/*
 * 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.onlab.graph;

import java.util.Map;
import java.util.Set;

/**
 * Representation of a graph path search algorithm.
 *
 * @param <V> vertex type
 * @param <E> edge type
 */
public interface GraphPathSearch<V extends Vertex, E extends Edge<V>> {

    /**
     * Abstraction of a path search result.
     */
    public interface Result<V extends Vertex, E extends Edge<V>> {

        /**
         * Returns the search source.
         *
         * @return search source
         */
        public V src();

        /**
         * Returns the search destination, if was was given.
         *
         * @return optional search destination
         */
        public V dst();

        /**
         * Returns the set of paths produced as a result of the graph search.
         *
         * @return set of paths
         */
        Set<Path<V, E>> paths();

        /**
         * Returns bindings of each vertex to its parent edges in the path.
         *
         * @return map of vertex to its parent edge bindings
         */
        public Map<V, Set<E>> parents();

        /**
         * Return a bindings of each vertex to its cost in the path.
         *
         * @return map of vertex to path cost bindings
         */
        public Map<V, Double> costs();
    }

    /**
     * Searches the specified graph.
     *
     * @param graph  graph to be searched
     * @param src    optional source vertex
     * @param dst    optional destination vertex; if null paths to all vertex
     *               destinations will be searched
     * @param weight optional edge-weight; if null cost of each edge will be
     *               assumed to be 1.0
     * @return search results
     */
    Result<V, E> search(Graph<V, E> graph, V src, V dst, EdgeWeight<V, E> weight);

}