/*
 * Autopsy Forensic Browser
 *
 * Copyright 2014-16 Basis Technology Corp.
 * Contact: carrier <at> sleuthkit <dot> org
 *
 * 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.sleuthkit.autopsy.timeline.filters;

import java.util.List;
import java.util.Objects;
import javafx.collections.FXCollections;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;

/**
 * A Filter with a collection of {@link Filter} sub-filters. If this filter is
 * not active than none of its sub-filters are applied either. Concrete
 * implementations can decide how to combine the sub-filters.
 *
 * a {@link CompoundFilter} uses listeners to enforce the following
 * relationships between it and its sub-filters: if all of a compound filter's
 * sub-filters become un-selected, un-select the compound filter.
 */
public abstract class CompoundFilter<SubFilterType extends Filter> extends AbstractFilter {

    /**
     * the list of sub-filters that make up this filter
     */
    private final ObservableList<SubFilterType> subFilters = FXCollections.observableArrayList();

    public final ObservableList<SubFilterType> getSubFilters() {
        return subFilters;
    }

    /**
     * construct a compound filter from a list of other filters to combine.
     *
     * @param subFilters
     */
    public CompoundFilter(List<SubFilterType> subFilters) {
        super();

        //listen to changes in list of subfilters 
        this.subFilters.addListener((ListChangeListener.Change<? extends SubFilterType> change) -> {
            while (change.next()) {
                //add a listener to the selected property of each added subfilter
                change.getAddedSubList().forEach(addedSubFilter -> {
                    //if a subfilter's selected property changes...
                    addedSubFilter.selectedProperty().addListener(selectedProperty -> {
                        //set this compound filter selected af any of the subfilters are selected.
                        setSelected(getSubFilters().parallelStream().anyMatch(Filter::isSelected));
                    });
                });
            }
        });

        this.subFilters.setAll(subFilters);
    }

    static <SubFilterType extends Filter> boolean areSubFiltersEqual(final CompoundFilter<SubFilterType> oneFilter, final CompoundFilter<SubFilterType> otherFilter) {
        if (oneFilter.getSubFilters().size() != otherFilter.getSubFilters().size()) {
            return false;
        }
        for (int i = 0; i < oneFilter.getSubFilters().size(); i++) {
            final SubFilterType subFilter = oneFilter.getSubFilters().get(i);
            final SubFilterType otherSubFilter = otherFilter.getSubFilters().get(i);
            if (subFilter.equals(otherSubFilter) == false) {
                return false;
            }
        }
        return true;
    }

    @Override
    public int hashCode() {
        int hash = 3;
        hash = 61 * hash + Objects.hashCode(this.subFilters);
        return hash;
    }
}