package zenity

import (
	"encoding/xml"
	"math/rand"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"syscall"
	"text/template"
	"time"
	"unsafe"

	"github.com/ncruces/zenity/internal/win"
	"github.com/ncruces/zenity/internal/zenutil"
)

func notify(text string, opts options) error {
	if opts.ctx != nil && opts.ctx.Err() != nil {
		return opts.ctx.Err()
	}

	file, err := os.CreateTemp("", "*.ps1")
	if err != nil {
		return err
	}
	defer os.Remove(file.Name())

	data := struct {
		Title string
		Text  string
		Icon  string
	}{
		Title: "zenity",
		Text:  text,
	}

	if opts.title != nil {
		data.Title = *opts.title
	}

	if i, ok := opts.icon.(string); ok {
		_, err := os.Stat(i)
		if err != nil {
			return err
		}
		data.Icon, err = filepath.Abs(i)
		if err != nil {
			return err
		}
	}

	err = script.Execute(file, data)
	if err != nil {
		return err
	}
	err = file.Close()
	if err != nil {
		return err
	}

	var cmd *exec.Cmd
	if opts.ctx != nil {
		cmd = exec.CommandContext(opts.ctx, "PowerShell", "-ExecutionPolicy", "Bypass", "-File", file.Name())
	} else {
		cmd = exec.Command("PowerShell", "-ExecutionPolicy", "Bypass", "-File", file.Name())
	}
	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
	err = cmd.Run()

	if opts.ctx != nil && opts.ctx.Err() != nil {
		return opts.ctx.Err()
	}
	if err != nil {
		return shellNotify(text, opts)
	}
	return nil
}

func shellNotify(text string, opts options) error {
	var args win.NOTIFYICONDATA
	args.StructSize = uint32(unsafe.Sizeof(args))
	args.ID = rand.Uint32()
	args.Flags = win.NIF_INFO
	args.State = win.NIS_HIDDEN

	info := syscall.StringToUTF16(text)
	copy(args.Info[:len(args.Info)-1], info)

	if opts.title != nil {
		title := syscall.StringToUTF16(*opts.title)
		copy(args.InfoTitle[:len(args.InfoTitle)-1], title)
	}

	switch opts.icon {
	case InfoIcon, QuestionIcon:
		args.InfoFlags |= win.NIIF_INFO
	case WarningIcon:
		args.InfoFlags |= win.NIIF_WARNING
	case ErrorIcon:
		args.InfoFlags |= win.NIIF_ERROR
	default:
		icon, _ := getIcon(opts.icon)
		if icon.handle != 0 {
			defer icon.delete()
			args.Icon = icon.handle
			args.Flags |= win.NIF_ICON
			args.InfoFlags |= win.NIIF_USER
		}
	}

	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	if !win.ShellNotifyIcon(win.NIM_ADD, &args) {
		return wtsMessage(text, opts)
	}

	major, minor, _ := win.RtlGetNtVersionNumbers()
	// On Windows 7 (6.1) and lower, wait up to 10 seconds to clean up.
	if major < 6 || major == 6 && minor < 2 {
		if opts.ctx != nil {
			select {
			case <-opts.ctx.Done():
			case <-time.After(10 * time.Second):
			}
		} else {
			time.Sleep(10 * time.Second)
		}
	}

	win.ShellNotifyIcon(win.NIM_DELETE, &args)
	return nil
}

func wtsMessage(text string, opts options) error {
	var flags uint32

	switch opts.icon {
	case ErrorIcon:
		flags |= win.MB_ICONERROR
	case QuestionIcon:
		flags |= win.MB_ICONQUESTION
	case WarningIcon:
		flags |= win.MB_ICONWARNING
	case InfoIcon:
		flags |= win.MB_ICONINFORMATION
	}

	title := opts.title
	if title == nil {
		title = ptr("Notification")
	}

	timeout := zenutil.Timeout
	if timeout == 0 {
		timeout = 10
	}

	ptext := syscall.StringToUTF16(text)
	ptitle := syscall.StringToUTF16(*title)

	var res uint32
	return win.WTSSendMessage(
		win.WTS_CURRENT_SERVER_HANDLE, win.WTS_CURRENT_SESSION,
		&ptitle[0], 2*len(ptitle), &ptext[0], 2*len(ptext),
		flags, timeout, &res, false)
}

var script = template.Must(template.New("").Funcs(template.FuncMap{"xml": func(s string) string {
	var buf strings.Builder
	xml.EscapeText(&buf, []byte(s))
	return buf.String()
}}).Parse("\xEF\xBB\xBF" + `
[Windows.UI.Notifications.ToastNotificationManager, Windows.UI.Notifications, ContentType = WindowsRuntime]
[Windows.UI.Notifications.ToastNotification, Windows.UI.Notifications, ContentType = WindowsRuntime]
[Windows.Data.Xml.Dom.XmlDocument, Windows.Data.Xml.Dom.XmlDocument, ContentType = WindowsRuntime]

$title = @"
{{.Title}}
"@

$data = @"
<toast activationType="protocol">
 <visual>
  <binding template="ToastGeneric">
   {{- if .Text}}
    <text><![CDATA[{{.Text}}]]></text>
   {{- end}}
   {{- if .Icon}}
    <image placement="appLogoOverride" src="{{xml .Icon}}" />
   {{- end}}
  </binding>
 </visual>
 <audio src="ms-winsoundevent:Notification.Default" />
</toast>
"@

$xml = New-Object Windows.Data.Xml.Dom.XmlDocument
$xml.LoadXml($data)

$toast = New-Object Windows.UI.Notifications.ToastNotification $xml
[Windows.UI.Notifications.ToastNotificationManager]::CreateToastNotifier($title).Show($toast)
`))