(row=rrow,column=n+1)

quit = Button( root , borderwidth=3, padx=12,pady=12,text="quit" , fg="red", command=root.quit )
quit.grid(row=0,column=0)

noise = Button( root , borderwidth=3, text="make noise" , bg="red1", command=makenoise )
noise.grid(row=0,column=1, columnspan=3)

root.mainloop()