//go:build windows

package main

import (
	"bytes"
	"encoding/base64"
	"fmt"
	"os"
	"os/exec"
	"strings"
)

// Common file dialog (WinForms SaveFileDialog) owned by an invisible topmost
// form so it appears above the printing app. OverwritePrompt asks before
// replacing an existing file.
const saveDialogPS = `
$ErrorActionPreference = 'Stop'
Add-Type -AssemblyName System.Windows.Forms
[Windows.Forms.Application]::EnableVisualStyles()
function D($v) { [Text.Encoding]::UTF8.GetString([Convert]::FromBase64String($v)) }
$d = New-Object Windows.Forms.SaveFileDialog
$d.Title = 'Save timestamped print as'
$d.Filter = 'PDF files (*.pdf)|*.pdf'
$d.DefaultExt = 'pdf'
$d.AddExtension = $true
$d.OverwritePrompt = $true
$d.CheckPathExists = $true
$d.InitialDirectory = D $env:VERAE_SAVE_DIR
$d.FileName = D $env:VERAE_SAVE_NAME
$o = New-Object Windows.Forms.Form
$o.TopMost = $true
$o.ShowInTaskbar = $false
$o.FormBorderStyle = 'None'
$o.StartPosition = 'CenterScreen'
$o.Size = New-Object Drawing.Size(1, 1)
$o.Opacity = 0
$o.Show()
$o.Activate()
$r = $d.ShowDialog($o)
$o.Close()
if ($r -eq [Windows.Forms.DialogResult]::OK) { 'ok|' + [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes($d.FileName)) } else { 'cancel' }
`

func nativeSaveDialog(name, dir string) (string, bool, error) {
	cmd := exec.Command("powershell.exe", "-NoProfile", "-NonInteractive", "-STA", "-ExecutionPolicy", "Bypass", "-WindowStyle", "Hidden", "-Command", saveDialogPS)
	cmd.Env = append(os.Environ(), "VERAE_SAVE_NAME="+b64(name), "VERAE_SAVE_DIR="+b64(dir))
	hideWindow(cmd)
	var out, errb bytes.Buffer
	cmd.Stdout, cmd.Stderr = &out, &errb
	if err := cmd.Run(); err != nil {
		return "", false, fmt.Errorf("%v: %s", err, strings.TrimSpace(errb.String()))
	}
	s := strings.TrimSpace(out.String())
	if s == "cancel" {
		return "", false, nil
	}
	if !strings.HasPrefix(s, "ok|") {
		return "", false, fmt.Errorf("unexpected dialog output")
	}
	p, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(s, "ok|"))
	if err != nil || len(p) == 0 {
		return "", false, fmt.Errorf("bad dialog output")
	}
	return string(p), true, nil
}