package main

import (
	"log"
	"os"
	"syscall"
	"unsafe"
)

var (
	kernel32             = syscall.NewLazyDLL("kernel32.dll")
	globalMemoryStatusEx = kernel32.NewProc("GlobalMemoryStatusEx")
)

type globalMemoryStatusExT struct {
	dwLength     uint32
	dwMemoryLoad uint32
	ullTotalPhys uint64
	ullAvailPhys uint64
	unused       [5]uint64
}

func init() {
	if h, err := os.Hostname(); err != nil {
		log.Fatalf("error reading hostname: %s", err)
	} else {
		hostname = h
	}
}

func (s *applyState) populateLoadavg() {
	if s.loadavg != nil {
		return
	}

	// loadavg is unsupported on Windows
	s.loadavg = &[3]string{"0.00", "0.00", "0.00"}
}

func (s *applyState) populateMem() {
	if s.mem != nil {
		return
	}

	// failure defaults
	s.mem = &[2]int{-1, -1}

	v := new(globalMemoryStatusExT)
	v.dwLength = 64
	r1, _, err := globalMemoryStatusEx.Call(uintptr(unsafe.Pointer(v)))
	log.Printf("call to globalMemoryStatusEx, r1=%d, %s", r1, err)
	s.mem[0] = int(v.ullAvailPhys / (1 << 10))
	s.mem[1] = int(v.ullTotalPhys / (1 << 10))
}