/**
    * Oshi (https://github.com/dblock/oshi)
    * 
    * Copyright (c) 2010 - 2015 The Oshi Project Team
    * 
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the Eclipse Public License v1.0
    * which accompanies this distribution, and is available at
    * http://www.eclipse.org/legal/epl-v10.html
   * 
   * Contributors:
   * dblock[at]dblock[dot]org
   * alessandro[at]perucchi[dot]org
   * widdis[at]gmail[dot]com
   * https://github.com/dblock/oshi/graphs/contributors
   */
  package oshi.software.os.windows.nt;
  
  import java.lang.management.ManagementFactory;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import oshi.hardware.Processor;
  import oshi.software.os.windows.nt.Pdh.PdhFmtCounterValue;
  import oshi.util.ParseUtil;
  
  import com.sun.jna.LastErrorException;
  import com.sun.jna.Native;
  import com.sun.jna.platform.win32.WinBase;
  import com.sun.jna.platform.win32.WinBase.SYSTEM_INFO;
  import com.sun.jna.ptr.IntByReference;
  import com.sun.jna.ptr.PointerByReference;
  
  /**
   * A CPU as defined in Windows registry.
   * 
   * @author dblock[at]dblock[dot]org
   * @author alessio.fachechi[at]gmail[dot]com
   * @author widdis[at]gmail[dot]com
   */
  @SuppressWarnings("restriction")
  public class CentralProcessor implements Processor {
  	private static final java.lang.management.OperatingSystemMXBean OS_MXBEAN = ManagementFactory
  			.getOperatingSystemMXBean();
  	private static boolean sunMXBean;
  	static {
  		try {
  			Class.forName("com.sun.management.OperatingSystemMXBean");
  			// Initialize CPU usage
  			((com.sun.management.OperatingSystemMXBean) OS_MXBEAN)
  					.getSystemCpuLoad();
  			sunMXBean = true;
  		} catch (ClassNotFoundException e) {
  			sunMXBean = false;
  		}
  	}
  	// Maintain two sets of previous ticks to be used for calculating usage
  	// between them.
  	// System ticks (static)
  	private static long tickTime = System.currentTimeMillis();
  	private static long[] prevTicks = new long[4];
  	private static long[] curTicks = new long[4];
  	static {
  		updateSystemTicks();
  		System.arraycopy(curTicks, 0, prevTicks, 0, curTicks.length);
  	}
  
  	// Maintain similar arrays for per-processor ticks (class variables)
  	private long procTickTime = System.currentTimeMillis();
  	private long[] prevProcTicks = new long[4];
  	private long[] curProcTicks = new long[4];
  
  	// Initialize numCPU and open a Performance Data Helper Thread for
  	// monitoring each processor
  	private static PointerByReference phQuery = new PointerByReference();
  	private static final IntByReference zero = new IntByReference(0);
  	private static final int numCPU;
  	static {
  		// Get number of processors
  		SYSTEM_INFO sysinfo = new SYSTEM_INFO();
  		Kernel32.INSTANCE.GetSystemInfo(sysinfo);
  		numCPU = sysinfo.dwNumberOfProcessors.intValue();
  
  		// Set up query for this processor
  		int ret = Pdh.INSTANCE.PdhOpenQuery(null, zero, phQuery);
  		if (ret != 0)
  			throw new LastErrorException("Cannot open PDH query. Error code: "
  					+ String.format("0x%08X", ret));
  
