# 6.00 Problem Set 3 solution
# 
# Hangman
#

import random
import string
# -----------------------------------
# Helper code
# (you don't need to understand this helper code)

WORDLIST_FILENAME = "words.txt"

def load_words():
    """
    Returns a list of valid words. Words are strings of lowercase letters.
    
    Depending on the size of the word list, this function may
    take a while to finish.
    """
    print "Loading word list from file..."
    # inFile: file
    inFile = open(WORDLIST_FILENAME, 'r', 0)
    # line: string
    line = inFile.readline()
    # wordlist: list of strings
    wordlist = string.split(line)
    print "  ", len(wordlist), "words loaded."
    return wordlist

# end of helper code
# -----------------------------------

def chooseWord(wordlist):
    """
    wordlist (list): list of words (strings)

    Returns a word from wordlist at random
    """
    # You could have also used randrange here, but I think this is a
    # bit cleaner. Take a look at help(random.choice) after importing
    # random to learn more
    return random.choice(wordlist)


def update_hand(guess, word, revealed):
    """
    guess (string): The letter guessed. This letter must be in word
    word  (string): The word we're playing hangman with
    revealed (list of bools):
          if revealed[i] is True, then we've guessed the letter
          at word[i]
          
    Returns: Nothing
    Updates revealed, changing 0s to 1s in the spots
    corresponding to the guessed letters
    """
    # The idea here is that we are walking through the word and the
    # list simultaneously -- word[i] is the letter at that spot, and
    # revealed[i] represents whether or not the character at that spot
    # has been revealed yet.
    #
    # Remember that lists are mutable, so this actually works; this
    # function /modifies/ the 'revealed' list.
    #
    # e.g.
    # word      =  "hello"
    # revealed  =  [F F T T T]
    # would be the state of the world if the user had guessed
    # (and we had revealed) "l" and "o"
    for i in range(len(revealed)):
        if word[i] == guess:
            revealed[i] = True
    return

def get_display_hand(word, revealed):
    """
    Returns a string that is the printable representation
    of word, given revealed (i.e. the letters from word
    when they are revealed, _ when they are not)
    """
    output = ""
    for i in range(len(word)):
        if revealed[i]:
            output += word[i]
        else:
            output += "_"
    return output

def word_solved(revealed):
    """
    Returns True if the whole word has
    been revealed, False otherwise
    """
    # I'm being cute by writing this
    # on one line here -- make sure
    # you understand how (and why)
    # this works.
    return revealed.count(False) == 0

def play_one_game(wordlist):
    print "Welcome to the game, Hangman!"
    # Initialize the variables we're going
    # to use to store the state of things

    # The word we've guessed
    word = chooseWord(wordlist)
    # Representation of which letters we've revealed
    # (True in slot i means "Show word[i]")
    revealed = [False] * len(word)
    # Remaining letters that can be guessed
    letters = []
    for letter in string.lowercase:
        letters.append(letter)
    guesses = 8
    
    print "I am thinking of a word that is", len(word), "letters long."
    while guesses > 0 and not word_solved(revealed):
        print "-" * 10
        print "You have", guesses, "guesses left."
        print "Available letters:", ''.join(letters)
        print
        guess = raw_input("Please guess a letter: ")
        if guess not in letters:
            print "You've already guessed that letter."
            continue
        letters.remove(guess)
        if guess in word:
            update_hand(guess, word, revealed)
            print "Good guess: ",
        else:
            print "Oops! That letter is not in my word: ",
            guesses -= 1
        print get_display_hand(word, revealed)
    print
    if word_solved(revealed):
        print "Congratulations, you won!"
    else:
        print "You lose. The word was:", word
    print "*" * 70

def play_game(wordlist):
    """
    Repeatedly kick off a new game of hangman
    until the user responds negatively to
    'Play again?
    """
    while True:
        play_one_game(wordlist)
        again = raw_input("Play again <y/n>?")
        if len(again) > 0 and again[0] in ['n', 'N']:
            break
        print


wordlist = load_words()
if __name__ == "__main__":
    play_game(wordlist)