#!/usr/bin/env python
"""
Word arithmetic
Script helps to generate combinations of words on which arithmetic can be applied
assuming the characters represent digits

AEIBCDFGHI (A=0, E=1, I=2, B=3, C=4, D=5, F=6, G=7, H=8, I=9)

Some word combinations for the set of chars above are:
AID + ICED = IDEA (024 + 2415 = 2510)
DADA + ADD = DEAD (5050 + 055 = 5105)
"""

import sys
import string
import random
import optparse

DEFAULT_LETTERS = 'AEIOUBCDFG'

def load_words(words_fname):
    return [word.strip() for word in file(words_fname).readlines()]

def choose_words(letters, words):
    letters = set(letters)
    chosen_words = [word for word in words if letters.issuperset(set(word))]
    return chosen_words

def compute_word_values(words, letters):
    value_map = {}
    lmap = dict([ (letter, str(index).strip()) 
                        for index, letter in enumerate(letters)])
    for word in words:
        value = int(''.join([lmap[l] for l in word]))
        value_map[word] = value;

    return value_map

def find_combinations(value_map):

    combinations = []
    
    for word1, value1 in value_map.iteritems():
        for word2, value2 in value_map.iteritems():
            for word3, value3 in value_map.iteritems():
                if value1 + value2 == value3:
                    combinations.append((word1, word2, word3))

    return combinations

def remove_duplicate_combinations(combinations):
    combos = {}
    for c in combinations:
        word1, word2, word3 = c
        l = [word1, word2]
        l.sort()
        key = '.'.join(l)
        combos[key] = c
    combos = combos.values()
    return combos

def show_combinations(combinations):
    for w1, w2, w3 in combinations:
        print "%s + %s = %s" % (w1, w2, w3)

def main(options):
   letters = list(options.letters)[:10]
   print "letters = %s" % (', '.join(["%s=%d" % (l,index) for index, l in enumerate(letters)]))

   words_fname = options.words_file
   words = load_words(words_fname)

   words = choose_words(letters, words)
   value_map = compute_word_values(words, letters)
   combinations = find_combinations(value_map)
   combinations = remove_duplicate_combinations(combinations)
   show_combinations(combinations)

if __name__ == "__main__":
    parser = optparse.OptionParser()
    parser.add_option('-w', '--words-file', help='word list')
    parser.add_option('-l', '--letters', help='ten letter sequence', default=DEFAULT_LETTERS)
    (options, args) = parser.parse_args()

    if options.words_file is None:
        print '--words-file is needed'
        sys.exit(-1)

    main(options)