/*
    * Copyright 2019-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.hardware.platform.windows;
   
   import static oshi.util.Memoizer.defaultExpiration;
   import static oshi.util.Memoizer.memoize;
   
  import java.util.Map;
  import java.util.function.Supplier;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.sun.jna.platform.win32.Kernel32;
  import com.sun.jna.platform.win32.Psapi;
  
  import oshi.annotation.concurrent.ThreadSafe;
  import oshi.driver.windows.perfmon.MemoryInformation;
  import oshi.driver.windows.perfmon.MemoryInformation.PageSwapProperty;
  import oshi.driver.windows.perfmon.PagingFile;
  import oshi.driver.windows.perfmon.PagingFile.PagingPercentProperty;
  import oshi.hardware.common.AbstractVirtualMemory;
  import oshi.jna.Struct.CloseablePerformanceInformation;
  import oshi.util.tuples.Pair;
  import oshi.util.tuples.Triplet;
  
  /**
   * Memory obtained from WMI
   */
  @ThreadSafe
  final class WindowsVirtualMemory extends AbstractVirtualMemory {
  
      private static final Logger LOG = LoggerFactory.getLogger(WindowsVirtualMemory.class);
  
      private final WindowsGlobalMemory global;
  
      private final Supplier<Long> used = memoize(WindowsVirtualMemory::querySwapUsed, defaultExpiration());
  
      private final Supplier<Triplet<Long, Long, Long>> totalVmaxVused = memoize(
              WindowsVirtualMemory::querySwapTotalVirtMaxVirtUsed, defaultExpiration());
  
      private final Supplier<Pair<Long, Long>> swapInOut = memoize(WindowsVirtualMemory::queryPageSwaps,
              defaultExpiration());
  
      /**
       * Constructor for WindowsVirtualMemory.
       *
       * @param windowsGlobalMemory The parent global memory class instantiating this
       */
      WindowsVirtualMemory(WindowsGlobalMemory windowsGlobalMemory) {
          this.global = windowsGlobalMemory;
      }
  
      @Override
      public long getSwapUsed() {
          return this.global.getPageSize() * used.get();
      }
  
      @Override
      public long getSwapTotal() {
          return this.global.getPageSize() * totalVmaxVused.get().getA();
      }
  
      @Override
      public long getVirtualMax() {
          return this.global.getPageSize() * totalVmaxVused.get().getB();
      }
  
      @Override
      public long getVirtualInUse() {
          return this.global.getPageSize() * totalVmaxVused.get().getC();
      }
  
      @Override
      public long getSwapPagesIn() {
          return swapInOut.get().getA();
      }
  
      @Override
      public long getSwapPagesOut() {
          return swapInOut.get().getB();
      }
  
      private static long querySwapUsed() {
          return PagingFile.querySwapUsed().getOrDefault(PagingPercentProperty.PERCENTUSAGE, 0L);
      }
  
      private static Triplet<Long, Long, Long> querySwapTotalVirtMaxVirtUsed() {
          try (CloseablePerformanceInformation perfInfo = new CloseablePerformanceInformation()) {
              if (!Psapi.INSTANCE.GetPerformanceInfo(perfInfo, perfInfo.size())) {
                  LOG.error("Failed to get Performance Info. Error code: {}", Kernel32.INSTANCE.GetLastError());
                  return new Triplet<>(0L, 0L, 0L);
              }
              return new Triplet<>(perfInfo.CommitLimit.longValue() - perfInfo.PhysicalTotal.longValue(),
                      perfInfo.CommitLimit.longValue(), perfInfo.CommitTotal.longValue());
          }
      }
 
     private static Pair<Long, Long> queryPageSwaps() {
         Map<PageSwapProperty, Long> valueMap = MemoryInformation.queryPageSwaps();
         return new Pair<>(valueMap.getOrDefault(PageSwapProperty.PAGESINPUTPERSEC, 0L),
                 valueMap.getOrDefault(PageSwapProperty.PAGESOUTPUTPERSEC, 0L));
     }
 }