Inventory logger

Shared/RateLimiter.cs

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+using System;
+using System.Diagnostics;
+
+namespace Mag.Shared
+{
+    public class RateLimiter
+    {
+        public readonly int MaxNumberOfEvents;
+        private readonly double overPeriodInSeconds;
+        private readonly double targetEventSpacingInSeconds;
+
+        private readonly Stopwatch stopwatch = Stopwatch.StartNew();
+
+        public RateLimiter(int maxNumberOfEvents, TimeSpan overPeriod)
+        {
+            if (maxNumberOfEvents <= 0)
+                throw new ArgumentOutOfRangeException(nameof(maxNumberOfEvents), $"{nameof(maxNumberOfEvents)} must be greater than 0");
+
+            if (overPeriod <= TimeSpan.Zero)
+                throw new ArgumentOutOfRangeException(nameof(overPeriod), $"{nameof(overPeriod)} must be greater than TimeSpan.Zero");
+
+            MaxNumberOfEvents = maxNumberOfEvents;
+            overPeriodInSeconds = overPeriod.TotalSeconds;
+
+            targetEventSpacingInSeconds = overPeriodInSeconds / maxNumberOfEvents;
+        }
+
+
+        private int numberOfEventsRegistered;
+
+        /// <summary>
+        /// Result > 0 : We're able to meet our target rate and must pause between events.<para />
+        /// Result = 0 : We're running right no time. A new event should be registered without delay.<para />
+        /// Result &lt; 0 : We're running behind. A new event should be registered without delay. We're failing to meet our target rate.
+        /// </summary>
+        /// <returns></returns>
+        public double GetSecondsToWaitBeforeNextEvent()
+        {
+            var elapsedSeconds = stopwatch.Elapsed.TotalSeconds;
+
+            return ((targetEventSpacingInSeconds * numberOfEventsRegistered) - elapsedSeconds);
+        }
+
+        public void RegisterEvent()
+        {
+            numberOfEventsRegistered++;
+
+            var elapsedSeconds = stopwatch.Elapsed.TotalSeconds;
+
+            if (numberOfEventsRegistered > MaxNumberOfEvents || elapsedSeconds > overPeriodInSeconds)
+            {
+                numberOfEventsRegistered = 1;
+
+	            stopwatch.Reset();
+	            stopwatch.Start();
+			}
+        }
+    }
+}