using System;

using System.Collections.ObjectModel;

using System.Diagnostics;

using System.Windows.Threading;

using Microsoft.Research.DynamicDataDisplay.Common;



namespace PerfCounterChart

{

	public class PerformanceInfo

	{

		public DateTime Time { get; set; }

		public double Value { get; set; }

	}



	public class PerformanceData : RingArray<PerformanceInfo>

	{

		private readonly PerformanceCounter counter;

		public PerformanceData(string categoryName, string counterName) : this(new PerformanceCounter(categoryName, counterName)) { }



		public PerformanceData(PerformanceCounter counter)

			: base(200)

		{

			if (counter == null)

				throw new ArgumentNullException("counter");



			this.counter = counter;

			timer.Tick += OnTimerTick;

			timer.Start();

		}



		private void OnTimerTick(object sender, EventArgs e)

		{

			var newInfo = new PerformanceInfo { Time = DateTime.Now, Value = counter.NextValue() };

			this.Add(newInfo);



			Debug.WriteLine(String.Format("{0}.{1}: {2}", newInfo.Time.Second, newInfo.Time.Millisecond, newInfo.Value));

		}



		private TimeSpan updateInterval = TimeSpan.FromMilliseconds(500);

		public TimeSpan UpdateInterval

		{

			get { return updateInterval; }

			set

			{

				updateInterval = value;

				timer.Interval = updateInterval;

			}

		}



		private readonly DispatcherTimer timer = new DispatcherTimer();



		public void Run()

		{

			timer.Interval = updateInterval;

			timer.IsEnabled = true;

		}



		public void Pause()

		{

			timer.IsEnabled = false;

		}

	}

}