using System;
using System.IO;


using CPUx86 = Indy.IL2CPU.Assembler.X86;
using CPU = Indy.IL2CPU.Assembler;
using Indy.IL2CPU.Assembler;
using Indy.IL2CPU.Assembler.X86;

namespace Indy.IL2CPU.IL.X86 {
  [OpCode(OpCodeEnum.Clt_Un)]
  public class Clt_Un: Op {
    private readonly string NextInstructionLabel;
    private readonly string CurInstructionLabel;
    private uint mCurrentOffset;
    private MethodInformation mMethodInfo;
    public Clt_Un(ILReader aReader, MethodInformation aMethodInfo)
      : base(aReader, aMethodInfo) {
      NextInstructionLabel = GetInstructionLabel(aReader.NextPosition);
      CurInstructionLabel = GetInstructionLabel(aReader);
      mMethodInfo = aMethodInfo;
      mCurrentOffset = aReader.Position;
    }
    public override void DoAssemble() {
      var xStackItem = Assembler.StackContents.Pop();
      if (xStackItem.IsFloat) {
        EmitNotImplementedException(Assembler, GetServiceProvider(), "Clt_Un: Floats not yet supported", CurInstructionLabel, mMethodInfo, mCurrentOffset, NextInstructionLabel);
        return;
      }
      if (xStackItem.Size > 8) {
        EmitNotImplementedException(Assembler, GetServiceProvider(), "Clt_Un: StackSizes>8 not supported", CurInstructionLabel, mMethodInfo, mCurrentOffset, NextInstructionLabel);
        return;
      }
      Assembler.StackContents.Push(new StackContent(4, typeof(bool)));
      string BaseLabel = CurInstructionLabel + "__";
      string LabelTrue = BaseLabel + "True";
      string LabelFalse = BaseLabel + "False";
      if (xStackItem.Size > 4) {
        new CPUx86.Xor { DestinationReg = CPUx86.Registers.ESI, SourceReg = CPUx86.Registers.ESI };
        new CPUx86.Add { DestinationReg = Registers.ESI, SourceValue = 1 };
        new CPUx86.Xor { DestinationReg = CPUx86.Registers.EDI, SourceReg = CPUx86.Registers.EDI };
        //esi = 1
        new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
        new CPUx86.Pop { DestinationReg = CPUx86.Registers.EDX };
        //value2: EDX:EAX
        new CPUx86.Pop { DestinationReg = CPUx86.Registers.EBX };
        new CPUx86.Pop { DestinationReg = CPUx86.Registers.ECX };
        //value1: ECX:EBX
        new CPUx86.Sub { DestinationReg = CPUx86.Registers.EBX, SourceReg = CPUx86.Registers.EAX };
        new CPUx86.SubWithCarry { DestinationReg = CPUx86.Registers.ECX, SourceReg = CPUx86.Registers.EDX };
        //result = value1 - value2
        new CPUx86.ConditionalMove { Condition = ConditionalTestEnum.Below, DestinationReg = CPUx86.Registers.EDI, SourceReg = CPUx86.Registers.ESI };
        new CPUx86.Push { DestinationReg = Registers.EDI };
      } else {
        new CPUx86.Pop { DestinationReg = CPUx86.Registers.ECX };
        new CPUx86.Pop { DestinationReg = CPUx86.Registers.EAX };
        new CPUx86.Push { DestinationReg = CPUx86.Registers.ECX };
        new CPUx86.Compare { DestinationReg = CPUx86.Registers.EAX, SourceReg = CPUx86.Registers.ESP, SourceIsIndirect = true };
        new CPUx86.ConditionalJump { Condition = CPUx86.ConditionalTestEnum.LessThan, DestinationLabel = LabelTrue };
        new CPUx86.Jump { DestinationLabel = LabelFalse };
        new CPU.Label(LabelTrue);
        new CPUx86.Add { DestinationReg = CPUx86.Registers.ESP, SourceValue = 4 };
        new CPUx86.Push { DestinationValue = 1 };
        new CPUx86.Jump { DestinationLabel = NextInstructionLabel };
        new CPU.Label(LabelFalse);
        new CPUx86.Add { DestinationReg = CPUx86.Registers.ESP, SourceValue = 4 };
        new CPUx86.Push { DestinationValue = 0 };
        new CPUx86.Jump { DestinationLabel = NextInstructionLabel };
      }
    }
  }
}