/**
 * 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 com.alibaba.jstorm.task.master.timer;

import java.util.Set;

import backtype.storm.task.TopologyContext;
import com.alibaba.jstorm.cluster.StormClusterState;
import com.alibaba.jstorm.task.error.ErrorConstants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.alibaba.jstorm.schedule.Assignment;
import com.alibaba.jstorm.schedule.default_assign.ResourceWorkerSlot;
import com.alibaba.jstorm.task.master.TMHandler;
import com.alibaba.jstorm.task.master.TopologyMasterContext;

public class WorkerSetUpdater implements TMHandler {
    private static final Logger LOG = LoggerFactory.getLogger(WorkerSetUpdater.class);

    TopologyMasterContext tmContext;

    private StormClusterState zkCluster;
    private TopologyContext context;

    @Override
    public void init(TopologyMasterContext tmContext) {
        this.tmContext = tmContext;
        this.zkCluster = tmContext.getZkCluster();
        this.context = tmContext.getContext();
    }


    @Override
    public void process(Object event) throws Exception {
        try {
            Assignment assignment = tmContext.getZkCluster().assignment_info(tmContext.getTopologyId(), null);
            if (assignment != null) {
                Set<ResourceWorkerSlot> oldWorkerSet = tmContext.getWorkerSet().get();
                Set<ResourceWorkerSlot> newWorkerSet = assignment.getWorkers();
                if (!oldWorkerSet.equals(newWorkerSet)) {
                    LOG.info("Find worker slots has been changed, old:{}, \nnew:{}", oldWorkerSet, newWorkerSet);
                    tmContext.getWorkerSet().set(newWorkerSet);
                    tmContext.getTopologyMetricContext().setWorkerSet(newWorkerSet);
                }
            }
        } catch (Exception e) {
            String errorInfo = "Failed to get assignment for " + tmContext.getTopologyId();
            LOG.error(errorInfo + e);
            zkCluster.report_task_error(context.getTopologyId(), context.getThisTaskId(),
                    errorInfo, ErrorConstants.WARN, ErrorConstants.CODE_USER);
        }
    }


    @Override
    public void cleanup() {
    }

}