feat: slash-command dropdown with a themed panel

src/lecode/tui/app.py

@@ -21,6 +21,7 @@
 from prompt_toolkit import Application
 from prompt_toolkit.buffer import Buffer
 from prompt_toolkit.completion import merge_completers
+from prompt_toolkit.data_structures import Point
 from prompt_toolkit.document import Document
 from prompt_toolkit.filters import Condition
 from prompt_toolkit.formatted_text import ANSI
@@ -34,6 +35,8 @@
 from prompt_toolkit.layout.dimension import Dimension
 from prompt_toolkit.output import Output
 from prompt_toolkit.patch_stdout import patch_stdout
+from prompt_toolkit.styles import Style
+from prompt_toolkit.utils import get_cwidth
 from prompt_toolkit.widgets import Frame, TextArea
 from rich.console import Console
 
@@ -96,14 +99,20 @@
 )
 from lecode.tui.notify import Notifier
 from lecode.tui.permission import ApprovalPrompt, approval_prompt_text
-from lecode.tui.pickers import TriggerCompleter, persona_names
+from lecode.tui.pickers import (
+    TriggerCompleter,
+    command_candidates,
+    persona_names,
+    prefix_matches,
+    trigger_token,
+)
 from lecode.tui.statusline import (
     CachedGitInfo,
     StatusLineState,
     StatusState,
     render_statusline,
 )
-from lecode.tui.themes import THEME
+from lecode.tui.themes import PICKER_MENU_BG, PICKER_MENU_SELECTED_BG, THEME
 
 if TYPE_CHECKING:
     from lecode.agent.builder import Runtime
@@ -116,6 +125,9 @@
 #: Spinner/statusline refresh period while the app runs.
 SPINNER_INTERVAL_S = 0.3
 
+#: Visible rows in a completion dropdown (slash panel and @/./path menu).
+DROPDOWN_MAX_ROWS = 8
+
 #: Timeout for ``!cmd`` shell-outs.
 SHELL_TIMEOUT_S = 120.0
 
@@ -267,6 +279,9 @@ def __init__(
         )
         self._input_area: TextArea | None = None
         self._chatbox: Frame | None = None
+        #: Prefix whose "No matching commands" row Escape dismissed (Tab or
+        #: any edit clears it — see _close_completion_menu / _tab).
+        self._no_match_dismissed: str | None = None
 
     # -- public seams for slash-command handlers -------------------------------
 
@@ -536,14 +551,33 @@ def _deny(event: Any) -> None:
         def _deny_escape(event: Any) -> None:
             self._approval.resolve(Deny())
 
+        @kb.add("escape", filter=~approval_pending)
+        def _close_completion_menu(event: Any) -> None:
+            # Approval owns Escape while pending; otherwise dismiss the
+            # dropdown, restoring typed text a navigation overwrote. The
+            # no-match row has no completion state, so its dismissal is
+            # remembered per prefix (any edit or Tab brings it back).
+            # Longer M-* sequences still win over this bare-key handler.
+            buffer = event.current_buffer
+            if buffer.complete_state is not None:
+                buffer.cancel_completion()
+                return
+            prefix = self._slash_prefix()
+            if prefix:
+                self._no_match_dismissed = prefix
+
         @kb.add("enter")
         def _enter(event: Any) -> None:
             if self._approval.is_pending:
                 return  # y/a/n/ESC only while an approval is pending
-            text = event.current_buffer.text
+            buffer = event.current_buffer
+            if buffer.complete_state is not None:
+                self._accept_completion(buffer)
+                return
+            text = buffer.text
             if text.strip():
-                event.current_buffer.append_to_history()
-            event.current_buffer.reset()
+                buffer.append_to_history()
+            buffer.reset()
             self._spawn(self._submit(text))
 
         @kb.add("escape", "enter")
@@ -588,8 +622,12 @@ def _ctrl_d(event: Any) -> None:
 
         @kb.add("tab")
         def _tab(event: Any) -> None:
-            if event.current_buffer.text:
-                event.current_buffer.start_completion()
+            buffer = event.current_buffer
+            if buffer.complete_state is not None:
+                self._accept_completion(buffer)
+            elif buffer.text:
+                self._no_match_dismissed = None  # Tab reopens a dismissed row
+                buffer.start_completion()
             else:
                 self.cycle_agent()
 
