wagner_fischer.py

from typing import List, Tuple, Generator
import os

def load_dictionary(file_path: str) -> Generator[str, None, None]:
    """Load a dictionary from a file, yielding each word."""
    if not os.path.exists(file_path):
        raise FileNotFoundError(f"The file {file_path} does not exist.")
    try:
        with open(file_path, 'r') as file:
            for line in file:
                yield line.strip()
    except IOError as e:
        raise IOError(f"Error occurred while trying to read the file: {file_path}") from e
    
def wagner_fischer(word1: str, word2: str, threshold: int) -> float:
    if abs(len(word1) - len(word2)) > threshold:
        return float('inf')

    if len(word1) < len(word2):
        word1, word2 = word2, word1

    previous_row_distances = range(len(word1) + 1)
    for i2, c2 in enumerate(word2):
        current_row_distances = [i2+1]
        min_distance = float('inf')
        for i1, c1 in enumerate(word1):
            if c1 == c2:
                current_row_distances.append(previous_row_distances[i1])
            else:
                current_row_distances.append(1 + min((previous_row_distances[i1], previous_row_distances[i1 + 1], current_row_distances[-1])))
            min_distance = min(min_distance, current_row_distances[-1])
        previous_row_distances = current_row_distances
        if min_distance > threshold:
            return float('inf')
    
    return previous_row_distances[-1]

def spell_check(word: str, dictionary: Generator[str, None, None], top: int, threshold: float) -> List[Tuple[str, float]]:
    results = []
    for w in dictionary:
        if abs(len(word) - len(w)) <= threshold:
            distance = wagner_fischer(word, w, threshold)
            if distance < threshold:
                threshold = distance
            results.append((w, distance))
    return sorted(results, key=lambda x: x[1])[:top]

def print_help():
    print("\n📜 Commands:")
    print("  🔍 check <word> - Check the spelling of a word")
    print("  ⚙️  settings - Display the settings menu")
    print("  🆘 help - Display this help menu")
    print("  🚪 bye - Exit the program")

def print_settings():
    print("\n ⚙️  Settings:")
    print("  📚 dictionary <file_path> - Load a different dictionary file.")
    print("  🎯 threshold <value> - Set the maximum Wagner-Fischer distance for suggestions.")
    print("  🔝 top <number> - Set the number of suggestions to display.")

def user_interface() -> None:
    dictionary = load_dictionary("words.txt")
    threshold = float('inf')
    top = 10

    print("\n🎉 Welcome to the spell checker. Type 'help' for a list of commands.")
    while True:
        command = input("\n🔹 Enter a command: ").strip().lower().split()
        action = command[0]
        
        if action == 'bye':
            print("\n👋 Exiting the spell checker. Goodbye!")
            break
        elif action == 'check':
            word = ' '.join(command[1:])
            suggestions = spell_check(word, dictionary, top, threshold)
            if suggestions:
                print(f"\n🔝 Top {top} suggestions for '{word}':")
                for i, (word, distance) in enumerate(suggestions):
                    if i == 0:
                        print(f"  ⭐ Closest match: {word} (Distance: {distance})")
                    else:
                        print(f"  - {word} (Distance: {distance})")
            else:
                print(f"\n❌ No suggestions found for '{word}'.")
        elif action == 'help':
            print_help()
        elif action == 'settings':
            print_settings()
        elif action == 'threshold':
            threshold = float(' '.join(command[1:]))
            print(f"\n🎯 Threshold set to {threshold}.")
        elif action == 'dictionary':
            file_path = ' '.join(command[1:])
            dictionary = load_dictionary(file_path)
            print(f"\n📚 Dictionary loaded from {file_path}.")
        elif action == 'top':
            top = int(' '.join(command[1:]))
            print(f"\n🔝 Number of suggestions set to {top}.")
        else:
            print("\n❌ Invalid command. Type 'help' for a list of commands.")

user_interface()