import math
import random
from ex1 import WeakRNG

def byte2bin(bval):
  return bin(bval)[2:].zfill(8)

def monobit(bin_data):
    count = 0
    # If the char is 0 minus 1, else add 1
    for char in bin_data:
        if char == '0':
            count -= 1
        else:
            count += 1
    # Calculate the p value
    sobs = count / math.sqrt(len(bin_data))
    p_val = math.erfc(math.fabs(sobs) / math.sqrt(2))
    return p_val

def get_random_string(n): #generate random bit string
  bstr = bin(random.getrandbits(n)).lstrip('0b').zfill(n)
  return bstr

numbits = 128

wr = WeakRNG()
wr.init_state()

gbytes = [666]
for i in range(numbits/8 - 1):
    gbytes.append(wr.get_prg_byte())

byteString = ''
for i in gbytes:
	byteString += byte2bin(i)

newByteString = ''
for gbit in byteString:
    if gbit == '0':
        newByteString += str(random.randint(0, 1))
    else:
        newByteString += '1'

mb_val = monobit(newByteString)

print newByteString
print mb_val
if mb_val >= 0.01:
    print 'ok'
else:
    print 'not ok'

print "-------------------------"

newByteString = get_random_string(numbits)
print newByteString
mb_val = monobit(newByteString)

print mb_val
if mb_val >= 0.01:
    print 'ok'
else:
    print 'not ok'