Examine Facets proposal about examine HOT 31 CLOSED

public LuceneSearchResults SearchByDistance(Query query, Coordinate coordinate, int distanceInKm, QueryOptions? options = null)
{
    if (Index is not LuceneIndex luceneIndex)
        throw new InvalidOperationException($"Index {Index.Name} is not a LuceneIndex");

    int maxLevels = 11;

    // Create an SpatialStrategy
    var ctx = SpatialContext.Geo;
    var strategy = new RecursivePrefixTreeStrategy(
                    new GeohashPrefixTree(ctx, maxLevels),
                    fieldName: Constants.Examine.CourseInstance.FieldNames.GeoLocation);

    var lat = coordinate.Latitude;
    var lng = coordinate.Longitude;

    var results = DoSpatialSearch(ctx, strategy, luceneIndex, query, distanceInKm, lat, lng, options ?? QueryOptions.Default);

    return results;
}

private static LuceneSearchResults DoSpatialSearch(
            SpatialContext ctx, SpatialStrategy strategy,
            LuceneIndex index, Query q, double distanceInKm, double lat, double lng,
            QueryOptions options)
  {
      var searcher = (LuceneSearcher)index.Searcher;
      var searchContext = searcher.GetSearchContext();

      using ISearcherReference searchRef = searchContext.GetSearcher();

      var indexSearcher = searchRef.IndexSearcher;

      GetXYFromCoords(lat, lng, out var x, out var y);

      var distance = DistanceUtils.Dist2Degrees(distanceInKm, DistanceUtils.EarthMeanRadiusKilometers);

      // Make a circle around the search point
      var shape = ctx.MakeCircle(x, y, distance);
      var args = new SpatialArgs(
                  SpatialOperation.Intersects, shape);

      // Create the Lucene Filter
      var filter = strategy.MakeFilter(args);

      // Create the Lucene Query
      var query = strategy.MakeQuery(args);

      var startingPoint = ctx.MakePoint(x, y);
      var valueSource = strategy.MakeDistanceValueSource(startingPoint);

      var sortByDistance = new Sort(valueSource.GetSortField(false)).Rewrite(indexSearcher);

      ValueSourceFilter vsf = new ValueSourceFilter(new QueryWrapperFilter(query), valueSource, 0, distance);
      var filteredSpatial = new FilteredQuery(new MatchAllDocsQuery(), vsf);
      var spatialRankingQuery = new FunctionQuery(valueSource);

      IList<BooleanClause> existingClauses = ((BooleanQuery)q).GetClauses();

      BooleanQuery bq = new()
      {
          { filteredSpatial, Occur.MUST },
          { spatialRankingQuery, Occur.MUST }
      };

      var includesStartDate = existingClauses.Where(x => x.Query.ToString().Contains("startDate")).Any();
      foreach (var c in existingClauses)
      {
          var queryString = c.Query.ToString();
          if (queryString.Contains("latestValidDate"))
          {
              if (!includesStartDate)
              {
                  bq.Add(GetRangeQuery(queryString), Occur.MUST);
                  continue;
              }
              else
              {
                  continue;
              }
          }
          if (queryString.Contains("startDate"))
          {
              bq.Add(GetRangeQuery(queryString), Occur.MUST);
              continue;
          }

          bq.Add(c);
      }

      int maxDoc = indexSearcher.IndexReader.MaxDoc;

      var maxResults = Math.Min((options.Skip + 1) * options.Take, maxDoc);
      maxResults = maxResults >= 1 ? maxResults : QueryOptions.DefaultMaxResults;

      ICollector topDocsCollector = TopFieldCollector.Create(sortByDistance, maxResults, false, false, false, false);

      indexSearcher.Search(bq, filter, topDocsCollector);

