/*
 * Copyright 2015 Tomi Valkeinen
 * 
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;

namespace xServer.Core.NetSerializer
{
	static class Helpers
	{
		public static readonly ConstructorInfo ExceptionCtorInfo = typeof(Exception).GetConstructor(BindingFlags.Public | BindingFlags.Instance, null, new Type[0], null);

		public static IEnumerable<FieldInfo> GetFieldInfos(Type type)
		{
			Debug.Assert(type.IsSerializable);

			var fields = type.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.DeclaredOnly)
				.Where(fi => (fi.Attributes & FieldAttributes.NotSerialized) == 0)
				.OrderBy(f => f.Name, StringComparer.Ordinal);

			if (type.BaseType == null)
			{
				return fields;
			}
			else
			{
				var baseFields = GetFieldInfos(type.BaseType);
				return baseFields.Concat(fields);
			}
		}

		public static DynamicMethod GenerateDynamicSerializerStub(Type type)
		{
			var dm = new DynamicMethod("Serialize", null,
				new Type[] { typeof(Serializer), typeof(Stream), type },
				typeof(Serializer), true);

			dm.DefineParameter(1, ParameterAttributes.None, "serializer");
			dm.DefineParameter(2, ParameterAttributes.None, "stream");
			dm.DefineParameter(3, ParameterAttributes.None, "value");

			return dm;
		}

		public static DynamicMethod GenerateDynamicDeserializerStub(Type type)
		{
			var dm = new DynamicMethod("Deserialize", null,
				new Type[] { typeof(Serializer), typeof(Stream), type.MakeByRefType() },
				typeof(Serializer), true);
			dm.DefineParameter(1, ParameterAttributes.None, "serializer");
			dm.DefineParameter(2, ParameterAttributes.None, "stream");
			dm.DefineParameter(3, ParameterAttributes.Out, "value");

			return dm;
		}

#if GENERATE_DEBUGGING_ASSEMBLY
		public static MethodBuilder GenerateStaticSerializerStub(TypeBuilder tb, Type type)
		{
			var mb = tb.DefineMethod("Serialize", MethodAttributes.Public | MethodAttributes.Static, null,
				new Type[] { typeof(Serializer), typeof(Stream), type });
			mb.DefineParameter(1, ParameterAttributes.None, "serializer");
			mb.DefineParameter(2, ParameterAttributes.None, "stream");
			mb.DefineParameter(3, ParameterAttributes.None, "value");
			return mb;
		}

		public static MethodBuilder GenerateStaticDeserializerStub(TypeBuilder tb, Type type)
		{
			var mb = tb.DefineMethod("Deserialize", MethodAttributes.Public | MethodAttributes.Static, null,
				new Type[] { typeof(Serializer), typeof(Stream), type.MakeByRefType() });
			mb.DefineParameter(1, ParameterAttributes.None, "serializer");
			mb.DefineParameter(2, ParameterAttributes.None, "stream");
			mb.DefineParameter(3, ParameterAttributes.Out, "value");
			return mb;
		}
#endif
	}
}