wordle/wordle.py

#!/usr/bin/python

import random
import string

from enum import Enum
from collections import defaultdict

WORDLE_LENGTH = 5


class LetterResult(Enum):
    """Is an individual letter in a word in the result?"""
    CORRECT = 1
    MOVE = 2
    INCORRECT = 3
    UNKNOWN = 4


class InvalidWord(Exception):
    """Thrown when an input word is not a valid Wordle."""
    pass


_wordle_dictionary = set()


_invalid_words = set(['staia', 'erept', 'boily', 'bolty', 'pindy', 'hyrse', 'hirse', 'retan', 'sisel', 'skeel', 'telae', 'genae', 'beata', 'beala', 'macco', 'beele', 'divet', 'vedet', 'stail', 'roter'])


def dictionary():
    if not _wordle_dictionary:
        with open('words_alpha.txt') as word_file:
            all_words = word_file.read().split()
        _wordle_dictionary.update(
            filter(lambda w: len(w) == WORDLE_LENGTH and w not in _invalid_words, all_words))

    return _wordle_dictionary


def select_word():
    return random.choice(list(dictionary()))


def grade_word(target, guess):
    # We don't check word length, since all valid words are 5 letters.
    if guess not in dictionary():
        raise InvalidWord(f"{guess} is not a valid Wordle.")

    result = [LetterResult.UNKNOWN] * WORDLE_LENGTH

    # We copy target, and remove letters if we find them. This handles duplicate letters correctly.
    # For example, if the target is "pulls" and we guess "apple", only the first "p" should be a
    # MOVE. The second should be INCORRECT.
    remaining = list(target)

    # Find all correct results first.
    for i in range(WORDLE_LENGTH):
        if target[i] == guess[i]:
            result[i] = LetterResult.CORRECT
            remaining.remove(guess[i])

    for i in range(WORDLE_LENGTH):
        if result[i] == LetterResult.UNKNOWN:
            if guess[i] in remaining:
                # Letter is in the wrong place.
                result[i] = LetterResult.MOVE
                remaining.remove(guess[i])
            else:
                # Letter is not in target.
                result[i] = LetterResult.INCORRECT

    return result


def display_result(result, text):
    opening = {
        LetterResult.CORRECT: '\033[92m',
        LetterResult.MOVE: '\033[33m',
        LetterResult.INCORRECT: '\033[36m',
        LetterResult.UNKNOWN: '',
    }
    closing = '\033[0m'

    return f"{opening[result]}{text}{closing}"


def success_result(result):
    for r in result:
        if r != LetterResult.CORRECT:
            return False

    return True


def analyze_dictionary(wordle_dictionary):
    # Word Position, Letter: Count
    position_matches = [defaultdict(int),
                        defaultdict(int),
                        defaultdict(int),
                        defaultdict(int),
                        defaultdict(int)]

    # Letter: Count
    word_matches = defaultdict(int)

    for word in wordle_dictionary:
        unique_letters = set(word)
        for letter in unique_letters:
            word_matches[letter] += 1

        for index in range(len(word)):
            letter = word[index]
            assert (letter in string.ascii_lowercase)
            position_matches[index][letter] += 1

    return position_matches, word_matches


def score_word(position_matches, word_matches, word):
    result = 0

    # Green Score
    for index in range(len(word)):
        letter = word[index]
        green_score = position_matches[index][letter]
        result += 10 * green_score

    # Yellow Score
    for letter in set(word):
        yellow_score = word_matches[letter]
        result += yellow_score

    return result


def scored_words(wordle_dictionary=dictionary()):
    # word: score
    scored_words = dict()

    position_matches, word_matches = analyze_dictionary(wordle_dictionary)

    for word in wordle_dictionary:
        scored_words[word] = score_word(position_matches, word_matches, word)

    result = list(wordle_dictionary)
    result.sort(key=lambda word: scored_words[word], reverse=True)

    return [(word, scored_words[word]) for word in result]


class Constraints():
    correct = [None] * WORDLE_LENGTH  # Letter is None, or known.
    # Sets of letters that must be elsewhere
    move = defaultdict(set)
    min = defaultdict(int)
    exact = set()

    # List of LetterResult values.
    def update_graded(self, guess, grade):

        guess = guess.lower()

        new_min = defaultdict(int)
        new_exact = set()

        for i, letter in enumerate(guess):
            match grade[i]:
                case LetterResult.CORRECT:
                    self.correct[i] = letter
                    new_min[letter] += 1
                case LetterResult.MOVE:
                    self.move[letter].add(i)
                    new_min[letter] += 1
                case LetterResult.INCORRECT:
                    new_exact.add(letter)
                    new_min[letter] += 0  # Ensure letter is in min.

        for letter, m in new_min.items():
            self.min[letter] = max(m, self.min[letter])

        self.exact |= new_exact

    def matches(self, guess):

        counts = defaultdict(int)

        # All known correct letters in place.
        for i, letter in enumerate(guess):
            if self.correct[i] and self.correct[i] != letter:
                return False  # If it's incorrect, the word is incorrect.

            # Any MOVE letters in known wrong locations.
            if letter in self.move:
                if i in self.move[letter]:
                    return False

            counts[letter] += 1

        for letter, min in self.min.items():
            if letter in self.exact:
                if counts[letter] != min:
                    return False
            else:
                if counts[letter] < min:
                    return False

        return True


def filter_dictionary(constraints, wordle_dictionary=dictionary()):
    return set(filter(lambda w: constraints.matches(w), wordle_dictionary))


if __name__ == '__main__':
    constraints = Constraints()
    constraints.update_graded('cares', [LetterResult.INCORRECT, LetterResult.INCORRECT, LetterResult.MOVE, LetterResult.CORRECT, LetterResult.INCORRECT])
    constraints.update_graded('rover', [LetterResult.INCORRECT, LetterResult.CORRECT, LetterResult.MOVE, LetterResult.CORRECT, LetterResult.CORRECT])
    constraints.update_graded('vomer', [LetterResult.CORRECT, LetterResult.CORRECT, LetterResult.INCORRECT, LetterResult.CORRECT, LetterResult.CORRECT])

    valid_words = filter_dictionary(constraints)

    print("Top: ", scored_words(valid_words)[:1])