      TopDocs topDocs = ((TopFieldCollector)topDocsCollector).GetTopDocs(options.Skip, options.Take);

      var totalItemCount = topDocs.TotalHits;

      var results = new List<ISearchResult>();
      for (int i = 0; i < topDocs.ScoreDocs.Length; i++)
      {
          var result = GetSearchResult(i, topDocs, indexSearcher);
          results.Add(result);
      }

      return new LuceneSearchResults(results, totalItemCount);
  }

[23-10-27 10:21:17.275]Error:Error extracting metadata for /github/workspace/src/Examine.Lucene/Examine.Lucene.csproj,/github/workspace/src/Examine.Core/Examine.Core.csproj,/github/workspace/src/Examine.Host/Examine.csproj: System.NullReferenceException: Object reference not set to an instance of an object
  at Microsoft.DocAsCode.Metadata.ManagedReference.CopyInherited.InheritDoc (Microsoft.DocAsCode.Metadata.ManagedReference.MetadataItem dest, Microsoft.DocAsCode.Metadata.ManagedReference.ResolverContext context) [0x0007f] in <a8c39[85](https://github.com/Shazwazza/Examine/actions/runs/6672776075/job/18137309467#step:6:86)37c454be982e8eaec7eb97dd4>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.CopyInherited+<>c__DisplayClass0_0.<Run>b__1 (Microsoft.DocAsCode.Metadata.ManagedReference.MetadataItem current, Microsoft.DocAsCode.Metadata.ManagedReference.MetadataItem parent) [0x00008] in <a8c398537c454be982e8eaec7eb97dd4>:0 
  at Microsoft.DocAsCode.Common.TreeIterator.Preorder[T] (T current, T parent, System.Func`2[T,TResult] childrenGetter, System.Func`3[T1,T2,TResult] action) [0x0000c] in <f27dcd834d6d4f32ac0a576c1732f2f1>:0 
  at Microsoft.DocAsCode.Common.TreeIterator.Preorder[T] (T current, T parent, System.Func`2[T,TResult] childrenGetter, System.Func`3[T1,T2,TResult] action) [0x00036] in <f27dcd834d6d4f32ac0a576c1732f2f1>:0 
  at Microsoft.DocAsCode.Common.TreeIterator.Preorder[T] (T current, T parent, System.Func`2[T,TResult] childrenGetter, System.Func`3[T1,T2,TResult] action) [0x00036] in <f27dcd834d6d4f32ac0a576c1732f2f1>:0 
  at Microsoft.DocAsCode.Common.TreeIterator.Preorder[T] (T current, T parent, System.Func`2[T,TResult] childrenGetter, System.Func`3[T1,T2,TResult] action) [0x00036] in <f27dcd834d6d4f32ac0a576c1732f2f1>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.CopyInherited.Run (Microsoft.DocAsCode.Metadata.ManagedReference.MetadataModel yaml, Microsoft.DocAsCode.Metadata.ManagedReference.ResolverContext context) [0x00013] in <a8c398537c454be982e8eaec7eb97dd4>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.YamlMetadataResolver.ExecutePipeline (Microsoft.DocAsCode.Metadata.ManagedReference.MetadataModel yaml, Microsoft.DocAsCode.Metadata.ManagedReference.ResolverContext context) [0x00015] in <a8c398537c454be982e8eaec7eb97dd4>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.YamlMetadataResolver.ResolveMetadata (System.Collections.Generic.Dictionary`2[TKey,TValue] allMembers, System.Collections.Generic.Dictionary`2[TKey,TValue] allReferences, System.Boolean preserveRawInlineComments) [0x00092] in <a8c398537c454be982e8eaec7eb97dd4>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.ExtractMetadataWorker+<ResolveAndExportYamlMetadata>d__19.MoveNext () [0x0003b] in <a8c398537c454be982e8eaec7eb97dd4>:0 
  at System.Collections.Generic.List`1[T].AddEnumerable (System.Collections.Generic.IEnumerable`1[T] enumerable) [0x00059] in <533173d24dae460[89](https://github.com/Shazwazza/Examine/actions/runs/6672776075/job/18137309467#step:6:90)9d2b10[97](https://github.com/Shazwazza/Examine/actions/runs/6672776075/job/18137309467#step:6:98)5534bb0>:0 
  at System.Collections.Generic.List`1[T]..ctor (System.Collections.Generic.IEnumerable`1[T] collection) [0x00062] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Linq.Enumerable.ToList[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x00018] in <5b415632df1f4365ae2242b1a257bb5b>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.ExtractMetadataWorker.SaveAllMembersFromCacheAsync () [0x00be7] in <a8c3[98](https://github.com/Shazwazza/Examine/actions/runs/6672776075/job/18137309467#step:6:99)537c454be982e8eaec7eb97dd4>:0 
  at Microsoft.DocAsCode.Metadata.ManagedReference.ExtractMetadataWorker.ExtractMetadataAsync () [0x000c0] in <a8c398537c454be982e8eaec7eb97dd4>:0