/*
    * Copyright 2021-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.hardware.platform.unix.openbsd;
   
   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.tuples.Triplet;
  
  /**
   * Memory info on OpenBSD
   */
  @ThreadSafe
  final class OpenBsdVirtualMemory extends AbstractVirtualMemory {
  
      private final OpenBsdGlobalMemory global;
  
      private final Supplier<Triplet<Integer, Integer, Integer>> usedTotalPgin = memoize(
              OpenBsdVirtualMemory::queryVmstat, defaultExpiration());
      private final Supplier<Integer> pgout = memoize(OpenBsdVirtualMemory::queryUvm, defaultExpiration());
  
      OpenBsdVirtualMemory(OpenBsdGlobalMemory freeBsdGlobalMemory) {
          this.global = freeBsdGlobalMemory;
      }
  
      @Override
      public long getSwapUsed() {
          return usedTotalPgin.get().getA() * global.getPageSize();
      }
  
      @Override
      public long getSwapTotal() {
          return usedTotalPgin.get().getB() * global.getPageSize();
      }
  
      @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 usedTotalPgin.get().getC() * global.getPageSize();
      }
  
      @Override
      public long getSwapPagesOut() {
          return pgout.get() * global.getPageSize();
      }
  
      private static Triplet<Integer, Integer, Integer> queryVmstat() {
          int used = 0;
          int total = 0;
          int swapIn = 0;
          for (String line : ExecutingCommand.runNative("vmstat -s")) {
              if (line.contains("swap pages in use")) {
                  used = ParseUtil.getFirstIntValue(line);
              } else if (line.contains("swap pages")) {
                  total = ParseUtil.getFirstIntValue(line);
              } else if (line.contains("pagein operations")) {
                  swapIn = ParseUtil.getFirstIntValue(line);
              }
          }
          return new Triplet<>(used, total, swapIn);
      }
  
      private static int queryUvm() {
          for (String line : ExecutingCommand.runNative("systat -ab uvm")) {
              if (line.contains("pdpageouts")) {
                  // First column is non-numeric "Constants" header
                  return ParseUtil.getFirstIntValue(line);
              }
          }
          return 0;
      }
  }