package system_check

import (
	"log"
	"unsafe"

	"golang.org/x/sys/windows"
)

type memoryStatusEx struct {
	/*
	 * Struct for storing memory status information.
	 *
	 * It gets populated via syscall.
	 */
	dwLength                uint32
	dwMemoryLoad            uint32
	ullTotalPhys            uint64
	ullAvailPhys            uint64
	ullTotalPageFile        uint64
	ullAvailPageFile        uint64
	ullTotalVirtual         uint64
	ullAvailVirtual         uint64
	ullAvailExtendedVirtual uint64
}

func getWinRamInfo(procGlobalMemoryStatusEx *windows.LazyProc) MemoryInformation {
	var mem memoryStatusEx

	// * Windows requires the dwLength field to be set to the struct's size
	// * before execution so it knows which OS struct version is being used.
	mem.dwLength = uint32(unsafe.Sizeof(mem))

	ret, _, err := procGlobalMemoryStatusEx.Call(uintptr(unsafe.Pointer(&mem))) // exec syscall

	if ret == 0 { // winapi syscalls return 0 on failure
		log.Fatalf("GlobalMemoryStatusEx failed: %v", err)
	}

	return MemoryInformation{
		SystemMemory:    mem.ullTotalPhys,
		AvailableMemory: mem.ullAvailPhys,
	}
}