feat: add slash command fuzzymatching

src/agent_chat_cli/components/slash_command_menu.py

@@ -1,36 +1,76 @@
+from typing import Callable
+
 from textual.widget import Widget
 from textual.app import ComposeResult
+from textual.containers import VerticalScroll
 from textual.widgets import OptionList
 from textual.widgets.option_list import Option
 
 from agent_chat_cli.core.actions import Actions
 
+COMMANDS = [
+    {"id": "new", "label": "/new   - Start new conversation"},
+    {"id": "clear", "label": "/clear - Clear chat history"},
+    {"id": "exit", "label": "/exit  - Exit"},
+]
+
 
 class SlashCommandMenu(Widget):
-    def __init__(self, actions: Actions) -> None:
+    def __init__(
+        self, actions: Actions, on_filter_change: Callable[[str], None] | None = None
+    ) -> None:
         super().__init__()
         self.actions = actions
+        self.filter_text = ""
+        self.on_filter_change = on_filter_change
 
     def compose(self) -> ComposeResult:
-        yield OptionList(
-            Option("/new   - Start new conversation", id="new"),
-            Option("/clear - Clear chat history", id="clear"),
-            Option("/exit  - Exit", id="exit"),
-        )
+        yield OptionList(*[Option(cmd["label"], id=cmd["id"]) for cmd in COMMANDS])
 
     def show(self) -> None:
+        self.filter_text = ""
         self.add_class("visible")
-        option_list = self.query_one(OptionList)
-        option_list.highlighted = 0
-        option_list.focus()
+        self._refresh_options()
+
+        scroll_containers = self.app.query(VerticalScroll)
+        if scroll_containers:
+            scroll_containers.first().scroll_end(animate=False)
 
     def hide(self) -> None:
         self.remove_class("visible")
+        self.filter_text = ""
 
     @property
     def is_visible(self) -> bool:
         return self.has_class("visible")
 
+    def _refresh_options(self) -> None:
+        option_list = self.query_one(OptionList)
+        option_list.clear_options()
+
+        filtered = [
+            cmd for cmd in COMMANDS if self.filter_text.lower() in cmd["id"].lower()
+        ]
+
+        for cmd in filtered:
+            option_list.add_option(Option(cmd["label"], id=cmd["id"]))
+
+        if filtered:
+            option_list.highlighted = 0
+
+        option_list.focus()
+
+    def on_key(self, event) -> None:
+        if not self.is_visible:
+            return
+
+        if event.is_printable and event.character:
+            self.filter_text += event.character
+            self._refresh_options()
+
+            if self.on_filter_change:
+                self.on_filter_change(event.character)
+
     async def on_option_list_option_selected(
         self, event: OptionList.OptionSelected
     ) -> None:

src/agent_chat_cli/components/user_input.py

@@ -28,13 +28,25 @@ def compose(self) -> ComposeResult:
                 show_line_numbers=False,
                 soft_wrap=True,
             )
-        yield SlashCommandMenu(actions=self.actions)
+        yield SlashCommandMenu(
+            actions=self.actions, on_filter_change=self._on_filter_change
+        )
+
+    def _on_filter_change(self, char: str) -> None:
+        text_area = self.query_one(TextArea)
+        if char == Key.BACKSPACE.value:
+            text_area.action_delete_left()
+        else:
+            text_area.insert(char)
 
     def on_mount(self) -> None:
         input_widget = self.query_one(TextArea)
         input_widget.focus()
 
     def on_descendant_blur(self, event: DescendantBlur) -> None:
+        if not self.display:
+            return
+
         menu = self.query_one(SlashCommandMenu)
 
         if isinstance(event.widget, TextArea) and not menu.is_visible:
@@ -68,20 +80,29 @@ def _insert_newline(self, event) -> None:
         input_widget.insert("\n")
 
