//go:build windows

package memory

import (
	"log"
	"unsafe"

	"rpi5-health/internal/windows_system"

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

type DWORD uint32
type DWORDLONG uint64

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

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 = DWORD(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:    uint64(mem.ullTotalPhys),
		AvailableMemory: uint64(mem.ullAvailPhys),
	}
}

func GetRamInformation() (MemoryInformation, error) {
	return getWinRamInfo(windows_system.GetWindowsTools().ProcGlobalMemoryStatusEx), nil
}