teamctl-ui 0.8.3

//! Detail-pane → inner-tmux-session size sync.
//!
//! Background: teamctl-ui's `Detail` pane reads the focused agent's
//! tmux scrollback via `tmux capture-pane` (see `pane::TmuxPaneSource`)
//! and renders the captured content inside a ratatui rect. The inner
//! tmux session is spawned with `-x 200 -y 50` (see
//! `team-core::supervisor`) and stays that size until something tells
//! it to resize. T-098 / #99 wired SIGWINCH propagation through
//! `rl-watch` so the inner session reflows when the *outer* host
//! terminal resizes — but that signal only fires on real OS terminal
//! changes, not on teamctl-ui's own layout shifts.
//!
//! Net effect (T-199): when the operator resizes the host terminal so
//! that teamctl-ui's `Detail` rect becomes smaller than 200×50, claude
//! keeps rendering at the inner pane's original 200×50, the captured
//! output is wider+taller than the rect, and the operator sees an
//! overflowing pane.
//!
//! Fix: after every `terminal.draw`, compute the `Detail` rect the
//! Triptych layout would produce for the current terminal size and
//! call `tmux resize-pane -t <session> -x W -y H` to keep the inner
//! pane sized to match. Cache the last value we pushed per session
//! so the common case (no resize, no focus switch) is a HashMap
//! lookup, not a subprocess spawn.

use std::collections::HashMap;
use std::process::Command;

use ratatui::layout::{Constraint, Direction, Layout, Rect};

/// Compute the `Rect` the Triptych layout would allocate to the
/// `Detail` pane given a total terminal area and whether the approvals
/// stripe is visible. Mirrors `triptych::Triptych::render` so the
/// run-loop sync path and the actual render path stay in lockstep —
/// any future tweak to Triptych geometry must update this helper too.
///
/// Returns `None` when the area is too small for the layout to produce
/// a non-empty Detail rect (e.g. an 80×24 terminal in the middle of a
/// resize-down before crossterm catches up). The caller skips the
/// sync in that case rather than push a degenerate size to tmux.
pub fn triptych_detail_area(total: Rect, has_pending_approvals: bool) -> Option<Rect> {
    if total.width == 0 || total.height == 0 {
        return None;
    }
    let body = if has_pending_approvals {
        // One-line approvals stripe at the top.
        let v = Layout::default()
            .direction(Direction::Vertical)
            .constraints([Constraint::Length(1), Constraint::Min(0)])
            .split(total);
        v[1]
    } else {
        total
    };
    let outer = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Length(28), // agents sidebar
            Constraint::Min(0),     // right-stack
        ])
        .split(body);
    let right_stack = Layout::default()
        .direction(Direction::Vertical)
        .constraints([Constraint::Ratio(3, 5), Constraint::Ratio(2, 5)])
        .split(outer[1]);
    let detail = right_stack[0];
    if detail.width == 0 || detail.height == 0 {
        return None;
    }
    Some(detail)
}

/// Decide whether to push a `tmux resize-pane` to `session` given the
/// current Detail dimensions and the last size we already pushed for
/// this session. The common case (same agent focused, no resize) is
/// a no-op; we only fire the subprocess when the size has actually
/// changed or we haven't synced this session before.
pub fn should_sync(
    cache: &HashMap<String, (u16, u16)>,
    session: &str,
    current: (u16, u16),
) -> bool {
    cache.get(session) != Some(&current)
}

/// Pushes a `tmux resize-pane` for a session. Production resizers
/// shell out via [`TmuxPaneResizer`]; tests pass a stub that records
/// calls without touching tmux.
pub trait PaneResizer: Send + Sync {
    /// Best-effort resize. Implementations should not panic or
    /// propagate errors — a missing/killed session is a normal
    /// transient state, not a fatal condition. The cache should
    /// advance regardless so we don't retry-spam a dead session.
    fn resize(&self, session: &str, cols: u16, rows: u16);
}

/// Production implementation — shells out to `tmux resize-pane`.
/// `-t <session>` targets the agent's tmux session; `-x W -y H` sets
/// the pane dimensions. Stdout/stderr are dropped: a failure (session
/// gone, tmux not on PATH) is silently ignored and the cache still
/// advances so a fresh spawn next tick can re-sync.
#[derive(Debug, Default, Clone, Copy)]
pub struct TmuxPaneResizer;

impl PaneResizer for TmuxPaneResizer {
    fn resize(&self, session: &str, cols: u16, rows: u16) {
        let _ = Command::new("tmux")
            .args([
                "resize-pane",
                "-t",
                session,
                "-x",
                &cols.to_string(),
                "-y",
                &rows.to_string(),
            ])
            .status();
    }
}

