Added SortAnalyzer to enable case-insensitive sorting

Author: Grastveit

Diff for: src/Nest/Domain/Mapping/Attributes/ElasticPropertyAttribute.cs

@@ -21,6 +21,7 @@ public class ElasticPropertyAttribute : Attribute, IElasticPropertyAttribute
 		public string Analyzer { get; set; }
 		public string IndexAnalyzer { get; set; }
 		public string SearchAnalyzer { get; set; }
+	    public string SortAnalyzer { get; set; }
 		public string NullValue { get; set; }
 		public string Similarity { get; set; }
 

Diff for: src/Nest/Domain/Mapping/Attributes/IElasticPropertyAttribute.cs

@@ -16,6 +16,7 @@ public interface IElasticPropertyAttribute
         string Analyzer { get; set; }
         string IndexAnalyzer { get; set; }
         string SearchAnalyzer { get; set; }
+        string SortAnalyzer { get; set; }
         string NullValue { get; set; }
 
         bool OmitNorms { get; set; }

Diff for: src/Nest/Resolvers/Writers/WritePropertiesFromAttributeVisitor.cs

@@ -131,8 +131,17 @@ public void VisitBaseAttribute(IElasticPropertyAttribute att) {
                     this._jsonWriter.WritePropertyName("type");
                     this._jsonWriter.WriteValue(this._type);
                 }
-                this._jsonWriter.WritePropertyName("index");
-                this._jsonWriter.WriteValue(Enum.GetName(typeof (FieldIndexOption), FieldIndexOption.not_analyzed));
+                if (att.SortAnalyzer.IsNullOrEmpty())
+                {
+                    this._jsonWriter.WritePropertyName("index");
+                    this._jsonWriter.WriteValue(Enum.GetName(typeof(FieldIndexOption), FieldIndexOption.not_analyzed));
+                }
+                else
+                {
+                    this._jsonWriter.WritePropertyName("index_analyzer");
+                    this._jsonWriter.WriteValue(att.SortAnalyzer);
+                }
+
                 this._jsonWriter.WriteEnd();
                 this._jsonWriter.WriteEnd();
             }

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/Properties/PropertiesTests.cs

@@ -200,6 +200,22 @@ public void IPProperty()
 			);
 			this.JsonEquals(result.ConnectionStatus.Request, MethodInfo.GetCurrentMethod());
 		}
+
+	    public class Foo
+	    {
+	        public int Id { get; set; }
+            [ElasticProperty(AddSortField = true, SortAnalyzer = "simple")]
+	        public string Name { get; set; }
+	    }
+
+	    [Test]
+	    public void SortAnalyzeryReadFromAttribute()
+	    {
+            var result = _client.Map<Foo>(m => m.MapFromAttributes());
+            this.JsonEquals(result.ConnectionStatus.Request, MethodInfo.GetCurrentMethod());
+	        
+	    }
+
 		[Test]
 		public void GeoPointProperty()
 		{
@@ -215,6 +231,7 @@ public void GeoPointProperty()
 			);
 			this.JsonEquals(result.ConnectionStatus.Request, MethodInfo.GetCurrentMethod());
 		}
+
 		[Test]
 		public void GeoShapeProperty()
 		{

Diff for: src/Tests/Nest.Tests.Unit/Core/Map/Properties/SortAnalyzeryReadFromAttribute.json

@@ -0,0 +1,21 @@
+{
+  "foo": {
+    "properties": {
+      "id": {
+        "type": "integer"
+      },
+      "name": {
+        "type": "multi_field",
+        "fields": {
+          "name": {
+            "type": "string"
+          },
+          "sort": {
+            "type": "string",
+            "index_analyzer": "simple"
+          }
+        }
+      }
+    }
+  }
+}