package com.doumee.core.utils;


import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.SecureRandom;
import java.util.Random;

/**
 * A null-safe utility to handle the String instances.
 *
 * @author Guang YANG
 * @version 1.1
 */
public final class Strings {

    public static final String EMPTY = "";
    public static final String INSTANTIATION_PROHIBITED = "Instantiation prohibited.";
    private static final Logger LOGGER = LoggerFactory.getLogger(Strings.class);

    private Strings() {
        throw new AssertionError(INSTANTIATION_PROHIBITED);
    }

    /**
     * Generate random string with alpha and numeric of given length.
     */
    public static String randomAlphanumeric(int length) {
        return new RandomString(length).nextString();
    }

    public static String randomNumeric(int length) {
        return new RandomString(length, new SecureRandom(), "0123456789").nextString();
    }

    public static String getRandomNumberString(Integer strLength) {

        Random rnd = new Random();

        String str = "9999";

        if(strLength >= str.length()){
            str = StringUtils.leftPad(str,strLength,"9");
        }

        int number = rnd.nextInt(Integer.parseInt(str));

        return String.format("%06d", number);

    }


}