/* IfThenElseOperator Copyright (C) 1998-2002 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; see the file COPYING.LESSER.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

package net.sf.jode.expr;
import net.sf.jode.type.Type;
import net.sf.jode.bytecode.ClassPath;
import net.sf.jode.decompiler.FieldAnalyzer;
import net.sf.jode.decompiler.TabbedPrintWriter;

public class IfThenElseOperator extends Operator {
    public IfThenElseOperator(Type type) {
        super(type, 0);
	initOperands(3);
    }
    
    public int getPriority() {
        return 200;
    }

    public void updateSubTypes() {
	subExpressions[0].setType(Type.tBoolean);
	subExpressions[1].setType(Type.tSubType(type));
	subExpressions[2].setType(Type.tSubType(type));
    }

    public void updateType() {
	Type commonType = Type.tSuperType(subExpressions[1].getType())
	    .intersection(Type.tSuperType(subExpressions[2].getType()));
	updateParentType(commonType);
    }

    public Expression simplify() {
	if (getType().isOfType(Type.tBoolean)) {
            if (subExpressions[1] instanceof ConstOperator
		&& subExpressions[2] instanceof ConstOperator) {
                ConstOperator c1 = (ConstOperator) subExpressions[1];
                ConstOperator c2 = (ConstOperator) subExpressions[2];
                if (c1.getValue().equals(new Integer(1)) &&
                    c2.getValue().equals(new Integer(0)))
                    return subExpressions[0].simplify();
                if (c2.getValue().equals(new Integer(1)) &&
                    c1.getValue().equals(new Integer(0)))
                    return subExpressions[0].negate().simplify();
            }
        }
  	if (subExpressions[0] instanceof CompareUnaryOperator
	    && ((((CompareUnaryOperator) subExpressions[0])
		.getOperatorIndex() & ~1) == Operator.COMPARE_OP)) {
	    CompareUnaryOperator cmp 
		= (CompareUnaryOperator) subExpressions[0];
	    int cmpType = cmp.getOperatorIndex() & 1;
	    if ((subExpressions[2 - cmpType] instanceof GetFieldOperator)
		&& (subExpressions[1 + cmpType] instanceof StoreInstruction)) {
		// Check for
		//   class$classname != null ? class$classname :
		//       (class$classname = class$("classname"))
		// and replace with
		//   classname.class
		GetFieldOperator get
		    = (GetFieldOperator) subExpressions[2 - cmpType];
		StoreInstruction put
		    = (StoreInstruction) subExpressions[1 + cmpType];
		FieldAnalyzer field;
		if (put.getLValue() instanceof PutFieldOperator
		    && ((field = ((PutFieldOperator)put.getLValue())
			 .getField()) != null) && field.isSynthetic() 
		    && put.lvalueMatches(get)
		    && (cmp.subExpressions[0] instanceof GetFieldOperator)
		    && put.lvalueMatches((GetFieldOperator) 
					 cmp.subExpressions[0])
		    && put.subExpressions[1] instanceof InvokeOperator) {
		    InvokeOperator invoke = (InvokeOperator) 
			put.subExpressions[1];
		    if (invoke.isGetClass()
			&& invoke.subExpressions[0] instanceof ConstOperator
			&& (invoke.subExpressions[0].getType()
			    .equals(Type.tString))) {
			String clazz = (String)
			    ((ConstOperator)invoke.subExpressions[0])
			    .getValue();
			ClassPath cp = field.getClassAnalyzer().getClassPath();
			if (field.setClassConstant(clazz))
			    return new ClassFieldOperator
				(clazz.charAt(0) == '[' 
				 ? Type.tType(cp, clazz)
				 : Type.tClass(cp, clazz));
		    }
		}
	    }
	}
	return super.simplify();
    }

    public boolean opEquals(Operator o) {
	return (o instanceof IfThenElseOperator);
    }

    public void dumpExpression(TabbedPrintWriter writer)
	throws java.io.IOException {
	subExpressions[0].dumpExpression(writer, 201);
	writer.breakOp();
	writer.print(" ? ");
	int subPriority = 0;
	if (!subExpressions[1].getType().getHint().isOfType
	    (subExpressions[2].getType())) {
	    writer.startOp(TabbedPrintWriter.IMPL_PAREN, 2);
	    /* We need a cast here */
	    writer.print("(");
	    writer.printType(getType().getHint());
	    writer.print(") ");
	    subPriority = 700;
	}
	subExpressions[1].dumpExpression(writer, subPriority);
	if (subPriority == 700)
	    writer.endOp();
	writer.breakOp();
	writer.print(" : ");
	subExpressions[2].dumpExpression(writer, 200);
    }
}