using System;
using System.Linq;
using Indy.IL2CPU.Assembler;


using CPUx86 = Indy.IL2CPU.Assembler.X86;

namespace Indy.IL2CPU.IL.X86 {
	[OpCode(OpCodeEnum.Stloc)]
	public class Stloc: Op {
		private bool mNeedsGC = false;
		private MethodInformation.Variable mLocal;
		private string mBaseLabel;

		protected void SetLocalIndex(int aIndex, MethodInformation aMethodInfo) {
			mLocal = aMethodInfo.Locals[aIndex];
			mNeedsGC = aMethodInfo.Locals[aIndex].IsReferenceType;
			mNeedsGC &= aMethodInfo.Locals[aIndex].VariableType.FullName != "System.String";
		}

		public Stloc(ILReader aReader, MethodInformation aMethodInfo)
			: base(aReader, aMethodInfo) {
			int xLocalIndex;
			mBaseLabel = GetInstructionLabel(aReader);
			xLocalIndex = aReader.OperandValueInt32;
			SetLocalIndex(xLocalIndex, aMethodInfo);
			//VariableDefinition xVarDef = aReader.Operand as VariableDefinition;
			//if (xVarDef != null) {
			//    SetLocalIndex(xVarDef.Index, aMethodInfo);
			//}
		}

		public sealed override void DoAssemble() {
			if (mNeedsGC) {
                new CPUx86.Push { DestinationReg = CPUx86.Registers.EBP, DestinationIsIndirect = true, DestinationDisplacement = mLocal.VirtualAddresses[0] };
				Engine.QueueMethod(GCImplementationRefs.DecRefCountRef);
                new CPUx86.Call { DestinationLabel = Label.GenerateLabelName(GCImplementationRefs.DecRefCountRef) };
			}
			foreach (int i in mLocal.VirtualAddresses.Reverse()) {
                new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX }; ;
                new CPUx86.Move { DestinationReg = CPUx86.Registers.EBP, DestinationIsIndirect = true, DestinationDisplacement = i, SourceReg = CPUx86.Registers.EAX };
			}
			// no need to inc again, items on the transient stack are also counted
			Assembler.StackContents.Pop();
		}
	}
}