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NitroxClient/GameLogic/CorrectedTimeManager.cs

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+using System;
+using NitroxClient.Communication.NetworkingLayer.LiteNetLib;
+using NitroxModel.Networking;
+
+namespace NitroxClient.GameLogic;
+
+public partial class TimeManager
+{
+    private readonly NtpSyncer ntpSyncer;
+
+    /// <summary>
+    /// Whether or not the local player could obtain a correction from the global NTP server
+    /// </summary>
+    private bool clientOnlineMode;
+    /// <summary>
+    /// Local's UTC correction with a global NTP server ("real"). Client Correction = Real UTC Time - Client UTC Time
+    /// </summary>
+    private TimeSpan clientCorrection;
+
+
+    /// <summary>
+    /// Whether or not server could obtain a correction from the global NTP server
+    /// </summary>
+    private bool serverOnlineMode;
+    /// <summary>
+    /// Server's UTC correction with a global NTP server ("real"). Server Correction = Real UTC Time - Server UTC Time
+    /// </summary>
+    private TimeSpan serverCorrection;
+
+    /// <summary>
+    /// Correction Delta = Server UTC Time - Client UTC Time. Calculated thanks to <see cref="ClockSyncProcedure"/>
+    /// </summary>
+    private TimeSpan correctionDelta;
+
+    public DateTimeOffset ServerUtcNow()
+    {
+        if (clientOnlineMode && serverOnlineMode)
+        {
+            // From clientCorrection and serverCorrection we deduce the following equation:
+            // Server UTC Time + Server correction = Client UTC Time + Client correction
+            // from this equation we deduce Server UTC Time which is the below value
+            return DateTimeOffset.UtcNow + clientCorrection - serverCorrection;
+        }
+
+        // In any other case than the above one, we can only rely on the clock sync procedure for which the equation gives the below value
+        return DateTimeOffset.UtcNow + correctionDelta;
+    }
+
+    public void SetCorrectionDelta(long remoteTimeDelta)
+    {
+        correctionDelta = new TimeSpan(remoteTimeDelta);
+        Log.Info($"OFFLINE mode: delta = {correctionDelta}");
+    }
+
+    public void SetClientCorrectionData(bool clientOnlineMode, TimeSpan correctionOffset)
+    {
+        this.clientOnlineMode = clientOnlineMode;
+        clientCorrection = correctionOffset;
+        Log.Info($"Client ONLINE: correction = {correctionOffset}");
+    }
+
+    public void SetServerCorrectionData(bool serverOnlineMode, long serverUtcCorrectionTicks)
+    {
+        this.serverOnlineMode = serverOnlineMode;
+        serverCorrection = new(serverUtcCorrectionTicks);
+        Log.Info($"Server ONLINE: correction = {serverCorrection}");
+    }
+
+    public void AttemptNtpSync()
+    {
+        ntpSyncer.Setup(false, (onlineMode, correction) =>
+        {
+            if (onlineMode)
+            {
+                SetClientCorrectionData(onlineMode, correction);
+            }
+        });
+        ntpSyncer.RequestNtpService();
+    }
+}