refactor(auditlog): consolidate AuditEvent DTO mappers into Communication

src/ScadaLink.AuditLog/Site/Telemetry/ClusterClientSiteAuditClient.cs

@@ -1,5 +1,4 @@
 using Akka.Actor;
-using ScadaLink.AuditLog.Telemetry;
 using ScadaLink.Commons.Entities.Audit;
 using ScadaLink.Commons.Messages.Audit;
 using ScadaLink.Commons.Types;
@@ -35,7 +34,7 @@ namespace ScadaLink.AuditLog.Site.Telemetry;
 /// The batches arrive as proto DTOs (<see cref="AuditEventBatch"/> /
 /// <see cref="CachedTelemetryBatch"/>) because the
 /// <see cref="SiteAuditTelemetryActor"/> builds them with
-/// <see cref="AuditEventMapper.ToDto"/>. This client converts them back into
+/// <see cref="AuditEventDtoMapper.ToDto"/>. This client converts them back into
 /// the <see cref="AuditEvent"/> / <see cref="SiteCall"/> entities the Akka
 /// command messages carry — the same DTO→entity translation the
 /// <c>SiteStreamGrpcServer</c> performs for the gRPC reconciliation path.
@@ -71,7 +70,7 @@ public sealed class ClusterClientSiteAuditClient : ISiteStreamAuditClient
         var events = new List<AuditEvent>(batch.Events.Count);
         foreach (var dto in batch.Events)
         {
-            events.Add(AuditEventMapper.FromDto(dto));
+            events.Add(AuditEventDtoMapper.FromDto(dto));
         }
 
         // Ask<T> throws AskTimeoutException on timeout and rethrows a
@@ -92,7 +91,7 @@ public sealed class ClusterClientSiteAuditClient : ISiteStreamAuditClient
         var entries = new List<CachedTelemetryEntry>(batch.Packets.Count);
         foreach (var packet in batch.Packets)
         {
-            var audit = AuditEventMapper.FromDto(packet.AuditEvent);
+            var audit = AuditEventDtoMapper.FromDto(packet.AuditEvent);
             var siteCall = MapSiteCall(packet.Operational);
             entries.Add(new CachedTelemetryEntry(audit, siteCall));
         }

src/ScadaLink.AuditLog/Site/Telemetry/SiteAuditTelemetryActor.cs

@@ -1,7 +1,6 @@
 using Akka.Actor;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
-using ScadaLink.AuditLog.Telemetry;
 using ScadaLink.Commons.Entities.Audit;
 using ScadaLink.Commons.Interfaces.Services;
 using ScadaLink.Communication.Grpc;
@@ -136,7 +135,7 @@ public class SiteAuditTelemetryActor : ReceiveActor
         var batch = new AuditEventBatch();
         foreach (var e in events)
         {
-            batch.Events.Add(AuditEventMapper.ToDto(e));
+            batch.Events.Add(AuditEventDtoMapper.ToDto(e));
         }
         return batch;
     }

