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use std::io;
use crossterm::{
event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode, KeyModifiers},
execute,
terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use ratatui::{
backend::CrosstermBackend,
layout::{Constraint, Direction, Layout},
style::{Color, Modifier, Style},
text::{Line, Span, Text},
widgets::{Block, Borders, Paragraph, Wrap},
Terminal,
};
use tokio::sync::mpsc;
#[derive(Debug, Clone)]
pub enum AgentEvent {
#[allow(dead_code)]
Output(String),
OutputChunk(String),
Thinking,
Done {
iterations: u32,
input_tokens: u32,
output_tokens: u32,
},
Error(String),
}
#[derive(Debug, Clone)]
pub enum TuiEvent {
Submit(String),
Quit,
NewSession,
ChangeModel(String),
}
pub struct Tui {
input: String,
messages: Vec<(Role, String)>,
status: String,
scroll: u16,
streaming: bool,
}
#[derive(Clone)]
enum Role {
User,
Assistant,
Error,
Banner,
}
impl Tui {
pub fn new() -> Self {
Self {
input: String::new(),
messages: Vec::new(),
status: "Ready — press Enter to send, Ctrl+C to quit".into(),
scroll: 0,
streaming: false,
}
}
pub async fn run(
tx_event: mpsc::Sender<TuiEvent>,
mut rx_agent: mpsc::Receiver<AgentEvent>,
) -> io::Result<()> {
enable_raw_mode()?;
let mut stdout = io::stdout();
execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
let backend = CrosstermBackend::new(stdout);
let mut term = Terminal::new(backend)?;
let mut tui = Tui::new();
let v = env!("CARGO_PKG_VERSION");
tui.messages.push((
Role::Banner,
format!(
" ★\n /|\\\n \\\\ (◉ ◉) //\n \\\\ ▼ //\n \\\\ | //\n \\|||/\n |||\n / \\\n\n G A R U D U S T v{v}\n AI Agent Runtime"
),
));
tui.messages.push((
Role::Assistant,
"Type your task and press Enter. /help for commands.".into(),
));
loop {
// Drain agent events (non-blocking)
while let Ok(ev) = rx_agent.try_recv() {
tui.handle_agent_event(ev);
}
term.draw(|f| tui.render(f))?;
// Poll keyboard (50 ms timeout so agent events render promptly)
if event::poll(std::time::Duration::from_millis(50))? {
if let Event::Key(key) = event::read()? {
match (key.code, key.modifiers) {
(KeyCode::Char('c' | 'q'), KeyModifiers::CONTROL) => {
let _ = tx_event.send(TuiEvent::Quit).await;
break;
}
(KeyCode::Enter, _) => {
let text = tui.input.trim().to_string();
if !text.is_empty() {
tui.input.clear();
if let Some(rest) = text.strip_prefix('/') {
let (cmd, args) = rest
.split_once(' ')
.map_or((rest, None), |(c, a)| (c, Some(a.trim())));
match cmd {
"new" => {
tui.messages.clear();
tui.messages.push((
Role::Assistant,
"New session started.".into(),
));
let _ = tx_event.send(TuiEvent::NewSession).await;
}
"model" => match args {
Some(m) if !m.is_empty() => {
tui.messages.push((
Role::Assistant,
format!("Model → {m}"),
));
let _ = tx_event
.send(TuiEvent::ChangeModel(m.to_string()))
.await;
}
_ => tui.messages.push((
Role::Error,
"Usage: /model <model-name>".into(),
)),
},
"help" => {
tui.messages.push((
Role::Assistant,
"/new — clear history and start fresh\n\
/model <n> — switch to a different model\n\
/help — show this help"
.into(),
));
}
_ => {
tui.messages.push((
Role::Error,
format!(
"Unknown command /{cmd}. Type /help for help."
