#include <node_version.h>

#if NODE_VERSION_AT_LEAST(0, 11, 1) && !defined(_MSC_VER)
#include <sys/types.h>
#endif

#include <errno.h>

#include <nan.h>

#if defined(_MSC_VER)
#include <time.h>
#include <windows.h>

// Pick GetSystemTimePreciseAsFileTime or GetSystemTimeAsFileTime depending
// on which is available at runtime.
typedef VOID(WINAPI *WinGetSystemTime)(LPFILETIME);
static WinGetSystemTime getSystemTime = NULL;

struct timezone {
  int tz_minuteswest;
  int tz_dsttime;
};

int gettimeofday(struct timeval *tv, struct timezone *tz) {
  FILETIME ft;
  (*getSystemTime)(&ft);
  unsigned long long t = ft.dwHighDateTime;
  t <<= 32;
  t |= ft.dwLowDateTime;
  t /= 10;
  t -= 11644473600000000ULL;
  tv->tv_sec = (long)(t / 1000000UL);
  tv->tv_usec = (long)(t % 1000000UL);

  return 0;
}
#else
#include <sys/time.h>
#endif

void Now(const Nan::FunctionCallbackInfo<v8::Value> &info) {
  timeval t;
  int r = gettimeofday(&t, NULL);

  if (r < 0) {
    return Nan::ThrowError(Nan::ErrnoException(errno, "gettimeofday"));
  }

  info.GetReturnValue().Set(
      Nan::New<v8::Number>((t.tv_sec * 1000000.0) + t.tv_usec));
}

void NowDouble(const Nan::FunctionCallbackInfo<v8::Value> &info) {
  timeval t;
  int r = gettimeofday(&t, NULL);

  if (r < 0) {
    return Nan::ThrowError(Nan::ErrnoException(errno, "gettimeofday"));
  }

  info.GetReturnValue().Set(
      Nan::New<v8::Number>(t.tv_sec + (t.tv_usec * 0.000001)));
}

void NowStruct(const Nan::FunctionCallbackInfo<v8::Value> &info) {
  timeval t;
  int r = gettimeofday(&t, NULL);

  if (r < 0) {
    return Nan::ThrowError(Nan::ErrnoException(errno, "gettimeofday"));
  }

  v8::Local<v8::Array> array = Nan::New<v8::Array>(2);
  array->Set(Nan::New<v8::Integer>(0), Nan::New<v8::Number>((double)t.tv_sec));
  array->Set(Nan::New<v8::Integer>(1), Nan::New<v8::Number>((double)t.tv_usec));

  info.GetReturnValue().Set(array);
}

NAN_MODULE_INIT(InitAll) {
  Nan::Export(target, "now", Now);
  Nan::Export(target, "nowDouble", NowDouble);
  Nan::Export(target, "nowStruct", NowStruct);

#if defined(_MSC_VER)
  getSystemTime = (WinGetSystemTime)GetProcAddress(
      GetModuleHandle(TEXT("kernel32.dll")), "GetSystemTimePreciseAsFileTime");
  if (getSystemTime == NULL) {
    getSystemTime = &GetSystemTimeAsFileTime;
  }
#endif
}

NODE_MODULE(microtime, InitAll)