Core: add a local yaml creator GUI (#4900)

Adds a GUI for the creation of simple yamls (no weighting) locally.

Utils.py

@@ -751,6 +751,11 @@ def _mp_open_filename(res: "multiprocessing.Queue[typing.Optional[str]]", *args:
     res.put(open_filename(*args))
 
 
+def _mp_save_filename(res: "multiprocessing.Queue[typing.Optional[str]]", *args: Any) -> None:
+    if is_kivy_running():
+        raise RuntimeError("kivy should not be running in multiprocess")
+    res.put(save_filename(*args))
+    
 def _run_for_stdout(*args: str):
     env = os.environ
     if "LD_LIBRARY_PATH" in env:
@@ -801,6 +806,51 @@ def open_filename(title: str, filetypes: typing.Iterable[typing.Tuple[str, typin
                                                   initialfile=suggest or None)
 
 
+def save_filename(title: str, filetypes: typing.Iterable[typing.Tuple[str, typing.Iterable[str]]], suggest: str = "") \
+        -> typing.Optional[str]:
+    logging.info(f"Opening file save dialog for {title}.")
+
+    def run(*args: str):
+        return subprocess.run(args, capture_output=True, text=True).stdout.split("\n", 1)[0] or None
+
+    if is_linux:
+        # prefer native dialog
+        from shutil import which
+        kdialog = which("kdialog")
+        if kdialog:
+            k_filters = '|'.join((f'{text} (*{" *".join(ext)})' for (text, ext) in filetypes))
+            return run(kdialog, f"--title={title}", "--getsavefilename", suggest or ".", k_filters)
+        zenity = which("zenity")
+        if zenity:
+            z_filters = (f'--file-filter={text} ({", ".join(ext)}) | *{" *".join(ext)}' for (text, ext) in filetypes)
+            selection = (f"--filename={suggest}",) if suggest else ()
+            return run(zenity, f"--title={title}", "--file-selection", "--save", *z_filters, *selection)
+
+    # fall back to tk
+    try:
+        import tkinter
+        import tkinter.filedialog
+    except Exception as e:
+        logging.error('Could not load tkinter, which is likely not installed. '
+                      f'This attempt was made because save_filename was used for "{title}".')
+        raise e
+    else:
+        if is_macos and is_kivy_running():
+            # on macOS, mixing kivy and tk does not work, so spawn a new process
+            # FIXME: performance of this is pretty bad, and we should (also) look into alternatives
+            from multiprocessing import Process, Queue
+            res: "Queue[typing.Optional[str]]" = Queue()
+            Process(target=_mp_save_filename, args=(res, title, filetypes, suggest)).start()
+            return res.get()
+        try:
+            root = tkinter.Tk()
+        except tkinter.TclError:
+            return None  # GUI not available. None is the same as a user clicking "cancel"
+        root.withdraw()
+        return tkinter.filedialog.asksaveasfilename(title=title, filetypes=((t[0], ' '.join(t[1])) for t in filetypes),
+                                                    initialfile=suggest or None)
+
+
 def _mp_open_directory(res: "multiprocessing.Queue[typing.Optional[str]]", *args: Any) -> None:
     if is_kivy_running():
         raise RuntimeError("kivy should not be running in multiprocess")