//-----------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation.  All Rights Reserved.
//
//-----------------------------------------------------------------------------
//---------------------------------------------------------------------------------------------
// BoogiePL - Duplicator.cs
//---------------------------------------------------------------------------------------------

using System.Collections;
using System.Collections.Generic;

namespace Microsoft.Boogie 
{
  public class Duplicator : StandardVisitor 
  {
    public override Absy! Visit(Absy! node)
    {
      node = base.Visit(node);
      return node;
    }

    public override Cmd! VisitAssertCmd(AssertCmd! node)
    {
      return base.VisitAssertCmd ((AssertCmd)node.Clone());
    }
    public override Cmd! VisitAssignCmd(AssignCmd! node)
    {
      AssignCmd clone = (AssignCmd)node.Clone();
      clone.Lhss = new List<AssignLhs!>(clone.Lhss);
      clone.Rhss = new List<Expr!>(clone.Rhss);
      return base.VisitAssignCmd(clone);
    }
    public override Cmd! VisitAssumeCmd(AssumeCmd! node)
    {
      return base.VisitAssumeCmd ((AssumeCmd)node.Clone());
    }
    public override AtomicRE! VisitAtomicRE(AtomicRE! node)
    {
      return base.VisitAtomicRE ((AtomicRE)node.Clone());
    }
    public override Axiom! VisitAxiom(Axiom! node)
    {
      return base.VisitAxiom ((Axiom)node.Clone());
    }
    public override Type! VisitBasicType(BasicType! node)
    {
      // do /not/ clone the type recursively
      return (BasicType)node.Clone();
    }
    public override Block! VisitBlock(Block! node)
    {
      return base.VisitBlock ((Block)node.Clone());
    }
    public override BlockSeq! VisitBlockSeq(BlockSeq! blockSeq)
    {
      return base.VisitBlockSeq (blockSeq);
    }
    public override BoundVariable! VisitBoundVariable(BoundVariable! node)
    {
      return base.VisitBoundVariable ((BoundVariable)node.Clone());
    }
    public override Type! VisitBvType(BvType! node)
    {
      // do /not/ clone the type recursively
      return (BvType)node.Clone();
    }
    public override Cmd! VisitCallCmd(CallCmd! node)
    {
      CallCmd! clone = (CallCmd)node.Clone();
      clone.Ins = new List<Expr>(clone.Ins);
      clone.Outs = new List<IdentifierExpr>(clone.Outs);
      return base.VisitCallCmd(clone);
    }
    public override Cmd! VisitCallForallCmd(CallForallCmd! node)
    {
      CallForallCmd! clone = (CallForallCmd)node.Clone();
      clone.Ins = new List<Expr>(clone.Ins);
      return base.VisitCallForallCmd(clone);
    }
    public override Choice! VisitChoice(Choice! node)
    {
      return base.VisitChoice ((Choice)node.Clone());
    }
    public override CmdSeq! VisitCmdSeq(CmdSeq! cmdSeq)
    {
      return base.VisitCmdSeq (cmdSeq);
    }
    public override Constant! VisitConstant(Constant! node)
    {
      return base.VisitConstant ((Constant)node.Clone());
    }
    public override CtorType! VisitCtorType(CtorType! node)
    {
      // do /not/ clone the type recursively
      return (CtorType)node.Clone();
    }
    public override Declaration! VisitDeclaration(Declaration! node)
    {
      return base.VisitDeclaration ((Declaration)node.Clone());
    }
    public override List<Declaration!>! VisitDeclarationList(List<Declaration!>! declarationList)
    {
      return base.VisitDeclarationList(declarationList);
    }
    public override DeclWithFormals! VisitDeclWithFormals(DeclWithFormals! node)
    {
      return base.VisitDeclWithFormals ((DeclWithFormals)node.Clone());
    }
    public override ExistsExpr! VisitExistsExpr(ExistsExpr! node)
    {
      return base.VisitExistsExpr ((ExistsExpr)node.Clone());
    }
    public override Expr! VisitExpr(Expr! node)
    {
      return base.VisitExpr ((Expr)node.Clone());
    }
    public override ExprSeq! VisitExprSeq(ExprSeq! list)
    {
      return base.VisitExprSeq (new ExprSeq(list));
    }
    public override ForallExpr! VisitForallExpr(ForallExpr! node)
    {
      return base.VisitForallExpr ((ForallExpr)node.Clone());
    }
    public override Formal! VisitFormal(Formal! node)
    {
      return base.VisitFormal ((Formal)node.Clone());
    }
    public override Function! VisitFunction(Function! node)
    {
      return base.VisitFunction ((Function)node.Clone());
    }
    public override GlobalVariable! VisitGlobalVariable(GlobalVariable! node)
