From 77da6e29f388c101bf782c3f67e569a112c51e92 Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@users.noreply.github.com>
Date: Wed, 7 Feb 2024 13:00:08 +0000
Subject: [PATCH] Use IFileSaveDialog where available.

---
 file_windows.go         | 84 +++++++++++++++++++++++++++++++++++++++++
 internal/win/shell32.go | 12 ++++++
 2 files changed, 96 insertions(+)

diff --git a/file_windows.go b/file_windows.go
index c730cfd..478b42a 100644
--- a/file_windows.go
+++ b/file_windows.go
@@ -130,6 +130,10 @@ func selectFileMultiple(opts options) ([]string, error) {
 }
 
 func selectFileSave(opts options) (string, error) {
+	name, shown, err := fileSaveDialog(opts)
+	if shown || opts.ctx != nil && opts.ctx.Err() != nil {
+		return name, err
+	}
 	if opts.directory {
 		return selectFile(opts)
 	}
@@ -280,6 +284,86 @@ func fileOpenDialog(opts options, multi bool) (string, []string, bool, error) {
 	}
 }
 
+func fileSaveDialog(opts options) (string, bool, error) {
+	uninit, err := coInitialize()
+	if err != nil {
+		return "", false, err
+	}
+	defer uninit()
+
+	owner, _ := opts.attach.(win.HWND)
+	defer setup(owner)()
+
+	var dialog *win.IFileSaveDialog
+	err = win.CoCreateInstance(
+		win.CLSID_FileSaveDialog, nil, win.CLSCTX_ALL,
+		win.IID_IFileSaveDialog, unsafe.Pointer(&dialog))
+	if err != nil {
+		return "", false, err
+	}
+	defer dialog.Release()
+
+	flgs, err := dialog.GetOptions()
+	if err != nil {
+		return "", false, err
+	}
+	flgs |= win.FOS_NOCHANGEDIR | win.FOS_PATHMUSTEXIST | win.FOS_NOREADONLYRETURN | win.FOS_FORCEFILESYSTEM
+	if opts.confirmOverwrite {
+		flgs |= win.FOS_OVERWRITEPROMPT
+	}
+	if opts.confirmCreate {
+		flgs |= win.FOS_CREATEPROMPT
+	}
+	if opts.showHidden {
+		flgs |= win.FOS_FORCESHOWHIDDEN
+	}
+	err = dialog.SetOptions(flgs)
+	if err != nil {
+		return "", false, err
+	}
+
+	if opts.title != nil {
+		dialog.SetTitle(strptr(*opts.title))
+	}
+
+	if opts.filename != "" {
+		var item *win.IShellItem
+		dir, name, _ := splitDirAndName(opts.filename)
+		dialog.SetFileName(strptr(name))
+		if ext := filepath.Ext(name); len(ext) > 1 {
+			dialog.SetDefaultExtension(strptr(ext[1:]))
+		}
+		win.SHCreateItemFromParsingName(strptr(dir), nil, win.IID_IShellItem, &item)
+		if item != nil {
+			defer item.Release()
+			dialog.SetFolder(item)
+		}
+	}
+
+	unhook, err := hookDialog(opts.ctx, opts.windowIcon, nil, nil)
+	if err != nil {
+		return "", false, err
+	}
+	defer unhook()
+
+	err = dialog.Show(owner)
+	if opts.ctx != nil && opts.ctx.Err() != nil {
+		return "", true, opts.ctx.Err()
+	}
+	if err == win.E_CANCELED {
+		return "", true, ErrCanceled
+	}
+	if err != nil {
+		return "", true, err
+	}
+
+	str, err := shellItemPath(dialog.GetResult())
+	if err != nil {
+		return "", true, err
+	}
+	return str, true, nil
+}
+
 func shellItemPath(item *win.IShellItem, err error) (string, error) {
 	if err != nil {
 		return "", err
diff --git a/internal/win/shell32.go b/internal/win/shell32.go
index 04597a3..af187d7 100644
--- a/internal/win/shell32.go
+++ b/internal/win/shell32.go
@@ -123,7 +123,9 @@ type IDLIST struct{}
 var (
 	IID_IShellItem       = guid("\x1e\x6d\x82\x43\x18\xe7\xee\x42\xbc\x55\xa1\xe2\x61\xc3\x7b\xfe")
 	IID_IFileOpenDialog  = guid("\x88\x72\x7c\xd5\xad\xd4\x68\x47\xbe\x02\x9d\x96\x95\x32\xd9\x60")
+	IID_IFileSaveDialog  = guid("\x23\xcd\xbc\x84\xde\x5f\xdb\x4c\xae\xa4\xaf\x64\xb8\x3d\x78\xab")
 	CLSID_FileOpenDialog = guid("\x9c\x5a\x1c\xdc\x8a\xe8\xde\x4d\xa5\xa1\x60\xf8\x2a\x20\xae\xf7")
+	CLSID_FileSaveDialog = guid("\xf3\xe2\xb4\xc0\x21\xba\x73\x47\x8d\xba\x33\x5e\xc9\x46\xeb\x8b")
 )
 
 type IFileOpenDialog struct{ IFileDialog }
@@ -142,6 +144,16 @@ func (u *IFileOpenDialog) GetResults() (res *IShellItemArray, err error) {
 	return
 }
 
+type IFileSaveDialog struct{ IFileDialog }
+type IFileSaveDialogVtbl struct {
+	iFileDialogVtbl
+	SetSaveAsItem          uintptr
+	SetProperties          uintptr
+	SetCollectedProperties uintptr
+	GetProperties          uintptr
+	ApplyProperties        uintptr
+}
+
 type IFileDialog struct{ IModalWindow }
 type iFileDialogVtbl struct {
 	iModalWindowVtbl