  		// Set up hook to close the query on shutdown
  		Runtime.getRuntime().addShutdownHook(new Thread() {
  			@Override
  			public void run() {
  				Pdh.INSTANCE.PdhCloseQuery(phQuery.getValue());
  			}
  		});
  	}
  	// Set up a counter for each processor
  	private static PointerByReference[] phUserCounters = new PointerByReference[numCPU];
 	private static PointerByReference[] phIdleCounters = new PointerByReference[numCPU];
 	static {
 		for (int p = 0; p < numCPU; p++) {
 			// Options are (only need 2 to calculate all)
 			// "\Processor(0)\% processor time"
 			// "\Processor(0)\% idle time" (1 - processor)
 			// "\Processor(0)\% privileged time" (subset of processor)
 			// "\Processor(0)\% user time" (other subset of processor)
 			// Note need to make \ = \\ for Java Strings and %% for format
 			String counterPath = String.format("\\Processor(%d)\\%% user time",
 					p);
 			phUserCounters[p] = new PointerByReference();
 			int ret = Pdh.INSTANCE.PdhAddEnglishCounterA(phQuery.getValue(),
 					counterPath, zero, phUserCounters[p]);
 			if (ret != 0)
 				throw new LastErrorException(
 						"Cannot add PDH Counter for % user time for processor "
 								+ p + ". Error code: "
 								+ String.format("0x%08X", ret));
 			counterPath = String.format("\\Processor(%d)\\%% idle time", p);
 			phIdleCounters[p] = new PointerByReference();
 			ret = Pdh.INSTANCE.PdhAddEnglishCounterA(phQuery.getValue(),
 					counterPath, zero, phIdleCounters[p]);
 			if (ret != 0)
 				throw new LastErrorException(
 						"Cannot add PDH Counter for % idle time for processor "
 								+ p + ". Error code: "
 								+ String.format("0x%08X", ret));
 		}
 		// Initialize by collecting data the first time
 		int ret = Pdh.INSTANCE.PdhCollectQueryData(phQuery.getValue());
 		if (ret != 0)
 			throw new LastErrorException(
 					"Cannot collect PDH query data. Error code: "
 							+ String.format("0x%08X", ret));
 	}
 	// Set up array to maintain current ticks for rapid reference. This array
 	// will be updated in place and used to increment ticks based on processor
 	// data helper which only gives % between reads
 	private static long[][] allProcessorTicks = new long[numCPU][4];
 	private static long allProcTickTime = System.currentTimeMillis() - 100;
 
 	private int processorNumber;
 	private String cpuVendor;
 	private String cpuName;
 	private String cpuIdentifier;
 	private Long cpuVendorFreq;
 
 	/**
 	 * Create a Processor with the given number
 	 * 
 	 * @param procNo
 	 */
 	public CentralProcessor(int procNo) {
 		if (procNo >= numCPU)
 			throw new IllegalArgumentException("Processor number (" + procNo
 					+ ") must be less than the number of CPUs: " + numCPU);
 		this.processorNumber = procNo;
 		updateProcessorTicks();
 		System.arraycopy(allProcessorTicks[processorNumber], 0, curProcTicks,
 				0, curProcTicks.length);
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public int getProcessorNumber() {
 		return processorNumber;
 	}
 
 	/**
 	 * Vendor identifier, eg. GenuineIntel.
 	 * 
 	 * @return Processor vendor.
 	 */
 	@Override
 	public String getVendor() {
 		return this.cpuVendor;
 	}
 
 	/**
 	 * Set processor vendor.
 	 * 
 	 * @param vendor
 	 *            Vendor.
 	 */
 	@Override
 	public void setVendor(String vendor) {
 		this.cpuVendor = vendor;
 	}
 
 	/**
 	 * Name, eg. Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz
 	 * 
 	 * @return Processor name.
 	 */
 	@Override
 	public String getName() {
 		return this.cpuName;
 	}
 
 	/**
 	 * Set processor name.
 	 * 
 	 * @param name
 	 *            Name.
 	 */
 	@Override
 	public void setName(String name) {
 		this.cpuName = name;
 	}
 
 	/**
 	 * Vendor frequency (in Hz), eg. for processor named Intel(R) Core(TM)2 Duo
 	 * CPU T7300 @ 2.00GHz the vendor frequency is 2000000000.
 	 * 
 	 * @return Processor frequency or -1 if unknown.
 	 */
 	@Override
 	public long getVendorFreq() {
 		if (this.cpuVendorFreq == null) {
 			Pattern pattern = Pattern.compile("@ (.*)$");
 			Matcher matcher = pattern.matcher(getName());
 
 			if (matcher.find()) {
 				String unit = matcher.group(1);
 				this.cpuVendorFreq = Long.valueOf(ParseUtil.parseHertz(unit));
 			} else {
 				this.cpuVendorFreq = Long.valueOf(-1L);
 			}
 		}
 
 		return this.cpuVendorFreq.longValue();
 	}
 
 	/**
 	 * Set vendor frequency.
 	 * 
 	 * @param freq
 	 *            Frequency.
 	 */
 	@Override
 	public void setVendorFreq(long freq) {
 		this.cpuVendorFreq = Long.valueOf(freq);
 	}
 
