/*
 * 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.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;

import org.apache.solr.common.NonExistentCoreException;
import org.apache.solr.common.SolrException;
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.CoreAdminParams;
import org.apache.solr.common.params.ModifiableSolrParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.common.util.Utils;
import org.apache.solr.core.snapshots.SolrSnapshotManager;
import org.apache.solr.util.TimeOut;
import org.apache.zookeeper.KeeperException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.solr.common.params.CollectionParams.CollectionAction.DELETE;
import static org.apache.solr.common.params.CommonAdminParams.ASYNC;
import static org.apache.solr.common.params.CommonParams.NAME;

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

  public DeleteCollectionCmd(OverseerCollectionMessageHandler ocmh) {
    this.ocmh = ocmh;
  }

  @Override
  public void call(ClusterState state, ZkNodeProps message, NamedList results) throws Exception {
    ZkStateReader zkStateReader = ocmh.zkStateReader;
    final String collection = message.getStr(NAME);
    try {
      // Remove the snapshots meta-data for this collection in ZK. Deleting actual index files
      // should be taken care of as part of collection delete operation.
      SolrZkClient zkClient = zkStateReader.getZkClient();
      SolrSnapshotManager.cleanupCollectionLevelSnapshots(zkClient, collection);

      if (zkStateReader.getClusterState().getCollectionOrNull(collection) == null) {
        if (zkStateReader.getZkClient().exists(ZkStateReader.COLLECTIONS_ZKNODE + "/" + collection, true)) {
          // if the collection is not in the clusterstate, but is listed in zk, do nothing, it will just
          // be removed in the finally - we cannot continue, because the below code will error if the collection
          // is not in the clusterstate
          return;
        }
      }
      ModifiableSolrParams params = new ModifiableSolrParams();
      params.set(CoreAdminParams.ACTION, CoreAdminParams.CoreAdminAction.UNLOAD.toString());
      params.set(CoreAdminParams.DELETE_INSTANCE_DIR, true);
      params.set(CoreAdminParams.DELETE_DATA_DIR, true);

      String asyncId = message.getStr(ASYNC);
      Map<String, String> requestMap = null;
      if (asyncId != null) {
        requestMap = new HashMap<>();
      }

      Set<String> okayExceptions = new HashSet<>(1);
      okayExceptions.add(NonExistentCoreException.class.getName());

      ocmh.collectionCmd(message, params, results, null, asyncId, requestMap, okayExceptions);

      ZkNodeProps m = new ZkNodeProps(Overseer.QUEUE_OPERATION, DELETE.toLower(), NAME, collection);
      Overseer.getStateUpdateQueue(zkStateReader.getZkClient()).offer(Utils.toJSON(m));

      // wait for a while until we don't see the collection
      TimeOut timeout = new TimeOut(30, TimeUnit.SECONDS);
      boolean removed = false;
      while (! timeout.hasTimedOut()) {
        Thread.sleep(100);
        removed = !zkStateReader.getClusterState().hasCollection(collection);
        if (removed) {
          Thread.sleep(500); // just a bit of time so it's more likely other
          // readers see on return
          break;
        }
      }
      if (!removed) {
        throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
            "Could not fully remove collection: " + collection);
      }

    } finally {

      try {
        if (zkStateReader.getZkClient().exists(
            ZkStateReader.COLLECTIONS_ZKNODE + "/" + collection, true)) {
          zkStateReader.getZkClient().clean(
              ZkStateReader.COLLECTIONS_ZKNODE + "/" + collection);
        }
      } catch (InterruptedException e) {
        SolrException.log(log, "Cleaning up collection in zk was interrupted:"
            + collection, e);
        Thread.currentThread().interrupt();
      } catch (KeeperException e) {
        SolrException.log(log, "Problem cleaning up collection in zk:"
            + collection, e);
      }
    }
  }
}