package com.ruoyi.web.tool;


/**
 * id生成器
 */
public class IDUtil {
    /**
     * 存储时间戳
     */
    private static long timestamp = System.currentTimeMillis();
    /**
     * 自增长值
     */
    private static int self = 0;
    /**
     * 最大自增长值
     */
    private static int max_self = 9999;
    /**
     * 设备号
     */
    private static int device = 0;
    /**
     * 时针回拨增长值
     */
    private static int hour_hand_variable = 0;
    /**
     * 时针回拨最大增长值
     */
    private static int max_hour_hand_variable = 999;


    /**
     * 时间戳id
     * @return
     */
    public static long timestamp_id(){
        return timestamp;
    }

    /**
     * 生成唯一ID
     * @return
     */
    public static long sole_id(){
        return sole_id(null);
    }


    /**
     * 唯一ID生成
     * @param workId    工作ID
     * @return
     */
    public synchronized static long sole_id(Integer workId){
        if(null != workId){
            device = workId;
        }
        long timeMillis = System.currentTimeMillis();
        /**
         * 时间戳相同
         * 自增长值使用完后，休眠等待时间戳更新
         */
        if(timeMillis == timestamp && self > max_self){
            try {
                Thread.sleep(1);
                self = 0;
                return sole_id(workId);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }
        //处理时针回拨的情况
        if(timeMillis < timestamp) {
            if (hour_hand_variable >= max_hour_hand_variable) {
                hour_hand_variable = 0;
            } else {
                hour_hand_variable++;
            }
        }
        //处理
        if(timeMillis > timestamp){
            timestamp = timeMillis;
            self = 0;
        }
        return splice();
    }


    /**
     * 拼接最终的id
     * @return
     */
    private static long splice(){
        //格式化自增长数据格式，前位补0
        String format = String.format("%04d", self);
        Long id = Long.valueOf(timestamp + "" + hour_hand_variable + "" + device + format);
        self++;
        return id;
    }
}