 	/**
 	 * Identifier, eg. x86 Family 6 Model 15 Stepping 10.
 	 * 
 	 * @return Processor identifier.
 	 */
 	@Override
 	public String getIdentifier() {
 		return this.cpuIdentifier;
 	}
 
 	/**
 	 * Set processor identifier.
 	 * 
 	 * @param identifier
 	 *            Identifier.
 	 */
 	@Override
 	public void setIdentifier(String identifier) {
 		this.cpuIdentifier = identifier;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public boolean isCpu64bit() {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public void setCpu64(boolean cpu64) {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public String getStepping() {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public void setStepping(String stepping) {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public String getModel() {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public void setModel(String model) {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public String getFamily() {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public void setFamily(String family) {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	@Deprecated
 	public float getLoad() {
 		// TODO Remove in 2.0
 		return (float) getSystemCpuLoadBetweenTicks() * 100;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public double getSystemCpuLoadBetweenTicks() {
 		// Check if > ~ 0.95 seconds since last tick count.
 		long now = System.currentTimeMillis();
 		boolean update = (now - tickTime > 950);
 		if (update) {
 			// Enough time has elapsed.
 			// Update latest
 			updateSystemTicks();
 			tickTime = now;
 		}
 		// Calculate total
 		long total = 0;
 		for (int i = 0; i < curTicks.length; i++) {
 			total += (curTicks[i] - prevTicks[i]);
 		}
 		// Calculate idle from last field [3]
 		long idle = curTicks[3] - prevTicks[3];
 
 		// Copy latest ticks to earlier position for next call
 		if (update) {
 			System.arraycopy(curTicks, 0, prevTicks, 0, curTicks.length);
 		}
 
 		// return
 		if (total > 0 && idle >= 0) {
 			return (double) (total - idle) / total;
 		}
 		return 0d;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public long[] getSystemCpuLoadTicks() {
 		updateSystemTicks();
 		// Make a copy
 		long[] ticks = new long[curTicks.length];
 		System.arraycopy(curTicks, 0, ticks, 0, curTicks.length);
 		return ticks;
 	}
 
 	/**
 	 * Updates system tick information from native call to GetSystemTimes().
 	 * Array with four elements representing clock ticks or milliseconds
 	 * (platform dependent) spent in User (0), Nice (1), System (2), and Idle
 	 * (3) states. By measuring the difference between ticks across a time
 	 * interval, CPU load over that interval may be calculated.
 	 */
 	private static void updateSystemTicks() {
 		WinBase.FILETIME lpIdleTime = new WinBase.FILETIME();
 		WinBase.FILETIME lpKernelTime = new WinBase.FILETIME();
 		WinBase.FILETIME lpUserTime = new WinBase.FILETIME();
 		if (0 == Kernel32.INSTANCE.GetSystemTimes(lpIdleTime, lpKernelTime,
 				lpUserTime))
 			throw new LastErrorException("Error code: " + Native.getLastError());
 		// Array order is user,nice,kernel,idle
 		curTicks[0] = lpUserTime.toLong() + Kernel32.WIN32_TIME_OFFSET;
 		curTicks[1] = 0L; // Windows is not 'nice'
 		curTicks[2] = lpKernelTime.toLong() - lpIdleTime.toLong();
 		curTicks[3] = lpIdleTime.toLong() + Kernel32.WIN32_TIME_OFFSET;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public double getSystemCpuLoad() {
 		if (sunMXBean) {
 			return ((com.sun.management.OperatingSystemMXBean) OS_MXBEAN)
 					.getSystemCpuLoad();
 		}
 		return getSystemCpuLoadBetweenTicks();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public double getSystemLoadAverage() {
 		// Expected to be -1 for Windows
 		return OS_MXBEAN.getSystemLoadAverage();
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public double getProcessorCpuLoadBetweenTicks() {
 		// Check if > ~ 0.95 seconds since last tick count.
 		long now = System.currentTimeMillis();
 		if (now - procTickTime > 950) {
 			// Enough time has elapsed. Update array in place
 			updateProcessorTicks();
 			// Copy arrays in place
 			System.arraycopy(curProcTicks, 0, prevProcTicks, 0,
 					curProcTicks.length);
 			System.arraycopy(allProcessorTicks[processorNumber], 0,
 					curProcTicks, 0, curProcTicks.length);
 			procTickTime = now;
 		}
 		long total = 0;
 		for (int i = 0; i < curProcTicks.length; i++) {
 			total += (curProcTicks[i] - prevProcTicks[i]);
 		}
 		// Calculate idle from last field [3]
 		long idle = curProcTicks[3] - prevProcTicks[3];
 		// update
 		return (total > 0 && idle >= 0) ? (double) (total - idle) / total : 0d;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	public long[] getProcessorCpuLoadTicks() {
 		updateProcessorTicks();
 		return allProcessorTicks[processorNumber];
 	}
 
