M2 TUI: EngineHandle, ratatui app, markdown renderer, permission modal, session picker, snapshot tests

harness-app:
- EngineHandle: non-blocking multi-turn API (prompt/abort/permission_reply/
  list_sessions/session_messages/message_parts), persistent SQLite store,
  no auto-approve — TUI handles permission asks via real oneshot path
- App refactored to wrap EngineHandle; headless run -p keeps auto-approve

harness-tui:
- Terminal guard (raw mode, alternate screen, panic hook, Drop restore)
- Event loop: tokio::select! over crossterm events, bus events, 33ms render tick
- AppState with MessageView/PartView (cached Vec<Line> field), ModalState
- pulldown-cmark → ratatui markdown renderer (headings, bold, italic, code
  blocks, lists, blockquotes, links, manual word-wrap)
- Layout: header, chat viewport, input (tui-textarea), status bar
- Permission modal (y/a/n) wired to EngineHandle::permission_reply
- Session picker (Ctrl+S) with resume
- Abort (Esc), Ctrl+C×2 quit, slash commands (/new /model /agent /sessions)
- 7 TestBackend snapshot tests (empty, messages, tool cards, modals)
This commit is contained in:
2026-07-08 23:35:40 +02:00
parent b6e94c67c7
commit 0812f6d94c
18 changed files with 2848 additions and 79 deletions
+262
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use crossterm::event::{Event, KeyCode, KeyEvent, KeyModifiers};
use harness_app::EngineHandle;
use harness_core::permission::PermissionReply;
use crate::modal;
use crate::state::{AppState, ModalState};
/// Possible high-level actions produced by key input.
#[derive(Debug)]
pub enum InputAction {
None,
Submit { text: String },
Abort,
Quit,
LoadSessions,
NewSession,
SetModel(String),
SetAgent(String),
CloseModal,
ScrollUp(u16),
ScrollDown(u16),
PermissionReply(PermissionReply),
SessionPickerUp,
SessionPickerDown,
SessionPickerSelect,
}
/// Translate a crossterm event into an action and/or mutate `state` directly.
pub fn handle_event(event: Event, state: &mut AppState, _engine: &EngineHandle) -> InputAction {
match event {
Event::Key(key) => {
let action = handle_key(key, state);
// Any keypress can change the input buffer or cursor; force a redraw so typed
// characters appear immediately rather than only when some other event sets dirty.
state.dirty = true;
action
}
Event::Resize(_, _) => {
state.dirty = true;
InputAction::None
}
Event::Mouse(_) | Event::FocusGained | Event::FocusLost | Event::Paste(_) => {
InputAction::None
}
}
}
fn handle_key(key: KeyEvent, state: &mut AppState) -> InputAction {
match &state.modal {
ModalState::Permission { .. } => handle_permission_key(key, state),
ModalState::SessionPicker { .. } => handle_session_picker_key(key, state),
ModalState::None => handle_normal_key(key, state),
}
}
fn handle_permission_key(key: KeyEvent, _state: &mut AppState) -> InputAction {
match key.code {
KeyCode::Char('y') | KeyCode::Char('Y') => {
InputAction::PermissionReply(PermissionReply::Once)
}
KeyCode::Char('a') | KeyCode::Char('A') => {
InputAction::PermissionReply(PermissionReply::Always)
}
KeyCode::Char('n') | KeyCode::Char('N') => {
InputAction::PermissionReply(PermissionReply::Reject)
}
// Esc rejects the pending request rather than merely hiding the modal — closing
// without a reply would leave the tool call blocked on its oneshot forever.
KeyCode::Esc => InputAction::PermissionReply(PermissionReply::Reject),
_ => InputAction::None,
}
}
fn handle_session_picker_key(key: KeyEvent, _state: &mut AppState) -> InputAction {
match key.code {
KeyCode::Up => InputAction::SessionPickerUp,
KeyCode::Down => InputAction::SessionPickerDown,
KeyCode::Enter => InputAction::SessionPickerSelect,
KeyCode::Esc => InputAction::CloseModal,
_ => InputAction::None,
}
}
fn handle_normal_key(key: KeyEvent, state: &mut AppState) -> InputAction {
let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
// Reset the double-Ctrl+C guard on any key that isn't another Ctrl+C.
