feat(jsonapi-exception): add logic for getting error collectoon status

Author: jaredcnance

src/JsonApiDotNetCore/Internal/Error.cs

@@ -28,5 +28,7 @@ public Error(string status, string title, string detail)
 
         [JsonProperty("status")]
         public string Status { get; set; }
+
+        public int StatusCode { get { return int.Parse(Status); } }
     }
 }

src/JsonApiDotNetCore/Internal/JsonApiException.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 
 namespace JsonApiDotNetCore.Internal
 {
@@ -33,5 +34,19 @@ public ErrorCollection GetError()
         {
             return _errors;
         }
+
+        public int GetStatusCode()
+        {
+            if(_errors.Errors.Count == 1)
+                return _errors.Errors[0].StatusCode;
+
+            if(_errors.Errors.FirstOrDefault(e => e.StatusCode >= 500) != null)
+                return 500;
+                
+            if(_errors.Errors.FirstOrDefault(e => e.StatusCode >= 400) != null)
+                return 400;
+            
+            return 500;
+        }
     }
 }

src/JsonApiDotNetCore/Middleware/JsonApiExceptionFilter.cs

@@ -23,7 +23,7 @@ public void OnException(ExceptionContext context)
 
             var error = jsonApiException.GetError();
             var result = new ObjectResult(error);
-            result.StatusCode = Convert.ToInt16(error.Status);
+            result.StatusCode = jsonApiException.GetStatusCode();
             context.Result = result;         
         }
     }