/*
 * Copyright 2005 Red Hat, Inc. and/or its affiliates.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.drools.drl.ast.descr;

import java.util.ArrayList;
import java.util.List;

public class OrDescr extends AnnotatedBaseDescr
    implements
    ConditionalElementDescr {

    private static final long serialVersionUID = 510l;
    private List<BaseDescr>   descrs           = new ArrayList<>();

    public OrDescr() { }

    private OrDescr(BaseDescr baseDescr) {
        addDescr(baseDescr);
    }

    public void insertBeforeLast( final Class<?> clazz,
                                  final BaseDescr baseDescr ) {
        if ( clazz.isInstance( baseDescr ) ) {
            if ( this.descrs.isEmpty() ) {
                addDescr( baseDescr );
                return;
            }
            for ( int i = this.descrs.size() - 1; i >= 0; i-- ) {
                if ( clazz.isInstance( this.descrs.get( i ) ) ) {
                    insertDescr( i - 1,
                                 baseDescr );
                    return;
                }
            }
        }
        addDescr( baseDescr );
    }

    public void insertDescr( int index,
                             final BaseDescr baseDescr ) {
        this.descrs.add( index,
                         baseDescr );
    }

    public void addDescr( final BaseDescr baseDescr ) {
        this.descrs.add( baseDescr );
    }

    public List<BaseDescr> getDescrs() {
        return this.descrs;
    }

    public void addOrMerge( final BaseDescr baseDescr ) {
        if ( baseDescr instanceof OrDescr ) {
            this.descrs.addAll( ((OrDescr) baseDescr).getDescrs() );
        } else {
            this.descrs.add( baseDescr );
        }
    }


     public boolean removeDescr(BaseDescr baseDescr) {
        return baseDescr == null ? false : descrs.remove(baseDescr);
    }

    @Override
    public String toString() {
        return "[OR "+descrs+" ]";
    }

    @Override
    public void accept(DescrVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    public BaseDescr negate() {
        if (descrs.isEmpty()) {
            return new OrDescr(new ExprConstraintDescr( "false" ));
        }

        if (descrs.size() == 1) {
            return new OrDescr(descrs.get(0).negate());
        }

        AndDescr and = new AndDescr();
        for (BaseDescr descr : descrs) {
            and.addDescr( descr.negate() );
        }
        return and;
    }
}
