using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;

using MongoDB.Bson;
using MongoDB.Bson.Serialization;
using MongoDB.Bson.Serialization.Conventions;
using MongoDB.Driver;

namespace TestNeverSerializeDefaultValueConvention {
    public class C {
        public int Id;
        public Guid G;
    }

    public class EmptyGuidDefaultValueConvention : IDefaultValueConvention {
        public object GetDefaultValue(
            MemberInfo memberInfo
        ) {
            var type = (memberInfo.MemberType == MemberTypes.Field) ? ((FieldInfo) memberInfo).FieldType : ((PropertyInfo) memberInfo).PropertyType;
            if (type == typeof(Guid)) {
                return Guid.Empty;
            } else {
                return null;
            }
        }
    }

    public static class Program {
        public static void Main(string[] args) {
            try {
                InitializeSerialization();

                var server = MongoServer.Create("mongodb://localhost/?safe=true");
                var database = server["test"];
                var collection = database["test"];
                collection.Drop();

                collection.Insert(new C { Id = 1 });

                foreach (var document in collection.FindAll()) {
                    Console.WriteLine(document.ToJson()); // document should NOT have a "G" element but does
                }
            } catch (Exception ex) {
                Console.WriteLine("Unhandled exception:");
                Console.WriteLine(ex);
            }

            Console.WriteLine("Press Enter to continue");
            Console.ReadLine();
        }

        private static void InitializeSerialization() {
            var conventions = new ConventionProfile();
            conventions.SetDefaultValueConvention(new EmptyGuidDefaultValueConvention());
            conventions.SetSerializeDefaultValueConvention(new NeverSerializeDefaultValueConvention());
            BsonClassMap.RegisterConventions(conventions, type => type.FullName.StartsWith("TestNeverSerializeDefaultValueConvention."));
        }
    }
}