/*
 * 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.apache.flink.graph.spargel;

import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.graph.EdgeDirection;
import org.apache.flink.graph.IterationConfiguration;

import java.util.ArrayList;
import java.util.List;

/**
 * A ScatterGatherConfiguration object can be used to set the iteration name and
 * degree of parallelism, to register aggregators and use broadcast sets in
 * the {@link GatherFunction} and {@link ScatterFunction}
 *
 * The VertexCentricConfiguration object is passed as an argument to
 * {@link org.apache.flink.graph.Graph#runScatterGatherIteration (
 * org.apache.flink.graph.spargel.GatherFunction, org.apache.flink.graph.spargel.ScatterFunction, int,
 * ScatterGatherConfiguration)}.
 */
public class ScatterGatherConfiguration extends IterationConfiguration {

	/** the broadcast variables for the scatter function **/
	private List<Tuple2<String, DataSet<?>>> bcVarsScatter = new ArrayList<>();

	/** the broadcast variables for the gather function **/
	private List<Tuple2<String, DataSet<?>>> bcVarsGather = new ArrayList<>();

	/** flag that defines whether the degrees option is set **/
	private boolean optDegrees = false;

	/** the direction in which the messages should be sent **/
	private EdgeDirection direction = EdgeDirection.OUT;

	public ScatterGatherConfiguration() {}

	/**
	 * Adds a data set as a broadcast set to the scatter function.
	 *
	 * @param name The name under which the broadcast data is available in the scatter function.
	 * @param data The data set to be broadcasted.
	 */
	public void addBroadcastSetForScatterFunction(String name, DataSet<?> data) {
		this.bcVarsScatter.add(new Tuple2<String, DataSet<?>>(name, data));
	}

	/**
	 * Adds a data set as a broadcast set to the gather function.
	 *
	 * @param name The name under which the broadcast data is available in the gather function.
	 * @param data The data set to be broadcasted.
	 */
	public void addBroadcastSetForGatherFunction(String name, DataSet<?> data) {
		this.bcVarsGather.add(new Tuple2<String, DataSet<?>>(name, data));
	}

	/**
	 * Get the broadcast variables of the ScatterFunction.
	 *
	 * @return a List of Tuple2, where the first field is the broadcast variable name
	 * and the second field is the broadcast DataSet.
	 */
	public List<Tuple2<String, DataSet<?>>> getScatterBcastVars() {
		return this.bcVarsScatter;
	}

	/**
	 * Get the broadcast variables of the GatherFunction.
	 *
	 * @return a List of Tuple2, where the first field is the broadcast variable name
	 * and the second field is the broadcast DataSet.
	 */
	public List<Tuple2<String, DataSet<?>>> getGatherBcastVars() {
		return this.bcVarsGather;
	}

	/**
	 * Gets whether the degrees option is set.
	 * By default, the degrees option is not set.
	 *
	 * @return True, if the degree option is set, false otherwise.
	 */
	public boolean isOptDegrees() {
		return optDegrees;
	}

	/**
	 * Sets the degree option.
	 * By default, the degrees option is not set.
	 *
	 * @param optDegrees True, to set this option, false otherwise.
	 */
	public void setOptDegrees(boolean optDegrees) {
		this.optDegrees = optDegrees;
	}

	/**
	 * Gets the direction in which messages are sent in the ScatterFunction.
	 * By default the messaging direction is OUT.
	 *
	 * @return an EdgeDirection, which can be either IN, OUT or ALL.
	 */
	public EdgeDirection getDirection() {
		return direction;
	}

	/**
	 * Sets the direction in which messages are sent in the ScatterFunction.
	 * By default the messaging direction is OUT.
	 *
	 * @param direction - IN, OUT or ALL
	 */
	public void setDirection(EdgeDirection direction) {
		this.direction = direction;
	}

}