/*
 * 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.solr.cloud;


import java.lang.invoke.MethodHandles;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.solr.cloud.OverseerCollectionMessageHandler.Cmd;
import org.apache.solr.common.cloud.ClusterState;
import org.apache.solr.common.cloud.SolrZkClient;
import org.apache.solr.common.cloud.ZkNodeProps;
import org.apache.solr.common.cloud.ZkStateReader;
import org.apache.solr.common.params.CollectionParams.CollectionAction;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.common.util.Utils;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.solr.common.params.CollectionParams.CollectionAction.ADDROLE;
import static org.apache.solr.common.params.CollectionParams.CollectionAction.REMOVEROLE;

public class OverseerRoleCmd implements Cmd {
  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

  private final OverseerCollectionMessageHandler ocmh;
  private final CollectionAction operation;
  private final OverseerNodePrioritizer overseerPrioritizer;



  public OverseerRoleCmd(OverseerCollectionMessageHandler ocmh, CollectionAction operation, OverseerNodePrioritizer prioritizer) {
    this.ocmh = ocmh;
    this.operation = operation;
    this.overseerPrioritizer = prioritizer;
  }

  @Override
  @SuppressWarnings("unchecked")
  public void call(ClusterState state, ZkNodeProps message, NamedList results) throws Exception {
    ZkStateReader zkStateReader = ocmh.zkStateReader;
    SolrZkClient zkClient = zkStateReader.getZkClient();
    Map roles = null;
    String node = message.getStr("node");

    String roleName = message.getStr("role");
    boolean nodeExists = false;
    if (nodeExists = zkClient.exists(ZkStateReader.ROLES, true)) {
      roles = (Map) Utils.fromJSON(zkClient.getData(ZkStateReader.ROLES, null, new Stat(), true));
    } else {
      roles = new LinkedHashMap(1);
    }

    List nodeList = (List) roles.get(roleName);
    if (nodeList == null) roles.put(roleName, nodeList = new ArrayList());
    if (ADDROLE == operation) {
      log.info("Overseer role added to {}", node);
      if (!nodeList.contains(node)) nodeList.add(node);
    } else if (REMOVEROLE == operation) {
      log.info("Overseer role removed from {}", node);
      nodeList.remove(node);
    }

    if (nodeExists) {
      zkClient.setData(ZkStateReader.ROLES, Utils.toJSON(roles), true);
    } else {
      zkClient.create(ZkStateReader.ROLES, Utils.toJSON(roles), CreateMode.PERSISTENT, true);
    }
    //if there are too many nodes this command may time out. And most likely dedicated
    // overseers are created when there are too many nodes  . So , do this operation in a separate thread
    new Thread(() -> {
      try {
        overseerPrioritizer.prioritizeOverseerNodes(ocmh.myId);
      } catch (Exception e) {
        log.error("Error in prioritizing Overseer", e);
      }

    }).start();

  }

}