#!/usr/bin/env python

import getpass
import hashlib

usernamedb=[]
passworddb=[]
salt='dae9Eu2Ughiwu9maeNeichah1Pho6aaT'
loginstatus=False

def create_user():
    running=True
    while running:
        newusername=raw_input('Please enter a new username : ')
        newuserspassword=getpass.getpass('Please enter a password : ')
        newhashedpassword=hashlib.sha512()
        newuserspassword2=getpass.getpass('Please confirm the password : ')
        if newuserspassword==newuserspassword2:
            newhashedpassword.update(newuserspassword+salt)
            hashedtoaddtodb=newhashedpassword.hexdigest()
            usernamedb.append(newusername)
            passworddb.append(hashedtoaddtodb)
            print 'The new user has been created'
            makenewuser=raw_input('Would you like to create another user? (y/n) : ')
            if makenewuser=='n':
                break
            if makenewuser=='y':
                continue
            else:
                print 'Invalid input, taking you to login screen'
                break
        else:
            print 'Error, passwords do not match'
            continue


def login():
    print 'Welcome to the system'
    running=True
    attempts=0
    remaining=3
    while running:
        username=raw_input('Please enter your username : ')
        password=getpass.getpass('Please enter your password : ')
        hashedinputpassword=hashlib.sha512()
        hashedinputpassword.update(password+salt)
        inputpassworddigest=hashedinputpassword.hexdigest()
        ID=usernamedb.index(username)
        if passworddb[ID]==inputpassworddigest:
            global loginstatus
            loginstatus=True
            print 'Welcome', username
            break
        if passworddb[ID]!=inputpassworddigest and remaining!=0:
            print 'Invalid password, please try again'
            attempts=attempts+1
            remaining=3-attempts
            print remaining, 'attempts remaining'
            continue
        if passworddb[ID]!=inputpassworddigest and remaining==0:
            'You have failed to login too many times'
            break

create_user()
login()