@@ -641,6 +679,44 @@ async def _edit() -> None:
 
         return kb
 
+    @staticmethod
+    def _accept_completion(buffer: Buffer) -> None:
+        """Fill in the highlighted completion (first when none) and close the menu.
+
+        Commands insert ``/name `` — a following Enter submits it. Selecting
+        never submits, so browsing the dropdown can't run a command.
+        """
+        state = buffer.complete_state
+        if state is None:
+            return
+        if state.complete_index is None:
+            buffer.go_to_completion(0)
+        buffer.complete_state = None
+
+    def _slash_prefix(self) -> str | None:
+        """The typed ``/`` prefix while the slash picker owns the input, else ``None``.
+
+        Navigation rewrites the buffer with the candidate text, so an open
+        menu reads the prefix from the document the completion started from.
+        """
+        if self._input_area is None:
+            return None
+        state = self._input_area.buffer.complete_state
+        document = (
+            state.original_document if state is not None else self._input_area.buffer.document
+        )
+        trigger = trigger_token(document)
+        if trigger is None or trigger[0] != "/":
+            return None
+        return trigger[1]
+
+    def _slash_menu_empty(self) -> bool:
+        """Show the inert no-match row: a slash prefix is set, nothing matches it."""
+        prefix = self._slash_prefix()
+        if not prefix or prefix == self._no_match_dismissed:
+            return False
+        return not prefix_matches(prefix, command_candidates(self._runtime.skills))
+
     def _build_app(self, input: Input | None = None, output: Output | None = None) -> Application:
         _register_shift_enter()
         draft = self._input_history.load_draft()
@@ -673,8 +749,98 @@ def _build_app(self, input: Input | None = None, output: Output | None = None) -
         # The chatbox: a framed input area directly above the statusline.
         # Enter submits the text into the transcript above (see _enter).
         self._chatbox = Frame(self._input_area, title="message")
+        buffer = self._input_area.buffer
+
+        @Condition
+        def picker_menu_visible() -> bool:
+            # Every completion in this app comes from the trigger pickers
+            # (@/./commands) or the path completer, so the themed panel owns
+            # them all. Rows stream in asynchronously (the @/path pickers
+            # await the fd listing first), so wait for the first row; the
+            # no-match row adds the empty slash case.
+            state = buffer.complete_state
+            return (state is not None and bool(state.completions)) or self._slash_menu_empty()
+
+        def menu_heading() -> str:
+            state = buffer.complete_state
+            count = len(state.completions) if state else 0
+            if state is None:
+                label = "commands"  # the inert no-match row (slash picker)
+            else:
+                trigger = trigger_token(state.original_document)
+                label = {"@": "context", "/": "commands", ".": "personas"}.get(
+                    trigger[0] if trigger else None, "files"
+                )
+            return f" {label}  {count} {'match' if count == 1 else 'matches'}"
+
+        def menu_rows() -> list[tuple[str, str]]:
+            state = buffer.complete_state
+            if state is None:
+                return [("", " No matching commands")]
+            if not state.completions:
+                return []  # rows still streaming in; nothing to render yet
+            width = max(get_cwidth(c.display_text) for c in state.completions)
+            rows = []
+            for index, completion in enumerate(state.completions):
+                selected = index == state.complete_index
+                style = "class:picker-menu.selected" if selected else "class:picker-menu.command"
+                if index:
+                    rows.append(("", "\n"))
+                rows.extend(
+                    [
+                        (style, "> " if selected else "  "),
+                        (style, completion.display_text),
+                        ("", " " * (width - get_cwidth(completion.display_text) + 2)),
+                        ("", completion.display_meta_text),
+                    ]
+                )
+            return rows
+
+        picker_panel = ConditionalContainer(
+            Frame(
+                HSplit(
+                    [
+                        Window(FormattedTextControl(menu_heading), height=1),
+                        Window(
+                            FormattedTextControl(
+                                menu_rows,
+                                get_cursor_position=lambda: Point(
+                                    0,
+                                    (buffer.complete_state.complete_index or 0)
+                                    if buffer.complete_state
+                                    else 0,
+                                ),
+                            ),
+                            height=Dimension(min=1, max=DROPDOWN_MAX_ROWS),
+                            dont_extend_height=True,
+                            cursorline=Condition(
+                                lambda: (
+                                    buffer.complete_state is not None
+                                    and buffer.complete_state.complete_index is not None
+                                )
+                            ),
+                        ),
+                        Window(
+                            FormattedTextControl(" ↑↓ navigate  Enter/Tab select  Esc close"),
+                            height=1,
+                        ),
+                    ]
+                ),
+                style="class:picker-menu",
+            ),
+            picker_menu_visible,
+        )
         return Application(
-            layout=Layout(HSplit([live_area, self._chatbox, toolbar])),
+            layout=Layout(HSplit([live_area, self._chatbox, picker_panel, toolbar])),
+            style=Style.from_dict(
+                {
+                    "picker-menu": f"bg:{PICKER_MENU_BG} {self._theme.muted}",
+                    "picker-menu frame.border": self._theme.muted,
+                    "picker-menu.command": self._theme.text,
+                    "picker-menu.selected": f"{self._theme.accent} bold",
+                    "picker-menu cursor-line": f"bg:{PICKER_MENU_SELECTED_BG}",
+                }
+            ),
             key_bindings=self._build_keybindings(),
             full_screen=False,
             mouse_support=False,

src/lecode/tui/input.py

@@ -23,6 +23,7 @@
 import tempfile
 import time
 from collections.abc import AsyncGenerator, Callable, Iterable
+from itertools import islice
 from pathlib import Path
 
 from prompt_toolkit.application.run_in_terminal import run_in_terminal
@@ -42,6 +43,9 @@
 #: Timeout for the fd subprocess itself.
 FD_TIMEOUT_S = 5.0
 
