using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Timers;
using Yitter.IdGenerator;
using YuanXuan.IM.Infrastructure.Redis;

namespace YuanXuan.IM.Api.Helper
{
    /// <summary>
    /// IdWorker自动注册帮助类 需要先注册Redis
    /// </summary>
    public class WorkerIdAutoRegisterHelper
    {

        private static System.Timers.Timer _timer;

        public static IdGeneratorOptions GetIdGeneratorOptions()
        {
            byte workerIdBitLength = 6;
            var maxWorkId = Math.Pow(2, workerIdBitLength) - 1; 
            var workIdKey = "idgen:workid";

            var workId = GetNextWorkId();

            while (!RedisHelper.Instance.SetNx($"{workIdKey}:{workId}", 1))
            {
                // workId 已被占用，获取下一个workId
                workId = GetNextWorkId();
            };

            // 设置5分钟过期
            RedisHelper.Instance.Expire($"{workIdKey}:{workId}", 60 * 5);

            // 设置定时器，每4分钟更新一次过期时间
            SetTimer(4, (s, e) =>
            {
                RedisHelper.Instance.Expire($"{workIdKey}:{workId}", 60 * 5);
            });
             
            // WorkerIdBitLength + SeqBitLength 不超过 22 
            return new IdGeneratorOptions
            {
                WorkerIdBitLength = workerIdBitLength,
                SeqBitLength = 6,  // 数值越高，性能越好，但是Id也越长
                WorkerId = (ushort)workId
            };

            long GetNextWorkId()
            {
                var workId = RedisHelper.Instance.IncrBy(workIdKey,1);
                if (workId > maxWorkId)
                {
                    // 大于了最大可用WorkId,重置workId，并获取
                    RedisHelper.Instance.Set(workIdKey, 0);
                    workId = RedisHelper.Instance.IncrBy(workIdKey, 1);
                }
                Console.WriteLine($"================================================分配到的workId:{workId}===============================================================================");
                return workId;
            }
        }

        private static void SetTimer(int mins, ElapsedEventHandler eh)
        {
            // 创建一个 Timer 实例，并设置其相关属性
            _timer = new System.Timers.Timer(TimeSpan.FromMinutes(mins).TotalMilliseconds); // 4 分钟
            _timer.Elapsed += eh;
            _timer.AutoReset = true; // 设置 Timer 实例能否多次触发
            _timer.Enabled = true; // 启动 Timer 实例
        }
    }
}