import java.io.File;
import java.io.FileNotFoundException;
import java.util.*;

public class Main {

    public static void main(String[] args) throws Exception {
        //ArrayList<String> l1 = new ArrayList<>(Arrays.asList(new String("Happy families are all alike; every unhappy family is unhappy in its own way Everything was in confusion in the Oblonskys' house.  The wife had discovered that the husband was carrying on an intrigue with a French girl, who had been a governess in their family, and she had announced to her husband that she could not go on living in the same house with him.").toLowerCase().split(" ")));
        //ArrayList<String> l2 = new ArrayList<>(Arrays.asList(new String("In the words of Leo Tolstoy: Every unhappy family is unhappy in its own way").toLowerCase().split(" ")));
        ArrayList l1 = readDocument("/home/lofibytes/Downloads/moby_dick.txt");
        ArrayList l2 = readDocument("/home/lofibytes/Downloads/huck_finn_plagiarized.txt");
        ArrayList<String> duplicates = getDuplicatesList(Arrays.copyOf(l1.toArray(), l1.size(),String[].class), Arrays.copyOf(l2.toArray(), l2.size(),String[].class));
        System.out.println(duplicates);
    }

    private static ArrayList<String> getDuplicatesList(String[] l1, String[] l2) {
        long millis = System.currentTimeMillis();
        ArrayList<String> duplicates = new ArrayList<>();
        HashMap<String, ArrayList<Integer>> words = new HashMap<>();
        for (int i = 0; i < l2.length; i += 1) { // unindexed word create arraylist of locations of word
            if (words.get(l2[i]) == null) {
                ArrayList wordLocations = new ArrayList();
                wordLocations.add(i);
                words.put(l2[i], wordLocations);
            } else {
                words.get(l2[i]).add(i); // Word already indexed so just add the next location
            }
        }
        ArrayList<Integer> indexes;
        String match;
        int i, j, k, offset;
        for (i = 0; i < l1.length; i ++) {
            if (!words.containsKey(l1[i])) continue;
            indexes = words.get(l1[i]);
            if (indexes != null) {
                for (j = 0; j < indexes.size(); j++) {
                    match = l1[i];
                    offset = 0;
                    for (k = indexes.get(j) + 1; k < l2.length && i + offset < l1.length; k++) {
                        offset++;
                        if (l1[i + offset].equalsIgnoreCase(l2[k]))
                            match += " " + l2[k];
                        else {
                            i += offset - 1;
                            break;
                        }
                    }
                    if (offset <= 3) continue;
                    duplicates.add(match);
                }
            }
        }
        System.out.println((System.currentTimeMillis() - millis) / 1000);
        return duplicates;
    }
    /*private static ArrayList<String> getDuplicatesList(ArrayList<String> l1, ArrayList<String> l2) {
        ArrayList<String> duplicates = new ArrayList<>();
        long n1 = System.nanoTime();
        for (int i = 0; i < l1.size(); i++)
            for (int j = 0; j < l2.size(); j++)
                if (l1.get(i).equalsIgnoreCase(l2.get(j))) {
                    String match = l1.get(i);
                    for (int k = 1; i + k < l1.size() && j + k < l2.size(); k++)
                        if (l1.get(i + k).equalsIgnoreCase(l2.get(j + k)))
                            match += " " + l2.get(k + j);
                        else {
                            j += k - 1;
                            break;
                        }
                    int longest = 0;
                    for (int l = 0; l < duplicates.size(); l++)
                        if (longest < duplicates.get(l).length())
                            longest = duplicates.get(l).length();
                    if (longest < match.length())
                        duplicates.add(match);
                }
        System.out.println(System.nanoTime() - n1);
        return duplicates;
    }
*/
/*
    private static ArrayList<String> getDuplicatesList(ArrayList<String> l3, ArrayList<String> l4) {
        ArrayList<String> duplicates = new ArrayList<>();
        LinkedHashSet<String> l1 = new LinkedHashSet<>(l3);
        LinkedHashSet<String> l2 = new LinkedHashSet<>(l4);
        Iterator<String> i = l1.iterator();
        int _i = -1;
        long n1 = System.nanoTime();
        while (i.hasNext()) {
            _i++;
            String iVal = i.next();
            if (l2.contains(iVal)) {
                System.out.println(iVal);
                for (int e = _i; e < l3.size(); e++) {
                    for (int j = 0; j < l4.size(); j++) {
                        if (l3.get(e).equalsIgnoreCase(iVal) && l4.get(j).equalsIgnoreCase(iVal)) {
                            String match = iVal;
                            for (int k = 1; e + k < l3.size() && j + k < l4.size(); k++)
                                if (l3.get(e + k).equalsIgnoreCase(l4.get(j + k)))
                                    match += " " + l4.get(k + j);
                                else
                                    break;
                            int longest = 0;
                            for (int l = 0; l < duplicates.size(); l++)
                                if (longest < duplicates.get(l).length())
                                    longest = duplicates.get(l).length();
                            if (longest < match.length())
                                duplicates.add(match);
                        }
                    }
                }
            }
        }
        System.out.println(System.nanoTime() - n1);
        return duplicates;
    }*/



    public static ArrayList<String> readDocument(String fileName) throws FileNotFoundException
    {
        Scanner scanner;
        ArrayList<String> words = new ArrayList<String>();

        scanner = new Scanner(new File(fileName));
        scanner.useDelimiter("[\\W]"); // all non-word characters
        int k = 0;
        String word = "";
        while (scanner.hasNext())
        {
            String cur = scanner.next();
            if (!cur.equals(""))
            {
                k++;
                if (k == 1) {
                    word = cur.toLowerCase();
                } else
                    word += " " + cur.toLowerCase();
                if (k >= 3 || !scanner.hasNext()) {
                    words.add(word.trim());
                    word = "";
                }
            }
        }
        scanner.close();
        return words;
    }

}