ztmux 3.7.20

//! `ztmux destroy` — sessions that self-destruct when the last client detaches.
//!
//! With `destroy-unattached` set, a session is removed the moment its last
//! client detaches — handy for throwaway or popup sessions, dangerous when you
//! forget it is on and detach expecting to come back. `destroy` reports the
//! sessions where the option is armed: the ones that will vanish when you leave.
//! Where [`super::detached`] lists sessions currently without a client, `destroy`
//! warns which ones will not survive losing theirs. Sessions with the default
//! (`off`) are omitted. With `-o json` / `--json` it emits the same rows as a
//! machine-readable array; a server with none armed prints just the header.

use std::io::IsTerminal;

use super::tmux_query::query_lines;

/// The `\x1f`-delimited per-session format the option is read through.
const FORMAT: &str = "#{session_name}\u{1f}#{destroy-unattached}";

/// One output row: a session that will self-destruct when unattached.
struct Row {
    session: String,
}

pub(crate) fn run(socket: &str) -> i32 {
    let lines = query_lines(socket, &["list-sessions", "-F", FORMAT]);
    let rows = build_rows(&lines);
    let json = std::env::args().any(|a| a == "--json")
        || std::env::args()
            .collect::<Vec<_>>()
            .windows(2)
            .any(|w| w[0] == "-o" && w[1] == "json");
    if json {
        print!("{}", render_json(&rows));
    } else {
        print!("{}", render_text(&rows, std::io::stdout().is_terminal()));
    }
    0
}

/// Parse one formatted line into `(session, destroy_unattached)`. The option
/// reports `on` or `off`.
fn parse_line(line: &str) -> Option<(String, bool)> {
    let mut it = line.split('\u{1f}');
    let session = it.next()?;
    let armed = it.next()? == "on";
    Some((session.to_string(), armed))
}

/// One row per session with `destroy-unattached` on, ordered by session name.
fn build_rows(lines: &[String]) -> Vec<Row> {
    let mut rows: Vec<Row> = lines
        .iter()
        .filter_map(|l| parse_line(l))
        .filter(|(_, armed)| *armed)
        .map(|(session, _)| Row { session })
        .collect();
    rows.sort_by(|a, b| a.session.cmp(&b.session));
    rows
}

fn render_text(rows: &[Row], color: bool) -> String {
    let paint = |s: &str, code: &str| -> String {
        if color {
            format!("\x1b[{code}m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    };
    let mut out = String::new();
    out.push_str(&format!("{}\n", paint("SESSION", "1")));
    for r in rows {
        out.push_str(&format!("{}\n", r.session));
    }
    out
}

fn render_json(rows: &[Row]) -> String {
    let arr: Vec<serde_json::Value> = rows
        .iter()
        .map(|r| serde_json::json!({ "session": r.session }))
        .collect();
    format!(
        "{}\n",
        serde_json::to_string_pretty(&serde_json::Value::Array(arr)).unwrap_or_default()
    )
}

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

    #[test]
    fn parses_a_formatted_line() {
        let (s, armed) = parse_line("work\u{1f}on").unwrap();
        assert_eq!(s, "work");
        assert!(armed);
    }

    #[test]
    fn only_armed_sessions_are_kept() {
        let lines = vec!["a\u{1f}off".to_string(), "b\u{1f}on".to_string()];
        let rows = build_rows(&lines);
        assert_eq!(rows.len(), 1);
        assert_eq!(rows[0].session, "b");
    }

    #[test]
    fn none_armed_renders_header_only() {
        let lines = vec!["a\u{1f}off".to_string()];
        let rows = build_rows(&lines);
        assert!(rows.is_empty());
        let s = render_text(&rows, false);
        assert_eq!(s.lines().count(), 1);
        assert!(s.contains("SESSION"));
    }

    #[test]
    fn json_carries_session() {
        let lines = vec!["b\u{1f}on".to_string()];
        let rows = build_rows(&lines);
        let v: serde_json::Value = serde_json::from_str(&render_json(&rows)).unwrap();
        assert_eq!(v[0]["session"], "b");
    }
}