/*******************************************************************************
 * Copyright Technophobia Ltd 2012
 * 
 * This file is part of the Substeps Eclipse Plugin.
 * 
 * The Substeps Eclipse Plugin is free software: you can redistribute it and/or modify
 * it under the terms of the Eclipse Public License v1.0.
 * 
 * The Substeps Eclipse Plugin 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
 * Eclipse Public License for more details.
 * 
 * You should have received a copy of the Eclipse Public License
 * along with the Substeps Eclipse Plugin.  If not, see <http://www.eclipse.org/legal/epl-v10.html>.
 ******************************************************************************/
package com.technophobia.substeps.runner.junit4;

import java.util.Arrays;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Set;

import org.junit.runner.Description;

/**
 * Comparator for descriptions to sort according to inclusion in a failure list.
 * A description is considered to have failures if its name or one of its
 * transitive children's names are in the failures list. If neither or both have
 * failures, returns 0.
 * 
 * @since 3.6
 */
public class FailuresFirstSorter implements Comparator<Description> {

    private final Set<String> failuresList;


    /**
     * Creates a sorter.
     * 
     * @param failuresList
     *            list of failed tests based on the description's display string
     */
    public FailuresFirstSorter(final String[] failuresList) {
        this.failuresList = new HashSet<String>(Arrays.asList(failuresList));
    }


    /**
     * Compares two descriptions based on the failure list.
     * 
     * @param d1
     *            the first Description to compare with
     * @param d2
     *            the second Description to compare with
     * @return -1 if only d1 has failures, 1 if only d2 has failures, 0
     *         otherwise
     */
    @Override
    public int compare(final Description d1, final Description d2) {
        final boolean d1HasFailures = hasFailures(d1);
        final boolean d2HasFailures = hasFailures(d2);

        if (d1HasFailures) {
            return -1;
        } else if (d2HasFailures) {
            return 1;
        } else { // ((d1HasFailures && d2HasFailures) || (!d1HasFailures &&
                 // !d2HasFailures))
            return 0;
        }
    }


    private boolean hasFailures(final Description d) {
        if (failuresList.contains(d.getDisplayName())) {
            return true;
        }
        for (final Description child : d.getChildren()) {
            if (hasFailures(child)) {
                return true;
            }
        }
        return false;
    }

}