// Copyright 2004-2011 Castle Project - http://www.castleproject.org/

// 

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

// 

//     http://www.apache.org/licenses/LICENSE-2.0

// 

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.



namespace Castle.DynamicProxy.Generators

{

	using System.Reflection;



	using Castle.DynamicProxy.Generators.Emitters;

	using Castle.DynamicProxy.Generators.Emitters.SimpleAST;

	using Castle.DynamicProxy.Tokens;



	public static class GeneratorUtil

	{

		public static void CopyOutAndRefParameters(TypeReference[] dereferencedArguments, LocalReference invocation,

		                                           MethodInfo method, MethodEmitter emitter)

		{

			var parameters = method.GetParameters();

			if (!ArgumentsUtil.IsAnyByRef(parameters))

			{

				return; //saving the need to create locals if there is no need

			}



			var arguments = StoreInvocationArgumentsInLocal(emitter, invocation);



			for (var i = 0; i < parameters.Length; i++)

			{

				if (!parameters[i].ParameterType.IsByRef)

				{

					continue;

				}



				emitter.CodeBuilder.AddStatement(AssignArgument(dereferencedArguments, i, arguments));

			}

		}



		private static ConvertExpression Argument(int i, LocalReference invocationArgs, TypeReference[] arguments)

		{

			return new ConvertExpression(arguments[i].Type, new LoadRefArrayElementExpression(i, invocationArgs));

		}



		private static AssignStatement AssignArgument(TypeReference[] dereferencedArguments, int i,

		                                              LocalReference invocationArgs)

		{

			return new AssignStatement(dereferencedArguments[i], Argument(i, invocationArgs, dereferencedArguments));

		}



		private static AssignStatement GetArguments(LocalReference invocationArgs, LocalReference invocation)

		{

			return new AssignStatement(invocationArgs, new MethodInvocationExpression(invocation, InvocationMethods.GetArguments));

		}



		private static LocalReference StoreInvocationArgumentsInLocal(MethodEmitter emitter, LocalReference invocation)

		{

			var invocationArgs = emitter.CodeBuilder.DeclareLocal(typeof(object[]));

			emitter.CodeBuilder.AddStatement(GetArguments(invocationArgs, invocation));

			return invocationArgs;

		}

	}

}