Simplify aggregation base classes and add meta to response

Author: gmarz

src/Nest/Aggregations/AggregationContainer.cs

@@ -527,7 +527,7 @@ Func<TAggregator, TAggregatorInterface> selector
 			where TAggregatorInterface : IAggregation
 		{
 			var aggregator = selector(new TAggregator());
-
+			
 			//create new isolated container for new aggregator and assign to the right property
 			var container = new AggregationContainer();
 			assignToProperty(container, aggregator);

src/Nest/Aggregations/AggregationResult.cs

@@ -8,5 +8,6 @@ namespace Nest
 	[ExactContractJsonConverter(typeof(AggregationResultJsonConverter))]
 	public interface IAggregationResult
 	{
+		Dictionary<string, object> Meta { get; }
 	}
 }

src/Nest/Aggregations/AggregationResultJsonConverter.cs

@@ -376,19 +376,18 @@ private IAggregationResult GetBucketAggregation(JsonReader reader, JsonSerialize
 			if (reader.TokenType == JsonToken.StartObject)
 			{
 				reader.Read();
-				var temp = new Dictionary<string, IAggregationResult>();
+				var aggs = new Dictionary<string, IAggregationResult>();
 				do
 				{
 					var name = reader.Value.ToString();
 					reader.Read();
 					var innerAgg = this.ReadAggregation(reader, serializer);
-					temp.Add(name, innerAgg);
+					aggs.Add(name, innerAgg);
 					reader.Read();
 				} while (reader.TokenType != JsonToken.EndObject);
 
-				var agg = new AggregationsHelper(temp);
 				reader.Read();
-				return new FiltersBucket(agg);
+				return new FiltersBucket(aggs);
 			}
 
 			if (reader.TokenType != JsonToken.StartArray)

src/Nest/Aggregations/Bucket/Bucket.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace Nest
@@ -7,15 +8,14 @@ public interface IBucket : IAggregationResult
 		IDictionary<string, IAggregationResult> Aggregations { get; }
 	}
 
-	public interface IBucketItem : IAggregationResult
-	{
-	}
+	public interface IBucketItem { }
 
 	public class Bucket : IAggregationResult
 	{
 		public IEnumerable<IAggregationResult> Items { get; set; }
 		public long? DocCountErrorUpperBound { get; set; }
 		public long? SumOtherDocCount { get; set; }
+		public Dictionary<string, object> Meta { get; set; }
 	}
 
 	public class Bucket<TBucketItem> : BucketBase
@@ -31,5 +31,7 @@ public abstract class BucketBase : AggregationsHelper, IBucket
 	{
 		protected BucketBase() { }
 		protected BucketBase(IDictionary<string, IAggregationResult> aggregations) : base(aggregations) { }
+
+		public Dictionary<string, object> Meta { get; set; }
 	}
 }

src/Nest/Aggregations/Bucket/DocCountBucket.cs

@@ -18,9 +18,10 @@ public DocCountBucket(IDictionary<string, IAggregationResult> aggregations) : ba
 		public long DocCount { get; internal set; }
 	}
 
-	public class DocCountBucket : IAggregationResult
+	public class DocCountBucket : BucketBase, IAggregationResult
 	{
 		public long DocCount { get; set; }
 		public IEnumerable<IAggregationResult> Items { get; set; }
+
 	}
 }

src/Nest/Aggregations/Bucket/Filters/FiltersBucket.cs

@@ -4,24 +4,19 @@
 
 namespace Nest
 {
-	public class FiltersBucket : IAggregationResult
+	public class FiltersBucket : BucketBase, IAggregationResult
 	{
 		public FiltersBucket(IEnumerable<IAggregationResult> items)
 		{
 			Items = items;
 		}
 
-		public FiltersBucket(AggregationsHelper helper)
-		{
-			Aggregations = helper;
-		}
+		public FiltersBucket(IDictionary<string, IAggregationResult> aggregations) : base(aggregations) { }
 
-		public SingleBucket NamedBucket(string key) => this.Aggregations?.Global(key);
+		public SingleBucket NamedBucket(string key) => this.Global(key);
 
 		public IList<SingleBucket> AnonymousBuckets() => this.Items?.OfType<SingleBucket>().ToList();
 
-		public AggregationsHelper Aggregations { get; set; }
-
 		public IEnumerable<IAggregationResult> Items { get; set; }
 	}
 }

src/Nest/Aggregations/Metric/ExtendedStats/ExtendedStatsMetric.cs

@@ -1,6 +1,6 @@
 namespace Nest
 {
-	public class ExtendedStatsMetric : IMetric
+	public class ExtendedStatsMetric : MetricBase
 	{
 		public long Count { get; set; }
 		public double? Min { get; set; }

src/Nest/Aggregations/Metric/GeoBounds/GeoBoundsMetric.cs

@@ -1,6 +1,6 @@
 namespace Nest
 {
-	public class GeoBoundsMetric : IMetric
+	public class GeoBoundsMetric : MetricBase
 	{
 		public GeoBoundsMetric()
 		{

src/Nest/Aggregations/Metric/Metric.cs

@@ -1,6 +1,14 @@
-namespace Nest
+using System;
+using System.Collections.Generic;
+
+namespace Nest
 {
 	public interface IMetric : IAggregationResult
 	{
 	}
+
+	public abstract class MetricBase : IMetric
+	{
+		public Dictionary<string, object> Meta { get; internal set; }
+	}
 }

src/Nest/Aggregations/Metric/Percentiles/PercentilesMetric.cs

@@ -9,7 +9,7 @@ public class PercentileItem
 		public double Value { get; internal set; }
 	}
 
-	public class PercentilesMetric : IMetric
+	public class PercentilesMetric : MetricBase
 	{
 		public IList<PercentileItem> Items { get; internal set; } = new List<PercentileItem>();
 	}