//! Queue-core unit tests: what c0re's templates **declare** — node kinds,
//! parent nesting, dep edges with the outcomes that satisfy them, and the
//! resources each construction site states it holds — plus the read layer over
//! that graph (wire projection, history retention, error truncation).
//!
//! **Nothing here runs a node.** Everything a template declares is in the graph
//! the moment `submit` returns, so the assertions read it there. Whether the
//! scheduler then honours those declarations — cascade, roll-up, grant
//! borrow/release, fairness, the `Finishing` gate — is `hive_jobq`'s property
//! and is tested in `hive_jobq`, against its own primitives rather than through
//! this module's templates.
//!
//! That split is why this file can't claim or complete: those are not part of
//! c0re's surface. A test helper that reached for them was reaching across the
//! boundary the two crates exist to draw.

use super::model::NodeKind;
use super::*;

/// Submit a declared shape with the metadata every mechanics test uses.
/// `Source::Manual` because none of these exercise provenance — the tests that
/// do name their own source at the call site.
fn submit(q: &JobQueue, reason: &str, declare: impl FnOnce(&JobBuilder)) -> u64 {
    q.submit(Source::Manual, reason.to_owned(), declare)
        .expect("valid shape")
}

fn ident(s: &str) -> hive_types::Ident {
    hive_types::Ident::parse(s).expect("valid test ident")
}

fn rebuild(builder: &JobBuilder, agent: &str) {
    templates::rebuild(builder, agent, true);
}

/// Restart shape with every agent treated as **running** — the online
/// shape (`[Signal→Drain→] StopForUpdate → Reconcile`, no `SetWanted` head)
/// most queue-mechanics tests assume. Mirrors the pre-dynamic
/// `templates::restart` (which is now the state-aware `submit::restart_nodes`).
fn restart_online(builder: &JobBuilder, agents: &[&str], graceful: bool) {
    let targets: Vec<(String, bool)> = agents.iter().map(|a| ((*a).to_owned(), true)).collect();
    submit::restart_nodes(builder, &targets, graceful);
}

/// Stop shape with every agent treated as **running** — the online shape
/// (`SetWanted → [Signal→Drain→](graceful) Reconcile`).
fn stop_online(builder: &JobBuilder, agents: &[&str], graceful: bool) {
    let targets: Vec<(String, bool)> = agents.iter().map(|a| ((*a).to_owned(), true)).collect();
    submit::stop_nodes(builder, &targets, graceful);
}

// `Claimed` / `ClaimReady` / `CompleteNode` lived here: a claim snapshot type
// and two extension traits that let this module start and finish nodes by
// hand. Nothing in this file drives the scheduler any more, so they are gone
// — which is the point. Production completes a node **inside** the future
// `hive_jobq::scheduler::Scheduler::claim_next` hands back, so "run the node,
// then remember to complete it" is not an expressible sequence there. A test
// helper that re-expressed it was a hole in exactly the seam it was testing.

/// One node's **declared** shape: what it is, what it hangs under, and what it
/// waits for — all by kind, since ids are not stable across runs.
#[derive(Debug, PartialEq, Eq)]
struct Declared {
    kind: &'static str,
    /// Parent kind, or `None` when the node hangs directly under the DAG
    /// container (i.e. it is a group root).
    parent: Option<&'static str>,
    /// Kinds this node declared a node-dep on, in declaration order, each with
    /// the outcome set that satisfies it.
    ///
    /// The outcome set is **not** decoration: a template emits its tails as a
    /// pair edged on the same upstream nodes, and the *only* thing telling the
    /// ok-tail from the fail-tail is which outcomes each accepts. Without it
    /// two structurally different nodes read as identical.
    after: Vec<(&'static str, String)>,
}

/// Render a dep's outcome set as the outcomes it actually accepts.
///
/// ⚠️ Spelled out rather than bucketed into `ok` / `any` / other. The first
/// version of this did bucket, and a template's three `ResolveApproval` tails —
/// which differ ONLY in their accepted outcomes — all rendered as `"other"`.
/// A helper that prints two structurally different nodes identically turns an
/// assertion into a tautology.
fn when_tag(when: hive_jobq::DepWhen) -> String {
    [
        (TerminalState::Done, "done"),
        (TerminalState::Failed, "failed"),
        (TerminalState::Cancelled, "cancelled"),
        (TerminalState::Skipped, "skipped"),
    ]
    .into_iter()
    .filter(|(outcome, _)| when.accepts(*outcome))
    .map(|(_, name)| name)
    .collect::<Vec<_>>()
    .join("|")
}

/// Every work node under `dag`, in insertion order, as its declared shape.
///
/// **This is what the template tests are actually about.** A template's output
/// is fully determined the moment `submit` returns: the kinds, the parent
/// nesting and the dep edges are all sitting in the graph. Reading them here
/// keeps the assertion on c0re's own product. Whether the scheduler then
/// *honours* those edges — runs a chain serially, holds a grant across a
/// subtree — is `hive_jobq`'s property and is tested in `hive_jobq`.
fn declared_shape(q: &JobQueue, dag: u64) -> Vec<Declared> {
    declared_shape_filtered(q, dag, &|_| true)
}

fn declared_shape_filtered(
    q: &JobQueue,
    dag: u64,
    keep: &dyn Fn(&NodeKind) -> bool,
) -> Vec<Declared> {
    let sched = q.sched().lock().expect("job_queue mutex poisoned");
    let graph = sched.graph();
    let root = graph.resolve_id(dag).expect("dag id is a real node id");
    let kind_of = |id: NodeId| graph.node(id).map(|n| n.payload.as_str());
    graph
        .nodes()
        .filter(|n| n.id != root && graph.root_of(n.id) == Some(root) && keep(&n.payload))
        .map(|n| Declared {
            kind: n.payload.as_str(),
            parent: n.parent.filter(|p| *p != root).and_then(kind_of),
            after: n
                .deps
                .iter()
                .filter_map(|dep| match dep {
                    hive_jobq::Dep::Node { id, when } => kind_of(*id).map(|k| (k, when_tag(*when))),
                    hive_jobq::Dep::Resource { .. } => None,
                })
                .collect(),
        })
        .collect()
}

/// The id of the one node of `kind` under `dag`, for the resource assertions.
///
/// Panics unless there is exactly one — every caller is about a shape where the
/// kind is unique, so two would mean the assertion had quietly stopped being
/// about the node the test names.
fn node_of(q: &JobQueue, dag: u64, kind: &str) -> hive_jobq::NodeId {
    let sched = q.sched().lock().expect("job_queue mutex poisoned");
    let graph = sched.graph();
    let root = graph.resolve_id(dag).expect("dag id is a real node id");
    let mut found: Vec<_> = graph
        .nodes()
        .filter(|n| n.id != root && graph.root_of(n.id) == Some(root) && n.payload.as_str() == kind)
        .map(|n| n.id)
        .collect();
    assert_eq!(
        found.len(),
        1,
        "expected exactly one {kind} node in the dag"
    );
    found.pop().expect("checked above")
}

/// The payload of the one node of `kind` under `dag`, for assertions about what
/// a node *carries* rather than how it is wired.
fn payload_of(q: &JobQueue, dag: u64, kind: &str) -> NodeKind {
    let id = node_of(q, dag, kind);
    let sched = q.sched().lock().expect("job_queue mutex poisoned");
    sched.graph().node(id).expect("node exists").payload.clone()
}

/// Kinds of every node under `dag` still `Pending` — the nodes that could yet
/// run. Stronger than asking the scheduler what is *ready right now*: a node
/// blocked on a dep is not ready but is very much still alive.
fn pending_kinds(q: &JobQueue, dag: u64) -> Vec<&'static str> {
    pending_kinds_filtered(q, dag, &|_| true)
}

/// [`pending_kinds`] restricted to the nodes whose payload names `agent`.
fn pending_kinds_for(q: &JobQueue, dag: u64, agent: &str) -> Vec<&'static str> {
    pending_kinds_filtered(q, dag, &|kind: &NodeKind| kind.agent() == agent)
}

