#
# 1. Read word list
#       word list is long (over 200,000 words!) so we
#       just print the first 100; this goes away later
# 2. Eliminate words that are not exactly 5 characters long
# 3. Read pattern, characters that must be in the word ("good
#       letters"), characters that are not in the word ("bad
#       letters")
#       print them to verify they are right, and then quit;
#       this goes away later
#   3a. Check no letters are both good and bad
# 4. Eliminate words with bad letters
#   4a. Make all letters lower case
#
import sys

#
# the word list
#
wordlist = "/usr/share/dict/words"

#
# get pattern, good, bad letters
#
try:
    pat = input("Pattern: ")
    good = input("Letters you know are in the word: ")
    bad = input("Letters you know are not in the word: ")
except Exception as msg:
    print(msg)
    sys.exit(1) 

#
# make good, bad letters all lower case
#
good = good.lower()
bad = bad.lower()

#
# print them
#
print(f"Pattern: '{pat}'")
print(f"Good: '{good}'")
print(f"Bad: '{bad}'")

#
# sanity check: no letters are both good and bad
#
# doing this with sets is the easiest way
#
goodset = set(good)
badset = set(bad)
commonchars = goodset & badset
# see if any letters are both good and bad
if commonchars:
    # yes -- say what they are and this isn't allowed
    print("These letters are both good and bad: ", end='')
    c = ''
    # list them in alphabetical order
    for x in sorted(commonchars):
        c = c + x
    print(f"'{c}'; not allowed!")
    sys.exit(1)

#
# open the word list
#
try:
    wl = open(wordlist, "r")
except Exception as msg:
    print(msg)
    sys.exit(1)

#
# return True if no bad letters in word
#
def nobad(w):
    for x in bad:
        if x in w:
            return False
    return True

#
# print possible words
#
for word in wl:
    # remove trailing (and leading!) space
    word = word.strip()
    # make all letters lower case
    word = word.lower()
    # skip words not exactly 5 characters long
    if len(word) != 5:
        continue
    # skip words with bad letters
    if nobad(word):
        print(word)