import random

def random_line(filename):
	"Returns a random line from a file."
	file = open(filename)
	try:		return random.choice(file.readlines())
	finally:	file.close()

class AlreadyGuessed(Exception):
	def __init__(self, letters):
		self.letters = letters

class Word(object):
	def __init__(self, word, lives = 10):
		self.word    = word
		self.guesses = set()
		self.lives   = lives

	def guess(self, letters):
		"Guess letter(s) in the word."
		same = set(letters).intersection(self.guesses)
		if same: raise AlreadyGuessed(same)
		self.guesses.add(letters)
		self.lives -= len([l for l in letters if l not in self.word])

	@property
	def lost(self): return self.lives == 0

	@property
	def won(self):	return set(self.word).issubset(self.guesses)

	@property
	def wrong_guesses(self):
		return word.guesses.difference(set(self.word))
		
	def __str__(self):
		"Returns a string showing how much the user has guessed of the word."
		return " ".join(l not in self.guesses and "_" or l for l in self.word)

if __name__ == '__main__':
	word = Word(random_line("words.txt").strip().lower())

	while not word.lost and not word.won:
		print "Word:", word
		print "Wrong guesses:", " ".join(word.wrong_guesses)
		print "Lives left:", word.lives
		print
		try:
			word.guess(raw_input("Please enter a letter: ").lower())
		except AlreadyGuessed, e:
			print "Already guessed:", " ".join(e.letters)

	if word.lost:	print "You've lost."
	elif word.won:	print "You've won."

	print "The word was:", word.word