/**
 * 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.storm;

import java.nio.channels.ClosedByInterruptException;
import java.util.Collection;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.storm.daemon.Shutdownable;
import org.apache.storm.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * In local mode, {@code ProcessSimulator} keeps track of Shutdownable objects
 * in place of actual processes (in cluster mode).
 */
public class ProcessSimulator {
    protected static ConcurrentHashMap<String, Shutdownable> processMap = new ConcurrentHashMap<String, Shutdownable>();
    private static Logger LOG = LoggerFactory.getLogger(ProcessSimulator.class);
    private static Object lock = new Object();

    /**
     * Register a process' handle.
     */
    public static void registerProcess(String pid, Shutdownable shutdownable) {
        processMap.put(pid, shutdownable);
    }

    /**
     * Get all process handles.
     */
    public static Collection<Shutdownable> getAllProcessHandles() {
        return processMap.values();
    }

    /**
     * Kill a process.
     */
    public static void killProcess(String pid) {
        synchronized (lock) {
            LOG.info("Begin killing process " + pid);
            Shutdownable shutdownHandle = processMap.get(pid);
            if (shutdownHandle != null) {
                shutdownHandle.shutdown();
            }
            processMap.remove(pid);
            LOG.info("Successfully killed process " + pid);
        }
    }

    /**
     * Kill all processes.
     */
    public static void killAllProcesses() {
        Set<String> pids = processMap.keySet();
        for (String pid : pids) {
            try {
                killProcess(pid);
            } catch (Exception e) {
                if (Utils.exceptionCauseIsInstanceOf(InterruptedException.class, e)) {
                    LOG.warn("process {} not killed (Ignoring InterruptedException)", pid, e);
                } else if (Utils.exceptionCauseIsInstanceOf(ClosedByInterruptException.class, e)) {
                    LOG.warn("process {} not killed (Ignoring ClosedByInterruptException)", pid, e);
                } else if (e instanceof RuntimeException) {
                    throw e;
                } else {
                    //TODO once everything is in java this should not be possible any more
                    throw new RuntimeException(e);
                }
            }
        }
    }
}