/// The payloads of every node under `dag` still `Pending`, for the cases where
/// *which* of a family of same-kind nodes survived is the assertion — a
/// template emits one tail per outcome and they differ only in what they carry.
fn pending_payloads(q: &JobQueue, dag: u64) -> Vec<NodeKind> {
    let sched = q.sched().lock().expect("job_queue mutex poisoned");
    let graph = sched.graph();
    let root = graph.resolve_id(dag).expect("dag id is a real node id");
    graph
        .nodes()
        .filter(|n| n.id != root && graph.root_of(n.id) == Some(root) && n.state == State::Pending)
        .map(|n| n.payload.clone())
        .collect()
}

fn pending_kinds_filtered(
    q: &JobQueue,
    dag: u64,
    keep: &dyn Fn(&NodeKind) -> bool,
) -> Vec<&'static str> {
    let sched = q.sched().lock().expect("job_queue mutex poisoned");
    let graph = sched.graph();
    let root = graph.resolve_id(dag).expect("dag id is a real node id");
    graph
        .nodes()
        .filter(|n| {
            n.id != root
                && graph.root_of(n.id) == Some(root)
                && n.state == State::Pending
                && keep(&n.payload)
        })
        .map(|n| n.payload.as_str())
        .collect()
}

/// Shorthand for one expected row, so the tables below read as a shape.
fn row(
    kind: &'static str,
    parent: Option<&'static str>,
    after: &[(&'static str, &str)],
) -> Declared {
    Declared {
        kind,
        parent,
        after: after.iter().map(|(k, w)| (*k, (*w).to_owned())).collect(),
    }
}

/// The resources a node **declared**, read off its graph edges.
///
/// The declaration is the thing under test now that construction sites state
/// their own holdings: asking the `NodeKind` what it "should" need would just
/// re-run the derivation this module removed, and would pass even if the
/// construction site declared nothing.
fn declared_resources(q: &JobQueue, node_id: hive_jobq::NodeId) -> Vec<Resource> {
    let inner = q.lock();
    inner
        .graph()
        .node(node_id)
        .expect("node exists")
        .deps
        .iter()
        .filter_map(|dep| match dep {
            hive_jobq::Dep::Resource { name, .. } => Some(name.clone()),
            hive_jobq::Dep::Node { .. } => None,
        })
        .collect()
}

/// The resources declared by **every** node of `kind` under `dag`, one row per
/// node, sorted so the rows read as a set rather than an insertion order.
///
/// The per-agent templates emit several nodes of one kind — one per agent — and
/// what makes them concurrent is that each holds only its *own* agent's lease.
/// That is a statement about the whole family, so it needs all the rows, not
/// [`declared_resources`]'s single node.
fn declared_resources_of_kind(q: &JobQueue, dag: u64, kind: &str) -> Vec<Vec<Resource>> {
    let sched = q.sched().lock().expect("job_queue mutex poisoned");
    let graph = sched.graph();
    let root = graph.resolve_id(dag).expect("dag id is a real node id");
    let mut rows: Vec<Vec<Resource>> = graph
        .nodes()
        .filter(|n| n.id != root && graph.root_of(n.id) == Some(root) && n.payload.as_str() == kind)
        .map(|n| {
            n.deps
                .iter()
                .filter_map(|dep| match dep {
                    hive_jobq::Dep::Resource { name, .. } => Some(name.clone()),
                    hive_jobq::Dep::Node { .. } => None,
                })
                .collect()
        })
        .collect();
    rows.sort_by_key(|r| format!("{r:?}"));
    rows
}

/// [`declared_shape`] restricted to the nodes whose payload names `agent`.
///
/// A hive-wide DAG interleaves one subgraph per agent, and the kinds alone
/// cannot tell them apart — two `set_wanted` rows look identical. Slicing by
/// agent is what makes "the fresh agent goes straight to reconcile while the
/// stale one rebuilds first" expressible as a declared shape.
fn declared_shape_for(q: &JobQueue, dag: u64, agent: &str) -> Vec<Declared> {
    declared_shape_filtered(q, dag, &|kind: &NodeKind| kind.agent() == agent)
}

fn state_of(q: &JobQueue, dag_id: u64) -> State {
    // A DAG whose nodes have all settled `Done` or `Skipped` drops out of the
    // snapshot — absence is the completion signal, so map it to `Done`.
    // Otherwise derive the roll-up from the node set, exactly as every wire
    // consumer does.
    q.snapshot()
        .iter()
        .find(|d| d.id == dag_id)
        .map_or(State::Done, DagView::rollup_state)
}

// ---- submit (dedup removed — every submit is a fresh DAG) ----

#[test]
fn submit_assigns_distinct_ids() {
    let q = JobQueue::new(1);
    let first = submit(&q, "first", |builder| rebuild(builder, "agent-a"));
    let second = submit(&q, "second", |builder| rebuild(builder, "agent-b"));
    assert_ne!(first, second);
    assert_eq!(q.snapshot().len(), 2);
}

/// Submit-time dedup was removed with the agent-per-node refactor (a
/// multi-agent DAG has no single agent to key a dedup on), so an identical
/// resubmit — same template + agent, still queued — now enqueues a distinct
/// DAG instead of collapsing into the pending one. Whether any dedup needs
/// reintroducing is tracked as a follow-up.
#[test]
fn identical_resubmit_is_a_distinct_dag() {
    let q = JobQueue::new(1);
    let first = submit(&q, "first", |builder| rebuild(builder, "agent-a"));
    let resubmit = submit(&q, "again", |builder| rebuild(builder, "agent-a"));
    assert_ne!(first, resubmit, "no dedup: identical resubmit is a new DAG");
    assert_eq!(q.snapshot().len(), 2);
}

#[test]
fn distinct_submits_never_collapse() {
    let q = JobQueue::new(1);
    let rebuild_a = submit(&q, "r", |builder| rebuild(builder, "agent-a"));
    let rebuild_b = submit(&q, "r", |builder| rebuild(builder, "agent-b"));
    let restart_a = submit(&q, "r", |builder| {
        restart_online(builder, &["agent-a"], false);
    });
    assert_ne!(rebuild_a, rebuild_b);
    assert_ne!(rebuild_a, restart_a);
    assert_eq!(q.snapshot().len(), 3);
}

#[test]
fn resubmit_while_running_is_new_dag() {
    // The "while running" is not load-bearing and used to be staged by claiming
    // a node first. `submit` appends a container and inserts the declared
    // group; it never consults the state of any existing node, so whether an
    // earlier DAG is running cannot change the outcome. What is actually being
    // asserted — no dedup, ever — is `identical_resubmit_is_a_distinct_dag`.
    //
    // Kept as the *named* case because "a config bump mid-build must not be
    // swallowed" is the scenario people worry about, and a reader looking for
    // it should find it.
    let q = JobQueue::new(1);
    let a = submit(&q, "first", |builder| rebuild(builder, "agent-a"));
    let again = submit(&q, "config bumped during build", |builder| {
        rebuild(builder, "agent-a");
    });
    assert_ne!(a, again);
    assert_eq!(q.snapshot().len(), 2);
}

// ---- malformed specs: no longer expressible ----
//
// Three tests lived here — a dependency cycle, a dependency on a node that
// does not exist, and an out-of-range parent index — each asserting that
// `submit` refused the spec. All three built their spec by hand out of
// positional indices, which is exactly the representation that made those
// shapes possible: an index can name a node that isn't there, or one that
// comes later.
//
// A job is now declared against handles that only exist for nodes already
// declared, so there is no index to put out of range, and every edge points
// backwards — a cycle needs a forward edge. The guard those tests covered was
// deleted along with the failure mode. What remains — a handle used against a
// builder that never issued it — is `hive_jobq`'s to reject, and its builder
// tests cover it (`a_forward_edge_is_rejected_by_name`,
// `a_forward_parent_is_rejected_by_name`, `graph_rejection_surfaces_as_is`).

