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/*
 * (C) Copyright 2015-2023, by Alexey Kudinkin and Contributors.
 *
 * JGraphT : a free Java graph-theory library
 *
 * See the CONTRIBUTORS.md file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0, or the
 * GNU Lesser General Public License v2.1 or later
 * which is available at
 * http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
 */
package org.jgrapht.alg.interfaces;

import java.util.*;

/**
 * Allows to derive maximum-flow
 * from the supplied flow network
 *
 * @author Alexey Kudinkin
 * @author Joris Kinable
 *
 * @param  the graph vertex type
 * @param  the graph edge type
 *
 */
public interface MaximumFlowAlgorithm
    extends FlowAlgorithm
{

    /**
     * Sets current source to source, current sink to sink, then
     * calculates maximum flow from source to sink. Returns an object
     * containing detailed information about the flow.
     *
     * @param source source of the flow inside the network
     * @param sink sink of the flow inside the network
     *
     * @return maximum flow
     */
    MaximumFlow getMaximumFlow(V source, V sink);

    /**
     * Sets current source to source, current sink to sink, then
     * calculates maximum flow from source to sink. Note, that
     * source and sink must be vertices of the 
     * network passed to the constructor, and they must be different.
     *
     * @param source source vertex
     * @param sink sink vertex
     * @return the value of the maximum flow
     */
    default double getMaximumFlowValue(V source, V sink)
    {
        return getMaximumFlow(source, sink).getValue();
    }

    /**
     * A maximum flow
     *
     * @param  the graph edge type
     */
    interface MaximumFlow
        extends Flow
    {
        /**
         * Returns value of the maximum-flow for the given network
         *
         * @return value of the maximum-flow
         */
        Double getValue();
    }

    /**
     * Default implementation of the maximum flow
     *
     * @param  the graph edge type
     */
    class MaximumFlowImpl
        extends FlowImpl
        implements MaximumFlow
    {
        private Double value;

        /**
         * Create a new maximum flow
         * 
         * @param value the flow value
         * @param flow the flow map
         */
        public MaximumFlowImpl(Double value, Map flow)
        {
            super(flow);
            this.value = value;
        }

        @Override
        public Double getValue()
        {
            return value;
        }

        @Override
        public String toString()
        {
            return "Flow Value: " + value + "\nFlow map:\n" + getFlowMap();
        }
    }
}