/*
 * Copyright 2010 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.eclipse.dsl.editor;

import org.drools.compiler.lang.dsl.DSLMappingEntry;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerSorter;

/** 
 * Provides sorting for the natural language table viewer.
 */
public class DSLMappingSorter extends ViewerSorter {

    public final static int OBJECT = 0;
    public final static int EXPRESSION = 1;
    public final static int MAPPING = 2;
    public final static int SCOPE = 3;

    // Criteria that the instance uses
    private int criteria;

    /**
     * Creates a resource sorter that will use the given sort criteria.
     *
     * @param criteria the sort criterion to use: one of <code>NAME</code> or
     *   <code>TYPE</code>
     */
    public DSLMappingSorter(int criteria) {
        super();
        this.criteria = criteria;
    }

    /* (non-Javadoc)
     * Method declared on ViewerSorter.
     */
    public int compare(Viewer viewer, Object o1, Object o2) {

        DSLMappingEntry item1 = (DSLMappingEntry) o1;
        DSLMappingEntry item2 = (DSLMappingEntry) o2;

        switch (criteria) {
            case OBJECT:
                return compareObject(item1, item2);
            case EXPRESSION :
                return compareExpressions(item1, item2);
            case MAPPING :
                return compareMappings(item1, item2);
            case SCOPE :
                return compareScope(item1, item2);
            default:
                return 0;
        }
    }



    private int compareScope(DSLMappingEntry item1,
                             DSLMappingEntry item2) {
        return item1.getSection().compareTo( item2.getSection() );
    }

    private int compareMappings(DSLMappingEntry item1,
                                DSLMappingEntry item2) {
        return item1.getMappingValue().compareTo( item2.getMappingValue() );
    }

    private int compareExpressions(DSLMappingEntry item1,
                                   DSLMappingEntry item2) {
        return item1.getMappingKey().compareTo( item2.getMappingKey() );
    }

    private int compareObject(DSLMappingEntry item1, 
                              DSLMappingEntry item2) {
        return item1.getMetaData().compareTo(item2.getMetaData());
    }
    
    /**
     * @return the sort criterion
     */
    public int getCriteria() {
        return criteria;
    }
}