// ---- dependency order within a DAG ----

#[test]
fn rebuild_chain_is_declared_serial() {
    // Was `rebuild_chain_claims_in_dep_order`, which drove the whole DAG to
    // observe an order that is fully declared the moment `submit` returns.
    //
    // ⚠️ The old name was also wrong about the mechanism, and reading it rather
    // than the graph is how you'd stay wrong: **only half this chain is dep
    // edges.** `stop_for_update` and `swap` declare no deps at all — they are
    // ordered by *parent nesting* ("a node's sub-nodes run after its own
    // logic"). Both axes are asserted below because a template can break either
    // one independently.
    let q = JobQueue::new(1);
    let id = submit(&q, "r", |builder| rebuild(builder, "agent-a"));
    assert_eq!(
        declared_shape(&q, id),
        vec![
            row("meta_sync", None, &[]),
            row("prebuild", None, &[("meta_sync", "done")]),
            // No dep: ordered by hanging under `prebuild`.
            row("stop_for_update", Some("prebuild"), &[]),
            row("swap", Some("stop_for_update"), &[]),
            row("post_swap", Some("stop_for_update"), &[("swap", "done")]),
            row("reconcile", None, &[("prebuild", "done|failed|skipped")]),
            // The tail pair. The ok tail needs every root to succeed; the !ok
            // tail hangs off the ok tail's *elimination* (`skipped`), which is
            // what makes exactly one of them run.
            row(
                "emit_rebuilt",
                None,
                &[
                    ("meta_sync", "done"),
                    ("prebuild", "done"),
                    ("reconcile", "done"),
                ],
            ),
            row(
                "emit_rebuilt",
                None,
                &[
                    ("emit_rebuilt", "skipped"),
                    ("meta_sync", "done|failed|skipped"),
                    ("prebuild", "done|failed|skipped"),
                    ("reconcile", "done|failed|skipped"),
                ],
            ),
        ]
    );
}

/// The boot sweep's graceful shape: the agent gets `Signal` → `Drain` to
/// finish its turn before `StopForUpdate` takes the container down. `Signal`
/// *parents* the rest of the stop rather than sitting beside it, so the agent
/// lease is held continuously across the whole bounce — as siblings, each of
/// `Signal` / `Drain` / `StopForUpdate` would acquire the lease separately and
/// leave a window for another DAG to claim the agent mid-stop.
#[test]
fn graceful_rebuild_chain_drains_before_stopping() {
    let q = JobQueue::new(1);
    let id = q
        .submit(
            Source::AutoUpdate,
            "sweep".to_owned(),
            |builder: &JobBuilder| {
                templates::graceful_rebuild_nodes(builder, "agent-a", true, None);
            },
        )
        .expect("valid shape");
    assert_eq!(
        declared_shape(&q, id)
            .iter()
            .map(|d| d.kind)
            .collect::<Vec<_>>(),
        vec![
            "meta_sync",
            "prebuild",
            // The graceful window goes between the build and the stop: the
            // agent gets its turn to finish before the container goes down.
            "signal",
            "drain",
            "stop_for_update",
            "swap",
            "post_swap",
            "reconcile",
        ],
        "graceful inserts signal + drain ahead of the stop, and nothing else"
    );
}

/// The non-graceful shape is the default everywhere except the boot sweep:
/// a manual rebuild, a meta-update cascade child and a deploy must NOT spend a
/// drain window, so `StopForUpdate` still hangs straight off `Prebuild`.
#[test]
fn non_graceful_rebuild_has_no_signal_or_drain() {
    // Read the shape off the queue rather than out of a node list: a declared
    // job keeps its nodes to itself and inserts them, so what it built is
    // observable where it matters — in what the scheduler runs.
    let q = JobQueue::new(1);
    let id = submit(&q, "manual", |builder| {
        templates::rebuild_nodes(builder, "agent-a", true, None);
    });
    assert_eq!(
        declared_shape(&q, id)
            .iter()
            .map(|d| d.kind)
            .collect::<Vec<_>>(),
        vec![
            "meta_sync",
            "prebuild",
            "stop_for_update",
            "swap",
            "post_swap",
            "reconcile"
        ],
        "exactly six nodes, and neither of them is signal or drain"
    );
}

/// Which nodes ride the wire, and whether a DAG is still worth showing.
///
/// This used to submit a rebuild, claim and complete all seven of its nodes,
/// then assert the DAG was absent from `snapshot()` — the scheduler, the
/// roll-up and the whole projection standing in for one predicate over a list
/// of states. `shown_on_wire` is that predicate, so the cases can be named
/// instead of arranged.
#[test]
fn skipped_nodes_ride_the_wire_but_do_not_hold_a_settled_dag_in_the_snapshot() {
    // Nothing left worth showing → the DAG drops out of the snapshot, and its
    // absence is what signals completion.
    assert_eq!(shown_on_wire(&[State::Done, State::Done]), None);
    // The case the old test was built around: a clean run whose not-taken
    // failure branch is still in the graph as `Skipped`. "The node list is
    // non-empty" and "there's something here worth showing" are different
    // questions, and conflating them pins every completed deploy in the queue
    // view forever.
    assert_eq!(
        shown_on_wire(&[State::Done, State::Skipped, State::Done]),
        None,
        "a skipped branch does not keep a finished DAG alive"
    );
    // A `Failed` DAG lingers — and takes its skipped branches with it, which is
    // how an operator sees which steps the run never reached.
    assert_eq!(
        shown_on_wire(&[State::Done, State::Failed, State::Skipped, State::Done]),
        Some(vec![1, 2]),
        "done nodes drop off, the failure and what it ruled out stay"
    );
    // Live DAGs keep everything but their finished steps.
    assert_eq!(
        shown_on_wire(&[State::Done, State::Running, State::Pending]),
        Some(vec![1, 2])
    );
    assert_eq!(
        shown_on_wire(&[State::Cancelled, State::Skipped]),
        Some(vec![0, 1]),
        "a cancelled DAG is still worth showing to whoever cancelled it"
    );
    // An empty DAG has nothing worth showing either — no special case needed,
    // but it is the one input where "any" and "all" disagree, so it is pinned.
    assert_eq!(shown_on_wire(&[]), None);
}

// ---- build slots ----

#[test]
fn rebuild_chain_declares_the_slot_where_the_nix_work_is() {
    // Was `fifo_fairness_for_the_slot`, which submitted three rebuilds and
    // drove one to completion to watch the freed slot go to the earlier
    // waiter. **That fairness guarantee is hive_jobq's**, and it had no test
    // there at all — its claim primitive scans nodes in insertion order and
    // takes the first satisfiable one, and nothing pinned that. It does now:
    // `a_contended_resource_goes_to_the_oldest_waiter`.
    //
    // What is c0re's is *which* nodes contend for the slot in the first place,
    // and that is a declaration. "Uniform hold across the chain" then follows
    // from the parent nesting asserted in `rebuild_chain_is_declared_serial`:
    // a resource unit is held for the acquirer's whole subtree, so the slot
    // `Prebuild` takes covers `StopForUpdate` → `Swap` → `PostSwap` beneath it.
    let q = JobQueue::new(1);
    let id = submit(&q, "r", |builder| rebuild(builder, "agent-a"));
    let res = |kind: &str| declared_resources(&q, node_of(&q, id, kind));

    let agent = || Resource::Agent("agent-a".to_owned());
    assert_eq!(
        [
            res("meta_sync"),
            res("prebuild"),
            res("stop_for_update"),
            res("swap"),
            res("reconcile"),
        ],
        [
            // The meta preamble takes the global window and *nothing else* —
            // no slot (it does no nix work) and no lease.
            vec![Resource::MetaWindow],
            // The nix build is the slot-needer, and takes **no lease**. That is
            // what lets a prebuild overlap another DAG on the same agent: the
            // container is still up and untouched while it builds.
            vec![Resource::BuildSlot],
            // The lease starts here — the first node that touches the
            // container — and not one node earlier.
            vec![agent()],
            // Swap needs both. It re-enters the slot its `Prebuild` ancestor
            // holds rather than acquiring a second unit.
            vec![Resource::BuildSlot, agent()],
            vec![agent()],
        ],
        "the slot follows the nix work and the lease follows the container"
    );
}

