Send commands over control mode

[package]
name = "libtmux-control-example"
version = "0.0.0"
edition = "2024"
publish = false

[workspace]
exclude = ["libtmux-source"]

[dependencies]
libtmux = { path = "libtmux-source/crates/libtmux", default-features = false, features = ["control-mode"] }
tempfile = "=3.27.0"
tokio = { version = "=1.53.1", features = ["macros", "rt", "time"] }

[[bin]]
name = "control"
path = "control.rs"

use std::error::Error;
use std::time::Duration;

use libtmux::control::ControlMode;
use libtmux::{NewSessionOptions, Server};

type ExampleError = Box<dyn Error>;

fn check(condition: bool, message: &str) -> Result<(), ExampleError> {
    if condition {
        Ok(())
    } else {
        Err(message.into())
    }
}

async fn demonstrate(server: &Server) -> Result<(), ExampleError> {
    let host = server
        .new_session(NewSessionOptions::new("work").command("cat"))
        .await?;
    let control = ControlMode::attach(server, host.id())
        .await?
        .reply_timeout(Duration::from_secs(3));
    let (sender, mut events) = control.split();

    let operation = async {
        let routed = server.over_control_mode(&sender).await?;
        let sessions = routed.sessions().await?;
        check(sessions.len() == 1, "expected one session")?;
        let panes = sessions[0].panes().await?;
        let pane = panes.first().ok_or("the session has no pane")?;
        pane.send_line("hello from control").await?;

        loop {
            let lines = pane.capture().await?;
            if lines
                .iter()
                .any(|line| line.as_bytes() == b"hello from control")
            {
                break;
            }
            tokio::time::sleep(Duration::from_millis(20)).await;
        }
        println!("captured: hello from control");

        // This original handle still uses subprocesses.
        check(
            server.clients().await?.len() == 1,
            "control client is missing",
        )?;
        println!("attached control clients: 1");
        Ok::<(), ExampleError>(())
    };

    // Drain notifications while commands wait for their replies.
    let outcome = tokio::select! {
        result = tokio::time::timeout(Duration::from_secs(10), operation) => {
            match result {
                Ok(result) => result,
                Err(error) => Err(Box::new(error) as ExampleError),
            }
        }
        error = async {
            loop {
                match events.next_event().await {
                    Some(Ok(_event)) => {}
                    Some(Err(error)) => break Box::new(error) as ExampleError,
                    None => break "control connection closed early".into(),
                }
            }
        } => Err(error),
    };

    let closed = events.shutdown().await;
    drop(sender);
    let mut failures = Vec::new();
    if let Err(error) = outcome {
        failures.push(format!("control operation: {error}"));
    }
    if let Err(error) = closed {
        failures.push(format!("control cleanup: {error}"));
    }
    if !failures.is_empty() {
        return Err(failures.join("; ").into());
    }

    server.check_alive().await?;
    check(
        server.clients().await?.is_empty(),
        "control client remained attached",
    )?;
    println!("connection closed; server still running");
    Ok(())
}

#[tokio::main(flavor = "current_thread")]
async fn main() -> Result<(), ExampleError> {
    let root = std::path::Path::new("/tmp/libtmux-rs-dev");
    std::fs::create_dir_all(root)?;
    let directory = tempfile::Builder::new()
        .prefix("docs-control-")
        .tempdir_in(root)?;
    std::fs::write(
        directory.path().join("owner"),
        std::process::id().to_string(),
    )?;
    let server = Server::builder()
        .socket_path(directory.path().join("tmux.sock"))
        .config_file("/dev/null")
        .default_timeout(Duration::from_secs(5))
        .build()?;
    let outcome = tokio::time::timeout(Duration::from_secs(20), demonstrate(&server)).await;

    // Stop the owned daemon before closing the client executor.
    let killed = server.kill().await;
    let closed = server.shutdown().await;
    let cleanup_failed = killed.is_err() || closed.is_err();
    let mut failures = Vec::new();
    match outcome {
        Ok(Ok(())) => {}
        Ok(Err(error)) => failures.push(format!("example failed: {error}")),
        Err(error) => failures.push(format!("example deadline: {error}")),
    }
    if let Err(error) = killed {
        failures.push(format!("daemon cleanup: {error}"));
    }
    if let Err(error) = closed {
        failures.push(format!("executor cleanup: {error}"));
    }
    if cleanup_failed {
        let retained = directory.keep();
        failures.push(format!("inspect retained directory {}", retained.display()));
    } else if let Err(error) = directory.close() {
        failures.push(format!("directory cleanup: {error}"));
    }
    if failures.is_empty() {
        Ok(())
    } else {
        Err(failures.join("; ").into())
    }
}