Add command suggestions and enhancements to Command mode

- Introduce `command_suggestions` feature for autocompletion in Command mode.
- Implement `render_command_suggestions` to display filtered suggestions in a popup.
- Enable navigation through suggestions using Up/Down keys and Tab for completion.
- Add dynamic filtering of suggestions based on input buffer.
- Improve input handling, ensuring suggestion state resets appropriately when exiting Command mode.

crates/owlen-tui/src/chat_app.rs

@@ -51,6 +51,8 @@ pub struct ChatApp {
     pending_key: Option<char>,            // For multi-key sequences like gg, dd
     clipboard: String,                    // Vim-style clipboard for yank/paste
     command_buffer: String,               // Buffer for command mode input
+    command_suggestions: Vec<String>,     // Filtered command suggestions based on current input
+    selected_suggestion: usize,           // Index of selected suggestion
     visual_start: Option<(usize, usize)>, // Visual mode selection start (row, col) for Input panel
     visual_end: Option<(usize, usize)>, // Visual mode selection end (row, col) for scrollable panels
     focused_panel: FocusedPanel,        // Currently focused panel for scrolling
@@ -100,6 +102,8 @@ impl ChatApp {
             pending_key: None,
             clipboard: String::new(),
             command_buffer: String::new(),
+            command_suggestions: Vec::new(),
+            selected_suggestion: 0,
             visual_start: None,
             visual_end: None,
             focused_panel: FocusedPanel::Input,
@@ -206,6 +210,76 @@ impl ChatApp {
         &self.command_buffer
     }
 
+    pub fn command_suggestions(&self) -> &[String] {
+        &self.command_suggestions
+    }
+
+    pub fn selected_suggestion(&self) -> usize {
+        self.selected_suggestion
+    }
+
+    /// Returns all available commands with their aliases
+    fn get_all_commands() -> Vec<(&'static str, &'static str)> {
+        vec![
+            ("quit", "Exit the application"),
+            ("q", "Alias for quit"),
+            ("clear", "Clear the conversation"),
+            ("c", "Alias for clear"),
+            ("w", "Alias for write"),
+            ("save", "Alias for write"),
+            ("load", "Load a saved conversation"),
+            ("open", "Alias for load"),
+            ("o", "Alias for load"),
+            ("sessions", "List saved sessions"),
+            ("ls", "Alias for sessions"),
+            ("help", "Show help documentation"),
+            ("h", "Alias for help"),
+            ("model", "Select a model"),
+            ("m", "Alias for model"),
+            ("new", "Start a new conversation"),
+            ("n", "Alias for new"),
+        ]
+    }
+
+    /// Update command suggestions based on current input
+    fn update_command_suggestions(&mut self) {
+        let input = self.command_buffer.trim();
+
+        if input.is_empty() {
+            // Show all commands when input is empty
+            self.command_suggestions = Self::get_all_commands()
+                .iter()
+                .map(|(cmd, _)| cmd.to_string())
+                .collect();
+        } else {
+            // Filter commands that start with the input
+            self.command_suggestions = Self::get_all_commands()
+                .iter()
+                .filter_map(|(cmd, _)| {
+                    if cmd.starts_with(input) {
+                        Some(cmd.to_string())
+                    } else {
+                        None
+                    }
+                })
+                .collect();
+        }
+
+        // Reset selection if out of bounds
+        if self.selected_suggestion >= self.command_suggestions.len() {
+            self.selected_suggestion = 0;
+        }
+    }
+
+    /// Complete the current command with the selected suggestion
+    fn complete_command(&mut self) {
+        if let Some(suggestion) = self.command_suggestions.get(self.selected_suggestion) {
+            self.command_buffer = suggestion.clone();
+            self.update_command_suggestions();
+            self.status = format!(":{}", self.command_buffer);
+        }
+    }
+
     pub fn focused_panel(&self) -> FocusedPanel {
         self.focused_panel
     }
@@ -416,6 +490,8 @@ impl ChatApp {
                         (KeyCode::Char(':'), KeyModifiers::NONE) => {
                             self.mode = InputMode::Command;
                             self.command_buffer.clear();
+                            self.selected_suggestion = 0;
+                            self.update_command_suggestions();
                             self.status = ":".to_string();
                         }
                         // Enter editing mode
@@ -1000,8 +1076,28 @@ impl ChatApp {
                     (KeyCode::Esc, _) => {
                         self.mode = InputMode::Normal;
                         self.command_buffer.clear();
+                        self.command_suggestions.clear();
                         self.reset_status();
                     }
+                    (KeyCode::Tab, _) => {
+                        // Tab completion
+                        self.complete_command();
+                    }
+                    (KeyCode::Up, _) | (KeyCode::Char('k'), KeyModifiers::CONTROL) => {
+                        // Navigate up in suggestions
+                        if !self.command_suggestions.is_empty() {
+                            self.selected_suggestion = self
+                                .selected_suggestion
+                                .saturating_sub(1);
+                        }
+                    }
+                    (KeyCode::Down, _) | (KeyCode::Char('j'), KeyModifiers::CONTROL) => {
+                        // Navigate down in suggestions
+                        if !self.command_suggestions.is_empty() {
+                            self.selected_suggestion = (self.selected_suggestion + 1)
+                                .min(self.command_suggestions.len().saturating_sub(1));
+                        }
+                    }
                     (KeyCode::Enter, _) => {
                         // Execute command
                         let cmd = self.command_buffer.trim();
@@ -1055,6 +1151,7 @@ impl ChatApp {
                                         self.selected_session_index = 0;
                                         self.mode = InputMode::SessionBrowser;
                                         self.command_buffer.clear();
+                                        self.command_suggestions.clear();
                                         return Ok(AppState::Running);
                                     }
                                     Err(e) => {
@@ -1070,6 +1167,7 @@ impl ChatApp {
                                         self.selected_session_index = 0;
                                         self.mode = InputMode::SessionBrowser;
                                         self.command_buffer.clear();
+                                        self.command_suggestions.clear();
                                         return Ok(AppState::Running);
                                     }
                                     Err(e) => {
@@ -1080,12 +1178,14 @@ impl ChatApp {
                             "h" | "help" => {
                                 self.mode = InputMode::Help;
                                 self.command_buffer.clear();
+                                self.command_suggestions.clear();
                                 return Ok(AppState::Running);
                             }
                             "m" | "model" => {
                                 self.refresh_models().await?;
                                 self.mode = InputMode::ProviderSelection;
                                 self.command_buffer.clear();
+                                self.command_suggestions.clear();
                                 return Ok(AppState::Running);
                             }
                             "n" | "new" => {
@@ -1097,15 +1197,18 @@ impl ChatApp {
                             }
                         }
                         self.command_buffer.clear();
+                        self.command_suggestions.clear();
                         self.mode = InputMode::Normal;
                     }
                     (KeyCode::Char(c), KeyModifiers::NONE)
                     | (KeyCode::Char(c), KeyModifiers::SHIFT) => {
                         self.command_buffer.push(c);
+                        self.update_command_suggestions();
                         self.status = format!(":{}", self.command_buffer);
                     }
                     (KeyCode::Backspace, _) => {
                         self.command_buffer.pop();
+                        self.update_command_suggestions();
                         self.status = format!(":{}", self.command_buffer);
                     }
                     _ => {}