// ---- per-agent lease ----

#[test]
fn multi_agent_restart_is_one_dag_with_concurrent_per_agent_subgraphs() {
    let q = JobQueue::new(4);
    let id = submit(&q, "hive-wide", |builder| {
        restart_online(builder, &["agent-a", "agent-b"], false);
    });
    // A hive-wide restart is ONE DAG, not one-per-agent.
    assert_eq!(q.snapshot().len(), 1);
    // Each agent's subgraph head (StopForUpdate, since both are running) is a
    // group root with no deps, so nothing orders them against each other; and
    // each declares only its OWN agent's lease, so nothing makes them contend.
    // Those two declared facts are what "they run concurrently" *means* here —
    // that a scheduler then does run independent, resource-disjoint roots at
    // once is hive_jobq's property, tested there.
    let heads: Vec<_> = declared_shape(&q, id)
        .into_iter()
        .filter(|d| d.kind == "stop_for_update")
        .collect();
    assert_eq!(
        heads,
        vec![
            row("stop_for_update", None, &[]),
            row("stop_for_update", None, &[]),
        ],
        "both per-agent heads are independent group roots"
    );
    assert_eq!(
        declared_resources_of_kind(&q, id, "stop_for_update"),
        vec![
            vec![Resource::Agent("agent-a".to_owned())],
            vec![Resource::Agent("agent-b".to_owned())],
        ],
        "each head declares only its own agent's lease — disjoint, so no contention"
    );
}

#[test]
fn multi_agent_stop_is_one_dag_with_concurrent_per_agent_subgraphs() {
    let q = JobQueue::new(4);
    let id = submit(&q, "hive-wide stop", |builder| {
        stop_online(builder, &["agent-a", "agent-b"], false);
    });
    // A hive-wide stop is ONE DAG, not one-per-agent.
    assert_eq!(q.snapshot().len(), 1);
    // Same declared story as the restart case above: each agent's subgraph head
    // is a group root with no node-deps, holding only its own agent's lease.
    // Independent roots on disjoint resources is what "concurrently" means at
    // this layer — the running of them is hive_jobq's.
    let heads: Vec<_> = declared_shape(&q, id)
        .into_iter()
        .filter(|d| d.kind == "set_wanted")
        .collect();
    assert_eq!(
        heads,
        vec![row("set_wanted", None, &[]), row("set_wanted", None, &[])],
        "both per-agent stop subgraph heads are independent group roots"
    );
    assert_eq!(
        declared_resources_of_kind(&q, id, "set_wanted"),
        vec![
            vec![Resource::Agent("agent-a".to_owned())],
            vec![Resource::Agent("agent-b".to_owned())],
        ],
        "each head declares only its own agent's lease"
    );
}

#[test]
fn multi_agent_start_one_dag_folds_per_agent_stale_rebuild() {
    let q = JobQueue::new(4);
    // fresh: offline + not stale → SetWanted → Reconcile.
    // stale: offline + stale → SetWanted → «rebuild subgraph».
    let id = submit(&q, "hive-wide start", |builder| {
        submit::start_nodes(
            builder,
            &[
                ("fresh".to_owned(), false, false),
                ("stale".to_owned(), false, true),
            ],
        );
    });
    // One DAG spanning both agents.
    assert_eq!(q.snapshot().len(), 1);
    // The fold is a *declared* difference, readable the moment submit returns:
    // both agents get a `SetWanted(Up)` group root, but the fresh agent's
    // subgraph ends at the Reconcile behind it while the stale agent's carries
    // the whole rebuild chain in between.
    assert_eq!(
        declared_shape_for(&q, id, "fresh"),
        vec![
            row("set_wanted", None, &[]),
            row("reconcile", Some("set_wanted"), &[]),
        ],
        "a fresh agent is intent + convergence, nothing in between"
    );
    assert_eq!(
        declared_shape_for(&q, id, "stale"),
        vec![
            row("set_wanted", None, &[]),
            row("meta_sync", None, &[("set_wanted", "done")]),
            row("prebuild", None, &[("meta_sync", "done")]),
            row("stop_for_update", Some("prebuild"), &[]),
            row("swap", Some("stop_for_update"), &[]),
            row("post_swap", Some("stop_for_update"), &[("swap", "done")]),
            row("reconcile", None, &[("prebuild", "done|failed|skipped")]),
        ],
        "a stale agent gets the whole rebuild chain wedged between intent and \
         convergence — same DAG, same head kind, more in the middle"
    );
}

#[test]
fn offline_agents_skip_mechanical_nodes_but_keep_reconcile() {
    // The dynamic build skips Signal/Drain/StopForUpdate for a down agent
    // (nothing to quiesce/stop) but ALWAYS keeps the Reconcile tail — the
    // convergence guarantee that catches a race-up between the is_running
    // read and node exec.
    let q = JobQueue::new(4);
    // Offline graceful stop → SetWanted(Off) → Reconcile (no Signal/Drain).
    let stop = submit(&q, "stop down", |builder| {
        submit::stop_nodes(builder, &[("down".to_owned(), false)], true);
    });
    // Offline restart → a lone Reconcile (no SetWanted, no StopForUpdate):
    // nothing to bounce, and restart never rewrites intent, so the tail
    // Reconcile converges the down agent to its existing `wanted`.
    let restart = submit(&q, "restart down", |builder| {
        submit::restart_nodes(builder, &[("down2".to_owned(), false)], true);
    });
    let shape = |id: u64| -> Vec<String> {
        q.snapshot()
            .iter()
            .find(|d| d.id == id)
            .expect("dag")
            .nodes
            .iter()
            .map(|n| n.kind.clone())
            .collect()
    };
    assert_eq!(
        shape(stop),
        vec!["set_wanted".to_owned(), "reconcile".to_owned()],
        "offline graceful stop skips the signal/drain quiesce, keeps Reconcile"
    );
    assert_eq!(
        shape(restart),
        vec!["reconcile".to_owned()],
        "offline restart is a lone Reconcile (no SetWanted head, nothing to stop)"
    );
}

#[test]
fn boot_sweep_nodes_declare_their_own_resources() {
    // Regression, and the reason it needs its own test: `workers::auto_update`
    // is the only place job nodes are constructed *outside* `job_queue/`, so
    // nothing in this module covered it. When resource derivation moved to the
    // construction sites, this path was missed and both kinds silently declared
    // nothing — dropping the agent lease a boot `Reconcile` needs to not race
    // another DAG's container ops, and letting the sweep `MetaLock` land its
    // meta commit inside another node's staged deploy window. Nothing failed to
    // compile; only an exhaustive caller list would have caught it.
    let q = JobQueue::new(4);
    let id = q
        .submit(
            Source::AutoUpdate,
            "boot".to_owned(),
            |builder: &JobBuilder| {
                crate::workers::auto_update::boot_nodes(
                    builder,
                    true,
                    vec!["stale-agent".to_owned()],
                    vec!["drifted-agent".to_owned()],
                );
            },
        )
        .expect("valid shape");

    let mut lock = declared_resources(&q, node_of(&q, id, "meta_lock"));
    lock.sort_by_key(|r| format!("{r:?}"));
    assert_eq!(
        lock,
        vec![Resource::BuildSlot, Resource::MetaWindow],
        "the sweep MetaLock runs a nix lock bump and commits to meta"
    );

    assert_eq!(
        declared_resources(&q, node_of(&q, id, "reconcile")),
        vec![Resource::Agent("drifted-agent".to_owned())],
        "a boot Reconcile touches the container, so it holds that agent's lease"
    );
}