+#: Max path completions offered (same cap as the @ picker's file branch).
+PATH_COMPLETION_LIMIT = 20
+
 #: Word characters for Ctrl-W (kill word back).
 _WORD_CHARS = frozenset("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_")
 
@@ -212,6 +216,10 @@ def _path_token_before_cursor(document: Document) -> str | None:
     token = before.split(" ")[-1] if before else ""
     if not token:
         return None
+    # Buffer-start trigger chars: "/" (commands) and "." (personas) own the
+    # input — except "./" and "../", which are explicit path prefixes.
+    if before == token and token[0] in "/." and not token.startswith(("./", "../")):
+        return None
     if "/" in token or token.startswith(("~", ".")):
         return token
     return None
@@ -298,9 +306,9 @@ async def get_completions_async(
             return
         # fd lists paths relative to cwd; normalize the user's "./" away.
         prefix = token[2:] if token.startswith("./") else token
-        for path in await self._lister.files():
-            if path.startswith(prefix):
-                yield Completion(path, start_position=-len(token))
+        matches = (path for path in await self._lister.files() if path.startswith(prefix))
+        for path in islice(matches, PATH_COMPLETION_LIMIT):
+            yield Completion(path, start_position=-len(token))
 
     def get_completions(self, document: Document, complete_event: CompleteEvent):
         # Unused: prompt_toolkit drives the async variant.

src/lecode/tui/pickers.py

@@ -72,7 +72,25 @@ def _ranked[T](token: str, candidates: list[tuple[str, T]]) -> list[tuple[str, T
     return [(name, payload) for _, name, payload in scored]
 
 
-def _trigger_token(document: Document) -> tuple[str, str] | None:
+def prefix_matches[T](token: str, candidates: list[tuple[str, T]]) -> list[tuple[str, T]]:
+    """Case-insensitive prefix matches, alphabetical (the ``/`` picker)."""
+    prefix = token.lower()
+    return sorted(
+        (name, payload) for name, payload in candidates if name.lower().startswith(prefix)
+    )
+
+
+def command_candidates(skills: SkillRegistry) -> list[tuple[str, str]]:
+    """Built-in commands plus skill-registered ones (first name wins)."""
+    commands = list(BUILTIN_COMMANDS)
+    known = {name for name, _ in commands}
+    for info in skill_commands(skills).values():
+        if info["name"] not in known:
+            commands.append((info["name"], info["description"]))
+    return commands
+
+
+def trigger_token(document: Document) -> tuple[str, str] | None:
     """``(trigger, token)`` for ``@``/``/``/``.``, or ``None`` off-trigger."""
     before = document.text_before_cursor
     word = before.split(" ")[-1] if before else ""
@@ -107,23 +125,12 @@ def __init__(
         self._agents = agents
         self._skills = skills
 
-    # -- candidates ---------------------------------------------------------
-
-    def _command_candidates(self) -> list[tuple[str, str]]:
-        """Built-in commands plus skill-registered ones (first name wins)."""
-        commands = list(BUILTIN_COMMANDS)
-        known = {name for name, _ in commands}
-        for info in skill_commands(self._skills).values():
-            if info["name"] not in known:
-                commands.append((info["name"], info["description"]))
-        return commands
-
     # -- completions ----------------------------------------------------------
 
     async def get_completions_async(
         self, document: Document, complete_event: CompleteEvent
     ) -> AsyncGenerator[Completion, None]:
-        trigger = _trigger_token(document)
+        trigger = trigger_token(document)
         if trigger is None:
             return
         kind, token = trigger
@@ -145,7 +152,7 @@ async def get_completions_async(
                     display_meta="file",
                 )
         elif kind == "/":
-            for name, description in _ranked(token, self._command_candidates()):
+            for name, description in prefix_matches(token, command_candidates(self._skills)):
                 yield Completion(
                     f"/{name} ",
                     start_position=-word_len,

src/lecode/tui/themes.py

@@ -40,6 +40,10 @@ class Theme:
     permission: str
 
 
+#: Picker-dropdown panel colors, part of the one fixed theme.
+PICKER_MENU_BG = "#1c162b"
+PICKER_MENU_SELECTED_BG = "#35264f"
+
 #: The one and only theme: Kalvad purple on dark.
 THEME = Theme(
     name="kalvad",