Add inactivity safeguard and speaker diagnostics

MeetingAssistant/Speakers/SpeakerIdentityMergeService.cs

@@ -58,53 +58,97 @@ public sealed class SpeakerIdentityMergeService : ISpeakerIdentityMergeService
             .ToHashSet();
         var mergedPairs = 0;
         var attempts = 0;
+        logger.LogInformation(
+            "Speaker identity merge diagnostics started: cutoff {Cutoff}, recent identity ids {RecentIdentityIds}, candidate identity count {CandidateIdentityCount}",
+            cutoff,
+            FormatIds(recentIds),
+            identities.Count);
 
         foreach (var sourceId in recentIds.ToList())
         {
             var source = identities.SingleOrDefault(identity => identity.Id == sourceId);
             if (source is null || source.Snippets.Count == 0)
             {
+                logger.LogInformation(
+                    "Speaker identity merge diagnostics skipped source identity {SourceIdentityId} because it was missing or had no snippets",
+                    sourceId);
                 continue;
             }
 
             var targets = identities
                 .Where(identity => identity.Id != source.Id && identity.Snippets.Count > 0)
                 .ToList();
+            logger.LogInformation(
+                "Speaker identity merge diagnostics evaluating source identity {SourceIdentityId} ({SourceName}) with {SnippetCount} snippet(s) against target ids {TargetIdentityIds}",
+                source.Id,
+                source.GetDisplayName(),
+                source.Snippets.Count,
+                FormatIds(targets.Select(target => target.Id)));
             foreach (var batch in targets.Chunk(Math.Max(1, options.MatchBatchSize)))
             {
                 var firstSnippet = SelectSnippet(source, excludedSnippet: null);
                 if (firstSnippet is null)
                 {
+                    logger.LogInformation(
+                        "Speaker identity merge diagnostics stopped evaluating source identity {SourceIdentityId} because no first snippet was available",
+                        source.Id);
                     break;
                 }
 
                 attempts++;
+                logger.LogInformation(
+                    "Speaker identity merge diagnostics round 1 attempt {Attempt} for source identity {SourceIdentityId}: target ids {TargetIdentityIds}, source snippet {SnippetId}",
+                    attempts,
+                    source.Id,
+                    FormatIds(batch.Select(target => target.Id)),
+                    firstSnippet.Id);
                 var firstMatch = await matcher.MatchAsync(
                     CreateRequest(source, firstSnippet, batch),
                     cancellationToken);
                 if (firstMatch is null || firstMatch.IdentityId == source.Id)
                 {
+                    logger.LogInformation(
+                        "Speaker identity merge diagnostics round 1 found no usable target for source identity {SourceIdentityId}",
+                        source.Id);
                     continue;
                 }
 
                 var target = batch.SingleOrDefault(identity => identity.Id == firstMatch.IdentityId);
                 if (target is null)
                 {
+                    logger.LogInformation(
+                        "Speaker identity merge diagnostics round 1 matched identity {IdentityId}, but it was not in the current target batch",
+                        firstMatch.IdentityId);
                     continue;
                 }
 
                 var secondSnippet = SelectSnippet(source, excludedSnippet: firstSnippet);
                 if (secondSnippet is null)
                 {
+                    logger.LogInformation(
+                        "Speaker identity merge diagnostics could not validate source identity {SourceIdentityId} against target identity {TargetIdentityId} because no second source snippet was available",
+                        source.Id,
+                        target.Id);
                     continue;
                 }
 
                 attempts++;
+                logger.LogInformation(
+                    "Speaker identity merge diagnostics round 2 attempt {Attempt} for source identity {SourceIdentityId}: target identity {TargetIdentityId}, source snippet {SnippetId}",
+                    attempts,
+                    source.Id,
+                    target.Id,
+                    secondSnippet.Id);
                 var secondMatch = await matcher.MatchAsync(
                     CreateRequest(source, secondSnippet, batch),
                     cancellationToken);
                 if (secondMatch?.IdentityId != target.Id)
                 {
+                    logger.LogInformation(
+                        "Speaker identity merge diagnostics rejected merge source identity {SourceIdentityId} into target identity {TargetIdentityId}: second match was {SecondMatchIdentityId}",
+                        source.Id,
+                        target.Id,
+                        secondMatch?.IdentityId);
                     continue;
                 }
 
@@ -114,6 +158,12 @@ public sealed class SpeakerIdentityMergeService : ISpeakerIdentityMergeService
                     target,
                     source,
                     options.MaxSnippetsPerSpeaker);
+                logger.LogInformation(
+                    "Speaker identity merge diagnostics merging source identity {SourceIdentityId} ({SourceName}) into target identity {TargetIdentityId} ({TargetName})",
+                    source.Id,
+                    sourceName,
+                    target.Id,
+                    targetName);
                 await SpeakerIdentityTranscriptAudit.AppendMergedAsync(
                     target.References,
                     targetName,
@@ -164,4 +214,13 @@ public sealed class SpeakerIdentityMergeService : ISpeakerIdentityMergeService
             .FirstOrDefault(snippet => excludedSnippet is null || snippet.Id != excludedSnippet.Id);
     }
 
+    private static string FormatIds(IEnumerable<int> ids)
+    {
+        var formatted = ids
+            .Distinct()
+            .Order()
+            .Select(id => id.ToString(System.Globalization.CultureInfo.InvariantCulture))
+            .ToList();
+        return formatted.Count == 0 ? "<none>" : string.Join(", ", formatted);
+    }
 }