Batch commands with a plan

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

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

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

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

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

use libtmux::plan::{NewWindow, Outcome, Plan, Planner, SendKeys};
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 session = server
        .new_session(NewSessionOptions::new("work").command("cat"))
        .await?;

    for (name, planner, expected) in [
        ("sequential", Planner::Sequential, 3),
        ("folding", Planner::Folding, 2),
        ("marked", Planner::Marked, 1),
    ] {
        let mut plan = Plan::new();
        let window = plan.add(
            NewWindow::new(session.id().clone())
                .name(name)
                .command("cat")
                .focus(),
        );
        plan.add(SendKeys::new(window.pane()).text("one").enter());
        plan.add(SendKeys::new(window.pane()).text("two").enter());
        plan.validate()?;

        let result = plan.run(server, planner).await?;
        if !result.is_complete() {
            return Err(format!("{name} did not complete: {:?}", result.operations()).into());
        }
        check(result.dispatches() == expected, "unexpected dispatch count")?;

        let windows = session.windows().await?;
        let created = windows
            .iter()
            .find(|window| window.name().as_bytes() == name.as_bytes())
            .ok_or("created window is missing")?;
        let panes = created.panes().await?;
        let pane = panes.first().ok_or("created window has no pane")?;
        loop {
            let lines = pane.capture().await?;
            if lines.iter().any(|line| line.as_bytes() == b"one")
                && lines.iter().any(|line| line.as_bytes() == b"two")
            {
                break;
            }
            tokio::time::sleep(Duration::from_millis(20)).await;
        }
        println!("{name}: {} dispatches; one, two", result.dispatches());
    }

    // Index zero is occupied by the session's original window.
    let mut refused = Plan::new();
    refused.add(NewWindow::new(session.id().clone()).index(0));
    refused.add(NewWindow::new(session.id().clone()).name("must-not-exist"));
    let result = refused.run(server, Planner::Sequential).await?;
    check(
        !result.is_complete(),
        "tmux should refuse the occupied index",
    )?;
    check(
        result.operations()[0].outcome() == Outcome::Failed
            && result.operations()[1].outcome() == Outcome::Skipped,
        "the failed and skipped operations were not distinguished",
    )?;
    check(
        session
            .windows()
            .await?
            .iter()
            .all(|window| window.name().as_bytes() != b"must-not-exist"),
        "the operation after the failure ran",
    )?;
    println!("refused plan: failed, skipped");
    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-batching-")
        .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(10), 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())
    }
}