Fix function score query so that filters can be applied to all function types

Author: gmarz

src/Nest/DSL/Query/Functions/BoostFactorFunction.cs

@@ -3,7 +3,7 @@
 namespace Nest
 {
 	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-	public class BoostFactorFunction<T> : FunctionScoreFilteredFunction<T> where T : class
+	public class BoostFactorFunction<T> : FunctionScoreFunction<T> where T : class
 	{
 		[JsonProperty(PropertyName = "boost_factor")]
 		internal double _BoostFactor { get; set; }

src/Nest/DSL/Query/Functions/FunctionScoreFilteredFunction.cs

@@ -37,21 +37,21 @@ public FunctionScoreFunction<T> Exp(Expression<Func<T, object>> objectPath, Acti
 			return fn;
 		}
 
-		public BoostFactorFunction<T> BoostFactor(double value)
+		public FunctionScoreFunction<T> BoostFactor(double value)
 		{
 			var fn = new BoostFactorFunction<T>(value);
 			this._Functions.Add(fn);
 			return fn;
 		}
 
-		public ScriptScoreFunction<T> ScriptScore(Action<ScriptFilterDescriptor> scriptSelector)
+		public FunctionScoreFunction<T> ScriptScore(Action<ScriptFilterDescriptor> scriptSelector)
 		{
 			var fn = new ScriptScoreFunction<T>(scriptSelector);
 			this._Functions.Add(fn);
 			return fn;
 		}
 
-		public FieldValueFactor<T> FieldValueFactor(Action<FieldValueFactorDescriptor<T>> db)
+		public FunctionScoreFunction<T> FieldValueFactor(Action<FieldValueFactorDescriptor<T>> db)
 		{
 			var fn = new FieldValueFactor<T>(db);
 			this._Functions.Add(fn);
@@ -101,7 +101,7 @@ public FieldValueFactorDescriptor<T> Modifier(FieldValueFactorModifier modifier)
 	}
 
 	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-	public class FieldValueFactor<T> : FunctionScoreFilteredFunction<T> where T : class
+	public class FieldValueFactor<T> : FunctionScoreFunction<T> where T : class
 	{
 		[JsonProperty(PropertyName = "field_value_factor")]
 		internal FieldValueFactorDescriptor<T> _FieldValueFactor { get; set; }

src/Nest/DSL/Query/Functions/FunctionScoreFunctionsDescriptor.cs

@@ -1,5 +1,6 @@
 using Nest.Resolvers.Converters;
 using Newtonsoft.Json;
+using System;
 
 namespace Nest
 {
@@ -13,6 +14,17 @@ public interface IFunctionScoreFunction
 	public class FunctionScoreFunction<T> : IFunctionScoreFunction 
 		where T : class
 	{
-		
+		[JsonProperty(PropertyName = "filter")]
+		internal FilterContainer FilterDescriptor { get; set; }
+
+		public FunctionScoreFunction<T> Filter(Func<FilterDescriptor<T>, FilterContainer> filterSelector)
+		{
+			filterSelector.ThrowIfNull("filterSelector");
+			var filter = new FilterDescriptor<T>();
+			var f = filterSelector(filter);
+
+			this.FilterDescriptor = f;
+			return this;
+		}
 	}
 }

src/Nest/DSL/Query/Functions/IFunctionScoreFunction.cs

@@ -4,7 +4,7 @@
 namespace Nest
 {
 	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-	public class ScriptScoreFunction<T> : FunctionScoreFilteredFunction<T> where T : class
+	public class ScriptScoreFunction<T> : FunctionScoreFunction<T> where T : class
 	{
 		[JsonProperty(PropertyName = "script_score")]
 		internal ScriptFilterDescriptor _ScriptScore { get; set; }

src/Nest/DSL/Query/Functions/ScriptScoreFunction.cs

@@ -239,7 +239,6 @@
     <Compile Include="DSL\Query\Functions\FunctionBoostMode.cs" />
     <Compile Include="DSL\Query\Functions\FunctionScoreDecayFieldDescriptor.cs" />
     <Compile Include="DSL\Query\Functions\FunctionScoreDecayFunction.cs" />
-    <Compile Include="DSL\Query\Functions\FunctionScoreFilteredFunction.cs" />
     <Compile Include="DSL\Query\Functions\FunctionScoreFunctionsDescriptor.cs" />
     <Compile Include="DSL\Query\Functions\FunctionScoreMode.cs" />
     <Compile Include="DSL\Query\Functions\IFunctionScoreFunction.cs" />

src/Nest/Nest.csproj

@@ -18,7 +18,7 @@ public void FunctionScore_Deserializes()
 					.MaxBoost(0.95f)
 					.Functions(
 						ff => ff.Gauss(x => x.StartedOn, d => d.Scale("42w")),
-						ff => ff.Linear(x => x.FloatValue, d => d.Scale("0.3")),
+						ff => ff.Linear(x => x.FloatValue, d => d.Scale("0.3")).Filter(lff=>Filter2),
 						ff => ff.Exp(x => x.DoubleValue, d => d.Scale("0.5")),
 						ff => ff.BoostFactor(2).Filter(bff=>Filter1)
 					)

src/Tests/Nest.Tests.Unit/QueryParsers/Queries/FunctionScoreQueryTests.cs

@@ -163,5 +163,41 @@ public void TestBoostFactorWithFilter()
 			Assert.True(json.JsonEquals(expected), json);
 		}
 
+		[Test]
+		public void TestDecayFunctionWithFilter()
+		{
+			var s = new SearchDescriptor<ElasticsearchProject>().Query(
+				q => q.FunctionScore(
+					fs => fs.Functions(
+						f => f.Gauss(p => p.FloatValue, g => g.Origin("5").Scale("0.1"))
+							  .Filter(gf => gf.Term("term1", "termValue")
+							)
+						)
+					)
+				);
+			var json = TestElasticClient.Serialize(s);
+			var expected = @"{
+							  ""query"": {
+								""function_score"": {
+								  ""functions"": [
+									{
+									  ""gauss"": {
+										""floatValue"": {
+										  ""origin"": ""5"",
+										  ""scale"": ""0.1""
+										}
+									  },
+									  ""filter"": {
+										""term"": {
+										  ""term1"": ""termValue""
+										}
+									  }
+									}
+								  ]
+								}
+							  }
+							}";
+			Assert.IsTrue(json.JsonEquals(expected), json);
+		}
 	}
 }