package com.guinetik.hexafun.examples.sysmon;
   
   import oshi.SystemInfo;
   import oshi.hardware.CentralProcessor;
   import oshi.hardware.GlobalMemory;
   import oshi.software.os.OSFileStore;
   
   import java.util.List;
   
  /**
   * Cross-platform metrics provider using OSHI library.
   *
   * <p>OSHI (Operating System and Hardware Information) provides native
   * access to system metrics on Windows, Linux, macOS, and other platforms
   * without JNI dependencies.</p>
   *
   * <p>This implementation includes WSL compatibility fixes.</p>
   */
  public class OshiMetricsProvider implements MetricsProvider {
  
      private final SystemInfo si = new SystemInfo();
      private final CentralProcessor cpu = si.getHardware().getProcessor();
      private final GlobalMemory memory = si.getHardware().getMemory();
      private long[] prevTicks;
  
      public OshiMetricsProvider() {
          // Prime the CPU tick counter - first reading needs baseline
          prevTicks = cpu.getSystemCpuLoadTicks();
          try {
              Thread.sleep(100); // Brief pause to get meaningful delta
          } catch (InterruptedException ignored) {}
          prevTicks = cpu.getSystemCpuLoadTicks();
      }
  
      @Override
      public double getCpuUsage() {
          double load = cpu.getSystemCpuLoadBetweenTicks(prevTicks) * 100;
          prevTicks = cpu.getSystemCpuLoadTicks();
          return Math.max(0, Math.min(100, load)); // Clamp to 0-100
      }
  
      @Override
      public double getMemoryUsage() {
          long total = memory.getTotal();
          long available = memory.getAvailable();
          if (total <= 0) return 0;
          return ((double) (total - available) / total) * 100.0;
      }
  
      @Override
      public double getDiskUsage() {
          var fs = si.getOperatingSystem().getFileSystem();
          List<OSFileStore> stores = fs.getFileStores();
          if (stores.isEmpty()) return 0;
  
          // Find the best disk: prefer root "/" or "C:" over virtual mounts
          OSFileStore best = stores.get(0);
          long bestSize = 0;
  
          for (OSFileStore store : stores) {
              String mount = store.getMount();
              long total = store.getTotalSpace();
  
              // Skip virtual/empty filesystems
              if (total <= 0) continue;
  
              // Prefer root mounts
              if ("/".equals(mount) || mount.matches("[A-Z]:\\\\")) {
                  best = store;
                  break;
              }
  
              // Otherwise pick the largest real filesystem
              if (total > bestSize && !mount.startsWith("/snap") && !mount.startsWith("/boot")) {
                  best = store;
                  bestSize = total;
              }
          }
  
          long total = best.getTotalSpace();
          long usable = best.getUsableSpace();
          if (total <= 0) return 0;
          return ((double) (total - usable) / total) * 100.0;
      }
  }