// (c) 2007 Richard Grimes
// www.grimes.demon.co.uk

using System;
using System.Diagnostics;

class Server
{
   const string catName = "Data Generator";
   const string catHelp = "Generates random sample data";
   const string ctrName = "# Connected Clients";
   const string ctrHelp = "The number of clients connected to the server";
   const string ctrRateName = "# of clients connecting per sec";
   const string ctrRateHelp = "The rate that clients connect";

   static PerformanceCounter clients; 
   static PerformanceCounter totalClients;

   static void Main(string[] args)
   {
      if (args.Length > 0)
      {
         // Delete category
         if (PerformanceCounterCategory.Exists(catName))
         {
            PerformanceCounterCategory.Delete(catName);
         }
         return;
      }

      if (!PerformanceCounterCategory.Exists(catName))
      {
         // Create new counter if it does not exist
         CounterCreationDataCollection ccdc = new CounterCreationDataCollection();
         CounterCreationData ccd = 
            new CounterCreationData(ctrName, ctrHelp, 
            PerformanceCounterType.NumberOfItems32);
         ccdc.Add(ccd);
         ccd = new CounterCreationData(ctrRateName, ctrRateHelp,
            PerformanceCounterType.RateOfCountsPerSecond32);
         ccdc.Add(ccd);
         PerformanceCounterCategory.Create(
            catName, catHelp,
            PerformanceCounterCategoryType.SingleInstance,
            ccdc);
         Console.WriteLine("Category created, re-run the application");
         return;
      }

      Console.CancelKeyPress += CtrlCHandler; 

      // Provide counters
      clients = new PerformanceCounter(catName, ctrName, false);
      totalClients = new PerformanceCounter(catName, ctrRateName, false); 
      Random rand = new Random(Environment.TickCount);
      int numberOfClients = 5; 
      totalClients.RawValue = numberOfClients; 

      Console.WriteLine("Press Ctrl-C to end the server");
      while (true)
      {
         // Simulate clients attaching and detaching
         int val = rand.Next(100);
         if (val > 66)
         {
            numberOfClients++;
            totalClients.Increment();
         }
         if (val < 33) numberOfClients--;
         if (numberOfClients < 0) numberOfClients = 0;
         clients.RawValue = numberOfClients;
         System.Threading.Thread.Sleep(100);
      }
   }
   static void CtrlCHandler(object o, ConsoleCancelEventArgs a)
   {
      if (clients != null) clients.Close();
      if (totalClients != null) totalClients.Close(); 
      Console.WriteLine("Finished");
   }
}