feat: first go at ActionSchedulerService

ICD.Common.Utils/Services/Scheduler/ActionSchedulerService.cs

@@ -0,0 +1,176 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using ICD.Common.Utils.Extensions;
+using ICD.Common.Utils.Services.Logging;
+using ICD.Common.Utils.Timers;
+
+namespace ICD.Common.Utils.Services.Scheduler
+{
+	public sealed class ActionSchedulerService : IActionSchedulerService, IDisposable
+	{
+		private const long MAX_TIMER_INTERVAL = 5*60*1000; // 5 minutes
+
+		private readonly List<IScheduledAction> m_Actions;
+		private readonly SafeTimer m_Timer;
+		private readonly SafeCriticalSection m_CriticalSection;
+
+		public ActionSchedulerService()
+		{
+			m_Actions = new List<IScheduledAction>();
+			m_Timer = new SafeTimer(TimerCallback, -1);
+			m_CriticalSection = new SafeCriticalSection();
+		}
+
+		public void Dispose()
+		{
+			foreach (IScheduledAction action in m_Actions)
+			{
+				Unsubscribe(action);
+
+				IDisposable disposable = action as IDisposable;
+				if (disposable != null)
+					disposable.Dispose();
+			}
+
+			m_Actions.Clear();
+		}
+
+		#region Methods
+
+		public void Add(IScheduledAction action)
+		{
+			m_CriticalSection.Enter();
+			try
+			{
+				Subscribe(action);
+				m_Actions.AddSorted(action, a => a.NextRunTime);
+			}
+			finally
+			{
+				m_CriticalSection.Leave();
+			}
+		}
+
+		public void Remove(IScheduledAction action)
+		{
+			m_CriticalSection.Enter();
+			try
+			{
+				Unsubscribe(action);
+				m_Actions.Remove(action);
+			}
+			finally
+			{
+				m_CriticalSection.Leave();
+			}
+		}
+
+		public override string ToString()
+		{
+			return "ActionSchedulerService";
+		}
+
+		#endregion
+
+		#region Private Methods
+
+		private void TimerCallback()
+		{
+			IScheduledAction[] actionsToRun;
+
+			m_CriticalSection.Enter();
+			try
+			{
+				actionsToRun = m_Actions
+					.Where(a => a.NextRunTime < DateTime.Now)
+					.OrderBy(a => a.NextRunTime)
+					.ToArray();
+			}
+			finally
+			{
+				m_CriticalSection.Leave();
+			}
+
+			// leave the critical section so any actions that run can enter
+			foreach (IScheduledAction action in actionsToRun)
+			{
+				try
+				{
+					action.Run();
+				}
+				catch (Exception ex)
+				{
+					Log(eSeverity.Error, ex, "Error occurred while running scheduled action");
+				}
+			}
+
+			// enter again to check the closest next run time
+			m_CriticalSection.Enter();
+			try
+			{
+				var action = m_Actions.FirstOrDefault();
+				if (action == null)
+					return;
+
+				m_Timer.Reset((long)(DateTime.Now - action.NextRunTime).TotalMilliseconds);
+			}
+			finally
+			{
+				m_CriticalSection.Leave();
+			}
+		}
+
+		private void Log(eSeverity severity, string message, params object[] args)
+		{
+			ILoggerService logger = ServiceProvider.TryGetService<ILoggerService>();
+			if (logger == null)
+				return;
+
+			logger.AddEntry(severity, string.Format("{0} - {1}", this, message), args);
+		}
+
+		private void Log(eSeverity severity, Exception ex, string message, params object[] args)
+		{
+			ILoggerService logger = ServiceProvider.TryGetService<ILoggerService>();
+			if (logger == null)
+				return;
+
+			logger.AddEntry(severity, ex, string.Format("{0} - {1}", this, message), args);
+		}
+
+		#endregion
+
+		#region Action Callbacks
+
+		private void Subscribe(IScheduledAction action)
+		{
+			action.OnScheduledRunTimeChanged += ActionOnScheduledRunTimeChanged;
+		}
+
+		private void Unsubscribe(IScheduledAction action)
+		{
+			action.OnScheduledRunTimeChanged -= ActionOnScheduledRunTimeChanged;
+		}
+
+		private void ActionOnScheduledRunTimeChanged(object sender, EventArgs eventArgs)
+		{
+			IScheduledAction action = sender as IScheduledAction;
+			if (action == null)
+				return;
+
+			m_CriticalSection.Enter();
+			try
+			{
+				m_Actions.Remove(action);
+				m_Actions.AddSorted(action, a => a.NextRunTime);
+			}
+			finally
+			{
+				m_CriticalSection.Leave();
+			}
+		}
+
+		#endregion
+	}
+}