//! Supervisor-gated restart requests; the executable still owns normal shutdown.
use crate::{Host, RpcResult, error};
use serde_json::json;
use std::{ffi::OsStr, sync::atomic::Ordering, time::Duration};

pub(crate) fn enabled(value: Option<&OsStr>) -> bool {
    value == Some(OsStr::new("1"))
}

impl Host {
    pub(crate) fn request_restart(&self) -> RpcResult {
        if !self.0.loop_supervised {
            return Err(error(
                -32600,
                "restart needs the loop supervisor (SAUSAGE_LOOP not set); start with SAUSAGE_LOOP=1",
            ));
        }
        if !self.0.restart_pending.swap(true, Ordering::SeqCst) {
            let host = self.clone();
            tokio::spawn(async move {
                // Let the RPC response reach the caller before closing any stdin,
                // including that of a detached gateway carrying this response.
                tokio::time::sleep(Duration::from_millis(250)).await;
                host.0.exit.send_replace(true);
            });
        }
        Ok(json!({}))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{runtime::Runtime, world::World};
    use std::sync::Arc;
    use tokio::time::timeout;

    #[test]
    fn only_explicit_loop_marker_enables_restart() {
        assert!(!enabled(None));
        for value in ["", "0", "true", "yes", "2"] {
            assert!(!enabled(Some(OsStr::new(value))));
        }
        assert!(enabled(Some(OsStr::new("1"))));
    }

    async fn host(supervised: bool) -> (tempfile::TempDir, Host) {
        let dir = tempfile::tempdir().unwrap();
        World::create(&dir.path().join("world")).unwrap();
        let runtime = Runtime::new(&dir.path().join("cache")).unwrap();
        let mut host = Host::test_world(&dir.path().join("world"), runtime)
            .await
            .unwrap();
        // No global environment mutation: parallel tests have independent gates.
        Arc::get_mut(&mut host.0).unwrap().loop_supervised = supervised;
        (dir, host)
    }

    #[tokio::test]
    async fn restart_without_supervisor_never_triggers_exit() {
        timeout(Duration::from_secs(10), async {
            let (_dir, host) = host(false).await;
            for method in ["core.restart", "core.exit"] {
                let error = host.call(method, json!({})).await.unwrap_err();
                assert_eq!(error["code"], -32600);
                assert!(
                    error["message"]
                        .as_str()
                        .unwrap()
                        .contains("SAUSAGE_LOOP not set")
                );
                let indirect = host
                    .call("core.call", json!({"method":method}))
                    .await
                    .unwrap_err();
                assert_eq!(indirect, error);
            }
            assert!(!host.0.restart_pending.load(Ordering::SeqCst));
            assert!(
                timeout(Duration::from_millis(300), host.exit_requested())
                    .await
                    .is_err()
            );
            host.stop().await;
        })
        .await
        .unwrap();
    }

    #[tokio::test]
    async fn restart_and_exit_share_response_grace_and_coalescing() {
        timeout(Duration::from_secs(10), async {
            for first in ["core.restart", "core.exit"] {
                let (_dir, host) = host(true).await;
                // Same dispatch as a plugin's core.call, without killing this runner.
                assert_eq!(
                    host.call("core.call", json!({"method":first}))
                        .await
                        .unwrap(),
                    json!({})
                );
                assert!(!host.restart_requested());
                assert!(host.0.restart_pending.load(Ordering::SeqCst));
                assert_eq!(
                    host.call("core.restart", json!({})).await.unwrap(),
                    json!({})
                );
                timeout(Duration::from_secs(1), host.exit_requested())
                    .await
                    .unwrap();
                // A duplicate after the trigger must not schedule a second task.
                host.0.exit.send_replace(false);
                assert_eq!(
                    host.call("core.restart", json!({})).await.unwrap(),
                    json!({})
                );
                assert_eq!(host.call("core.exit", json!({})).await.unwrap(), json!({}));
                assert!(
                    timeout(Duration::from_millis(300), host.exit_requested())
                        .await
                        .is_err()
                );
                host.stop().await;
            }
        })
        .await
        .unwrap();
    }
}