/******************************************************************************
 * This program that searches a dictionary file to find palindromes.
 * 
 * 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.regex.Pattern;
import org.pureprogrammer.Utils;

public class PalindromeSearch {

    static boolean isPalindrome(String s) {
        String s0 = Pattern.compile("\\W+").matcher(s).replaceAll("");
        s0 = s0.toLowerCase();
        final int S_LEN = Utils.cpLength(s0);
        if (S_LEN < 4) {
            return false;
        }
        for (int x = 0; x <= (S_LEN - 1) / 2; ++x) {
            if (Utils.cpAt(s0, x) != Utils.cpAt(s0, S_LEN - 1 - x)) {
                return false;
            }
        }
        return true;
    }

    static void searchTextFile(String filespec) throws IOException {
        BufferedReader ifh = Files.newBufferedReader(FileSystems.getDefault().getPath(filespec), Charset.forName("UTF-8"));
        String line;
        while ((line = ifh.readLine()) != null) {
            if (isPalindrome(line)) {
                System.out.println(line);
            }
        }
        try {ifh.close();} catch (IOException ex) {};
    }

    public static void main(String[] args) {
        if (args.length != 1) {
            System.out.println(Utils.join("", "Syntax: ", "PalindromeSearch", " {filename}"));
            System.exit(1);
        }
        String filespec = args[0];
        try {
            searchTextFile(filespec);
        } catch (IOException ex) {
            System.out.println(Utils.join("", "Error: ", Utils.exceptionMessage(ex)));
        }
    }
}