#!/usr/bin/env python3

# Function to print words which can be created using a given set of characters 
# Inspired by https://www.geeksforgeeks.org/possible-words-using-given-characters-python/
# Improved for use in an online puzzle by me!
# CHANGE 2020-0415: Added click for argument handling, added comments.

import click

def possible_words(lwords, charSet): 
    ## Build and return a list of good words
    ## by iterating through every possible word
    ## and adding it to the list if all of its characters
    ## are in the character set.  
    good_words = []
    for word in lwords: 
        word_chars_in_charSet = [(char in charSet) for char in word]
        if all(word_chars_in_charSet):
            good_words.append(word) 
    return good_words

@click.command()
@click.argument('characters', required=False)
def find_words(characters):
    # if puzzle characters not passed via argument, 
    # prompt for them, and then split into list of characters.
    if not characters:
        characters = click.prompt('Please enter characters from the puzzle, center character first')
    charSet = [letter for letter in characters]

    # Find all possible words from the nltk english corpus using the characters,
    from nltk.corpus import words
    pwords = possible_words(words.words(), charSet) 

    # filter the list to only words containing the first (center) character and sort the list.
    filtered_list = sorted([word for word in pwords if len(word) >= 4 and charSet[0] in word])

    # Print the list with a navigation index, and highlights for long (high value) words.
    for i in range(len(filtered_list)):
        print(i,filtered_list[i],'*' if len(filtered_list[i]) >= 7 else '')   

if __name__ == "__main__": 
    find_words()