class Program
    {
        public static Random r = new Random();
        public static int GoodsStock = 30;
        public static Queue payq = new Queue();
        public static Queue waitq = new Queue();

        static void Main(string[] args)
        {
            //增加监视线程
            ThreadStart childref3 = new ThreadStart(LookAtActiveThread);
            Console.WriteLine("监视线程启动了！");
            Thread childThread3 = new Thread(childref3);
            childThread3.Start();
            //增加用户抢购线程
            ThreadStart childref1 = new ThreadStart(UserBuyInsertThread);
            Console.WriteLine("用户群1开始抢购了！");
            Thread childThread1 = new Thread(childref1);
            childThread1.Start();
            //增加用户抢购线程
            ThreadStart childref4 = new ThreadStart(UserBuyInsertThread);
            Console.WriteLine("用户群2开始抢购了！");
            Thread childThread4 = new Thread(childref4);
            childThread4.Start();
            //增加开始结账线程
            ThreadStart childref2 = new ThreadStart(UserPayEndThread);
            Console.WriteLine("结账线程启动了！");
            Thread childThread2 = new Thread(childref2);
            childThread2.Start();
            Console.ReadKey();
        }

        //监视线程，抢购结束后关闭所有线程
        public static void LookAtActiveThread()
        {
            DateTime TempDT = new DateTime();
            int totalCount = GoodsStock;
            while (true)
            {
                if (GoodsStock == 0 && payq.Count == 0 && waitq.Count == 0)
                {
                    TimeSpan ts = DateTime.Now.Subtract(TempDT);
                    Console.WriteLine("抢购活动已结束，" + totalCount + "个商品已在" + ts.Seconds + "秒售罄 当前时间：" + DateTime.Now);
                    break;
                }
                else
                {
                    Thread.Sleep(100);
                }
            }
        }

        //购买用户随机排队插入队列 排队总人数不能超过10个
        public static void UserBuyInsertThread()
        {
            try
            {
                while (true)
                {
                    if (GoodsStock > 0)
                    {
                        //判断等待队列是否为空，付款队列是否已满，直接加入到付款队列中
                        if (waitq.Count==0 && payq.Count < GoodsStock)
                        {
                            int userid = r.Next(10000, 99999);
                            payq.Enqueue(userid);
                            Console.WriteLine("用户" + userid + "下单成功，请尽快付款 当前付款队列：" + payq.Count + " 当前时间：" + DateTime.Now);
                            Thread.Sleep(r.Next(100));
                        }
                        else
                        {
                            int userid = r.Next(10000, 99999);
                            waitq.Enqueue(userid);
                            Console.WriteLine("用户" + userid + "已加入到等待队列中 当前等待队列：" + waitq.Count + " 当前时间：" + DateTime.Now);
                            Thread.Sleep(r.Next(500, 2000));
                        }
                    }
                    else
                    {
                        Console.WriteLine("对不起，您来晚了，商品已售罄");
                        Thread.Sleep(300);
                    }
                    if (GoodsStock == 0 && payq.Count == 0 && waitq.Count == 0)
                    {
                        //停止线程
                        Console.WriteLine("排队线程结束 当前时间：" + DateTime.Now);
                        break;
                    }
                }
            }
            catch (ThreadAbortException e)
            {
                Console.WriteLine("用户排队线程出错了：" + e.ToString());
            }
        }

        //用户购买操作，付款时间比较随机
        public static void UserPayEndThread() 
        {
            try
            {
                while (true)
                {
                    if (payq.Count == 0 && waitq.Count == 0)
                    {
                        Thread.Sleep(300);
                    }
                    else
                    {
                        if (GoodsStock == 0)
                        {
                            if (waitq.Count > 0)
                            {
                                int userid = (int)waitq.Dequeue();
                                Console.WriteLine("对不起" + userid + "，商品已被抢购一空！ 下次请努力！ 当前时间：" + DateTime.Now);
                                Thread.Sleep(100);
                            }
                        }
                        else
                        {
                            if (payq.Count > 0)
                            {
                                int userid = (int)payq.Dequeue();
                                //用户一定概率的超时或者取消订单
                                if (r.Next(1, 10) < 3)
                                {
                                    Console.WriteLine("对不起，用户" + userid + "已超时或取消订单！ 当前付款队列：" + payq.Count + " 当前时间：" + DateTime.Now + " 当前库存：" + GoodsStock);
                                }
                                else
                                {
                                    GoodsStock -= 1;
                                    Console.WriteLine("恭喜！用户" + userid + "已结账，购买成功！ 当前付款队列：" + payq.Count + " 当前时间：" + DateTime.Now + " 当前库存：" + GoodsStock);
                                }
                                //把等待队列中的用户加入到付款队列中，判断付款队列中是否超过库存数量s
                                if (GoodsStock > 0 && GoodsStock > payq.Count && waitq.Count > 0)
                                {
                                    userid = (int)waitq.Dequeue();
                                    payq.Enqueue(userid);
                                    Console.WriteLine("用户" + userid + "已从排队队列加入到付款队列，请尽快付款！当前付款队列：" + payq.Count + " 当前时间：" + DateTime.Now + " 当前库存：" + GoodsStock);
                                }
                                Thread.Sleep(r.Next(100, 500));
                            }
                        }
                    }
                    if (GoodsStock == 0 && payq.Count == 0 && waitq.Count == 0)
                    {
                        //停止线程
                        Console.WriteLine("付款线程结束 当前时间：" + DateTime.Now);
                        break;
                    }
                }
            }
            catch (ThreadAbortException e)
            {
                Console.WriteLine("用户结账线程出错了：" + e.ToString());
            }
        }
    }