import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.LongPoint;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.commons.io.FileUtils;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.Directory;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.nio.file.Paths;
import java.io.FileReader;

public class Indexer {

    public static void main(String[] args) throws Exception {
        if (args.length != 4) {
            throw new IllegalArgumentException("Usage: java " + Indexer.class.getName() + " <index dir> <data dir>");
        }
        String indexDir = args[0];
        String dataDir = args[1];

        String indexDir500 = args[2];
        String dataDir500 = args[3];

        // prvi indeks
        long start = System.currentTimeMillis();
        Indexer indexer = new Indexer(indexDir);
        int numIndexed;
        try {
            numIndexed = indexer.index(dataDir, new TextFilesFilter());
        } finally {
            indexer.close();
        }
        long end = System.currentTimeMillis();

        System.out.println("Indexing " + numIndexed + " files took " + (end - start) + " milliseconds");

        File f = new File(indexDir);
        double sizekb = FileUtils.sizeOfDirectory(f) / 1024;
        System.out.println("Index size is " + sizekb + " KB");

        // drugi indeks
        start = System.currentTimeMillis();
        Indexer indexer500 = new Indexer(indexDir500);

        try {
            numIndexed = indexer500.index(dataDir500, new TextFilesFilter());
        } finally {
            indexer500.close();
        }
        end = System.currentTimeMillis();

        System.out.println("Indexing " + numIndexed + " files took " + (end - start) + " milliseconds");

        f = new File(indexDir500);
        sizekb = FileUtils.sizeOfDirectory(f) / 1024;
        System.out.println("Index size is " + sizekb + " KB");

    }

    private IndexWriter writer;

    public Indexer(String indexDir) throws IOException {
        Directory dir = FSDirectory.open(Paths.get(indexDir));
        writer = new IndexWriter(dir, new IndexWriterConfig(new StandardAnalyzer()));
    }

    public void close() throws IOException {
        writer.close();
    }

    public int index(String dataDir, FileFilter filter) throws Exception {

        File[] files = new File(dataDir).listFiles();

        for (File f : files) {
            if (!f.isDirectory() && !f.isHidden() && f.exists() && f.canRead()
                    && (filter == null || filter.accept(f))) {
                indexFile(f);
            }
        }

        return writer.numDocs();
    }

    private static class TextFilesFilter implements FileFilter {
        public boolean accept(File path) {
            return path.getName().toLowerCase().endsWith(".txt");
        }
    }

    protected Document getDocument(File f) throws Exception {
        Document doc = new Document();
        doc.add(new TextField("contents", new FileReader(f)));
        doc.add(new StringField("filename", f.getName(), Field.Store.YES));
        doc.add(new StringField("fullpath", f.getCanonicalPath(), Field.Store.YES));
        doc.add(new LongPoint("filesize", f.length()));
        return doc;
    }

    private void indexFile(File f) throws Exception {
        // System.out.println("Indexing " + f.getCanonicalPath());
        Document doc = getDocument(f);
        writer.addDocument(doc);

    }
}