/*
 * Copyright 2014 Open Networking Laboratory
 *
 * 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.onlab.onos.net.intent.constraint;

import com.google.common.base.MoreObjects;
import com.google.common.collect.ImmutableSet;
import org.onlab.onos.net.DeviceId;
import org.onlab.onos.net.Link;
import org.onlab.onos.net.Path;
import org.onlab.onos.net.resource.LinkResourceService;

import java.util.Objects;
import java.util.Set;

/**
 * Constraint that evaluates elements not passed through.
 */
public class ObstacleConstraint extends BooleanConstraint {

    private final Set<DeviceId> obstacles;

    /**
     * Creates a new constraint that the specified device are not passed through.
     * @param obstacles devices not to be passed
     */
    public ObstacleConstraint(DeviceId... obstacles) {
        this.obstacles = ImmutableSet.copyOf(obstacles);
    }

    @Override
    public boolean isValid(Link link, LinkResourceService resourceService) {
        DeviceId src = link.src().deviceId();
        DeviceId dst = link.dst().deviceId();

        return !(obstacles.contains(src) || obstacles.contains(dst));
    }

    @Override
    public boolean validate(Path path, LinkResourceService resourceService) {
        for (Link link : path.links()) {
            if (!isValid(link, resourceService)) {
                return false;
            }
        }

        return true;
    }

    @Override
    public int hashCode() {
        return Objects.hash(obstacles);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (!(obj instanceof ObstacleConstraint)) {
            return false;
        }

        final ObstacleConstraint that = (ObstacleConstraint) obj;
        return Objects.equals(this.obstacles, that.obstacles);
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(this)
                .add("obstacles", obstacles)
                .toString();
    }
}