using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using UnityEngine;

public partial class UIdSystem : MonoBehaviour
{
    private static class GUID
    {
        private static ulong TimestampMask = 0xffffffff00000000;    //时间戳掩码
        private static ulong BigMask = 0x00000000f0000000;          //大区号掩码
        private static ulong SmallMask = 0x000000000ff00000;        //小区号掩码
        private static ulong BaseMask = 0x00000000000fffff;         //本地 ID 编号掩码
        private static int BaseId = 0;                              //本地 ID

        private static readonly DateTime Jan1st1970 = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

        /// <summary>
        /// 根据大区号和小区号生成 ID。
        /// </summary>
        public static ulong NewGuid(uint big = 0, uint small = 0)
        {
            ulong timeStamp = (ulong)(DateTime.UtcNow - Jan1st1970).TotalSeconds;

            ulong newId = ((timeStamp << 32) & TimestampMask) |
                            ((big << 28) & BigMask) |
                            ((small << 20) & SmallMask) |
                            ((uint)BaseId & BaseMask);

            Interlocked.Increment(ref BaseId);

            return newId;
        }
    }
}