//! Network sync over real HTTP (tech-spec §6.1, §12, slice 9a). A hub (the
//! `sync::router`) runs on an ephemeral TCP port; two spoke replicas exchange
//! ops with it via `sync_once` and converge — exactly the offline-first
//! everyday config (`local` + `hub_url`). The merge logic is `heph-core`'s,
//! proven in its own convergence tests; here we prove the transport carries it.

use std::sync::atomic::{AtomicI64, Ordering};
use std::sync::{Arc, Mutex};

use heph_core::{Attention, Clock, LocalStore, NewNode, NewTask, Store, TaskState};
use hephd::sync;

/// Every replica + the hub adopt this one canonical owner (tech-spec §13).
const OWNER: &str = "canonical-user";

#[derive(Clone)]
struct StepClock(Arc<AtomicI64>);
impl StepClock {
    fn new(ms: i64) -> Self {
        StepClock(Arc::new(AtomicI64::new(ms)))
    }
    fn set(&self, ms: i64) {
        self.0.store(ms, Ordering::SeqCst);
    }
}
impl Clock for StepClock {
    fn now_ms(&self) -> i64 {
        self.0.load(Ordering::SeqCst)
    }
}

type Shared = Arc<Mutex<LocalStore>>;

/// A replica backed by a temp SQLite file, sharing the canonical owner. The
/// `TempDir` is returned so the caller keeps the file alive.
fn replica(now: i64) -> (Shared, StepClock, tempfile::TempDir) {
    let dir = tempfile::tempdir().unwrap();
    let clock = StepClock::new(now);
    let mut store = LocalStore::open(dir.path().join("heph.db"), Box::new(clock.clone())).unwrap();
    store.adopt_owner(OWNER).unwrap();
    (Arc::new(Mutex::new(store)), clock, dir)
}

/// Start the hub router on an ephemeral port; return its base URL. The serve
/// task and the hub's `TempDir` are leaked for the test's lifetime.
async fn start_hub() -> String {
    let (hub, _clock, dir) = replica(1000);
    Box::leak(Box::new(dir)); // keep the hub DB file alive
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
    let addr = listener.local_addr().unwrap();
    let app = sync::router(hub, None);
    tokio::spawn(async move {
        axum::serve(listener, app).await.unwrap();
    });
    format!("http://{addr}")
}

#[tokio::test]
async fn a_node_propagates_a_to_hub_to_b() {
    let hub_url = start_hub().await;
    let http = reqwest::Client::new();
    let (a, _ca, _da) = replica(1000);
    let (b, _cb, _db) = replica(1000);

    let id = {
        let mut ga = a.lock().unwrap();
        ga.create_node(NewNode::doc("Roof", "shingles need work"))
            .unwrap()
            .id
    };

    // A pushes to the hub; B pulls from it.
    let up = sync::sync_once(a.clone(), &hub_url, &http, None)
        .await
        .unwrap();
    assert!(up.pushed > 0, "A pushed nothing");
    let down = sync::sync_once(b.clone(), &hub_url, &http, None)
        .await
        .unwrap();
    assert!(down.applied > 0, "B applied nothing");

    let on_b = b.lock().unwrap().get_node(&id).unwrap().expect("reached B");
    assert_eq!(on_b.title, "Roof");
    assert_eq!(on_b.body.as_deref(), Some("shingles need work"));
}

#[tokio::test]
async fn spoke_survives_an_unreachable_hub_then_reconciles_when_it_returns() {
    // "The hub can vanish at any moment" is the base case, not a guarded edge:
    // a spoke whose hub is down keeps serving + accepting writes, and when the
    // hub returns its accumulated ops reconcile with no special recovery. This
    // is what makes a self-updating hub (which restarts under its spokes) safe.
    let http = reqwest::Client::builder()
        .timeout(std::time::Duration::from_secs(5)) // never hang the test
        .build()
        .unwrap();
    let (a, _ca, _da) = replica(1000);

    // Hub down: work happens locally, and a sync attempt fails *fast* (Err — not
    // a panic, not a hang) and leaves the store untouched.
    let id = {
        let mut ga = a.lock().unwrap();
        ga.create_node(NewNode::doc(
            "Offline note",
            "written while the hub was down",
        ))
        .unwrap()
        .id
    };
    let dead_hub = "http://127.0.0.1:1"; // nothing listens → connection refused
    assert!(
        sync::sync_once(a.clone(), dead_hub, &http, None)
            .await
            .is_err(),
        "sync against a dead hub should error, not hang or panic"
    );

    // The spoke is unharmed: the note is intact and further writes still succeed.
    {
        let mut ga = a.lock().unwrap();
        assert_eq!(ga.get_node(&id).unwrap().unwrap().title, "Offline note");
        ga.create_node(NewNode::doc("Another", "still working offline"))
            .unwrap();
    }