 	/**
 	 * Updates the tick array for all processors if more than 100ms has elapsed
 	 * since the last update. This permits using the allProcessorTicks as a
 	 * cache when iterating over processors since pdh query updates all counters
 	 * at once so we can't separate individual processors
 	 */
 	private void updateProcessorTicks() {
 		// Update no more frequently than 100ms so this is only triggered once
 		// during iteration over Processors
 		long now = System.currentTimeMillis();
 		if (now - allProcTickTime < 100)
 			return;
 
 		// This call updates all process counters to % used since last call
 		int ret = Pdh.INSTANCE.PdhCollectQueryData(phQuery.getValue());
 		if (ret != 0)
 			throw new LastErrorException(
 					"Cannot collect PDH query data. Error code: "
 							+ String.format("0x%08X", ret));
 		// Multiply % usage times elapsed MS to recreate ticks, then increment
 		long elapsed = now - allProcTickTime;
 		for (int cpu = 0; cpu < numCPU; cpu++) {
 			PdhFmtCounterValue phUserCounterValue = new PdhFmtCounterValue();
 			ret = Pdh.INSTANCE.PdhGetFormattedCounterValue(
 					phUserCounters[cpu].getValue(), Pdh.PDH_FMT_LARGE
 							| Pdh.PDH_FMT_1000, null, phUserCounterValue);
 			if (ret != 0)
 				throw new LastErrorException(
 						"Cannot get PDH User % counter value. Error code: "
 								+ String.format("0x%08X", ret));
 
 			PdhFmtCounterValue phIdleCounterValue = new PdhFmtCounterValue();
 			ret = Pdh.INSTANCE.PdhGetFormattedCounterValue(
 					phIdleCounters[cpu].getValue(), Pdh.PDH_FMT_LARGE
 							| Pdh.PDH_FMT_1000, null, phIdleCounterValue);
 			if (ret != 0)
 				throw new LastErrorException(
 						"Cannot get PDH Idle % counter value. Error code: "
 								+ String.format("0x%08X", ret));
 
 			// Returns results in 1000's of percent, e.g. 5% is 5000
 			// Multiply by elapsed to get total ms and Divide by 100 * 1000
 			// Putting division at end avoids need to cast division to double
 			long user = elapsed * phUserCounterValue.value.largeValue / 100000;
 			long idle = elapsed * phIdleCounterValue.value.largeValue / 100000;
 			// Elasped is only since last read, so increment previous value
 			allProcessorTicks[cpu][0] += user;
 			// allProcessorTicks[cpu][1] is ignored, Windows is not nice
 			allProcessorTicks[cpu][2] += (elapsed - user - idle); // u+i+sys=100%
 			allProcessorTicks[cpu][3] += idle;
 		}
 		allProcTickTime = now;
 	}
 
 	@Override
 	public String toString() {
 		return getName();
 	}
 }