using System;
using System.Collections.Generic;
using Indy.IL2CPU.Assembler;


using CPUx86 = Indy.IL2CPU.Assembler.X86;
using System.Reflection;

namespace Indy.IL2CPU.IL.X86 {
	[OpCode(OpCodeEnum.Ldsfld)]
	public class Ldsfld: Op {
		private string mDataName;
		private uint mSize;
		private bool mNeedsGC;
        public static void ScanOp(ILReader aReader, MethodInformation aMethodInfo, SortedList<string, object> aMethodData) {
            FieldInfo xField = aReader.OperandValueField;
            Engine.QueueStaticField(xField);
        }

		public Ldsfld(ILReader aReader, MethodInformation aMethodInfo)
			: base(aReader, aMethodInfo) {
			FieldInfo xField = aReader.OperandValueField;
			mSize = Engine.GetFieldStorageSize(xField.FieldType);
			Engine.QueueStaticField(xField, out mDataName);
			mNeedsGC = !xField.FieldType.IsValueType && xField.FieldType.FullName != "System.String";
		}
		public override void DoAssemble() {
			if (mSize >= 4) {
				for (int i = 1; i <= (mSize / 4); i++) {
					//	Pop("eax");
					//	Move(Assembler, "dword [" + mDataName + " + 0x" + (i * 4).ToString("X") + "]", "eax");
                    new CPUx86.Push { DestinationRef = new ElementReference(mDataName), DestinationIsIndirect = true, DestinationDisplacement = (int)(mSize - (i * 4)) };
				}
				switch (mSize % 4) {
					case 1: {
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.EAX, SourceValue = 0 };
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.AL, SourceRef = new ElementReference(mDataName), SourceIsIndirect = true };
                            new CPUx86.Push { DestinationReg = CPUx86.Registers.EAX };
							break;
						}
					case 2: {
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.EAX, SourceValue = 0 };
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.AX, SourceRef = new ElementReference(mDataName), SourceIsIndirect = true };
							new CPUx86.Push{DestinationReg=CPUx86.Registers.EAX};
							break;
						}
					case 0: {
							break;
						}
					default:
						throw new Exception("Remainder size " + (mSize % 4) + " not supported!");
				}
			} else {
				switch (mSize) {
					case 1: {
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.EAX, SourceValue = 0 };
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.AL, SourceRef = new ElementReference(mDataName), SourceIsIndirect = true };
                            new CPUx86.Push { DestinationReg = CPUx86.Registers.EAX };
							break;
						}
					case 2: {
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.EAX, SourceValue = 0 };
                            new CPUx86.Move { DestinationReg = CPUx86.Registers.AX, SourceRef = new ElementReference(mDataName), SourceIsIndirect = true };
							new CPUx86.Push{DestinationReg=CPUx86.Registers.EAX};
							break;
						}
					case 0: {
							break;
						}
					default:
						throw new Exception("Remainder size " + (mSize) + " not supported!");
				}
			}
			Assembler.StackContents.Push(new StackContent((int)mSize, null));
			if (mNeedsGC) {
				new Dup(null, null) {
					Assembler = this.Assembler
				}.Assemble();
				Engine.QueueMethod(GCImplementationRefs.IncRefCountRef);
                new CPUx86.Call { DestinationLabel = Label.GenerateLabelName(GCImplementationRefs.IncRefCountRef) };
				Assembler.StackContents.Pop();
			}
		}
	}
}