/*******************************************************************************
 * Copyright (c) 2004, 2012 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     John Camelon (IBM) - Initial API and implementation
 *     Mike Kucera (IBM)
 *     Markus Schorn (Wind River Systems)
 *******************************************************************************/
package org.eclipse.cdt.internal.core.dom.parser.cpp;
 
import static org.eclipse.cdt.core.dom.ast.IASTExpression.ValueCategory.LVALUE;

import org.eclipse.cdt.core.dom.ast.ASTVisitor;
import org.eclipse.cdt.core.dom.ast.IASTExpression;
import org.eclipse.cdt.core.dom.ast.IASTImplicitName;
import org.eclipse.cdt.core.dom.ast.IASTInitializerClause;
import org.eclipse.cdt.core.dom.ast.IASTNode;
import org.eclipse.cdt.core.dom.ast.IType;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTArraySubscriptExpression;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTExpression;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTInitializerClause;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPFunction;
import org.eclipse.cdt.internal.core.dom.parser.ASTNode;
import org.eclipse.cdt.internal.core.dom.parser.IASTAmbiguityParent;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.EvalBinary;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.EvalFixed;

public class CPPASTArraySubscriptExpression extends ASTNode
		implements ICPPASTArraySubscriptExpression, IASTAmbiguityParent {
    private ICPPASTExpression arrayExpression;
    private ICPPASTInitializerClause subscriptExp;
    private ICPPEvaluation evaluation;
    private IASTImplicitName[] implicitNames;
    
    public CPPASTArraySubscriptExpression() {
	}

	public CPPASTArraySubscriptExpression(IASTExpression arrayExpression, IASTInitializerClause operand) {
		setArrayExpression(arrayExpression);
		setArgument(operand);
	}
	
	@Override
	public CPPASTArraySubscriptExpression copy() {
		return copy(CopyStyle.withoutLocations);
	}
	
	@Override
	public CPPASTArraySubscriptExpression copy(CopyStyle style) {
		CPPASTArraySubscriptExpression copy = new CPPASTArraySubscriptExpression();
		copy.setArrayExpression(arrayExpression == null ? null : arrayExpression.copy(style));
		copy.setArgument(subscriptExp == null ? null : subscriptExp.copy(style));
		copy.setOffsetAndLength(this);
		if (style == CopyStyle.withLocations) {
			copy.setCopyLocation(this);
		}
		return copy;
	}

	@Override
	public ICPPASTExpression getArrayExpression() {
        return arrayExpression;
    }

    @Override
	public void setArrayExpression(IASTExpression expression) {
        assertNotFrozen();
        if (expression != null) {
        	if (!(expression instanceof ICPPASTExpression))
        		throw new IllegalArgumentException(expression.getClass().getName());
			expression.setParent(this);
			expression.setPropertyInParent(ARRAY);
		}
        arrayExpression = (ICPPASTExpression) expression;        
    }

    @Override
	public ICPPASTInitializerClause getArgument() {
        return subscriptExp;
    }

    @Override
	public void setArgument(IASTInitializerClause arg) {
        assertNotFrozen();
        if (arg != null) {
        	if (!(arg instanceof ICPPASTInitializerClause))
        		throw new IllegalArgumentException(arg.getClass().getName());
        	arg.setParent(this);
        	arg.setPropertyInParent(SUBSCRIPT);
		}
        subscriptExp = (ICPPASTInitializerClause) arg;
    }

    @Override
	@Deprecated
    public IASTExpression getSubscriptExpression() {
    	if (subscriptExp instanceof IASTExpression)
    		return (IASTExpression) subscriptExp;
    	return null;
    }

    @Override
	@Deprecated
    public void setSubscriptExpression(IASTExpression expression) {
    	setArgument(expression);
    }

    @Override
	public IASTImplicitName[] getImplicitNames() {
		if (implicitNames == null) {
			ICPPFunction overload = getOverload();
			if (overload == null || overload instanceof CPPImplicitFunction)
				return implicitNames = IASTImplicitName.EMPTY_NAME_ARRAY;
			
			// create separate implicit names for the two brackets
			CPPASTImplicitName n1 = new CPPASTImplicitName(OverloadableOperator.BRACKET, this);
			n1.setBinding(overload);
			n1.computeOperatorOffsets(arrayExpression, true);

			CPPASTImplicitName n2 = new CPPASTImplicitName(OverloadableOperator.BRACKET, this);
			n2.setBinding(overload);
			n2.computeOperatorOffsets(subscriptExp, true);
			n2.setAlternate(true);
			
			implicitNames = new IASTImplicitName[] { n1, n2 };
		}
		
		return implicitNames;
	}
    
	private ICPPFunction getOverload() {
		ICPPEvaluation eval = getEvaluation();
		if (eval instanceof EvalBinary)
			return ((EvalBinary) eval).getOverload(this);
		return null;
	}

	@Override
	public boolean accept(ASTVisitor action) {
        if (action.shouldVisitExpressions) {
		    switch (action.visit(this)) {
	            case ASTVisitor.PROCESS_ABORT: return false;
	            case ASTVisitor.PROCESS_SKIP: return true;
	            default: break;
	        }
		}
        if (arrayExpression != null && !arrayExpression.accept(action))
        	return false;
        
        IASTImplicitName[] implicits = action.shouldVisitImplicitNames ? getImplicitNames() : null;
        
        if (implicits != null && implicits.length > 0 && !implicits[0].accept(action))
        	return false;
        
        if (subscriptExp != null && !subscriptExp.accept(action))
        	return false;
        
        if (implicits != null && implicits.length > 0 && !implicits[1].accept(action))
        	return false;
        
        if (action.shouldVisitExpressions) {
		    switch (action.leave(this)) {
	            case ASTVisitor.PROCESS_ABORT: return false;
	            case ASTVisitor.PROCESS_SKIP: return true;
	            default: break;
	        }
		}
        return true;
    }

    @Override
	public void replace(IASTNode child, IASTNode other) {
        if (child == subscriptExp) {
            other.setPropertyInParent(child.getPropertyInParent());
            other.setParent(child.getParent());
            subscriptExp  = (ICPPASTExpression) other;
        }
        if (child == arrayExpression) {
            other.setPropertyInParent(child.getPropertyInParent());
            other.setParent(child.getParent());
            arrayExpression  = (ICPPASTExpression) other;
        }
    }
    
	@Override
	public ICPPEvaluation getEvaluation() {
		if (evaluation == null) 
			evaluation= computeEvaluation();
		
		return evaluation;
	}
	
	private ICPPEvaluation computeEvaluation() {
		if (arrayExpression == null || subscriptExp == null)
			return EvalFixed.INCOMPLETE;
		return new EvalBinary(EvalBinary.op_arrayAccess, arrayExpression.getEvaluation(), subscriptExp.getEvaluation());
	}
    
    @Override
	public IType getExpressionType() {
    	return getEvaluation().getTypeOrFunctionSet(this);
    }

	@Override
	public ValueCategory getValueCategory() {
		return getEvaluation().getValueCategory(this);
	}

	@Override
	public boolean isLValue() {
		return getValueCategory() == LVALUE;
	}
}
