//! L3 integration tests for [`PortablePtyAdapter`] — exercising a **real** OS
//! PTY on Linux. We spawn tiny `/bin/sh` programs whose output is deterministic,
//! drain the blocking output stream on a dedicated thread, and assert on the
//! bytes / exit code.
//!
//! Robustness: every blocking drain runs on its own thread joined with a bounded
//! timeout so a misbehaving PTY can never hang the test suite/CI.

#![cfg(unix)]

use std::sync::mpsc;
use std::thread;
use std::time::Duration;

use domain::ports::{PtyPort, SpawnSpec};
use domain::{ProjectPath, PtySize};
use infrastructure::PortablePtyAdapter;

/// Hard ceiling for any single PTY interaction in these tests.
const TIMEOUT: Duration = Duration::from_secs(10);

fn sh_spec(script: &str) -> SpawnSpec {
    SpawnSpec {
        command: "/bin/sh".to_owned(),
        args: vec!["-c".to_owned(), script.to_owned()],
        cwd: ProjectPath::new("/").unwrap(),
        env: Vec::new(),
        context_plan: None,
    }
}

fn size() -> PtySize {
    PtySize::new(24, 80).unwrap()
}

/// Drains an output stream to a single `Vec<u8>` on a worker thread, returning
/// the collected bytes or panicking if it does not finish within `TIMEOUT`.
fn drain_with_timeout(
    stream: domain::ports::OutputStream,
    timeout: Duration,
) -> Vec<u8> {
    let (tx, rx) = mpsc::channel();
    let worker = thread::spawn(move || {
        let mut all = Vec::new();
        for chunk in stream {
            all.extend_from_slice(&chunk);
        }
        let _ = tx.send(all);
    });
    let bytes = rx
        .recv_timeout(timeout)
        .expect("output stream drained within timeout");
    worker.join().expect("drain thread joined");
    bytes
}

#[tokio::test]
async fn spawn_printf_streams_expected_bytes_and_exits_zero() {
    let pty = PortablePtyAdapter::new();
    let handle = pty
        .spawn(sh_spec("printf hello-pty"), size())
        .await
        .expect("spawn succeeds");

    let stream = pty.subscribe_output(&handle).expect("subscribe once");
    let bytes = drain_with_timeout(stream, TIMEOUT);
    let text = String::from_utf8_lossy(&bytes);
    assert!(
        text.contains("hello-pty"),
        "expected output to contain 'hello-pty', got {text:?}"
    );

    // Process already exited; kill collects the status. `sh` exiting cleanly → 0.
    let status = pty.kill(&handle).await.expect("kill succeeds");
    assert_eq!(status.code, Some(0), "clean exit reports code 0");
}

#[tokio::test]
async fn write_is_echoed_back_through_output_stream() {
    // `cat` echoes its stdin back to stdout; we feed it a line then close stdin
    // by killing it, and assert we saw the echoed bytes.
    let pty = PortablePtyAdapter::new();
    let handle = pty
        .spawn(sh_spec("cat"), size())
        .await
        .expect("spawn cat");

    let stream = pty.subscribe_output(&handle).expect("subscribe once");

    // Look for the marker on a worker thread, with a timeout, so we don't block
    // forever if `cat` never echoes.
    let (found_tx, found_rx) = mpsc::channel();
    let worker = thread::spawn(move || {
        let mut all = Vec::new();
        for chunk in stream {
            all.extend_from_slice(&chunk);
            if String::from_utf8_lossy(&all).contains("marker-123") {
                let _ = found_tx.send(true);
                // Keep draining until EOF so the thread can exit on kill.
            }
        }
    });

    pty.write(&handle, b"marker-123\n").expect("write to cat");

    let found = found_rx
        .recv_timeout(TIMEOUT)
        .expect("echoed marker observed within timeout");
    assert!(found, "cat echoed the written bytes back");

    pty.kill(&handle).await.expect("kill cat");
    worker.join().expect("drain thread joined after kill");
}

#[tokio::test]
async fn subscribe_output_is_re_subscribable_for_reattach() {
    // A live PTY can be subscribed to more than once over its lifetime: the
    // first view detaches (drops its stream), a second view re-attaches and
    // still receives subsequent output — the core of the no-kill navigation fix.
    let pty = PortablePtyAdapter::new();
    let handle = pty
        .spawn(sh_spec("cat"), size())
        .await
        .expect("spawn cat");

