/*
htop - darwin/PlatformHelpers.c
(C) 2018 Pierre Malhaire, 2020-2021 htop dev team, 2021 Alexander Momchilov
Released under the GNU GPLv2+, see the COPYING file
in the source distribution for its full text.
*/

#include "darwin/PlatformHelpers.h"

#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/sysctl.h>

#include "CRT.h"

#ifdef HAVE_MACH_MACH_TIME_H
#include <mach/mach_time.h>
#endif


void Platform_GetKernelVersion(KernelVersion* k) {
   static KernelVersion cachedKernelVersion;

   if (!cachedKernelVersion.major) {
      // just in case it fails someday
      cachedKernelVersion = (KernelVersion) { -1, -1, -1 };
      char str[256] = {0};
      size_t size = sizeof(str);
      int ret = sysctlbyname("kern.osrelease", str, &size, NULL, 0);
      if (ret == 0) {
         sscanf(str, "%hd.%hd.%hd", &cachedKernelVersion.major, &cachedKernelVersion.minor, &cachedKernelVersion.patch);
      }
   }
   memcpy(k, &cachedKernelVersion, sizeof(cachedKernelVersion));
}

int Platform_CompareKernelVersion(KernelVersion v) {
   struct KernelVersion actualVersion;
   Platform_GetKernelVersion(&actualVersion);

   if (actualVersion.major != v.major) {
      return actualVersion.major - v.major;
   }
   if (actualVersion.minor != v.minor) {
      return actualVersion.minor - v.minor;
   }
   if (actualVersion.patch != v.patch) {
      return actualVersion.patch - v.patch;
   }

   return 0;
}

bool Platform_KernelVersionIsBetween(KernelVersion lowerBound, KernelVersion upperBound) {
   return 0 <= Platform_CompareKernelVersion(lowerBound)
      && Platform_CompareKernelVersion(upperBound) < 0;
}

double Platform_calculateNanosecondsPerMachTick() {
   // Check if we can determine the timebase used on this system.
   // If the API is unavailable assume we get our timebase in nanoseconds.
#ifdef HAVE_MACH_TIMEBASE_INFO
   mach_timebase_info_data_t info;
   mach_timebase_info(&info);
   return (double)info.numer / (double)info.denom;
#else
   return 1.0;
#endif
}