fix: crash when menu of clone voices is empty

2 files changed, 58 insertions, 16 deletions

diff --git a/app/ui/hub.py b/app/ui/hub.py
index 6a82c83..80fe843 100644
--- a/app/ui/hub.py
+++ b/app/ui/hub.py
@@ -927,6 +927,13 @@ def _audiocpp_fields(stdscr, api_url: Optional[str] = None,
     the field keys ("" for the managed entry) so two entries of this
     backend can share one form without overwriting each other.
 
+    The Voice field tracks the selected entry's capability — built-in
+    speakers on CustomVoice, the server's clone voices on every other
+    entry. A clone-capable entry whose server lists no voices cannot be
+    picked from (empty menu) and refuses Generate! with a hint pointing
+    at the voice-clone .wav directory instead of crashing or producing a
+    run that fails at model-load time.
+
     With API_URL None (the managed entry) the model list is fed from the
     local checkout's server.json — the config of the server this tool
     manages. With API_URL set (the "[remote]" entry) the models and voices
@@ -1045,6 +1052,25 @@ def _audiocpp_fields(stdscr, api_url: Optional[str] = None,
                 fields, prefix + "model_id"))]
         return []  # design: the field is hidden
 
+    def no_voices_hint() -> str:
+        """Why a clone-capable entry has no selectable voices."""
+        if local:
+            return ("No .wav files available to clone — run Configure "
+                    "backends → audio.cpp and add voices to its "
+                    "voice-clone .wav directory.")
+        return ("No .wav files available to clone — the audio.cpp server "
+                f"at {url} hosts none. Configure its voice-clone .wav "
+                "directory on that machine.")
+
+    def voice_validate(value):
+        """Refuse Generate! when this entry's clone voice is unavailable."""
+        if model_capability(fields) != AUDIOCPP_VOICE_CLONE:
+            return None
+        if not voices_for(_field_value(fields, prefix + "model_id")):
+            return no_voices_hint()
+        return None if value \
+            else "This model needs a voice — pick one or switch models"
+
     model_ids = [m.get("id") for m in models]
     default_model = config.AUDIOCPP_MODEL_ID \
         if config.AUDIOCPP_MODEL_ID in model_ids else model_ids[0]
@@ -1080,9 +1106,8 @@ def _audiocpp_fields(stdscr, api_url: Optional[str] = None,
          "value": initial_voice,
          "choices": lambda fs: voice_choices(fs),
          "visible": lambda fs: model_capability(fs) != AUDIOCPP_VOICE_DESIGN,
-         "validate": lambda value: None
-         if (model_capability(fields) != AUDIOCPP_VOICE_CLONE or value)
-         else "This model needs a voice — pick one or switch models"},
+         "on_empty_choices": no_voices_hint,
+         "validate": voice_validate},
         {"key": prefix + "instructions", "label": "Instructions", "kind": "text",
          "value": config.AUDIOCPP_INSTRUCTIONS,
          "visible": lambda fs: model_capability(fs) in (AUDIOCPP_VOICE_DESIGN,
diff --git a/app/ui/tui.py b/app/ui/tui.py
index e2118eb..56aa79e 100644
--- a/app/ui/tui.py
+++ b/app/ui/tui.py
@@ -909,6 +909,10 @@ def form(scr, title: str, fields: Sequence[dict],
     keep their value across hide/show. A field may set ``on_change`` to
     a callable of the field list, invoked whenever its value changes so
     dependent fields (choices, visibility, defaults) can be recomputed.
+    A choice field whose resolved list is empty cannot be opened: Enter
+    is a no-op, or flashes the field's optional ``on_empty_choices``
+    message (string or callable of the field list) — an explanation the
+    submit-time ``validate`` can echo when an empty pick must be refused.
 
     An optional ``note`` string on a field renders as a dim,
     non-selectable line in a blank-line frame above that field's row — a
@@ -1064,20 +1068,33 @@ def form(scr, title: str, fields: Sequence[dict],
                         if callable(choices):
                             choices = choices(fields)
                         choices = list(choices)
-                        if choices and isinstance(choices[0], (tuple, list)) \
-                                and len(choices[0]) == 2:
-                            pairs = [(label, value) for label, value in choices]
+                        if not choices:
+                            # A dynamic choice list can legitimately come
+                            # back empty (e.g. an audio.cpp model whose
+                            # server hosts no clone voices). menu() would
+                            # raise; explain instead when the field says
+                            # how to fill the list.
+                            message = field.get("on_empty_choices")
+                            if callable(message):
+                                message = message(fields)
+                            if message:
+                                frame.flash(str(message), "err")
                         else:
-                            pairs = [(c, c) for c in choices]
-                        values = [value for _, value in pairs]
-                        default = values.index(field["value"]) \
-                            if field["value"] in values else 0
-                        chosen = menu(scr, field["label"], pairs,
-                                      default_index=default,
-                                      back_value=edit_cancel)
-                        if chosen is not edit_cancel:
-                            field["value"] = chosen
-                            run_on_change(field)
+                            if isinstance(choices[0], (tuple, list)) \
+                                    and len(choices[0]) == 2:
+                                pairs = [(label, value)
+                                         for label, value in choices]
+                            else:
+                                pairs = [(c, c) for c in choices]
+                            values = [value for _, value in pairs]
+                            default = values.index(field["value"]) \
+                                if field["value"] in values else 0
+                            chosen = menu(scr, field["label"], pairs,
+                                          default_index=default,
+                                          back_value=edit_cancel)
+                            if chosen is not edit_cancel:
+                                field["value"] = chosen
+                                run_on_change(field)
                     elif field.get("kind") == "dir":
                         start = field["value"]
                         start = Path(start) if start else Path.cwd()