/**
  *
  *                      OOAS Compiler (Deprecated)
  *
  * Copyright 2015, Institute for Software Technology, Graz University of
  * Technology. Portions are copyright 2015 by the AIT Austrian Institute
  * of Technology. All rights reserved.
  *
  * SEE THE "LICENSE" FILE FOR THE TERMS UNDER WHICH THIS FILE IS PROVIDED.
  *
  * Please notice that this version of the OOAS compiler is considered de-
  * precated. Only the Java version is maintained.
  *
  * Contributors:
  *               Willibald Krenn (TU Graz/AIT)
  *               Stefan Tiran (TU Graz/AIT)
  */

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

namespace TUG.Mogentes
{
    /// <summary>
    /// This visitor scans all methods and decides whether they are pure, i.e. there is no state-update.
    /// </summary>
    public sealed class OoaMethodPureClassifierVisitor : OoaCompleteAstTraversalVisitor
    {

        Stack<MethodIdentifier> currentMethod = new Stack<MethodIdentifier>();

        public override void visit(MethodIdentifier methodIdentifier)
        {
            
            currentMethod.Push( methodIdentifier);
            ((FunctionType)currentMethod.Peek().type).SetIsPureFunction(true); // assume is true..

            base.visit(currentMethod.Peek());
          
            if (((FunctionType)currentMethod.Peek().type).isPureFunction)
            {
                m_ParserState.AddMessage(
                    new ParserMessage(m_ParserState.filename, methodIdentifier.line,
                        methodIdentifier.column, String.Format("Found pure method: {0}",
                         methodIdentifier.tokenText)));
            } else
                m_ParserState.AddMessage(                    new ParserMessage(m_ParserState.filename, methodIdentifier.line,
                        methodIdentifier.column, String.Format("Found extended method: {0}",
                         methodIdentifier.tokenText)));

            currentMethod.Pop();
        }

        public override void visit(OoActionSystemType systemType)
        {
            bool functionPure = false; //introduce variable with save value 
            if (currentMethod.Count > 0 && currentMethod.Peek() != null) //if we are determining the pureness...
            {
                functionPure = ((FunctionType)currentMethod.Peek().type).isPureFunction; //...save the current value
            }
            base.visit(systemType); // go down in recursion 
            if ( currentMethod.Count > 0 && currentMethod.Peek() != null) //but restore old pureness!
            {
                         
                ((FunctionType)currentMethod.Peek().type).SetIsPureFunction(functionPure);
                
            }
                    
        }


        public override void visit(Assignment assignment)
        {
            
            bool assignmentPure = true;
            if (currentMethod.Count > 0 && currentMethod.Peek() != null)
            {
                foreach (var x in assignment.places)
                {
                    if (x.kind != ExpressionKind.Identifier)
                        assignmentPure = false;
                    else if (((IdentifierExpression)x).identifier.kind == IdentifierKind.AttributeIdentifier)
                        assignmentPure = false;
                }
                bool functionPure = assignmentPure && ((FunctionType)currentMethod.Peek().type).isPureFunction;
                ((FunctionType)currentMethod.Peek().type).SetIsPureFunction(functionPure);
            }
            base.visit(assignment);
        }



        public OoaMethodPureClassifierVisitor(ParserState aState)
            : base(aState)
        { }
    }
}