package com.szwl.util;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Random;
import java.util.concurrent.atomic.AtomicLong;

public class IDGenerator {
    private static final AtomicLong seq = new AtomicLong(0);
    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss");
    private static final SimpleDateFormat dateFormat1 = new SimpleDateFormat("yyyyMMddHHmmssSSS");


    /**
     * 生成唯一的16位长整型ID --> equipment等常用表
     *
     * @return 订单ID
     */
    public static synchronized long commonID() {
        String timestamp = dateFormat1.format(new Date()).substring(2);
        long threadId = Thread.currentThread().getId();
        String s1 = String.valueOf(threadId);
        char c = s1.charAt(s1.length() - 1);
        //huTool工具集的雪花算法 --> 生成19位id
        //参数1为终端ID
        //参数2为数据中心ID
//        Snowflake snowflake = IdUtil.getSnowflake(1, 1);
//        long id = snowflake.nextId();
//        System.out.println("id***" + id);

        return Long.parseLong(timestamp + c);
    }

    /**
     * 生成唯一的18位长整型ID --> 用于国内订单
     *
     * @return 订单ID
     */
    public static synchronized long orderID() {
        String timestamp = dateFormat.format(new Date()).substring(2);
        long threadId = Thread.currentThread().getId();
        String s1 = String.valueOf(threadId);
        char c = s1.charAt(s1.length() - 1);
        String randomNumber = generateRandomNumber();

        // 乐观锁部分
        long currentSeq;
        long nextSeq;
        do {
            currentSeq = seq.get();
            nextSeq = (currentSeq >= 999) ? 0 : currentSeq + 1;
        } while (!seq.compareAndSet(currentSeq, nextSeq));
        String s2 = String.valueOf(nextSeq);
        char c1 = s2.charAt(s2.length() - 1);

        String s = "5"; // 表示国内订单
        return Long.parseLong(s + timestamp + c + randomNumber + c1);
    }

    /**
     * 生成唯一的18位长整型ID --> 用于海外订单
     *
     * @return 订单ID
     */
    public static synchronized long coinOrderID() {
        String timestamp = dateFormat.format(new Date()).substring(2);
        long threadId = Thread.currentThread().getId();
        String s1 = String.valueOf(threadId);
        char c = s1.charAt(s1.length() - 1);
        String randomNumber = generateRandomNumber();

        // 乐观锁部分
        long currentSeq;
        long nextSeq;
        do {
            currentSeq = seq.get();
            nextSeq = (currentSeq >= 999) ? 0 : currentSeq + 1;
        } while (!seq.compareAndSet(currentSeq, nextSeq));
        String s2 = String.valueOf(nextSeq);
        char c1 = s2.charAt(s2.length() - 1);

        String s = "1"; // 表示海外订单
        return Long.parseLong(s + timestamp + c + randomNumber + c1);
    }

    /**
     * 生成3位伪随机数
     * 因为long类型范围是-9223372036854775808到9223372036854775807，无法容纳更大范围数字，可以将数据库字段类型改为无符号，或者使用varchar类型
     * @return 随机数
     */
    private static String generateRandomNumber() {
        Random random = new Random();
        int nextInt = random.nextInt(1000);
        // 格式化为3位数，并在不满三位的数字前面补零
        return String.format("%03d", nextInt);
    }
}