    // First attachment: subscribe, observe an echo, then drop the stream
    // (simulating a view tearing down on navigation — NOT a kill).
    {
        let first = pty.subscribe_output(&handle).expect("first subscribe");
        let (tx, rx) = mpsc::channel();
        let worker = thread::spawn(move || {
            let mut all = Vec::new();
            for chunk in first {
                all.extend_from_slice(&chunk);
                if String::from_utf8_lossy(&all).contains("first-marker") {
                    let _ = tx.send(());
                    return; // drop the stream → detach
                }
            }
        });
        pty.write(&handle, b"first-marker\n").expect("write 1");
        rx.recv_timeout(TIMEOUT).expect("first view saw its marker");
        worker.join().expect("first worker joined");
    }

    // Second attachment to the SAME live PTY (no re-spawn): must still receive
    // new output produced after re-subscription.
    let second = pty.subscribe_output(&handle).expect("re-subscribe");
    let (tx, rx) = mpsc::channel();
    let worker = thread::spawn(move || {
        let mut all = Vec::new();
        for chunk in second {
            all.extend_from_slice(&chunk);
            if String::from_utf8_lossy(&all).contains("second-marker") {
                let _ = tx.send(());
            }
        }
    });
    pty.write(&handle, b"second-marker\n").expect("write 2");
    rx.recv_timeout(TIMEOUT)
        .expect("re-attached view saw new output");

    pty.kill(&handle).await.expect("kill cat");
    worker.join().expect("second worker joined after kill");
}

#[tokio::test]
async fn scrollback_retains_recent_output_for_repaint() {
    // After output is produced and the process exits, the scrollback still holds
    // the recent bytes so a re-attaching view can repaint them.
    let pty = PortablePtyAdapter::new();
    let handle = pty
        .spawn(sh_spec("printf scrollback-content"), size())
        .await
        .expect("spawn");

    // Drain to EOF so all output has been pushed into the ring buffer.
    let stream = pty.subscribe_output(&handle).expect("subscribe");
    drain_with_timeout(stream, TIMEOUT);

    let sb = pty.scrollback(&handle).expect("scrollback readable");
    let text = String::from_utf8_lossy(&sb);
    assert!(
        text.contains("scrollback-content"),
        "scrollback should retain recent output, got {text:?}"
    );

    let _ = pty.kill(&handle).await;
}

#[tokio::test]
async fn scrollback_is_bounded_to_cap_and_keeps_most_recent_bytes() {
    // Emit clearly more than 100 KB of deterministic output, then assert the
    // retained scrollback is bounded and ends with the most recent bytes.
    let pty = PortablePtyAdapter::new();
    // 5000 lines of "....END<n>" → well over 100 KB; the tail is the freshest.
    let script = "i=0; while [ $i -lt 5000 ]; do \
        printf 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA-%d\\n' $i; \
        i=$((i+1)); done; printf 'FINAL-LINE-MARKER'";
    let handle = pty.spawn(sh_spec(script), size()).await.expect("spawn");

    let stream = pty.subscribe_output(&handle).expect("subscribe");
    drain_with_timeout(stream, TIMEOUT);

    let sb = pty.scrollback(&handle).expect("scrollback readable");
    assert!(
        sb.len() <= 100 * 1024,
        "scrollback must be bounded to ~100 KB, was {} bytes",
        sb.len()
    );
    // The newest output is retained even though the oldest was dropped.
    let text = String::from_utf8_lossy(&sb);
    assert!(
        text.contains("FINAL-LINE-MARKER"),
        "the most recent bytes must be kept in the ring buffer"
    );
    // And the very first lines must have been evicted.
    assert!(
        !text.contains("-0\n") || sb.len() < 100 * 1024,
        "oldest bytes should be dropped once the cap is exceeded"
    );

    let _ = pty.kill(&handle).await;
}

#[tokio::test]
async fn write_resize_kill_on_unknown_handle_are_not_found() {
    use domain::ports::{PtyError, PtyHandle};
    use domain::SessionId;

    let pty = PortablePtyAdapter::new();
    let ghost = PtyHandle {
        session_id: SessionId::new_random(),
    };

    assert_eq!(pty.write(&ghost, b"x"), Err(PtyError::NotFound));
    assert_eq!(pty.resize(&ghost, size()), Err(PtyError::NotFound));
    assert!(pty.subscribe_output(&ghost).is_err());
    assert_eq!(pty.kill(&ghost).await, Err(PtyError::NotFound));
}

#[tokio::test]
async fn resize_on_live_pty_succeeds() {
    let pty = PortablePtyAdapter::new();
    let handle = pty
        .spawn(sh_spec("sleep 0.2"), size())
        .await
        .expect("spawn");

    pty.resize(&handle, PtySize::new(40, 120).unwrap())
        .expect("resize a live pty succeeds");

    // Drain + reap so the test leaves no live process/thread behind.
    let stream = pty.subscribe_output(&handle).expect("subscribe");
    let _ = thread::spawn(move || stream.count());
    let _ = pty.kill(&handle).await;
}