    {
      return base.VisitGlobalVariable ((GlobalVariable)node.Clone());
    }
    public override GotoCmd! VisitGotoCmd(GotoCmd! node)
    {
      return base.VisitGotoCmd ((GotoCmd)node.Clone());
    }
    public override Cmd! VisitHavocCmd(HavocCmd! node)
    {
      return base.VisitHavocCmd ((HavocCmd)node.Clone());
    }
    public override Expr! VisitIdentifierExpr(IdentifierExpr! node)
    {
      return base.VisitIdentifierExpr ((IdentifierExpr) node.Clone());
    }
    public override IdentifierExprSeq! VisitIdentifierExprSeq(IdentifierExprSeq! identifierExprSeq)
    {
      return base.VisitIdentifierExprSeq (new IdentifierExprSeq(identifierExprSeq));
    }
    public override Implementation! VisitImplementation(Implementation! node)
    {
      return base.VisitImplementation ((Implementation)node.Clone());
    }
    public override LiteralExpr! VisitLiteralExpr(LiteralExpr! node)
    {
      return base.VisitLiteralExpr ((LiteralExpr)node.Clone());
    }
    public override LocalVariable! VisitLocalVariable(LocalVariable! node)
    {
      return base.VisitLocalVariable ((LocalVariable)node.Clone());
    }
    public override AssignLhs! VisitMapAssignLhs(MapAssignLhs! node)
    {
      MapAssignLhs clone = (MapAssignLhs)node.Clone();
      clone.Indexes = new List<Expr!>(clone.Indexes);
      return base.VisitMapAssignLhs(clone);
    }
    public override MapType! VisitMapType(MapType! node)
    {
      // do /not/ clone the type recursively
      return (MapType)node.Clone();
    }
    public override Expr! VisitNAryExpr(NAryExpr! node)
    {
      return base.VisitNAryExpr ((NAryExpr)node.Clone());
    }
    public override Expr! VisitOldExpr(OldExpr! node)
    {
      return base.VisitOldExpr ((OldExpr) node.Clone());
    }
    public override Procedure! VisitProcedure(Procedure! node)
    {
      return base.VisitProcedure ((Procedure)node.Clone());
    }
    public override Program! VisitProgram(Program! node)
    {
      return base.VisitProgram ((Program) node.Clone());
    }
    public override QuantifierExpr! VisitQuantifierExpr(QuantifierExpr! node)
    {
      return base.VisitQuantifierExpr ((QuantifierExpr) node.Clone());
    }
    public override Cmd! VisitRE(RE! node)
    {
      return base.VisitRE ((RE) node.Clone());
    }
    public override RESeq! VisitRESeq(RESeq! reSeq)
    {
      return base.VisitRESeq (new RESeq(reSeq));
    }
    public override ReturnCmd! VisitReturnCmd(ReturnCmd! node)
    {
      return base.VisitReturnCmd ((ReturnCmd) node.Clone());
    }
    public override Sequential! VisitSequential(Sequential! node)
    {
      return base.VisitSequential ((Sequential) node.Clone());
    }
    public override AssignLhs! VisitSimpleAssignLhs(SimpleAssignLhs! node)
    {
      return base.VisitSimpleAssignLhs ((SimpleAssignLhs)node.Clone());
    }
    public override Cmd! VisitStateCmd(StateCmd! node)
    {
      return base.VisitStateCmd ((StateCmd)node.Clone());
    }
    public override TransferCmd! VisitTransferCmd(TransferCmd! node)
    {
      return base.VisitTransferCmd ((TransferCmd) node.Clone());
    }
    public override Trigger! VisitTrigger(Trigger! node)
    {
      return base.VisitTrigger ((Trigger) node.Clone());
    }
    public override Type! VisitType(Type! node)
    {
      // do /not/ clone the type recursively
      return (Type)node.Clone();
    }
    public override TypedIdent! VisitTypedIdent(TypedIdent! node)
    {
      return base.VisitTypedIdent ((TypedIdent) node.Clone());
    }
    public override Variable! VisitVariable(Variable! node)
    {
      return node;
    }
    public override VariableSeq! VisitVariableSeq(VariableSeq! variableSeq)
    {
      return base.VisitVariableSeq (new VariableSeq(variableSeq));
    }
    public override Cmd! VisitAssertRequiresCmd(AssertRequiresCmd! node)
    {
      return base.VisitAssertRequiresCmd((AssertRequiresCmd)node.Clone()); 
    }
    public override Cmd! VisitAssertEnsuresCmd(AssertEnsuresCmd! node)
    {
      return base.VisitAssertEnsuresCmd((AssertEnsuresCmd)node.Clone()); 
    }    
    public override Ensures! VisitEnsures(Ensures! node)
    {
	  return base.VisitEnsures((Ensures)node.Clone());
    }    
    public override Requires! VisitRequires(Requires! node)
    {
	  return base.VisitRequires((Requires)node.Clone());
    }
  }
 
