import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidKeyException;
import java.util.Base64;
import java.util.Base64.Encoder;

public class TestBST {

    private static final String secret = "pKZFy7TpNKegCvxi8bxXftGRaJ8Y6KrGKpkxHVFM2uLBumzi2MVPW9K6m88jXPRq";
    private static final Encoder encoder = Base64.getEncoder().withoutPadding();
    
    private static Mac mac = null;
    private static int numberOfKeys = 100000000;

    private static MessageDigest digest = null;
    
    private static void initMac() {

        try {
	    mac = Mac.getInstance("HmacSHA256");
	    mac.init(new SecretKeySpec(secret.getBytes(), "HmacSHA256"));
	    
  	} catch (NoSuchAlgorithmException e) {
            System.err.println(e);
            System.exit(-1);
        } catch (InvalidKeyException e) {
            System.err.println(e);
            System.exit(-1);
        }

    }

    private static String getSHA256Encoding(String message) {
        return encoder.encodeToString(mac.doFinal(message.getBytes()));
    }

    private static void initDigest() {
        
        try {
            digest = MessageDigest.getInstance("MD5");
        } catch  (NoSuchAlgorithmException e) {
            System.err.println(e);
            System.exit(-1);
        }

    }

    private static String getMD5Encoding(String message) {

        digest.update(message.getBytes());
        byte messageDigest[] = digest.digest();
        StringBuilder hexString = new StringBuilder();
        for (byte b : messageDigest) {
            hexString.append(Integer.toHexString(0xFF & b));
        }
        return hexString.toString();
    }


    private static BinarySearchTree<String> buildBinarySearchTree() {

        System.out.println("building a tree!");

        BinarySearchTree<String> tree;
        tree = new BinarySearchTree<String>();

        long t0 = System.currentTimeMillis(), elapsed;

        for (int i=0; i<numberOfKeys; i++) {
            tree.add(getMD5Encoding(String.format("%010d", i)));
        }

        elapsed = System.currentTimeMillis() - t0;

        System.out.println(elapsed + " ms");

        System.out.println(tree.size());

        return tree;
        
    }

    public static void testContains(BinarySearchTree<String> tree, String value) {

        long t0 = System.currentTimeMillis(), elapsed;

        if (tree.contains(value)) {
            System.out.println(value + " was found!");
        } else {
            System.out.println(value + " was not found!");
        }

        elapsed = System.currentTimeMillis() - t0;

        System.out.println(elapsed + " ms");

    }

    public static void testAdd(BinarySearchTree<String> tree, String value) {
        
        System.out.println("adding " + value);

        long t0 = System.currentTimeMillis(), elapsed;

        tree.add(value);

        elapsed = System.currentTimeMillis() - t0;

        System.out.println(elapsed + " ms");


    }
        
    public static void main(String[] args) {

        // processing the command line arguments
        
        if (args.length == 1) {
            try {
                numberOfKeys = Integer.parseInt(args[0]);
            } catch (NumberFormatException e) {
                ; // using default value
            }
        }

        initMac();

        if (mac == null) {
            System.err.println("No MAC object!");
            return;
        }

        initDigest();

        if (digest == null) {
            System.err.println("No MD5 object!");
            return;
        }
        
        BinarySearchTree<String> tree;
        tree = buildBinarySearchTree();

        String value = getSHA256Encoding(String.format("%010d", numberOfKeys++));

        testContains(tree, value);

        testAdd(tree, value);

        testContains(tree, value);

    }

}

// > nohup java -Xmx128g TestBST 1000000000 > TestBST-$$.out &