/*

* Copyright (c) 2004-2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

using System;

using SymBuildParsingLib.Tree;

using SymBuildParsingLib.Token;

using SymBuildParsingLib.Parser.Framework.Nodes;

using SymBuildParsingLib.Utils;

using SymbianTree;

namespace SymBuildParsingLib.Parser.Framework.Workers

{

	public class SymParserWorkerCondition : SymParserWorkerConsumer

	{

		#region Constructors & destructor

		public SymParserWorkerCondition( SymParserWorkerContext aContext )

			: this( aContext, new SymNodeCondition( aContext.CurrentToken.Value ) )

		{

		}

		public SymParserWorkerCondition( SymParserWorkerContext aContext, SymNodeCondition aNodeCondition )

			: base( aContext, SymToken.TClass.EClassNewLine )

		{

			System.Diagnostics.Debug.Assert( aContext.Document.CurrentNode is SymNodeConditionalExpression );

			// Make a new child node for the conditions. 

			iConditionNode = aNodeCondition;

			aContext.Document.CurrentNode.Add( iConditionNode );

			aContext.Document.CurrentNode = iConditionNode;

			// Set up the token balancer event handler

			iTokenBalancer.EventLevelFinished += new SymBuildParsingLib.Token.SymTokenBalancer.LevelChangeEventHandler( TokenBalancer_EventLevelFinished );

			iTokenBalancer.EventLevelsImbalanced += new SymBuildParsingLib.Token.SymTokenBalancer.LevelsImbalancedEventHandler( TokenBalancer_EventLevelsImbalanced );

			// If we're handling an ifdef or ifndef expression, we can tell

			// the token balancer to discard all brackets, irrespective of their level.

			// For normal if statements, we want the brackets.

			bool emitLevelZeroBrackets = !( iConditionNode.Type == SymNodeCondition.TType.ETypeIfdef || iConditionNode.Type == SymNodeCondition.TType.ETypeIfndef );

			iTokenBalancer.RegisterBalancerTokens( emitLevelZeroBrackets );

		}

		#endregion

		#region From SymParserWorker

		public override SymParserWorker.TTokenConsumptionType OfferToken( SymToken aToken )

		{

			System.Diagnostics.Debug.Assert( WorkerContext.Document.CurrentNode is SymNodeCondition );

			//

			TTokenConsumptionType ret = TTokenConsumptionType.ETokenNotConsumed;

			if	( aToken.Class != SymToken.TClass.EClassNewLine )

			{

				if	( iTokenBalancer.OfferToken( aToken ) )

				{

					ret = TTokenConsumptionType.ETokenConsumed;

				}

			}

			// Try offering to base class....

			// Base class will dequeue us once we reach the new line

			if	( ret != TTokenConsumptionType.ETokenConsumed )

			{

				ret = base.OfferToken( aToken );

			}

			return ret;

		}

		#endregion

		#region From SymParserWorkerConsumer

		protected override void HandleTerminatingConditionMatch( SymToken aToken )

		{

			// Give the condition node ownership of the raw parsed tokens

			iConditionNode.AssignArgumentTokens( iTokenBalancer.DocumentTree );

			// We only need to evaluate the conditional arguments if we have not yet

			// found a positive branch.

			SymNodeConditionalExpression condExpNode = (SymNodeConditionalExpression) iConditionNode.Parent;

			if	( condExpNode.HasPositiveBranch == false )

			{

				iConditionNode.Evaluate( WorkerContext );

			}

			// We remain as the current node, even after we die. This allows

			// the body of the condition to be added as our child.

		}

		#endregion

		#region Properties

		public SymNodeCondition ConditionNode

		{

			get { return iConditionNode; }

		}

		#endregion

		#region Token balancer event handlers

		private void TokenBalancer_EventLevelFinished( int aLevelCount, SymNode aOldLevel, SymNode aNewLevel )

		{

		}

		private void TokenBalancer_EventLevelsImbalanced()

		{

			throw new Exception( "Levels not balanced during condition parsing" );

		}

		#endregion

		#region Data members

		private SymTokenBalancer iTokenBalancer = new SymTokenBalancer();

		private readonly SymNodeCondition iConditionNode;

		#endregion

	}

}