#include "ProcessCwd.h"

#ifdef __APPLE__
#include <libproc.h>
#elifdef __linux__
#include <unistd.h>
#include <cerrno>
#include <filesystem>
#endif

#ifdef __APPLE__

QString processCwd(qint64 pid) {
  if (pid <= 0) {
    return {};
  }
  struct proc_vnodepathinfo info{};
  const int ret = proc_pidinfo(static_cast<int>(pid), PROC_PIDVNODEPATHINFO, 0,
                               &info, sizeof(info));
  if (ret != sizeof(info)) {
    return {};
  }
  const char* path = info.pvi_cdir.vip_path;
  if (path[0] == '\0') {
    return {};
  }
  return QString::fromLocal8Bit(path);
}

#elifdef __linux__

QString processCwd(qint64 pid) {
  if (pid <= 0) {
    return {};
  }
  std::error_code ec;
  const std::filesystem::path link = std::filesystem::read_symlink(
      "/proc/" + std::to_string(pid) + "/cwd", ec);
  if (ec) {
    return {};
  }
  const std::string path = link.string();
  if (path.empty()) {
    return {};
  }
  return QString::fromLocal8Bit(path.data(),
                               static_cast<qsizetype>(path.size()));
}

#else

QString processCwd(qint64 pid) {
  Q_UNUSED(pid);
  return {};
}

#endif