package org.onlab.util;

import com.google.common.base.Strings;
import com.google.common.primitives.UnsignedLongs;
import com.google.common.util.concurrent.ThreadFactoryBuilder;

import java.util.concurrent.ThreadFactory;

public abstract class Tools {

    private Tools() {
    }

    /**
     * Returns a thread factory that produces threads named according to the
     * supplied name pattern.
     *
     * @param pattern name pattern
     * @return thread factory
     */
    public static ThreadFactory namedThreads(String pattern) {
        return new ThreadFactoryBuilder().setNameFormat(pattern).build();
    }

    /**
     * Converts a string from hex to long.
     *
     * @param string hex number in string form; sans 0x
     * @return long value
     */
    public static long fromHex(String string) {
        return UnsignedLongs.parseUnsignedLong(string, 16);
    }

    /**
     * Converts a long value to hex string; 16 wide and sans 0x.
     *
     * @param value long value
     * @return hex string
     */
    public static String toHex(long value) {
        return Strings.padStart(UnsignedLongs.toString(value, 16), 16, '0');
    }

    /**
     * Converts a long value to hex string; 16 wide and sans 0x.
     *
     * @param value long value
     * @param width string width; zero padded
     * @return hex string
     */
    public static String toHex(long value, int width) {
        return Strings.padStart(UnsignedLongs.toString(value, 16), width, '0');
    }

    /**
     * Suspends the current thread for a specified number of millis.
     *
     * @param ms number of millis
     */
    public static void delay(int ms) {
        try {
            Thread.sleep(ms);
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted", e);
        }
    }

}