/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.syncope.client.console.commons;

import java.io.Serializable;
import java.util.Comparator;
import org.apache.wicket.extensions.markup.html.repeater.util.SortableDataProvider;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.PropertyModel;

public class SortableDataProviderComparator<T> implements Comparator<T>, Serializable {

    private static final long serialVersionUID = -8897687699977460543L;

    protected final SortableDataProvider<T, String> provider;

    public SortableDataProviderComparator(final SortableDataProvider<T, String> provider) {
        this.provider = provider;
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    protected int compare(final IModel<Comparable> model1, final IModel<Comparable> model2) {
        int result;

        if (model1.getObject() == null && model2.getObject() == null) {
            result = 0;
        } else if (model1.getObject() == null) {
            result = 1;
        } else if (model2.getObject() == null) {
            result = -1;
        } else {
            result = model1.getObject().compareTo(model2.getObject());
        }

        result = provider.getSort().isAscending()
                ? result
                : -result;

        return result;
    }

    @SuppressWarnings("rawtypes")
    @Override
    public int compare(final T object1, final T object2) {
        IModel<Comparable> model1 = new PropertyModel<>(object1, provider.getSort().getProperty());
        IModel<Comparable> model2 = new PropertyModel<>(object2, provider.getSort().getProperty());

        return compare(model1, model2);
    }
}