     def _close_menu(self, event) -> None:
-        if event.key not in (Key.ESCAPE.value, Key.BACKSPACE.value, Key.DELETE.value):
-            return
-
-        event.stop()
-        event.prevent_default()
-
         menu = self.query_one(SlashCommandMenu)
-        menu.hide()
-
-        input_widget = self.query_one(TextArea)
-        input_widget.focus()
 
         if event.key == Key.ESCAPE.value:
+            event.stop()
+            event.prevent_default()
+            menu.hide()
+            input_widget = self.query_one(TextArea)
             input_widget.clear()
+            input_widget.focus()
+            return
+
+        if event.key in (Key.BACKSPACE.value, Key.DELETE.value):
+            if menu.filter_text:
+                menu.filter_text = menu.filter_text[:-1]
+                menu._refresh_options()
+                self.query_one(TextArea).action_delete_left()
+            else:
+                event.stop()
+                event.prevent_default()
+                menu.hide()
+                input_widget = self.query_one(TextArea)
+                input_widget.clear()
+                input_widget.focus()
 
     async def action_submit(self) -> None:
         menu = self.query_one(SlashCommandMenu)

tests/test_app.py

@@ -5,6 +5,7 @@
 from textual.widgets import TextArea
 
 from agent_chat_cli.app import AgentChatCLIApp
+from agent_chat_cli.components.slash_command_menu import SlashCommandMenu
 from agent_chat_cli.components.thinking_indicator import ThinkingIndicator
 from agent_chat_cli.components.tool_permission_prompt import ToolPermissionPrompt
 from agent_chat_cli.components.user_input import UserInput
@@ -161,3 +162,69 @@ async def test_escape_triggers_interrupt_when_menu_not_visible(
             await pilot.press("escape")
 
             assert app.ui_state.interrupting is True
+
+
+class TestSlashCommandMenuBehavior:
+    async def test_slash_opens_menu(self, mock_agent_loop, mock_config):
+        app = AgentChatCLIApp()
+        async with app.run_test() as pilot:
+            await pilot.press("/")
+
+            menu = app.query_one(SlashCommandMenu)
+            assert menu.is_visible is True
+
+    async def test_escape_closes_menu_and_clears_input(
+        self, mock_agent_loop, mock_config
+    ):
+        app = AgentChatCLIApp()
+        async with app.run_test() as pilot:
+            await pilot.press("/")
+            await pilot.press("c")
+            await pilot.press("escape")
+
+            menu = app.query_one(SlashCommandMenu)
+            text_area = app.query_one(UserInput).query_one(TextArea)
+
+            assert menu.is_visible is False
+            assert text_area.text == ""
+
+    async def test_typing_filters_menu_and_shows_in_textarea(
+        self, mock_agent_loop, mock_config
+    ):
+        app = AgentChatCLIApp()
+        async with app.run_test() as pilot:
+            await pilot.press("/")
+            await pilot.press("c", "l")
+
+            menu = app.query_one(SlashCommandMenu)
+            text_area = app.query_one(UserInput).query_one(TextArea)
+
+            assert menu.filter_text == "cl"
+            assert text_area.text == "cl"
+
+    async def test_backspace_removes_filter_character(
+        self, mock_agent_loop, mock_config
+    ):
+        app = AgentChatCLIApp()
+        async with app.run_test() as pilot:
+            await pilot.press("/")
+            await pilot.press("c", "l")
+            await pilot.press("backspace")
+
+            menu = app.query_one(SlashCommandMenu)
+            text_area = app.query_one(UserInput).query_one(TextArea)
+
+            assert menu.filter_text == "c"
+            assert text_area.text == "c"
+            assert menu.is_visible is True
+
+    async def test_backspace_on_empty_filter_closes_menu(
+        self, mock_agent_loop, mock_config
+    ):
+        app = AgentChatCLIApp()
+        async with app.run_test() as pilot:
+            await pilot.press("/")
+            await pilot.press("backspace")
+
+            menu = app.query_one(SlashCommandMenu)
+            assert menu.is_visible is False