/// Shared test fakes — mirrors `compose::test_support` /
/// `mailbox::test_support` / `keysender::test_support`. The
/// in-memory `MockPaneResizer` records every call so unit tests in
/// other modules (`app::tests::sync_*`) can assert the sequence
/// without spawning a real tmux subprocess.
pub mod test_support {
    use std::sync::Mutex;

    use super::PaneResizer;

    /// Records every `resize` invocation as `(session, cols, rows)`.
    /// Backed by `Mutex` (not `RefCell`) so the `Send + Sync` bound
    /// on `PaneResizer` is satisfiable for parity with `PaneSource`.
    #[derive(Debug, Default)]
    pub struct MockPaneResizer {
        pub calls: Mutex<Vec<(String, u16, u16)>>,
    }

    impl PaneResizer for MockPaneResizer {
        fn resize(&self, session: &str, cols: u16, rows: u16) {
            self.calls
                .lock()
                .unwrap()
                .push((session.to_string(), cols, rows));
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn detail_area_for_typical_terminal_without_approvals() {
        // 120×40: Agents=28 wide, right-stack=92 wide, Detail=24 rows
        // (3/5 of 40), Mailbox=16 rows (2/5 of 40).
        let total = Rect::new(0, 0, 120, 40);
        let detail = triptych_detail_area(total, false).unwrap();
        assert_eq!(detail.x, 28);
        assert_eq!(detail.y, 0);
        assert_eq!(detail.width, 92);
        assert_eq!(detail.height, 24);
    }

    #[test]
    fn detail_area_with_approvals_stripe_loses_one_row() {
        // Same 120×40 with the approvals stripe: stripe takes y=0
        // height=1, body starts at y=1 with height=39; Detail is
        // 3/5 of 39 = 23 rows, starting at y=1.
        let total = Rect::new(0, 0, 120, 40);
        let detail = triptych_detail_area(total, true).unwrap();
        assert_eq!(detail.x, 28);
        assert_eq!(detail.y, 1);
        assert_eq!(detail.width, 92);
        assert_eq!(detail.height, 23);
    }

    #[test]
    fn detail_area_returns_none_on_zero_dimension() {
        assert!(triptych_detail_area(Rect::new(0, 0, 0, 40), false).is_none());
        assert!(triptych_detail_area(Rect::new(0, 0, 120, 0), false).is_none());
    }

    #[test]
    fn detail_area_returns_none_when_sidebar_consumes_everything() {
        // Width 28 (or less) is exactly consumed by the Agents
        // sidebar; the right-stack has zero width, so Detail does too.
        let total = Rect::new(0, 0, 28, 40);
        assert!(triptych_detail_area(total, false).is_none());
    }

    #[test]
    fn should_sync_returns_true_on_first_call() {
        let cache = HashMap::new();
        assert!(should_sync(&cache, "t-hello-mgr", (92, 24)));
    }

    #[test]
    fn should_sync_returns_false_when_size_unchanged() {
        let mut cache = HashMap::new();
        cache.insert("t-hello-mgr".to_string(), (92, 24));
        assert!(!should_sync(&cache, "t-hello-mgr", (92, 24)));
    }

    #[test]
    fn should_sync_returns_true_when_size_differs() {
        let mut cache = HashMap::new();
        cache.insert("t-hello-mgr".to_string(), (92, 24));
        // Width changed.
        assert!(should_sync(&cache, "t-hello-mgr", (100, 24)));
        // Height changed.
        assert!(should_sync(&cache, "t-hello-mgr", (92, 25)));
    }

    #[test]
    fn should_sync_treats_different_sessions_independently() {
        let mut cache = HashMap::new();
        cache.insert("t-hello-mgr".to_string(), (92, 24));
        // Same size, different session → first-sync, should fire.
        assert!(should_sync(&cache, "t-hello-dev", (92, 24)));
    }

    use super::test_support::MockPaneResizer;

    #[test]
    fn mock_resizer_records_calls() {
        let m = MockPaneResizer::default();
        m.resize("t-a", 100, 30);
        m.resize("t-b", 80, 20);
        let calls = m.calls.lock().unwrap();
        assert_eq!(calls.len(), 2);
        assert_eq!(calls[0], ("t-a".to_string(), 100, 30));
        assert_eq!(calls[1], ("t-b".to_string(), 80, 20));
    }
}