# !python3
# This is a small test/game which asks the user to enter a four digit number.
# The number is then compared with a previously computer generated number -
# the players goal is to guess the computer generated number correctly.
# For each attempt the player sees the result with a "cow" and "bull" count.
# legend:
# cow = a user number matched exactly at the position within the random four digit number (4 cows = win)
# bull = a user number can be found within the digit number list, but at a different position

import re
from random import randint

# the following function creates a random 4-digit list which contains values
# within the range of 0 to 9 for each element
def randomFourDigitList():
    tmplist = []
    while len(tmplist) < 4:
        value = randint(0,9)
        if value not in tmplist:
            tmplist.append(value)
    return sorted(tmplist)

# converts the user input to a real list object with integer type elements
def convertToList(inputString):
    list =  [int(x) for x in inputString]
    return list

# actual game start, the player is being prompted to enter a four digit number
print('Welcome to the Cows and Bulls Game!\nEnter a number:')
bull = 0
cow = 0

# a random list is being created, called tmplist, by the use of the previously
# created method "randomFourDigitList"
tmplist = randomFourDigitList()

# the user needs to enter a guess what the random list/digits look like
userGuess = input()

# the script tests if the user really entered a four digit number.
# if the input is sth. different the script prompts the user to enter a value again
while not re.match('^\d\d\d\d$', userGuess):
    print ('Error! Make sure you only use four digits from 0 to 9 as your input.')
    userGuess = input('Try again: ')
else:
# that part is the actual comparison between the random list and the users input
# it also prints out the cows and/or bulls which are hit
    userGuess = convertToList(userGuess)
    while tmplist != userGuess:
        for i, x in enumerate(tmplist):
            print(str(tmplist[i])+str(userGuess[i]))
            if int(tmplist[i]) == int(userGuess[i]):
                cow += 1
            elif int(tmplist[i]) != int(userGuess[i]):
                if int(userGuess[i]) in tmplist:
                    bull += 1

        cowString = ''
        bullString = ''
        if cow > 1:
            cowString = 's'
        elif bull > 1:
            bullString = 's'

        print(str(cow)+' cow'+cowString+', '+str(bull)+' bull'+bullString )
        bull = 0
        cow = 0
        userGuess = input('Try again: ')
        userGuess = convertToList(userGuess)
# once the user guesses all the digits correctly the game ends and prints out the
# random number which has been guessed
print("Success! The correct numbers are "+str(tmplist)[1:-1]+"!")