if !(matches!(key.code, KeyCode::Char('c') | KeyCode::Char('C')) && ctrl) {
state.ctrl_c_pressed = false;
}
match key.code {
KeyCode::Enter => {
let text = state.input.lines().join("\n");
state.input = tui_textarea::TextArea::default();
state
.input
.set_cursor_line_style(ratatui::style::Style::default());
if let Some(action) = parse_slash_command(&text) {
action
} else {
InputAction::Submit { text }
}
}
KeyCode::Char('c') if ctrl => {
if state.ctrl_c_pressed {
InputAction::Quit
} else {
state.ctrl_c_pressed = true;
state.dirty = true;
InputAction::None
}
}
KeyCode::Esc => {
if state.running {
InputAction::Abort
} else {
InputAction::None
}
}
KeyCode::Char('s') if ctrl => InputAction::LoadSessions,
KeyCode::Up => {
let (row, _) = state.input.cursor();
if row == 0 {
InputAction::ScrollUp(3)
} else {
state.input.input(key);
InputAction::None
}
}
KeyCode::Down => {
let (row, _) = state.input.cursor();
let last_line = state.input.lines().len().saturating_sub(1);
if row == last_line {
InputAction::ScrollDown(3)
} else {
state.input.input(key);
InputAction::None
}
}
_ => {
state.input.input(key);
InputAction::None
}
}
}
fn parse_slash_command(text: &str) -> Option<InputAction> {
let trimmed = text.trim();
if !trimmed.starts_with('/') {
return None;
}
let mut parts = trimmed.split_whitespace();
let cmd = parts.next()?;
let rest: String = parts.collect::<Vec<_>>().join(" ");
match cmd {
"/new" => Some(InputAction::NewSession),
"/model" if !rest.is_empty() => Some(InputAction::SetModel(rest)),
"/agent" if !rest.is_empty() => Some(InputAction::SetAgent(rest)),
"/sessions" => Some(InputAction::LoadSessions),
"/quit" => Some(InputAction::Quit),
_ => None,
}
}
/// Apply an action that needs async engine calls. Non-async decisions are applied inline.
pub async fn apply_action(action: InputAction, state: &mut AppState, engine: &EngineHandle) {
match action {
InputAction::Submit { text } => {
if let Some(session_id) = state.session_id.clone() {
if let Err(e) = engine.prompt(session_id, text, &state.model_ref).await {
tracing::error!(error = %e, "prompt failed");
}
}
}
InputAction::Abort => {
if let Some(session_id) = state.session_id.clone() {
engine.abort(&session_id);
}
}
InputAction::LoadSessions => match engine.list_sessions().await {
Ok(sessions) => modal::open_session_picker(state, sessions),
Err(e) => tracing::error!(error = %e, "failed to list sessions"),
},
InputAction::NewSession => match engine.new_session(&state.agent, &state.model_ref).await {
Ok(id) => {
state.session_id = Some(id);
state.messages.clear();
state.scroll_offset = 0;
state.dirty = true;
}
Err(e) => tracing::error!(error = %e, "failed to create session"),
},
InputAction::SetModel(model_ref) => {
state.model_ref = model_ref;
state.dirty = true;
}
InputAction::SetAgent(agent) => {
state.agent = agent;
state.dirty = true;
}
InputAction::Quit => state.quit = true,
InputAction::CloseModal => state.close_modal(),
InputAction::ScrollUp(n) => state.scroll_up(n),
InputAction::ScrollDown(n) => state.scroll_down(n),
InputAction::PermissionReply(reply) => {
modal::resolve_permission(state, engine, reply);
}
InputAction::SessionPickerUp => {
if let ModalState::SessionPicker {
selected,
sessions: _,
} = &mut state.modal
{
*selected = selected.saturating_sub(1);
}
state.dirty = true;
}
InputAction::SessionPickerDown => {
if let ModalState::SessionPicker { selected, sessions } = &mut state.modal {
if *selected + 1 < sessions.len() {
*selected += 1;
}
}
state.dirty = true;
}
InputAction::SessionPickerSelect => {
if let ModalState::SessionPicker { sessions, selected } = &state.modal {
if let Some(session) = sessions.get(*selected).cloned() {
if let Err(e) = modal::select_session(state, engine, session).await {
tracing::error!(error = %e, "failed to load session");
}
}
}
}
InputAction::None => {}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::state::AppState;
use crossterm::event::KeyEvent;
#[tokio::test]
async fn typing_marks_frame_dirty_and_updates_input() {
let engine = EngineHandle::init_in_memory(std::env::temp_dir()).unwrap();
let mut state = AppState::new("anthropic/claude".into(), "orchestrator".into());
state.dirty = false;
let action = handle_event(
Event::Key(KeyEvent::from(KeyCode::Char('x'))),
&mut state,
&engine,
);
assert!(matches!(action, InputAction::None));
assert!(state.dirty, "a keystroke must request a redraw");
assert_eq!(state.input.lines().join("\n"), "x");
}
}