   
  #region A duplicator that also does substitutions for a set of variables 
  /// <summary>
  /// A substitution is a partial mapping from Variables to Exprs.
  /// </summary>
  public delegate Expr/*?*/ Substitution(Variable! v);
  
  public static class Substituter
  {
    public static Substitution! SubstitutionFromHashtable(Hashtable/*Variable!->Expr!*/! map)
    {
      // TODO: With Whidbey, could use anonymous functions.
      return new Substitution(new CreateSubstitutionClosure(map).Method);
    }
    private sealed class CreateSubstitutionClosure
    {
      Hashtable/*Variable!->Expr!*/! map;
      public CreateSubstitutionClosure(Hashtable/*Variable!->Expr!*/! map) { this.map = map; base(); }
      public Expr/*?*/ Method(Variable! v) { return (Expr) map[v]; }
    }
   
    /// <summary>
    /// Apply a substitution to an expression.  Any variables not in domain(subst)
    /// is not changed.  The substitutions applies within the "old", but the "old"
    /// expression remains.
    /// </summary>
    public static Expr! Apply(Substitution! subst, Expr! expr)
    {
      return (Expr) new NormalSubstituter(subst).Visit(expr);
    }

    /// <summary>
    /// Apply a substitution to a command.  Any variables not in domain(subst)
    /// is not changed.  The substitutions applies within the "old", but the "old"
    /// expression remains.
    /// </summary>
    public static Cmd! Apply(Substitution! subst, Cmd! cmd)
    {
      return (Cmd) new NormalSubstituter(subst).Visit(cmd);
    }

    /// <summary>
    /// Apply a substitution to an expression replacing "old" expressions.
    /// Outside "old" expressions, the substitution "always" is applied; any variable not in
    /// domain(always) is not changed.  Inside "old" expressions, apply map "oldExpr" to
    /// variables in domain(oldExpr), apply map "always" to variables in
    /// domain(always)-domain(oldExpr), and leave variable unchanged otherwise.
    /// </summary>    
    public static Expr! ApplyReplacingOldExprs(Substitution! always, Substitution! forold, Expr! expr)
    {
      return (Expr) new ReplacingOldSubstituter(always, forold).Visit(expr);
    }
  
    /// <summary>
    /// Apply a substitution to a command replacing "old" expressions.
    /// Outside "old" expressions, the substitution "always" is applied; any variable not in
    /// domain(always) is not changed.  Inside "old" expressions, apply map "oldExpr" to
    /// variables in domain(oldExpr), apply map "always" to variables in
    /// domain(always)-domain(oldExpr), and leave variable unchanged otherwise.
    /// </summary>    
    public static Cmd! ApplyReplacingOldExprs(Substitution! always, Substitution! forold, Cmd! cmd)
    {
      return (Cmd) new ReplacingOldSubstituter(always, forold).Visit(cmd);
    }
  
    private sealed class NormalSubstituter : Duplicator
    {
      private readonly Substitution! subst;
      public NormalSubstituter(Substitution! subst) { this.subst = subst; base(); }
      
      public override Expr! VisitIdentifierExpr(IdentifierExpr! node)
      {
        Expr/*?*/ e = subst((!)node.Decl);
        return e == null ? base.VisitIdentifierExpr(node) : e;
      }
    }
    
    private sealed class ReplacingOldSubstituter : Duplicator
    {
      private readonly Substitution! always;
      private readonly Substitution! forold;
      public ReplacingOldSubstituter(Substitution! always, Substitution! forold)
      { this.always = always; this.forold = forold; base(); }
      
      private bool insideOldExpr = false;
      
      public override Expr! VisitIdentifierExpr(IdentifierExpr! node)
      {
        Expr/*?*/ e = null;
        
        if (insideOldExpr)
        {
          e = forold((!)node.Decl);
        }
        
        if (e == null)
        {
          e = always((!)node.Decl);
        }
        
        return e == null ? base.VisitIdentifierExpr(node) : e;
      }
      
      public override Expr! VisitOldExpr(OldExpr! node)
      {
        bool previouslyInOld = insideOldExpr;
        insideOldExpr = true;
        Expr! e = (Expr!)this.Visit(node.Expr);
        insideOldExpr = previouslyInOld;
        return e;
      }
    }
  }
  #endregion
}