/* IfThenElseOperator Copyright (C) 1998-1999 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

package jode.expr;
import jode.type.Type;
import jode.decompiler.FieldAnalyzer;
import 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 subType = Type.tSuperType(subExpressions[1].getType())
	    .intersection(Type.tSuperType(subExpressions[2].getType()));
	updateParentType(subType);
    }

    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
	    && (subExpressions[1] instanceof GetFieldOperator)
	    && (subExpressions[2] instanceof StoreInstruction)) {
	    // Check for
	    //   class$classname != null ? class$classname :
	    //       (class$classname = class$("classname"))
	    // and replace with
	    //   classname.class
	    CompareUnaryOperator cmp 
		= (CompareUnaryOperator) subExpressions[0];
	    GetFieldOperator get = (GetFieldOperator) subExpressions[1];
	    StoreInstruction put = (StoreInstruction) subExpressions[2];
	    FieldAnalyzer field;
	    if (cmp.getOperatorIndex() == Operator.NOTEQUALS_OP
		&& 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();
		    if (field.setClassConstant(clazz))
			return new ClassFieldOperator(clazz.charAt(0) == '[' 
						      ? Type.tType(clazz)
						      : Type.tClass(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.print(" ? ");
	if (!subExpressions[1].getType().getHint().isOfType
	    (subExpressions[2].getType())) {
	    /* We need a cast here */
	    writer.print("(");
	    writer.printType(getType().getHint());
	    writer.print(") ");
	}
	subExpressions[1].dumpExpression(writer, 0);
	writer.print(" : ");
	subExpressions[2].dumpExpression(writer, 200);
    }
}