From 36a03587b93fe658d4a7a15af1c213171b91d13e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Burak=20=C3=96ner?= <info@burakoner.com>
Date: Wed, 6 Jan 2021 00:29:25 +0300
Subject: [PATCH] Create RateLimiterCredit.cs

---
 .../RateLimiter/RateLimiterCredit.cs          | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 CryptoExchange.Net/RateLimiter/RateLimiterCredit.cs

diff --git a/CryptoExchange.Net/RateLimiter/RateLimiterCredit.cs b/CryptoExchange.Net/RateLimiter/RateLimiterCredit.cs
new file mode 100644
index 0000000..ef6cc2b
--- /dev/null
+++ b/CryptoExchange.Net/RateLimiter/RateLimiterCredit.cs
@@ -0,0 +1,65 @@
+using CryptoExchange.Net.Interfaces;
+using CryptoExchange.Net.Objects;
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+
+namespace CryptoExchange.Net.RateLimiter
+{
+    /// <summary>
+    /// Limits the amount of requests per time period to a certain limit, counts the total amount of requests.
+    /// </summary>
+    public class RateLimiterCredit : IRateLimiter
+    {
+        internal List<DateTime> history = new List<DateTime>();
+
+        private readonly int limit;
+        private readonly TimeSpan perTimePeriod;
+        private readonly object requestLock = new object();
+
+        /// <summary>
+        /// Create a new RateLimiterTotal. This rate limiter limits the amount of requests per time period to a certain limit, counts the total amount of requests.
+        /// </summary>
+        /// <param name="limit">The amount to limit to</param>
+        /// <param name="perTimePeriod">The time period over which the limit counts</param>
+        public RateLimiterCredit(int limit, TimeSpan perTimePeriod)
+        {
+            this.limit = limit;
+            this.perTimePeriod = perTimePeriod;
+        }
+
+        /// <inheritdoc />
+        public CallResult<double> LimitRequest(RestClient client, string url, RateLimitingBehaviour limitBehaviour, int credits = 1)
+        {
+            var sw = Stopwatch.StartNew();
+            lock (requestLock)
+            {
+                sw.Stop();
+                double waitTime = 0;
+                var checkTime = DateTime.UtcNow;
+                history.RemoveAll(d => d < checkTime - perTimePeriod);
+
+                if (history.Count >= limit)
+                {
+                    waitTime = (history.First() - (checkTime - perTimePeriod)).TotalMilliseconds;
+                    if (waitTime > 0)
+                    {
+                        if (limitBehaviour == RateLimitingBehaviour.Fail)
+                            return new CallResult<double>(waitTime, new RateLimitError($"total limit of {limit} reached"));
+
+                        Thread.Sleep(Convert.ToInt32(waitTime));
+                        waitTime += sw.ElapsedMilliseconds;
+                    }
+                }
+
+                for (int i = 1; i <= credits; i++)
+                    history.Add(DateTime.UtcNow);
+
+                history.Sort();
+                return new CallResult<double>(waitTime, null);
+            }
+        }
+    }
+}