using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MongoDB.Driver.Builders;
using MongoDB.Bson;
using MongoDB.Driver;

namespace TestMongoPartialUpdate
{
    public class TestObject
    {
        public int Id { get; set; }
        public string Name { get; set; }

        /// <summary>
        /// The problematic object, the key and value can be anything - all fail.
        /// </summary>
        public Dictionary<string, int> TestDictionary { get; set; }
    }

    class Program
    {
        private static MongoCollection m_Collection;

        static void Main(string[] args)
        {
            var mongoServer = MongoServer.Create(new MongoConnectionStringBuilder { ConnectionString = "Server=localhost", SafeMode = SafeMode.True });
            var mongoDatabase = mongoServer.GetDatabase("TestMongoPartialUpdate");
            m_Collection = mongoDatabase.GetCollection(typeof(TestObject).Name);

            Console.WriteLine("1. Inserting object");
            var testObject = new TestObject { Id = 1, Name = "Test", TestDictionary = new Dictionary<string, int>() };
            m_Collection.Drop();
            m_Collection.Insert<TestObject>(testObject);
            Console.WriteLine("2. object was saved successfully, trying to fetch it");
            var insertedTestObject = m_Collection.FindOneAs<TestObject>();
            Console.WriteLine("3. Fetched object successfully, id: " + insertedTestObject.Id);
            
            Console.WriteLine("4. Updating object");
            testObject.TestDictionary.Add(Guid.NewGuid().ToString(), 1);
            var updatedSuccessfully = UpdateObject(testObject.Id, "TestDictionary", testObject.TestDictionary);
            try
            {
                if (updatedSuccessfully)
                {
                    Console.WriteLine("5. object was updated successfully, trying to fetch it");
                    var updatedTestObject = m_Collection.FindOneAs<TestObject>();
                    // Not getting here!
                    Console.WriteLine("6. Fetched object successfully, the problem is gone! id: " + updatedTestObject.Id);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine();
                Console.WriteLine("Error when trying to fetch the updated object: " + ex.Message);
            }
            finally
            {
                Console.ReadLine();
            }
        }


        private static bool UpdateObject(object id, string fieldName, object value)
        {
            var builder = new UpdateBuilder();
            var type = value.GetType();
            if (type.IsPrimitive || type.IsValueType || (type == typeof(string)))
            {
                builder.Set(fieldName, BsonValue.Create(value));
            }
            else
            {
                builder.Set(fieldName, value.ToBsonDocument());
            }
            var result = m_Collection.Update(Query.EQ("_id", BsonValue.Create(id)), builder, new MongoUpdateOptions { Flags = UpdateFlags.Multi });
            return result.UpdatedExisting;
        }
    }
}