/// Crash-watch suppression for a cascade rebuild, which the deleted half of
/// `meta_update_grows_cascade_in_dag` used to assert via a DAG-level
/// `transient` field on the submit-time spec (both the field and the spec type
/// are gone).
///
/// The property is unchanged — a container going down under a rebuild must not
/// read as a crash — but it is no longer a DAG-level declaration: each node
/// answers for itself, so the assertion moves to the nodes a cascade actually
/// runs. Kept as its own test rather than dropped, because it is the *property*
/// that mattered, not the field that used to carry it.
#[test]
fn rebuild_chain_nodes_suppress_crash_watch() {
    for kind in [
        NodeKind::StopForUpdate {
            agent: "a".to_owned(),
        },
        NodeKind::Swap {
            agent: "a".to_owned(),
        },
        NodeKind::Drain {
            agent: "a".to_owned(),
        },
    ] {
        assert!(
            kind.takes_container_down(),
            "{} must suppress crash-watch — a rebuild takes the container down \
             on purpose",
            kind.as_str()
        );
    }
    // The counter-case, and the reason this can't be "any node in a rebuild":
    // the tail brings the container back up, so a container that dies there
    // really did crash.
    assert!(
        !NodeKind::Start {
            agent: "a".to_owned()
        }
        .takes_container_down()
    );
}

// ---- failure: cancel-downstream + AfterAny ----
//
// `failed_node_cancels_downstream_but_afterany_reconcile_runs` lived here. It
// drove a rebuild to a failed `Prebuild` and then asserted three unrelated
// things at once, which is why it needed a running scheduler at all:
//
//   1. the cascade — a failed node cancels its `AfterOk` dependants while the
//      `AfterAny` reconcile still runs. That is hive_jobq's rule, and it owns
//      the test: `failed_after_ok_dep_cancels_dependents_but_after_any_runs`.
//      c0re's declaration of *which* edge is which is asserted in
//      `rebuild_chain_is_declared_serial` — the reconcile's accepted outcome
//      set is right there in the shape table.
//   2. the wire projection — `Done` off, `Skipped` on. That is
//      `shown_on_wire`, tested directly above.
//   3. the roll-up — a DAG with a failed node reads `Failed`, and `Skipped`
//      contributes nothing. That is `DagView::rollup_state`, which lives in
//      hive-host-sock and is now tested there, next to the invariant.
//
// Reconstructing all three from one arranged run made none of them
// individually legible, and the arrangement was the only reason this module
// needed to claim and complete nodes.

/// The swap-success path: `Swap` ok → the `AfterOk` `PostSwap` (bookkeeping
/// tail) runs, and only then does `Reconcile` fire — serialized behind
/// `PostSwap` (not racing it) because `Reconcile` deps `AfterAny(PostSwap)`.
#[test]
fn rebuild_reconcile_waits_for_the_whole_build_subtree() {
    // Replaces `swap_ok_runs_post_swap_before_reconcile` and
    // `swap_failure_still_runs_reconcile`, which walked the same DAG with the
    // swap succeeding in one and failing in the other.
    //
    // The interesting claim was "Reconcile must wait for PostSwap, not race
    // it" — and it does *not* come from an edge between them. `reconcile` deps
    // `AfterAny(prebuild)`, while `post_swap` sits inside prebuild's subtree
    // (post_swap → stop_for_update → prebuild). A parent is not terminal until
    // its subtree is, so prebuild cannot satisfy that edge while post_swap is
    // outstanding. **The ordering is the parent chain, not a dependency.**
    //
    // Both facts are asserted in `rebuild_chain_is_declared_serial`; this test
    // states the derived property explicitly because the indirection is the
    // easy thing to break — someone flattening the chain would keep every edge
    // and still lose the guarantee.
    let q = JobQueue::new(1);
    let id = submit(&q, "r", |builder| rebuild(builder, "agent-a"));
    let shape = declared_shape(&q, id);
    let parent_of = |kind: &str| {
        shape
            .iter()
            .find(|d| d.kind == kind)
            .unwrap_or_else(|| panic!("{kind} node"))
            .parent
    };
    assert_eq!(parent_of("post_swap"), Some("stop_for_update"));
    assert_eq!(parent_of("stop_for_update"), Some("prebuild"));
    assert_eq!(
        shape
            .iter()
            .find(|d| d.kind == "reconcile")
            .expect("reconcile node")
            .after,
        vec![("prebuild", "done|failed|skipped".to_owned())],
        "reconcile gates on prebuild's roll-up, which covers the whole build \
         subtree — including post_swap — and runs on failure too"
    );
}

// `swap_failure_still_runs_reconcile` lived here.
//
// It asserted that a failed swap leaves `post_swap` `Skipped` and `swap`
// `Failed`, and that reconcile still runs. All three are hive_jobq's cascade
// (`failed_after_ok_dep_cancels_dependents_but_after_any_still_runs`), and the
// "says so on the wire" half turned out to be nothing: `snapshot` fills
// `NodeView { state: node.state, .. }`, a straight copy of the same `State`
// type, so there is no c0re-side mapping to get wrong.
//
// `failed_reconcile_marks_dag_failed` lived here too — a one-node DAG whose
// node fails, asserting the DAG reads `Failed`. That is `failed_child_rolls_
// parent_up_to_failed` in hive_jobq, restated through a c0re template.

// `multi_agent_lease_frees_per_subgraph_not_whole_dag` and
// `dag_settles_terminal_and_releases_lease_after_work` lived here.
//
// Both drove a DAG to completion to watch an agent lease free up — one when a
// single agent's subgraph settled inside a still-running multi-agent DAG, the
// other when a whole power op finished. Releasing a grant once its owner's
// subtree is terminal is hive_jobq's (`owner_holds_grant_for_its_whole_subtree`,
// `child_borrows_ancestor_grant_released_when_subtree_done`,
// `leaf_owner_goes_done_directly_and_releases`).
//
// The c0re halves are declared and asserted elsewhere: that each agent's
// subgraph is an independent root holding only its own lease is in
// `multi_agent_restart_is_one_dag_with_concurrent_per_agent_subgraphs`, and
// that a power op emits no tail node is in
// `cancelled_power_op_runs_no_compensating_node`, which checks the DAG has no
// pending nodes left at all.

/// `Start` / `Stop` were lease-exempt *as kinds*, which was only safe because
/// every construction site fans them out from inside a lease-holding ancestor.
/// They declare the lease themselves now, and this pins that they do.
///
/// Was `a_fanned_out_start_declares_the_lease_and_re_enters_its_reconciles_
/// grant`, which submitted a `Reconcile`, claimed it, and then **re-declared
/// the fan-out inline** — *"same two calls the scheduler makes"*. That is a
/// copy of production in a test: had `exec.rs` stopped declaring the lease, it
/// would have kept passing. The declaration now lives in `templates::
/// fanned_out_mechanical`, so this calls the real thing.
///
/// The other half of the old test — that a descendant *re-enters* its
/// ancestor's grant rather than taking a second unit of a cap-1 lease — is
/// `hive_jobq`'s, and is tested there by
/// `child_borrows_ancestor_grant_released_when_subtree_done` and
/// `nested_borrowers_never_deadlock`.
#[test]
fn a_fanned_out_mechanical_node_declares_its_agent_lease() {
    let q = JobQueue::new(4);
    let id = submit(&q, "fan-out", |builder| {
        templates::fanned_out_mechanical(
            builder,
            NodeKind::Start {
                agent: "agent-a".to_owned(),
            },
        );
    });
    assert_eq!(declared_shape(&q, id), vec![row("start", None, &[])]);
    assert_eq!(
        declared_resources(&q, node_of(&q, id, "start")),
        vec![Resource::Agent("agent-a".to_owned())],
        "the fanned-out node carries the lease itself, rather than relying on \
         whoever happened to fan it out"
    );
}

