/*
 * 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.optimizer.operators;

import java.util.Collections;
import java.util.List;

import org.apache.flink.optimizer.costs.Costs;
import org.apache.flink.optimizer.dag.ReduceNode;
import org.apache.flink.optimizer.dag.SingleInputNode;
import org.apache.flink.optimizer.dataproperties.GlobalProperties;
import org.apache.flink.optimizer.dataproperties.LocalProperties;
import org.apache.flink.optimizer.dataproperties.RequestedGlobalProperties;
import org.apache.flink.optimizer.dataproperties.RequestedLocalProperties;
import org.apache.flink.optimizer.plan.Channel;
import org.apache.flink.optimizer.plan.SingleInputPlanNode;
import org.apache.flink.runtime.io.network.DataExchangeMode;
import org.apache.flink.runtime.operators.DriverStrategy;
import org.apache.flink.runtime.operators.shipping.ShipStrategyType;

public final class AllReduceProperties extends OperatorDescriptorSingle {

	@Override
	public DriverStrategy getStrategy() {
		return DriverStrategy.ALL_REDUCE;
	}

	@Override
	public SingleInputPlanNode instantiate(Channel in, SingleInputNode node) {
		if (in.getShipStrategy() == ShipStrategyType.FORWARD) {
			// locally connected, directly instantiate
			return new SingleInputPlanNode(node, "Reduce ("+node.getOperator().getName()+")",
											in, DriverStrategy.ALL_REDUCE);
		} else {
			// non forward case.plug in a combiner
			Channel toCombiner = new Channel(in.getSource());
			toCombiner.setShipStrategy(ShipStrategyType.FORWARD, DataExchangeMode.PIPELINED);
			
			// create an input node for combine with same parallelism as input node
			ReduceNode combinerNode = ((ReduceNode) node).getCombinerUtilityNode();
			combinerNode.setParallelism(in.getSource().getParallelism());

			SingleInputPlanNode combiner = new SingleInputPlanNode(combinerNode,
					"Combine ("+node.getOperator().getName()+")", toCombiner, DriverStrategy.ALL_REDUCE);
			combiner.setCosts(new Costs(0, 0));
			combiner.initProperties(toCombiner.getGlobalProperties(), toCombiner.getLocalProperties());
			
			Channel toReducer = new Channel(combiner);
			toReducer.setShipStrategy(in.getShipStrategy(), in.getShipStrategyKeys(),
										in.getShipStrategySortOrder(), in.getDataExchangeMode());
			toReducer.setLocalStrategy(in.getLocalStrategy(), in.getLocalStrategyKeys(),
										in.getLocalStrategySortOrder());

			return new SingleInputPlanNode(node, "Reduce ("+node.getOperator().getName()+")",
											toReducer, DriverStrategy.ALL_REDUCE);
		}
	}
	
	@Override
	protected List<RequestedGlobalProperties> createPossibleGlobalProperties() {
		return Collections.singletonList(new RequestedGlobalProperties());
	}

	@Override
	protected List<RequestedLocalProperties> createPossibleLocalProperties() {
		return Collections.singletonList(new RequestedLocalProperties());
	}
	
	@Override
	public GlobalProperties computeGlobalProperties(GlobalProperties gProps) {
		return new GlobalProperties();
	}
	
	@Override
	public LocalProperties computeLocalProperties(LocalProperties lProps) {
		return new LocalProperties();
	}
}