--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ServerMonitor/Objects/Schedule.cs	Mon Dec 31 18:32:14 2018 -0500
@@ -0,0 +1,72 @@
+using System;
+
+namespace ServerMonitorApp
+{
+    public class Schedule
+    {
+        public Schedule() { }
+
+        public Schedule(FrequencyUnits units, int frequency, TimeSpan startTime, TimeSpan endTime)
+        {
+            Units = units;
+            Frequency = frequency;
+            StartTime = startTime;
+            EndTime = endTime;
+        }
+
+        public int Frequency { get; set; }
+
+        public FrequencyUnits Units { get; set; }
+
+        public TimeSpan StartTime { get; set; }
+
+        public TimeSpan EndTime { get; set; }
+
+        public DateTime GetNextTime(DateTime lastScheduledTime)
+        {
+            return GetNextTime(lastScheduledTime, DateTime.Now);
+        }
+
+        public DateTime GetNextTime(DateTime lastScheduledTime, DateTime minStartTime)
+        {
+            DateTime nextTime = lastScheduledTime;
+            if (Units == FrequencyUnits.Day)
+            {
+                //TODO what if nextTime is null or really long ago?
+                while (nextTime < minStartTime)
+                    nextTime = nextTime.AddDays(Frequency).Date.Add(StartTime);
+            }
+            else
+            {
+                // If the last run time was more than a day ago, fast-forward to reduce the number of loops
+                if (nextTime < minStartTime.AddHours(-24))
+                    nextTime = minStartTime.Date.Add(StartTime).AddHours(-24);
+                //TODO handle start time and end time
+                while (nextTime < minStartTime)
+                {
+                    switch (Units)
+                    {
+                        case FrequencyUnits.Second: nextTime = nextTime.AddSeconds(Frequency); break;
+                        case FrequencyUnits.Minute: nextTime = nextTime.AddMinutes(Frequency); break;
+                        case FrequencyUnits.Hour:   nextTime = nextTime.AddHours(Frequency);   break;
+                        default: throw new InvalidOperationException("Unexpected frequency units: " + Units);
+                    }
+                }
+                if (StartTime < EndTime)
+                {
+                    if (nextTime.TimeOfDay < StartTime)
+                        nextTime = nextTime.Date + StartTime;
+                    else if (nextTime.TimeOfDay > EndTime)
+                        nextTime = nextTime.Date.AddDays(1) + StartTime;
+                }
+                else if (nextTime.TimeOfDay > EndTime && nextTime.TimeOfDay < StartTime)
+                {
+                    nextTime = nextTime.Date + StartTime;
+                }
+            }
+            return nextTime;
+        }
+    }
+
+    public enum FrequencyUnits { Second, Minute, Hour, Day }
+}
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