/// A running `MetaLock` grows one rebuild subgraph per agent into **its own
/// DAG**, rooted on itself — not as child DAGs. That is what keeps a boot sweep
/// (or a meta-update cascade) one unit of work, with every rebuild building
/// against the lock the emitter just bumped.
///
/// Replaces `grown_subgraph_roots_on_emitter_and_rebases_local_deps` and
/// `meta_update_grows_cascade_in_dag`, which differed only in which rebuild
/// flavour they grew and each minted a builder by hand to simulate the graft.
/// What they were checking is the `grown_*_rebuilds` templates, so this calls
/// one — the boot sweep's, since that is the caller that grows a graceful one.
///
/// That the grafted work lands under the emitter, and that the emitter parks in
/// `Finishing` until it settles, is `hive_jobq`'s
/// (`a_completing_node_grows_the_work_it_declared`).
#[test]
fn a_meta_lock_grows_one_rebuild_subgraph_per_agent() {
    let q = JobQueue::new(4);
    let agents = vec!["alice".to_owned(), "bob".to_owned()];
    let id = q
        .submit(
            Source::AutoUpdate,
            "sweep".to_owned(),
            |builder: &JobBuilder| {
                templates::grown_graceful_rebuilds(builder, &agents, true);
            },
        )
        .expect("valid shape");

    // One chain per agent, each an independent group root — so the two rebuild
    // concurrently, each on its own lease.
    let shape = declared_shape(&q, id);
    let heads: Vec<_> = shape
        .iter()
        .filter(|d| d.kind == "meta_sync")
        .map(|d| d.parent)
        .collect();
    assert_eq!(heads, vec![None, None], "one root chain per agent");
    assert_eq!(
        shape.iter().filter(|d| d.kind == "prebuild").count(),
        2,
        "both agents get their own build"
    );
    // `graceful: true` is the sweep's distinguishing knob — agents mid-turn
    // when the host came up get their drain window rather than being cut off.
    assert_eq!(
        shape.iter().filter(|d| d.kind == "drain").count(),
        2,
        "a boot sweep is graceful, so each agent gets a drain"
    );
}

// ---- cancel ----

#[test]
fn cancel_clears_queued_dag() {
    let q = JobQueue::new(1);
    let id = submit(&q, "r", |builder| rebuild(builder, "agent-a"));
    assert!(q.cancel(id), "fully-queued dag cancels");
    // The operator sees `Cancelled` the moment the cancel returns — the spared
    // tail is still `Pending`, and a DAG must not read `Queued` back to the
    // operator who just cancelled it (the dashboard renders this roll-up from
    // the snapshot `post_rebuild_queue_cancel` emits synchronously).
    assert_eq!(state_of(&q, id), State::Cancelled, "no stale Queued gap");
    // Neither `EmitRebuilt` tail accepts a *dropped* dependency — the ok one is
    // `AFTER_OK`, the failure one keys on elimination — so both are cancelled
    // with the work and **nothing is left that could still run**: no node is
    // spared, so a rebuild that never ran emits nothing.
    assert!(
        pending_kinds(&q, id).is_empty(),
        "a dropped rebuild leaves nothing alive, got {:?}",
        pending_kinds(&q, id)
    );
}

/// `cancel` takes a **node** id, not a DAG id — so an interior node can be
/// dropped without touching the rest of the group.
///
/// This is the capability the DAG-scoped version couldn't express, and the
/// reason it reads naturally: a DAG id *is* its root node's id, so the
/// whole-group cancel every other test does is just this called on a root.
/// Here a hive-wide restart drops **one agent's** subgraph and the other agent
/// still runs.
#[test]
fn cancel_drops_one_agents_branch_leaving_the_rest() {
    let q = JobQueue::new(2);
    let id = submit(&q, "r", |builder| {
        restart_online(builder, &["agent-a", "agent-b"], false);
    });
    // Per-agent subgraphs are independent roots; find agent-a's.
    let snap = q.snapshot();
    let dag = snap.iter().find(|d| d.id == id).expect("dag in snapshot");
    let a_root = dag
        .nodes
        .iter()
        .find(|n| n.agent == "agent-a" && n.parent.is_none())
        .expect("agent-a has a group root");

    assert!(q.cancel(a_root.id), "an interior/group root cancels alone");

    // agent-a's subgraph is gone; agent-b's is untouched and still alive.
    assert!(
        pending_kinds_for(&q, id, "agent-a").is_empty(),
        "agent-a's branch was dropped whole, got {:?}",
        pending_kinds_for(&q, id, "agent-a")
    );
    assert!(
        !pending_kinds_for(&q, id, "agent-b").is_empty(),
        "agent-b's branch survives its sibling's cancel"
    );
}

/// A cancelled power op must run **no** compensating node — not even one that
/// carries a `SetWanted` head.
///
/// Now structural rather than a property of a hook enum: a power op emits no
/// tail node at all, so once its work nodes cancel there is simply nothing left
/// to claim. `cancel` also refuses unless every work node is still `Pending`
/// (`hive_jobq`'s `cancel_node_refuses_a_group_with_anything_running`), so a
/// `Cancelled` DAG provably never executed a node: its `SetWanted` never ran
/// and the agent's intent still reads whatever
/// the operator last set. A "revert" instead writes the agent's *observed*
/// state, which for a down-but-`wanted = Up` agent (crashed, or caught
/// mid-bounce) flips the intent to `Offline` and leaves it
/// deliberately-stopped as far as reconcile and crash-watch are concerned.
#[test]
fn cancelled_power_op_runs_no_compensating_node() {
    /// Submit-cancel-assert for one power op. Taking the already-submitted DAG
    /// id is what removes the need to put three differently-typed recipes in
    /// one array: each caller submits its own spec, so no closure type has to
    /// be erased to a boxed one.
    fn assert_cancels_clean(q: &JobQueue, id: u64, writes_intent: bool, case: &str) {
        // Read the intent head off the submitted DAG rather than out of the
        // spec: a declared job holds its own nodes and inserts them.
        let has_intent = declared_shape(q, id).iter().any(|d| d.kind == "set_wanted");
        assert_eq!(has_intent, writes_intent, "{case}: intent head");
        assert!(q.cancel(id), "{case}: cancelled while queued");
        assert_eq!(state_of(q, id), State::Cancelled);
        // Nothing is left that *could* run. Asserting on the pending set rather
        // than on "what is ready this instant" also covers a node that is alive
        // but blocked — which is exactly what a leftover compensating node
        // would look like.
        assert_eq!(
            pending_kinds(q, id),
            Vec::<&str>::new(),
            "{case}: a power op emits no tail node, so a cancelled one leaves nothing"
        );
    }

    for graceful in [false, true] {
        for running in [false, true] {
            let targets = vec![("agent-a".to_owned(), running)];
            let case = format!("graceful={graceful} running={running}");

            let q = JobQueue::new(1);
            let id = submit(&q, "bounce", |builder| {
                submit::restart_nodes(builder, &targets, graceful);
            });
            assert_cancels_clean(&q, id, false, &format!("restart {case}"));

            let q = JobQueue::new(1);
            let id = submit(&q, "stop", |builder| {
                submit::stop_nodes(builder, &targets, graceful);
            });
            assert_cancels_clean(&q, id, true, &format!("stop {case}"));

            let q = JobQueue::new(1);
            let id = submit(&q, "start", |builder| {
                submit::start_nodes(builder, &[("agent-a".to_owned(), running, false)]);
            });
            assert_cancels_clean(&q, id, true, &format!("start {case}"));
        }
    }
}

