//go:build windows

package main

import (
	"fmt"
	"runtime"
	"unsafe"

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

// showTestWindow displays a native Win32 MessageBox with build info.
// The intent is to give end-users a visual smoke-test on first run:
// double-click drover.exe (or run `drover gui`) and see that:
//   1. the binary actually launches on Windows,
//   2. the embedded version metadata is correct,
//   3. the process can talk to user32.dll (i.e. the runtime is healthy).
//
// This is *not* the production GUI — that comes later via Wails. Here we
// purposely use only stdlib + golang.org/x/sys/windows so this works
// before any Wails/CGO machinery is wired up.
func showTestWindow() {
	user32 := windows.NewLazySystemDLL("user32.dll")
	messageBox := user32.NewProc("MessageBoxW")

	body := fmt.Sprintf(
		"Drover-Go v%s\n\n"+
			"Commit:   %s\n"+
			"Build:    %s\n"+
			"Go:       %s\n"+
			"Arch:     %s/%s\n\n"+
			"OK — the binary launched and the Windows API is reachable.",
		Version, Commit, BuildDate, runtime.Version(), runtime.GOOS, runtime.GOARCH,
	)
	title := fmt.Sprintf("Drover-Go v%s — test window", Version)

	bodyW, _ := windows.UTF16PtrFromString(body)
	titleW, _ := windows.UTF16PtrFromString(title)

	// MB_OK | MB_ICONINFORMATION | MB_SETFOREGROUND | MB_TOPMOST
	// MB_TOPMOST is essential — without it the message box can pop up
	// behind other windows and the user thinks nothing happened.
	const flags = 0x00000000 | 0x00000040 | 0x00010000 | 0x00040000

	messageBox.Call(
		0,
		uintptr(unsafe.Pointer(bodyW)),
		uintptr(unsafe.Pointer(titleW)),
		flags,
	)
}
