Merge feat/671-time-weighted-aggregates: Part 13 time-weighted aggregates (#671)

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/Historian/HistoryReadContracts.cs

@@ -47,6 +47,12 @@ public enum HistoryAggregateType
     AnnotationCount,
     StandardDeviationPopulation,
     VariancePopulation,
+
+    /// <summary>Part 13 TimeAverage2: time-weighted average over the interval's non-Bad data only (#671).</summary>
+    TimeAverage2,
+
+    /// <summary>Part 13 Total2: time-weighted integral (value·seconds) over the interval's non-Bad data only (#671).</summary>
+    Total2,
 }
 
 /// <summary>
@@ -65,6 +71,22 @@ public sealed class HistoryAggregateNotSupportedException : NotSupportedExceptio
         => Aggregate = aggregate;
 }
 
+/// <summary>
+///     Thrown by a history backend when a read would exceed a configured size limit (e.g. the raw-row cap of the SQL
+///     backends' time-weighted aggregates, #671). The Server HistoryRead path translates it to
+///     <c>BadTooManyOperations</c> for that node only; it is a client-request limit, not a backend fault.
+/// </summary>
+public sealed class HistoryReadLimitExceededException : InvalidOperationException
+{
+    /// <summary>The configured limit that was exceeded.</summary>
+    public long Limit { get; }
+
+    /// <summary>Creates the exception.</summary>
+    /// <param name="limit">The configured limit.</param>
+    /// <param name="message">Operator-facing description.</param>
+    public HistoryReadLimitExceededException(long limit, string message) : base(message) => Limit = limit;
+}
+
 /// <summary>
 ///     One row returned by <see cref="IHistorianDataSource.ReadEventsAsync"/> — a historical
 ///     alarm/event record, not the OPC UA live-event stream. Fields match the minimum set the