/**
 * 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.hadoop.hdds.scm.pipeline;

import org.apache.hadoop.hdds.protocol.DatanodeDetails;
import org.apache.hadoop.hdds.protocol.proto.HddsProtos.ReplicationType;
import org.apache.hadoop.hdds.protocol.proto.HddsProtos.ReplicationFactor;
import org.apache.hadoop.hdds.protocol.proto.HddsProtos.NodeState;
import org.apache.hadoop.hdds.scm.node.NodeManager;
import org.apache.hadoop.hdds.scm.pipeline.Pipeline.PipelineState;

import java.io.IOException;
import java.util.Collections;
import java.util.List;

/**
 * Implements Api for creating stand alone pipelines.
 */
public class SimplePipelineProvider implements PipelineProvider {

  private final NodeManager nodeManager;

  public SimplePipelineProvider(NodeManager nodeManager) {
    this.nodeManager = nodeManager;
  }

  @Override
  public Pipeline create(ReplicationFactor factor) throws IOException {
    List<DatanodeDetails> dns =
        nodeManager.getNodes(NodeState.HEALTHY);
    if (dns.size() < factor.getNumber()) {
      String e = String
          .format("Cannot create pipeline of factor %d using %d nodes.",
              factor.getNumber(), dns.size());
      throw new IOException(e);
    }

    Collections.shuffle(dns);
    return Pipeline.newBuilder()
        .setId(PipelineID.randomId())
        .setState(PipelineState.OPEN)
        .setType(ReplicationType.STAND_ALONE)
        .setFactor(factor)
        .setNodes(dns.subList(0, factor.getNumber()))
        .build();
  }

  @Override
  public Pipeline create(ReplicationFactor factor,
      List<DatanodeDetails> nodes) {
    return Pipeline.newBuilder()
        .setId(PipelineID.randomId())
        .setState(PipelineState.OPEN)
        .setType(ReplicationType.STAND_ALONE)
        .setFactor(factor)
        .setNodes(nodes)
        .build();
  }

  @Override
  public void shutdown() {
    // Do nothing.
  }
}