src/ScadaLink.AuditLog/Telemetry/AuditEventMapper.cs

@@ -1,112 +0,0 @@
-using ScadaLink.Commons.Entities.Audit;
-using ScadaLink.Commons.Types.Enums;
-using ScadaLink.Communication.Grpc;
-using Timestamp = Google.Protobuf.WellKnownTypes.Timestamp;
-
-namespace ScadaLink.AuditLog.Telemetry;
-
-/// <summary>
-/// Bridges Audit Log (#23) rows between the in-process <see cref="AuditEvent"/> record
-/// and the wire-format <see cref="AuditEventDto"/> exchanged over the
-/// <c>IngestAuditEvents</c> RPC.
-/// </summary>
-/// <remarks>
-/// <para><b>Lossy by design:</b> the proto contract intentionally omits two fields.</para>
-/// <list type="bullet">
-///   <item><see cref="AuditEvent.ForwardState"/> — site-local SQLite state, never travels.</item>
-///   <item><see cref="AuditEvent.IngestedAtUtc"/> — central-set at ingest time, not at the site.</item>
-/// </list>
-/// <para>
-/// String nullability convention: proto3 scalar strings cannot be absent, so nullable
-/// .NET strings round-trip as empty strings on the wire. Nullable integers use the
-/// <c>Int32Value</c> wrapper so they preserve true null semantics.
-/// </para>
-/// </remarks>
-public static class AuditEventMapper
-{
-    /// <summary>
-    /// Projects an <see cref="AuditEvent"/> into its wire-format DTO. Null reference
-    /// fields collapse to empty strings; null integer fields leave the wrapper unset.
-    /// </summary>
-    public static AuditEventDto ToDto(AuditEvent evt)
-    {
-        ArgumentNullException.ThrowIfNull(evt);
-
-        var dto = new AuditEventDto
-        {
-            EventId = evt.EventId.ToString(),
-            OccurredAtUtc = Timestamp.FromDateTime(EnsureUtc(evt.OccurredAtUtc)),
-            Channel = evt.Channel.ToString(),
-            Kind = evt.Kind.ToString(),
-            CorrelationId = evt.CorrelationId?.ToString() ?? string.Empty,
-            SourceSiteId = evt.SourceSiteId ?? string.Empty,
-            SourceInstanceId = evt.SourceInstanceId ?? string.Empty,
-            SourceScript = evt.SourceScript ?? string.Empty,
-            Actor = evt.Actor ?? string.Empty,
-            Target = evt.Target ?? string.Empty,
-            Status = evt.Status.ToString(),
-            ErrorMessage = evt.ErrorMessage ?? string.Empty,
-            ErrorDetail = evt.ErrorDetail ?? string.Empty,
-            RequestSummary = evt.RequestSummary ?? string.Empty,
-            ResponseSummary = evt.ResponseSummary ?? string.Empty,
-            PayloadTruncated = evt.PayloadTruncated,
-            Extra = evt.Extra ?? string.Empty
-        };
-
-        if (evt.HttpStatus.HasValue)
-        {
-            dto.HttpStatus = evt.HttpStatus.Value;
-        }
-
-        if (evt.DurationMs.HasValue)
-        {
-            dto.DurationMs = evt.DurationMs.Value;
-        }
-
-        return dto;
-    }
-
-    /// <summary>
-    /// Reconstructs an <see cref="AuditEvent"/> from its wire-format DTO. Empty strings
-    /// rehydrate as null reference values; absent integer wrappers stay null.
-    /// <see cref="AuditEvent.ForwardState"/> and <see cref="AuditEvent.IngestedAtUtc"/>
-    /// are intentionally left null — the central ingest actor sets the latter.
-    /// </summary>
-    public static AuditEvent FromDto(AuditEventDto dto)
-    {
-        ArgumentNullException.ThrowIfNull(dto);
-
-        return new AuditEvent
-        {
-            EventId = Guid.Parse(dto.EventId),
-            OccurredAtUtc = DateTime.SpecifyKind(dto.OccurredAtUtc.ToDateTime(), DateTimeKind.Utc),
-            IngestedAtUtc = null,
-            Channel = Enum.Parse<AuditChannel>(dto.Channel),
-            Kind = Enum.Parse<AuditKind>(dto.Kind),
-            CorrelationId = NullIfEmpty(dto.CorrelationId) is { } cid ? Guid.Parse(cid) : null,
-            SourceSiteId = NullIfEmpty(dto.SourceSiteId),
-            SourceInstanceId = NullIfEmpty(dto.SourceInstanceId),
-            SourceScript = NullIfEmpty(dto.SourceScript),
-            Actor = NullIfEmpty(dto.Actor),
-            Target = NullIfEmpty(dto.Target),
-            Status = Enum.Parse<AuditStatus>(dto.Status),
-            HttpStatus = dto.HttpStatus,
-            DurationMs = dto.DurationMs,
-            ErrorMessage = NullIfEmpty(dto.ErrorMessage),
-            ErrorDetail = NullIfEmpty(dto.ErrorDetail),
-            RequestSummary = NullIfEmpty(dto.RequestSummary),
-            ResponseSummary = NullIfEmpty(dto.ResponseSummary),
-            PayloadTruncated = dto.PayloadTruncated,
-            Extra = NullIfEmpty(dto.Extra),
-            ForwardState = null
-        };
-    }
-
-    private static string? NullIfEmpty(string? value) =>
-        string.IsNullOrEmpty(value) ? null : value;
-
-    private static DateTime EnsureUtc(DateTime value) =>
-        value.Kind == DateTimeKind.Utc
-            ? value
-            : DateTime.SpecifyKind(value.ToUniversalTime(), DateTimeKind.Utc);
-}