/**
 * 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.metric;

import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;

import com.codahale.metrics.Gauge;

public class MetricJstack implements Gauge<String> {

    private String getTaskName(long id, String name) {
        if (name == null) {
            return Long.toString(id);
        }
        return id + " (" + name + ")";
    }

    public String dumpThread() throws Exception {
        StringBuilder writer = new StringBuilder();

        ThreadMXBean threadMXBean = ManagementFactory.getThreadMXBean();

        boolean contention = threadMXBean.isThreadContentionMonitoringEnabled();

        long[] threadIds = threadMXBean.getAllThreadIds();
        writer.append(threadIds.length + " active threads:");
        for (long tid : threadIds) {
            writer.append(tid).append(" ");
        }
        writer.append("\n");

        long[] deadLockTids = threadMXBean.findDeadlockedThreads();
        if (deadLockTids != null) {
            writer.append(threadIds.length + " deadlocked threads:");
            for (long tid : deadLockTids) {
                writer.append(tid).append(" ");
            }
            writer.append("\n");
        }

        long[] deadLockMonitorTids = threadMXBean.findMonitorDeadlockedThreads();
        if (deadLockMonitorTids != null) {
            writer.append(threadIds.length + " deadlocked monitor threads:");
            for (long tid : deadLockMonitorTids) {
                writer.append(tid).append(" ");
            }
            writer.append("\n");
        }

        for (long tid : threadIds) {
            ThreadInfo info = threadMXBean.getThreadInfo(tid, Integer.MAX_VALUE);
            if (info == null) {
                writer.append("  Inactive").append("\n");
                continue;
            }
            writer.append("Thread " + getTaskName(info.getThreadId(), info.getThreadName()) + ":").append("\n");
            Thread.State state = info.getThreadState();
            writer.append("  State: " + state).append("\n");
            writer.append("  Blocked count: " + info.getBlockedCount()).append("\n");
            writer.append("  Waited count: " + info.getWaitedCount()).append("\n");
            writer.append(" Cpu time:").append(threadMXBean.getThreadCpuTime(tid) / 1000000).append("ms").append("\n");
            writer.append(" User time:").append(threadMXBean.getThreadUserTime(tid) / 1000000).append("ms").append("\n");
            if (contention) {
                writer.append("  Blocked time: " + info.getBlockedTime()).append("\n");
                writer.append("  Waited time: " + info.getWaitedTime()).append("\n");
            }
            if (state == Thread.State.WAITING) {
                writer.append("  Waiting on " + info.getLockName()).append("\n");
            } else if (state == Thread.State.BLOCKED) {
                writer.append("  Blocked on " + info.getLockName()).append("\n");
                writer.append("  Blocked by " + getTaskName(info.getLockOwnerId(), info.getLockOwnerName())).append("\n");
            }

        }
        for (long tid : threadIds) {
            ThreadInfo info = threadMXBean.getThreadInfo(tid, Integer.MAX_VALUE);
            if (info == null) {
                writer.append("  Inactive").append("\n");
                continue;
            }

            writer.append("Thread " + getTaskName(info.getThreadId(), info.getThreadName()) + ": Stack").append("\n");
            for (StackTraceElement frame : info.getStackTrace()) {
                writer.append("    " + frame.toString()).append("\n");
            }
        }

        return writer.toString();
    }

    @Override
    public String getValue() {
        try {
            return dumpThread();
        } catch (Exception e) {
            return "Failed to get jstack thread info";
        }
    }

}