),
));
}
}
} else {
tui.messages.push((Role::User, text.clone()));
tui.status = "Thinking…".into();
let _ = tx_event.send(TuiEvent::Submit(text)).await;
}
}
}
(KeyCode::Backspace, _) => {
tui.input.pop();
}
(KeyCode::Up, _) => tui.scroll = tui.scroll.saturating_sub(1),
(KeyCode::Down, _) => tui.scroll = tui.scroll.saturating_add(1),
(KeyCode::Char(c), _) => tui.input.push(c),
_ => {}
}
}
}
}
disable_raw_mode()?;
execute!(
term.backend_mut(),
LeaveAlternateScreen,
DisableMouseCapture
)?;
Ok(())
}
fn handle_agent_event(&mut self, ev: AgentEvent) {
match ev {
AgentEvent::Output(text) => {
self.streaming = false;
self.messages.push((Role::Assistant, text));
self.status = "Ready".into();
self.scroll = u16::MAX;
}
AgentEvent::OutputChunk(delta) => {
if self.streaming {
if let Some((Role::Assistant, buf)) = self.messages.last_mut() {
buf.push_str(&delta);
}
} else {
self.streaming = true;
self.messages.push((Role::Assistant, delta));
}
self.scroll = u16::MAX;
}
AgentEvent::Thinking => {
self.streaming = false;
self.status = "Thinking…".into();
}
AgentEvent::Done {
iterations,
input_tokens,
output_tokens,
} => {
self.streaming = false;
self.status = format!(
"Done — {iterations} iterations | {input_tokens} in / {output_tokens} out tokens"
);
}
AgentEvent::Error(e) => {
self.streaming = false;
self.messages.push((Role::Error, format!("Error: {e}")));
self.status = "Error — ready for next task".into();
}
}
}
fn render(&self, f: &mut ratatui::Frame) {
let chunks = Layout::default()
.direction(Direction::Vertical)
.constraints([
Constraint::Min(3),
Constraint::Length(1),
Constraint::Length(3),
])
.split(f.area());
// ── Messages pane ──
let lines: Vec<Line> = self
.messages
.iter()
.flat_map(|(role, text)| -> Vec<Line> {
if let Role::Banner = role {
let style = Style::default()
.fg(Color::Rgb(245, 166, 35))
.add_modifier(Modifier::BOLD);
return text
.lines()
.map(|line| Line::from(Span::styled(line.to_string(), style)))
.collect();
}
let (prefix, style) = match role {
Role::User => (
"You › ",
Style::default()
.fg(Color::Cyan)
.add_modifier(Modifier::BOLD),
),
Role::Assistant => (" AI › ", Style::default().fg(Color::Green)),
Role::Error => (" !! › ", Style::default().fg(Color::Red)),
Role::Banner => unreachable!(),
};
text.lines()
.enumerate()
.map(move |(i, line)| {
if i == 0 {
Line::from(vec![
Span::styled(prefix, style),
Span::raw(line.to_string()),
])
} else {
Line::from(vec![Span::raw(" "), Span::raw(line.to_string())])
}
})
.collect()
})
.collect();
let total_lines = u16::try_from(lines.len()).unwrap_or(u16::MAX);
let visible = chunks[0].height.saturating_sub(2);
let scroll = if self.scroll == u16::MAX {
total_lines.saturating_sub(visible)
} else {
self.scroll.min(total_lines.saturating_sub(visible))
};
let messages = Paragraph::new(Text::from(lines))
.block(Block::default().borders(Borders::ALL).title(" Garudust "))
.wrap(Wrap { trim: false })
.scroll((scroll, 0));
f.render_widget(messages, chunks[0]);
// ── Status bar ──
let status =
Paragraph::new(self.status.as_str()).style(Style::default().fg(Color::DarkGray));
f.render_widget(status, chunks[1]);
// ── Input box ──
let input = Paragraph::new(self.input.as_str())
.block(Block::default().borders(Borders::ALL).title(" Input "))
.style(Style::default().fg(Color::White));
f.render_widget(input, chunks[2]);
// Show cursor inside input box
let input_len = u16::try_from(self.input.len()).unwrap_or(u16::MAX);
f.set_cursor_position((chunks[2].x + input_len + 1, chunks[2].y + 1));
}
}