// ---- terminal reporting + lease release ----

/// A DAG cancelled while fully queued must still **run its tail**, or a queued
/// approval DAG cancelled by the operator would dangle its approval forever.
///
/// This is the load-bearing case for sparing tails in [`JobQueue::cancel`]: the
/// work nodes all cancel, but `ResolveApproval` is weak-edged, so a `Cancelled`
/// dep satisfies its edge and it becomes claimable instead of being cancelled
/// along with everything else. It reads `Cancelled` off its own deps and resolves
/// the approval as "cancelled before completion".
#[test]
fn cancelled_dag_still_runs_its_approval_tail() {
    let q = JobQueue::new(1);
    let id = submit(&q, "approval #7", |builder| {
        templates::approval_deploy(builder, "agent-a", 7);
    });
    assert!(q.cancel(id), "fully-queued dag cancels");
    // The `Cancelled` tail is the only node whose edge accepts a dropped
    // dependency, so it is the only one `cancel` spares — and *which* tail
    // survives is the whole assertion: the template emits one per outcome and
    // the spared one names how the approval row is about to be resolved.
    // Nothing computes it, so reading the survivor is reading the answer.
    let spared = pending_payloads(&q, id);
    assert!(
        matches!(
            spared.as_slice(),
            [NodeKind::ResolveApproval {
                approval_id: 7,
                outcome: TerminalState::Cancelled
            }]
        ),
        "only the cancelled-outcome tail is spared, got {spared:?}"
    );
    assert_eq!(state_of(&q, id), State::Cancelled);
    // An unrelated DAG landing in the same graph doesn't disturb this one's
    // roll-up — the snapshot is per-DAG, not a global state machine.
    let _other = submit(&q, "r", |builder| rebuild(builder, "agent-b"));
    assert_eq!(state_of(&q, id), State::Cancelled);
}

// ---- approval deploy subtree ----

/// The config-PR deploy is a subtree, not one opaque node. The
/// resource-holding root completes immediately (its `Finishing` state is the
/// parent gate that releases the children), then the phases run strictly in
/// order — and the `AfterAny` tail still runs when the irreversible half fails,
/// because it's the node that compensates for it.
#[test]
fn deploy_dag_runs_phases_in_order_and_tails_a_failed_apply() {
    let q = JobQueue::new(1);
    let id = submit(&q, "approval #7", |builder| {
        templates::approval_deploy(builder, "agent-a", 7);
    });

    assert_eq!(
        declared_shape(&q, id),
        vec![
            // The window is the group root and holds the meta window for the
            // whole subtree; the three phases are its sub-nodes.
            row("deploy_window", None, &[]),
            row("merge_verify", Some("deploy_window"), &[]),
            // Apply only on a clean verify — a failed verify cancel-cascades
            // it, which is what leaves the forge and the applied repo untouched.
            row(
                "deploy_apply",
                Some("deploy_window"),
                &[("merge_verify", "done")]
            ),
            // The compensation tail accepts every terminal outcome of apply,
            // *including `skipped`* — which is the state apply lands in when
            // verify failed and it never ran. That one edge is the entire
            // "still tails a failed apply / a failed verify" behaviour, and it
            // is why two separate DAG-driving tests collapsed into this table.
            row(
                "deploy_tail",
                Some("deploy_window"),
                &[("deploy_apply", "done|failed|skipped")]
            ),
            // One approval tail per outcome, gated on the window's roll-up.
            row("resolve_approval", None, &[("deploy_window", "done")]),
            row("resolve_approval", None, &[("deploy_window", "failed")]),
            row("resolve_approval", None, &[("deploy_window", "cancelled")]),
        ]
    );
}

/// The deploy's happy path: `DeployApply` does not build. It grows the ordinary
/// rebuild chain into the live DAG under itself, and `FinalizeDeploy` — gated on
/// that graft finishing — plants the deploy tag last.
///
/// The queue is built with **one** build slot on purpose. `DeployWindow` already
/// holds that slot (and the meta window) for the whole subtree, so the grafted
/// `Prebuild` can only ever claim by *re-entering* its ancestor's hold. If the
/// graft were rooted anywhere outside `DeployWindow`'s subtree it would block on
/// a resource its own DAG owns and deadlock — this test is what pins that down.
#[test]
fn deploy_apply_grows_rebuild_subgraph_and_finalizes_after_it() {
    // What `DeployApply` grows is `deploy_rebuild_nodes`' output, and that is a
    // pure declaration — so it is declared here directly rather than by running
    // a deploy far enough to graft it. **Reproducing the runtime path is not
    // needed to test what the runtime path declares.**
    //
    // The grafting mechanism itself is hive_jobq's and tested there: the work
    // lands under the emitter *before* it settles, and the emitter parks in
    // `Finishing` so a downstream `AfterAny` gate stays shut while the new
    // children run (`a_completing_node_grows_the_work_it_declared`,
    // `parent_parks_in_finishing_until_children_roll_up`).
    let q = JobQueue::new(1);
    let id = submit(&q, "deploy graft", |builder| {
        templates::deploy_rebuild_nodes(builder, "agent-a", 11);
    });

    assert_eq!(
        declared_shape(&q, id),
        vec![
            row("meta_sync", None, &[]),
            row("prebuild", None, &[("meta_sync", "done")]),
            row("stop_for_update", Some("prebuild"), &[]),
            row("swap", Some("stop_for_update"), &[]),
            row("post_swap", Some("stop_for_update"), &[("swap", "done")]),
            row("reconcile", None, &[("prebuild", "done|failed|skipped")]),
            // The deploy tag is planted only after the rebuild came up clean:
            // `AfterOk` on **both** roots, so either one failing skips it. That
            // pair of edges is the whole "skips finalize on a failed graft"
            // behaviour — no run needed to see it.
            row(
                "finalize_deploy",
                None,
                &[("prebuild", "done"), ("reconcile", "done")]
            ),
        ]
    );
}

// `deploy_dag_skips_finalize_but_still_tails_a_failed_graft` lived here.
//
// A failure *inside* the grafted rebuild is the failure mode subgraph growth
// introduces: the deploy is already merged and the container half-swapped, so
// `FinalizeDeploy` must be cancel-cascaded (no `deployed/<id>` tag planted)
// while the tail still runs to compensate, and `Reconcile` is deliberately
// still reached — it boots the container back up.
//
// Every declared half of that is asserted by
// `deploy_apply_grows_rebuild_subgraph_and_finalizes_after_it`, which reads
// `deploy_rebuild_nodes`' shape directly:
//
//   - "a failed swap still reaches Reconcile" is the `reconcile` row's
//     `AfterAny` edge on `prebuild` (`done|failed|skipped`);
//   - "finalize is cancel-cascaded" is `finalize_deploy`'s `AfterOk` pair —
//     either root failing skips it;
//   - "the tail still runs" is `deploy_tail`'s own `done|failed|skipped` edge
//     on apply, asserted in the `approval_deploy` table above.
//
// The runtime halves are hive_jobq's: cascade on failure, roll-up, and
// `first_error` digging past a group root that rolled up `Failed` while
// carrying no error of its own (`first_error_skips_a_rolled_up_failure_
// carrying_no_error`). That last one is why the DAG reports "profile swap
// failed" rather than nothing — the mechanism, not this shape.

// `deploy_dag_skips_apply_but_still_runs_tail_when_verify_fails` lived here.
//
// A pre-merge rejection (drift gate, eval failure) cancel-cascades the
// irreversible half via its `AfterOk` edge, while the tail is still reached —
// it owns the forge mirror, not just compensation. That test and
// `deploy_dag_runs_phases_in_order_and_tails_a_failed_apply` differed only in
// *where* they injected the failure, and each drove the whole DAG to watch the
// tail run anyway.
//
// Both outcomes follow from one declared edge, which the surviving test now
// asserts directly: the tail accepts `done|failed|skipped` on apply, and
// `skipped` is exactly the state apply lands in when verify failed and it never
// ran. The runtime halves are hive_jobq's and tested there —
// `failed_after_ok_dep_cancels_dependents_but_after_any_still_runs` and
// `failed_child_rolls_parent_up_to_failed` (an Ok tail cannot launder a failed
// deploy into a success).

// ---- history ----
//
// The node → build-log link is no longer queue state: the log row carries
// `node_id` and the lookup lives in `stores::build_logs` (see
// `node_link_survives_completion_and_newest_wins` there). Nothing in the queue
// needs testing for it any more, which is the point of that move.