    // The hub returns: the spoke pushes everything it accumulated while offline,
    // and a fresh replica pulls it — convergence resumes, no manual recovery.
    let hub_url = start_hub().await;
    let up = sync::sync_once(a.clone(), &hub_url, &http, None)
        .await
        .unwrap();
    assert!(up.pushed > 0, "spoke pushed nothing after the hub returned");
    let (b, _cb, _db) = replica(1000);
    sync::sync_once(b.clone(), &hub_url, &http, None)
        .await
        .unwrap();
    let on_b = b
        .lock()
        .unwrap()
        .get_node(&id)
        .unwrap()
        .expect("offline-authored node reached B after the hub recovered");
    assert_eq!(on_b.title, "Offline note");
}

#[tokio::test]
async fn divergent_scalar_edits_converge_through_the_hub_with_a_conflict() {
    let hub_url = start_hub().await;
    let http = reqwest::Client::new();
    let (a, ca, _da) = replica(1000);
    let (b, cb, _db) = replica(1000);

    // A creates a task and both replicas learn it through the hub.
    let task_id = {
        let mut ga = a.lock().unwrap();
        ga.create_task(NewTask {
            title: "Renew passport".into(),
            attention: Some(Attention::Orange),
            ..Default::default()
        })
        .unwrap()
        .node_id
    };
    sync::sync_once(a.clone(), &hub_url, &http, None)
        .await
        .unwrap();
    sync::sync_once(b.clone(), &hub_url, &http, None)
        .await
        .unwrap();

    // Divergent offline edits on conflict-tracked fields; B's is later (higher
    // HLC) so its whole scalar snapshot wins.
    ca.set(2000);
    a.lock()
        .unwrap()
        .set_task_state(&task_id, TaskState::Done)
        .unwrap();
    cb.set(3000);
    b.lock()
        .unwrap()
        .set_task_attention(&task_id, Attention::Red)
        .unwrap();

    // A few exchanges in each direction settle it.
    for _ in 0..2 {
        sync::sync_once(a.clone(), &hub_url, &http, None)
            .await
            .unwrap();
        sync::sync_once(b.clone(), &hub_url, &http, None)
            .await
            .unwrap();
    }

    let ta = a.lock().unwrap().get_task(&task_id).unwrap().unwrap();
    let tb = b.lock().unwrap().get_task(&task_id).unwrap().unwrap();
    assert_eq!(ta, tb, "replicas did not converge: {ta:?} vs {tb:?}");
    assert_eq!(ta.attention, Some(Attention::Red), "later HLC should win");
    assert!(
        !a.lock().unwrap().conflicts_list().unwrap().is_empty(),
        "A recorded no conflict"
    );
    assert!(
        !b.lock().unwrap().conflicts_list().unwrap().is_empty(),
        "B recorded no conflict"
    );
}

#[tokio::test]
async fn fresh_hub_seeded_with_owner_id_rebuilds_from_first_sync() {
    // Path-A seeding: a brand-new hub started with the device's owner id (the
    // `hephd --owner-id` flag) needs no snapshot copy — the spoke's first sync
    // replays its whole op-log into the hub, and the hub keeps its own fresh
    // device origin by construction.
    let http = reqwest::Client::new();

    // The device: its own generated owner, with pre-existing data.
    let dir = tempfile::tempdir().unwrap();
    let mut device =
        LocalStore::open(dir.path().join("heph.db"), Box::new(StepClock::new(1000))).unwrap();
    let owner = device.owner_id().to_string();
    let task = device
        .create_task(NewTask {
            title: "Pre-hub task".into(),
            ..Default::default()
        })
        .unwrap();
    let device = Arc::new(Mutex::new(device));

    // The hub: a fresh store adopting the device's owner (what --owner-id does).
    let hub_dir = tempfile::tempdir().unwrap();
    let mut hub_store = LocalStore::open(
        hub_dir.path().join("heph.db"),
        Box::new(StepClock::new(1000)),
    )
    .unwrap();
    hub_store.adopt_owner(&owner).unwrap();
    let hub = Arc::new(Mutex::new(hub_store));
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
    let addr = listener.local_addr().unwrap();
    let app = sync::router(hub.clone(), None);
    tokio::spawn(async move {
        axum::serve(listener, app).await.unwrap();
    });
    let hub_url = format!("http://{addr}");

    let report = sync::sync_once(device.clone(), &hub_url, &http, None)
        .await
        .unwrap();
    assert!(report.pushed > 0, "device pushed nothing");
    let on_hub = hub
        .lock()
        .unwrap()
        .get_node(&task.node_id)
        .unwrap()
        .expect("task reached the hub");
    assert_eq!(on_hub.title, "Pre-hub task");
}