/*
    * Copyright 2019-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.hardware.platform.unix.freebsd;
   
   import static oshi.util.Memoizer.defaultExpiration;
   import static oshi.util.Memoizer.memoize;
   
  import java.util.function.Supplier;
  
  import oshi.annotation.concurrent.ThreadSafe;
  import oshi.hardware.common.AbstractVirtualMemory;
  import oshi.util.ExecutingCommand;
  import oshi.util.ParseUtil;
  import oshi.util.platform.unix.freebsd.BsdSysctlUtil;
  
  /**
   * Memory obtained by swapinfo
   */
  @ThreadSafe
  final class FreeBsdVirtualMemory extends AbstractVirtualMemory {
  
      private final FreeBsdGlobalMemory global;
  
      private final Supplier<Long> used = memoize(FreeBsdVirtualMemory::querySwapUsed, defaultExpiration());
  
      private final Supplier<Long> total = memoize(FreeBsdVirtualMemory::querySwapTotal, defaultExpiration());
  
      private final Supplier<Long> pagesIn = memoize(FreeBsdVirtualMemory::queryPagesIn, defaultExpiration());
  
      private final Supplier<Long> pagesOut = memoize(FreeBsdVirtualMemory::queryPagesOut, defaultExpiration());
  
      FreeBsdVirtualMemory(FreeBsdGlobalMemory freeBsdGlobalMemory) {
          this.global = freeBsdGlobalMemory;
      }
  
      @Override
      public long getSwapUsed() {
          return used.get();
      }
  
      @Override
      public long getSwapTotal() {
          return total.get();
      }
  
      @Override
      public long getVirtualMax() {
          return this.global.getTotal() + getSwapTotal();
      }
  
      @Override
      public long getVirtualInUse() {
          return this.global.getTotal() - this.global.getAvailable() + getSwapUsed();
      }
  
      @Override
      public long getSwapPagesIn() {
          return pagesIn.get();
      }
  
      @Override
      public long getSwapPagesOut() {
          return pagesOut.get();
      }
  
      private static long querySwapUsed() {
          String swapInfo = ExecutingCommand.getAnswerAt("swapinfo -k", 1);
          String[] split = ParseUtil.whitespaces.split(swapInfo);
          if (split.length < 5) {
              return 0L;
          }
          return ParseUtil.parseLongOrDefault(split[2], 0L) << 10;
      }
  
      private static long querySwapTotal() {
          return BsdSysctlUtil.sysctl("vm.swap_total", 0L);
      }
  
      private static long queryPagesIn() {
          return BsdSysctlUtil.sysctl("vm.stats.vm.v_swappgsin", 0L);
      }
  
      private static long queryPagesOut() {
          return BsdSysctlUtil.sysctl("vm.stats.vm.v_swappgsout", 0L);
      }
  }