/*
 * 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.uima.ducc.agent.metrics.collectors;

import java.lang.management.ManagementFactory;
import java.lang.management.OperatingSystemMXBean;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

import org.apache.uima.ducc.common.agent.metrics.memory.DuccNodeMemory;
import org.apache.uima.ducc.common.agent.metrics.memory.NodeMemory;

public class DefaultNodeMemoryCollector implements CallableMemoryCollector {
  // private static final String TOTAL_MEMORY_SIZE="getTotalPhysicalMemorySize";
  private static final String FREE_PHYSICAL_MEMORY_SIZE = "getFreePhysicalMemorySize";

  private static final String FREE_SWAP_MEMORY_SIZE = "getFreeSwapSpaceSize";

  private static final String TOTAL_SWAP_SPACE_SIZE = "getTotalSwapSpaceSize";

  private long fakeMemorySize = -1;

  public DefaultNodeMemoryCollector() {
    String tmp;
    if ((tmp = System.getProperty("ducc.agent.node.metrics.fake.memory.size")) != null) {
      try {
        fakeMemorySize = Long.parseLong(tmp);
      } catch (NumberFormatException e) {
        e.printStackTrace();
      }
    }
  }

  public NodeMemory call() throws Exception {
    return collect();
  }

  private void setMetric(String metricName, long metricValue, DuccNodeMemory nodeMemory) {
    try {
      if (fakeMemorySize != -1) {
        nodeMemory.setMemTotal(fakeMemorySize);
      } else {
        nodeMemory.setMemTotal(Runtime.getRuntime().totalMemory());
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    if (metricName.equalsIgnoreCase(FREE_PHYSICAL_MEMORY_SIZE)) {
      if (fakeMemorySize != -1) { // UIMA-4114
        nodeMemory.setMemFree(fakeMemorySize);
      } else {
        nodeMemory.setMemFree(metricValue);
      }
    } else if (metricName.equalsIgnoreCase(FREE_SWAP_MEMORY_SIZE)) {
      nodeMemory.setSwapFree(metricValue);
    } else if (metricName.equalsIgnoreCase(TOTAL_SWAP_SPACE_SIZE)) {
      nodeMemory.setSwapTotal(metricValue);
    }
  }

  private DuccNodeMemory collect() {
    DuccNodeMemory nodeMemory = new DuccNodeMemory();
    OperatingSystemMXBean operatingSystemMXBean = ManagementFactory.getOperatingSystemMXBean();
    for (Method method : operatingSystemMXBean.getClass().getDeclaredMethods()) {
      method.setAccessible(true);
      if (method.getName().startsWith("get") && Modifier.isPublic(method.getModifiers())) {
        Long value;
        try {
          value = (Long) method.invoke(operatingSystemMXBean);
        } catch (Exception e) {
          value = 0L;
        } // try
        setMetric(method.getName(), value, nodeMemory);
      } // if
    } // for
    return nodeMemory;
  }

  public static void main(String[] args) {
    try {
      DefaultNodeMemoryCollector collector = new DefaultNodeMemoryCollector();
      ExecutorService pool = Executors.newFixedThreadPool(1);
      Future<NodeMemory> nmiFuture = pool.submit(collector);
      NodeMemory nodeMemory = nmiFuture.get();
      System.out.println("Total Memory:" + nodeMemory.getMemTotal());
      System.out.println("Total Free Memory:" + nodeMemory.getMemFree());
      System.out.println("Total Swap Space Size:" + nodeMemory.getSwapTotal());
      System.out.println("Total Free Swap Space Size:" + nodeMemory.getSwapFree());

    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}