package com.webank.core;

import java.lang.management.ManagementFactory;
import com.sun.management.OperatingSystemMXBean;
import java.lang.management.ThreadMXBean;
import java.lang.management.MemoryMXBean;
import java.lang.management.GarbageCollectorMXBean;
import java.util.*;

public class JVMStat implements JVMStatMBean {
	private OperatingSystemMXBean operatingSystem;
	private ThreadMXBean thread;
	private MemoryMXBean memory;
	private List<GarbageCollectorMXBean> gcBeans;

	private int processorCount;
	private long lastCpuTime;
	private long lastNanoTime;
	private final ArrayList<String> youngGenCollectorNames;
	private final ArrayList<String> oldGenCollectorNames;

	public JVMStat() {
		operatingSystem = (OperatingSystemMXBean)ManagementFactory.getOperatingSystemMXBean();
		thread = ManagementFactory.getThreadMXBean();
		memory = ManagementFactory.getMemoryMXBean();
		gcBeans = ManagementFactory.getGarbageCollectorMXBeans();
		
		processorCount = operatingSystem.getAvailableProcessors();
		lastCpuTime = operatingSystem.getProcessCpuTime();
		lastNanoTime = System.nanoTime();
		
		youngGenCollectorNames = new ArrayList();
		youngGenCollectorNames.add("Copy");
		youngGenCollectorNames.add("ParNew");
		youngGenCollectorNames.add("PS Scavenge");
		
		youngGenCollectorNames.add("Garbage collection optimized for short pausetimes Young Collector");
		youngGenCollectorNames.add("Garbage collection optimized for throughput Young Collector");
		youngGenCollectorNames.add("Garbage collection optimized for deterministic pausetimes Young Collector");
		
		oldGenCollectorNames = new ArrayList();
		oldGenCollectorNames.add("MarkSweepCompact");
		oldGenCollectorNames.add("PS MarkSweep");
		oldGenCollectorNames.add("ConcurrentMarkSweep");
		
		oldGenCollectorNames.add("Garbage collection optimized for short pausetimes Old Collector");
		oldGenCollectorNames.add("Garbage collection optimized for throughput Old Collector");
		oldGenCollectorNames.add("Garbage collection optimized for deterministic pausetimes Old Collector");
	}
	
	public String getUsedCpu() {
		long cpuTime = operatingSystem.getProcessCpuTime();
		long time = System.nanoTime();
		double pct = (cpuTime - lastCpuTime) / (double)(time - lastNanoTime) / processorCount;
		lastCpuTime = cpuTime;
		lastNanoTime = time;
		return String.format("%.2f%%", pct*100);
	}

	public long getUsedHeap() {
		return memory.getHeapMemoryUsage().getUsed() >> 20;
	}
	
	public long getCommittedHeap() {
		return memory.getHeapMemoryUsage().getCommitted() >> 20;
	}

	public long getYoungGCCount() {
		long gcCount = 0L;
		for (int i = 0; i < gcBeans.size(); i++) {
			GarbageCollectorMXBean gc = (GarbageCollectorMXBean)gcBeans.get(i);
			if (youngGenCollectorNames.contains(gc.getName())) {
				gcCount += gc.getCollectionCount();
			}
		}
		return gcCount;
	}

	public long getFullGCCount() {
		long gcCount = 0L;
		for (int i = 0; i < gcBeans.size(); i++) {
			GarbageCollectorMXBean gc = (GarbageCollectorMXBean)gcBeans.get(i);
			if (oldGenCollectorNames.contains(gc.getName())) {
				gcCount += gc.getCollectionCount();
			}
		}
		return gcCount;
	}

	public long getYoungGCTime() {
		long gcTime = 0L;
		for (int i = 0; i < gcBeans.size(); i++) {
			GarbageCollectorMXBean gc = (GarbageCollectorMXBean)gcBeans.get(i);
			if (youngGenCollectorNames.contains(gc.getName())) {
				gcTime += gc.getCollectionTime();
			}
		}
		return gcTime;
	}

	public long getFullGCTime() {
		long gcTime = 0L;
		for (int i = 0; i < gcBeans.size(); i++) {
			GarbageCollectorMXBean gc = (GarbageCollectorMXBean)gcBeans.get(i);
			if (oldGenCollectorNames.contains(gc.getName())) {
				gcTime += gc.getCollectionTime();
			}

		}
		return gcTime;
	}
}