/******************************************************************************
 * This program implements a spell checker.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import java.io.BufferedReader;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import org.pureprogrammer.Utils;

public class SpellChecker {

    static Map<String, Boolean> DICTIONARY = new HashMap<>();

    static void readDictionaryFile(String filespec) throws IOException {
        BufferedReader ifh = Files.newBufferedReader(FileSystems.getDefault().getPath(filespec), Charset.forName("UTF-8"));
        String line;
        while ((line = ifh.readLine()) != null) {
            DICTIONARY.put(line.toLowerCase(), true);
        }
        try {ifh.close();} catch (IOException ex) {};
    }

    static void spellcheckFile(String filespec) throws IOException {
        BufferedReader ifh = Files.newBufferedReader(FileSystems.getDefault().getPath(filespec), Charset.forName("UTF-8"));
        String line;
        Map<String, Boolean> misspelledWords = new HashMap<>();
        while ((line = ifh.readLine()) != null) {
            List<String> matches = Utils.findAll(Pattern.compile("\\w+"), line);
            if (Utils.defined(matches)) {
                for (String s : matches) {
                    final String SLOWER = s.toLowerCase();
                    if (!DICTIONARY.containsKey(SLOWER)) {
                        misspelledWords.put(SLOWER, true);
                    }
                }
            }
        }
        final List<String> sortedkeys = Utils.sort(List.copyOf(misspelledWords.keySet()));
        for (String s : sortedkeys) {
            System.out.println(s);
        }
        try {ifh.close();} catch (IOException ex) {};
    }

    public static void main(String[] args) {
        if (args.length != 2) {
            System.out.println(Utils.join("", "Syntax: ", "SpellChecker", " {dictionary} {filename}"));
            System.exit(1);
        }
        String dictionaryFile = args[0];
        String filename = args[1];

        try {
            readDictionaryFile(dictionaryFile);
            spellcheckFile(filename);
        } catch (IOException ex) {
            System.out.println(Utils.join("", "Error: ", Utils.exceptionMessage(ex)));
        }
    }
}