import re

class Terminal:
    """This class emulates a simple Terminal promt with a basic login and CLI"""
    def __init__(self):
        """self.user will contain the username of the currently logged in user, otherwise None
        self.users is a dictionary that should contain all users as keys with their
                   corresponding passwords as values
        self.run should be set to False to terminate the main loop"""
        self.user = None
        self.users = {}
        self.run = False

    def check_login(self):
        """This function checks if the currently logged in user, which is stored in
        the user string, exists in the users dictionary and return True, otherwise it
        will start a login attempt and return its value"""
        if self.user in self.users.keys():
            return True
        else:
            return self.do_login()

    def do_login(self):
        """This function will prompt the user for a name and password.
        If the given name exists as a key in the users dictionary it will check if
        the password matches the value of that key and set that user to be currently
        logged in.

        This function returns True for a successful login attempt, otherwise False."""
        username = raw_input('Username: ')
        password = raw_input('Password: ')
        if username in self.users.keys():
            if password == self.users[username]:
                print 'login ok!'
                print 'Welcome %s!' % (username)
                self.user = username
                return True
        print 'login failed!'
        return False

    def commandline(self):
        """This is a function to prompt for commands, check them and execute them.
        Sould not be called anywhere but the main loop"""
        cmd = raw_input('INPUT# ')
        if cmd == 'logout':
            print 'Bye!'
            self.user = None
        if cmd == 'quit':
            self.run = False

    def main(self):
        """This is the main loop. When this is called,
        control of the application is given to the Terminal class."""
        self.run = True
        while self.run:
            if self.check_login(): self.commandline()

term = Terminal()
term.users = { 'ndakota':'transltr', 'elite':'awesum' }
term.main()