using System;
using System.Collections.Generic;
using System.Text;
using Cosmos.Assembler;
using x86 = Cosmos.Assembler.x86;

namespace Orvid {
  public static class Optimizer {

    public static Assembler Optimize(Assembler asmb)
    {
      return asmb;
      Assembler asmblr = asmb;
      List<Instruction> instr = asmb.Instructions;
      //List<DataMember> dmbrs = asmb.DataMembers;

      SortedDictionary<string, Instruction> labels = new SortedDictionary<string, Instruction>();
      List<Instruction> comments = new List<Instruction>();
      List<String> usedLabels = new List<string>();
      usedLabels.Add("KernelStart");
      foreach (Instruction ins in instr) {
        if (ins is Label) {
          if (((Label)ins).IsGlobal) {
            usedLabels.Add(((Label)ins).QualifiedName);
          }
          labels.Add(((Label)ins).QualifiedName, ins);
        } else if (ins is x86.JumpToSegment) {
          if (((x86.JumpToSegment)ins).DestinationRef != null) {
            usedLabels.Add(((x86.JumpToSegment)ins).DestinationRef.Name);
          } else {
            usedLabels.Add(((x86.JumpToSegment)ins).DestinationLabel);
          }
        } else if (ins is x86.JumpBase) {
          usedLabels.Add(((x86.JumpBase)ins).DestinationLabel);
        } else if (ins is x86.Call) {
          usedLabels.Add(((x86.Call)ins).DestinationLabel);
        } else if (ins is x86.Push) {
          if (((x86.Push)ins).DestinationRef != null) {
            usedLabels.Add(((x86.Push)ins).DestinationRef.Name);
          }
        } else if (ins is x86.Mov) {
          if (((x86.Mov)ins).SourceRef != null) {
            usedLabels.Add(((x86.Mov)ins).SourceRef.Name);
          }
        }
      }
      foreach (string s in usedLabels) {
        labels.Remove(s);
      }
      usedLabels = null;
      instr.RemoveAll(
          delegate(Instruction inst) {
            if (inst is Comment)
              return true;
            else if (inst is Label) {
              if (labels.ContainsKey(((Label)inst).QualifiedName))
                return true;
              return false;
            }
            return false;
          }
      );
      labels = null;
      comments = null;




      asmblr.Instructions = instr;
      //asmblr.DataMembers = dmbrs;
      return asmblr;

    }

  }
}