crates/owlen-tui/src/ui.rs

@@ -82,6 +82,7 @@ pub fn render_chat(frame: &mut Frame<'_>, app: &mut ChatApp) {
         InputMode::ModelSelection => render_model_selector(frame, app),
         InputMode::Help => render_help(frame, app),
         InputMode::SessionBrowser => render_session_browser(frame, app),
+        InputMode::Command => render_command_suggestions(frame, app),
         _ => {}
     }
 }
@@ -1464,6 +1465,63 @@ fn render_session_browser(frame: &mut Frame<'_>, app: &ChatApp) {
     frame.render_widget(footer, layout[1]);
 }
 
+fn render_command_suggestions(frame: &mut Frame<'_>, app: &ChatApp) {
+    let suggestions = app.command_suggestions();
+
+    // Only show suggestions if there are any
+    if suggestions.is_empty() {
+        return;
+    }
+
+    // Create a small popup near the status bar (bottom of screen)
+    let frame_height = frame.area().height;
+    let suggestion_count = suggestions.len().min(8); // Show max 8 suggestions
+    let popup_height = (suggestion_count as u16) + 2; // +2 for borders
+
+    // Position the popup above the status bar
+    let popup_area = Rect {
+        x: 1,
+        y: frame_height.saturating_sub(popup_height + 3), // 3 for status bar height
+        width: 40.min(frame.area().width - 2),
+        height: popup_height,
+    };
+
+    frame.render_widget(Clear, popup_area);
+
+    let items: Vec<ListItem> = suggestions
+        .iter()
+        .enumerate()
+        .map(|(idx, cmd)| {
+            let is_selected = idx == app.selected_suggestion();
+            let style = if is_selected {
+                Style::default()
+                    .fg(Color::Black)
+                    .bg(Color::Yellow)
+                    .add_modifier(Modifier::BOLD)
+            } else {
+                Style::default().fg(Color::White)
+            };
+
+            ListItem::new(Span::styled(cmd.to_string(), style))
+        })
+        .collect();
+
+    let list = List::new(items)
+        .block(
+            Block::default()
+                .title(Span::styled(
+                    " Commands (Tab to complete) ",
+                    Style::default()
+                        .fg(Color::Yellow)
+                        .add_modifier(Modifier::BOLD),
+                ))
+                .borders(Borders::ALL)
+                .border_style(Style::default().fg(Color::Yellow)),
+        );
+
+    frame.render_widget(list, popup_area);
+}
+
 fn centered_rect(percent_x: u16, percent_y: u16, area: Rect) -> Rect {
     let vertical = Layout::default()
         .direction(Direction::Vertical)