//go:build windows

package update

import (
	"sync"
	"unsafe"

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

const (
	appModelErrorNoPackage   = 15700 // APPMODEL_ERROR_NO_PACKAGE
	errorInsufficientBuffer  = 122   // ERROR_INSUFFICIENT_BUFFER
)

var (
	storeOnce     sync.Once
	storePackaged bool
)

// IsStorePackaged reports whether this process has an MSIX / Store package identity.
// Store builds must not self-update (Store owns updates).
func IsStorePackaged() bool {
	storeOnce.Do(func() {
		storePackaged = detectStorePackage()
	})
	return storePackaged
}

func detectStorePackage() bool {
	mod := windows.NewLazySystemDLL("kernel32.dll")
	proc := mod.NewProc("GetCurrentPackageFullName")
	if err := proc.Find(); err != nil {
		return false
	}
	var n uint32
	r, _, _ := proc.Call(uintptr(unsafe.Pointer(&n)), 0)
	switch r {
	case appModelErrorNoPackage:
		return false
	case errorInsufficientBuffer:
		return true
	case 0:
		return n > 0
	default:
		return false
	}
}