/// History retention is a **flat** newest-first cap over all terminal DAGs
/// (`MAX_HISTORY_DAGS`), not a per-template bucket behind a grace window.
/// The dashboard renders one recent-builds list, so one number bounds it —
/// and with no bucketing there's nothing for a burst of same-shaped DAGs to
/// evict early, which is what the grace window used to paper over.
///
/// `retain_history` is a sort-and-truncate over `(handle, finished_at,
/// tiebreak)`. This used to submit `MAX_HISTORY_DAGS + 8` DAGs, claim and fail
/// each one's node, then read the ids back out of a snapshot — the scheduler,
/// the roll-up and the wire projection all in the path of a policy that reads
/// none of them.
///
/// Calling it directly also reaches the half the round-trip never could: every
/// DAG in that loop settled inside the same wall-clock second, so `finished_at`
/// tied on all of them and **only** the tiebreak was ever exercised. Eviction
/// by time — the actual policy — went untested.
#[test]
fn history_retains_live_dags_and_the_newest_terminals() {
    const CAP: usize = 3;
    // Live DAGs are kept whole, regardless of the cap.
    assert_eq!(
        retain_history(vec!["live-a", "live-b"], vec![], CAP),
        vec!["live-a", "live-b"],
    );
    // Terminals: newest `finished_at` first, oldest evicted past the cap.
    assert_eq!(
        retain_history(
            vec![],
            vec![
                ("oldest", 100, 1),
                ("newest", 400, 2),
                ("middle", 200, 3),
                ("later", 300, 4),
            ],
            CAP,
        ),
        vec!["newest", "later", "middle"],
        "the oldest terminal falls off"
    );
    // Same second → the tiebreak decides, descending, so the DAG inserted
    // last wins. This is the *common* case: a burst settles together.
    assert_eq!(
        retain_history(
            vec![],
            vec![("a", 100, 1), ("b", 100, 2), ("c", 100, 3), ("d", 100, 4)],
            CAP,
        ),
        vec!["d", "c", "b"],
    );
    // A live DAG never competes with history for the cap.
    assert_eq!(
        retain_history(
            vec!["live"],
            vec![("a", 100, 1), ("b", 200, 2), ("c", 300, 3), ("d", 400, 4)],
            CAP,
        ),
        vec!["live", "d", "c", "b"],
    );
}

#[test]
fn error_truncation_cuts_on_a_char_boundary() {
    // `truncate_error` is a pure `&str -> String`. This used to submit a DAG,
    // claim its head, fail it with a long string and read the error back out of
    // a snapshot — four moving parts to observe one transform, and the DAG
    // round-trip is covered by its own tests either way.
    //
    // Testing it directly also reaches the case the round-trip never did: the
    // cap is a **byte** length, so a multibyte char straddling it would panic
    // the slice. That boundary scan is the only non-obvious line in the fn and
    // it had no coverage at all.
    assert_eq!(
        truncate_error("short"),
        "short",
        "under the cap is untouched"
    );

    let ascii = truncate_error(&"x".repeat(5000));
    assert!(ascii.ends_with('…'));
    assert!(ascii.len() <= MAX_ERROR_LEN + '…'.len_utf8());

    // 'é' is 2 bytes, so the 2000-byte cap lands mid-char.
    let multibyte = truncate_error(&"é".repeat(5000));
    assert!(multibyte.ends_with('…'));
    assert!(multibyte.len() <= MAX_ERROR_LEN + '…'.len_utf8());
}

// ---- template shapes ----

#[test]
fn graceful_stop_shape_signal_drain_reconcile() {
    let q = JobQueue::new(1);
    let id = submit(&q, "graceful", |builder| {
        stop_online(builder, &["agent-a"], true);
    });
    assert_eq!(
        declared_shape(&q, id),
        vec![
            // The whole stop hangs under `set_wanted`: the durable intent is
            // written first, and the mechanical steps are its sub-nodes.
            row("set_wanted", None, &[]),
            row("signal", Some("set_wanted"), &[]),
            row("drain", Some("set_wanted"), &[("signal", "done")]),
            row("reconcile", Some("set_wanted"), &[("drain", "done")]),
        ]
    );
    // Neither half of the graceful window takes a build slot. That is what lets
    // a whole-hive graceful stop overlap every agent's drain even at
    // `buildSlots = 1` while a rebuild hogs the slot — the cost ceiling is one
    // `GRACEFUL_STOP_TIMEOUT` in total, not one per agent.
    let agent = Resource::Agent("agent-a".to_owned());
    assert_eq!(
        [
            declared_resources(&q, node_of(&q, id, "signal")),
            declared_resources(&q, node_of(&q, id, "drain")),
        ],
        [vec![agent.clone()], vec![agent]],
        "signal and drain hold the lease but never a build slot"
    );
}

#[test]
fn spawn_shape_provision_create_dropin_reconcile() {
    let q = JobQueue::new(1);
    let id = submit(&q, "approval #7 spawn", |builder| {
        templates::spawn(builder, "newbie", 7);
    });
    assert_eq!(
        declared_shape(&q, id),
        vec![
            row("provision", None, &[]),
            row("create", Some("provision"), &[]),
            row("write_dropin", Some("create"), &[]),
            row("reconcile", Some("create"), &[("write_dropin", "done")]),
            // One tail per outcome, each edged to accept only that one — so
            // *which* tail the graph lets run already is the answer, and
            // nothing branches at runtime. The three differ **only** in their
            // accepted outcome, which is why `declared_shape` spells the
            // outcome set out instead of bucketing it.
            row("resolve_approval", None, &[("provision", "done")]),
            row("resolve_approval", None, &[("provision", "failed")]),
            row("resolve_approval", None, &[("provision", "cancelled")]),
        ]
    );
}

#[test]
fn perm_change_shape_prefixes_rebuild_chain() {
    let q = JobQueue::new(1);
    let id = submit(&q, "perm", |builder| {
        templates::perm_change(
            builder,
            "agent-a",
            PermPayload::Combined {
                groups: Some(vec![]),
                caps: None,
            },
        );
    });
    assert_eq!(
        declared_shape(&q, id)
            .iter()
            .map(|d| d.kind)
            .collect::<Vec<_>>(),
        vec![
            "write_perm_file",
            "meta_sync",
            "prebuild",
            "stop_for_update",
            "swap",
            "post_swap",
            "reconcile",
            // the ok / !ok tail pair
            "emit_rebuilt",
            "emit_rebuilt",
        ],
        "the perm write prefixes an otherwise ordinary rebuild chain"
    );
}

#[test]
fn reparent_shape_is_a_lone_agentless_meta_window_node() {
    // Single-move `set-parent` shape: one node, no rebuild subgraph (no
    // container rebuild needed for a parent move), agentless like
    // `MetaLock`, and it must declare the meta window — a topology commit
    // must not land inside another node's staged deploy window.
    let q = JobQueue::new(1);
    let id = submit(&q, "set-parent", |builder| {
        templates::reparent(builder, vec![(ident("alice"), Some(ident("bob")))]);
    });
    assert_eq!(
        declared_shape(&q, id),
        vec![row("reparent", None, &[])],
        "one node, no rebuild subgraph"
    );
    let node = node_of(&q, id, "reparent");
    assert_eq!(
        declared_resources(&q, node),
        vec![Resource::MetaWindow],
        "a topology commit must declare the same MetaWindow as WritePermFile, \
         and nothing else — no lease (agentless), no build slot (no nix work)"
    );
}

#[test]
fn reparent_bulk_shape_carries_every_move_on_one_node() {
    // `set-parent-bulk`: still ONE node (one git commit, `moves.len() > 1`),
    // not one node per move — bulk atomicity across every move in the
    // request is the reason a single node was chosen in the first place.
    let moves = vec![(ident("alice"), Some(ident("bob"))), (ident("carol"), None)];
    let q = JobQueue::new(1);
    let id = submit(&q, "set-parent-bulk", |builder| {
        templates::reparent(builder, moves.clone());
    });
    assert_eq!(
        declared_shape(&q, id),
        vec![row("reparent", None, &[])],
        "one node for the whole request, not one per move"
    );
    let NodeKind::Reparent { moves: got } = payload_of(&q, id, "reparent") else {
        panic!("expected a Reparent node");
    };
    assert_eq!(got, moves, "every move rides the single node");
}