Different problems with real-time decoding addressed

Author: pgrawehr

src/devices/Nmea0183/AisManager.cs

@@ -225,6 +225,11 @@ public SentenceId GeneratedSentencesId
             }
         }
 
+        /// <summary>
+        /// Provides access to the positioning provider for the AIS manager
+        /// </summary>
+        public PositionProvider PositionProvider => _positionProvider;
+
         /// <summary>
         /// Gets the data of the own ship (including position and movement vectors) as a ship structure.
         /// </summary>

src/devices/Nmea0183/MagneticDeviationCorrection.cs

@@ -214,6 +214,7 @@ void MessageFilter(NmeaSinkAndSource nmeaSinkAndSource, NmeaSentence nmeaSentenc
             }
 
             NmeaLogDataReader reader = new NmeaLogDataReader("Reader", fileSet);
+            reader.DecodeInRealtime = false;
             reader.OnNewSequence += MessageFilter;
             reader.StartDecode();
             reader.StopDecode();

src/devices/Nmea0183/NmeaLogDataReader.cs

@@ -124,6 +124,7 @@ public override void StartDecode()
             }
             else
             {
+                _internalParser.LastPacketTime = DateTime.UnixEpoch; // Long ago
                 _internalParser.OnNewSequence += ForwardDecoded;
             }
 
@@ -149,18 +150,22 @@ private void ForwardDecoded(NmeaSinkAndSource source, NmeaSentence sentence)
 
         private bool DoForwardSequence(NmeaSentence sentence)
         {
-            if (sentence is RawSentence &&
-                (sentence.SentenceId == TimeDate.Id ||
-                 sentence.SentenceId == RecommendedMinimumNavigationInformation.Id ||
-                 sentence.SentenceId == BearingAndDistanceToWayPoint.Id ||
-                 sentence.SentenceId == GlobalPositioningSystemFixData.Id ||
-                 sentence.SentenceId == PositionFastUpdate.Id))
+            // If this is false, parse all messages with their original time stamps
+            if (DecodeInRealtime)
             {
-                // Do not forward these raw sentences, as these can only be used with a patched time.
-                return false;
-            }
+                if (sentence is RawSentence &&
+                    (sentence.SentenceId == TimeDate.Id ||
+                     sentence.SentenceId == RecommendedMinimumNavigationInformation.Id ||
+                     sentence.SentenceId == BearingAndDistanceToWayPoint.Id ||
+                     sentence.SentenceId == GlobalPositioningSystemFixData.Id ||
+                     sentence.SentenceId == PositionFastUpdate.Id))
+                {
+                    // Do not forward these raw sentences, as these can only be used with a patched time.
+                    return false;
+                }
 
-            sentence.DateTime = DateTime.UtcNow;
+                sentence.DateTime = DateTime.UtcNow;
+            }
 
             return true;
         }

src/devices/Nmea0183/PositionProvider.cs

@@ -48,6 +48,11 @@ public PositionProvider(SentenceCache cache)
             _cache = cache ?? throw new ArgumentNullException(nameof(cache));
         }
 
+        /// <summary>
+        /// Provides access to the underlying sentence cache
+        /// </summary>
+        public SentenceCache Cache => _cache;
+
         /// <summary>
         /// Get the current position from the latest message containing any of the relevant data parts. This does not extrapolate the position
         /// if the last received message is old

src/devices/Nmea0183/tests/Ais/AisManagerTest.cs

@@ -26,6 +26,10 @@ public class AisManagerTest : IDisposable
         public AisManagerTest()
         {
             _manager = new AisManager("Test", true, 269110660u, "Cirrus");
+
+            // Our test data isn't _that_ old.
+            // We need to disable this test when replaying data with their original time stamps
+            _manager.PositionProvider.Cache.MaxDataAge = TimeSpan.FromDays(10000);
         }
 
         public void Dispose()
@@ -158,9 +162,9 @@ public void CheckSafety1()
         }
 
         [Theory]
-        [InlineData(600, 1852, 20)] // Default settings
+        [InlineData(600, 1852, 18)] // Default settings
         [InlineData(600, 0, 0)] // Warning distance zero -> No warnings
-        [InlineData(10, 1852, 39)] // Very short warning timeout -> Many warnings
+        [InlineData(10, 1852, 34)] // Very short warning timeout -> Many warnings
         public void CheckSafetyPermanently(int warningRepeatSeconds, int warningDistance, int expectedWarningCount)
         {
             // This does a safety check all the time. Very expensive...
@@ -185,7 +189,8 @@ public void CheckSafetyPermanently(int warningRepeatSeconds, int warningDistance
             reader.OnNewSequence += (source, msg) =>
             {
                 _manager.SendSentence(source, msg);
-                if (msg.SentenceId == new SentenceId("VDM"))
+                // Do the test when we find VDM sequences, but ignore anything until we have a valid time sync for the data
+                if (msg.SentenceId == new SentenceId("VDM") && msg.DateTime.Year > 1970)
                 {
                     // This is a big number that misses some dangerous encounters, but causes the test to end in reasonable time (10s instead of 22s)
                     if ((msgCount++ % 60) == 0)
@@ -212,7 +217,7 @@ public void CheckSafetyPermanently(int warningRepeatSeconds, int warningDistance
             Assert.False(ship!.IsEstimate);
             Assert.NotNull(ship.RelativePosition);
             Assert.True(ship.RelativePosition!.From.Name == "Cirrus");
-            Assert.Equal(8260.2, ship.RelativePosition.Distance.Meters, 1);
+            Assert.Equal(8258.7, ship.RelativePosition.Distance.Meters, 1);
         }
 
         [Fact]