//! Data model for the generic job-DAG queue: the node kinds — the primitive
//! operations — and what each one carries. The `State` / `PermPayload` wire
//! enums live in `hive_host_sock::jobs` (they travel on the host admin
//! socket) and are re-exported here for the queue's internal use. The graph
//! itself is served through `hive_jobq_wire`'s generic projection — there is
//! no second, typed view of it any more.
//!
//! **One level, not two.** The node is the unit of everything: scheduling,
//! execution, build-log, cancel, and the dashboard group (a group root's
//! subtree *is* the group). A DAG used to be a second level above it, with
//! its own store and its own id; there is no container node any more, so a
//! job is exactly the nodes it declared. See `docs/scheduler/coordinator.md::Job queue`
//! for the full design.

pub use hive_host_sock::jobs::{PermPayload, State};
use serde::Serialize;

use hive_jobq::TerminalState;

/// The primitive operations — each kind maps to one executor fn in
/// `exec.rs`, a thin wrapper over existing `lifecycle.rs` / `meta.rs`
/// code. Concurrency is gated by two resource classes (see
/// [`Resource`](super::resource::Resource), declared per node where the node
/// is constructed rather than derived from its kind); the
/// meta *repo* is serialized by `meta::META_LOCK` inside the wrapped
/// functions themselves, which is why there is no `GitCommit` node —
/// a standalone commit node would open a dirty-working-tree window
/// between nodes that the fused `meta.rs` ops deliberately close.
///
/// What each kind does, the resource/lease rules, and the DAG shapes they
/// compose into live in the node-inventory table and surrounding sections
/// of `docs/scheduler/coordinator.md` — this enum is deliberately not a
/// second copy of that; each variant below gets a one-line pointer.
#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
#[serde(tag = "kind", rename_all = "snake_case")]
pub enum NodeKind {
    /// The rebuild's meta-repo preamble. `relock = false` only for
    /// meta-update cascade rebuilds (re-locking would revert the bump the
    /// cascade just committed).
    MetaSync { agent: String, relock: bool },
    /// Out-of-band toplevel build while the container keeps serving.
    Prebuild { agent: String },
    /// `nixos-container update` profile-swap.
    Swap { agent: String },
    /// The post-`Swap` bookkeeping tail as a first-class node.
    RebuildBookkeeping { agent: String },
    /// First-spawn pre-create provisioning.
    Provision { agent: String },
    /// First-spawn `nixos-container create` proper. Assumes the
    /// upstream `Provision` node already registered the agent in meta.
    Create { agent: String },
    /// `nixos-container destroy` plus the un-registration that follows it.
    ///
    /// Deliberately excluded from [`NodeKind::takes_container_down`] — see
    /// that method for why a node downstream of a `Stop` must not claim the
    /// container going down as its own.
    DestroyContainer { agent: String },
    /// The `purge = true` half of a destroy: delete the agent's state
    /// subvolume (via hive-priv, since a subvolume root defeats
    /// `remove_dir_all`) plus its state and applied dirs.
    PurgeState { agent: String },
    /// The post-destroy bookkeeping tail.
    DestroyBookkeeping { agent: String, purge: bool },
    /// Meta flake lock bump. `sweep = false`: `meta::lock_update` with this
    /// node's own `inputs`; `sweep = true`: `meta::lock_update_hyperhive`
    /// (boot sweep, `inputs` empty). See _Notable collapses_ for how the
    /// scheduler appends the fan-out `Rebuild` DAGs on completion.
    MetaLock {
        sweep: bool,
        fanout: Option<Vec<String>>,
        inputs: Vec<String>,
    },
    /// Idempotent power converge *planner*: fans a child
    /// [`NodeKind::Start`] / [`NodeKind::Stop`] out at runtime rather than
    /// doing the mechanical work itself.
    Reconcile { agent: String },
    /// Mechanical container start. Fanned out by a [`NodeKind::Reconcile`]
    /// that observed `wanted = Up` and the container down.
    Start { agent: String },
    /// Mechanical container stop. Fanned out by a [`NodeKind::Reconcile`]
    /// that observed `wanted = Offline` and up.
    Stop { agent: String },
    /// Mechanical `nixos-container stop` for the profile swap. Never
    /// touches `wanted`. Noop if already stopped.
    StopForUpdate { agent: String },
    /// Set the graceful-stop fence + kick the harness so it runs one
    /// stop-checkpoint turn.
    Signal { agent: String },
    /// Await the harness clearing the fence, bounded by
    /// `GRACEFUL_STOP_TIMEOUT`. Resolves ok either way — the
    /// downstream `Reconcile` performs the actual stop.
    Drain { agent: String },
    /// Write the pause marker (`Coordinator::set_paused`) + mark
    /// `pause_pending`.
    PauseSignal { agent: String },
    /// Await the harness reporting `PauseAcknowledged`, bounded by a
    /// timeout. Resolves ok either way — pausing is best-effort from
    /// the queue's perspective, same as `Drain`.
    PauseDrain { agent: String },
    /// `set_nspawn_flags` + `set_resource_limits` + daemon-reload.
    WriteDropin { agent: String },
    /// Commit `tool-groups.json` / `capabilities.json` per its `payload`.
    WritePermFile { agent: String, payload: PermPayload },
    /// Topology move(s) — `set-parent` (len 1) or `set-parent-bulk` (len N) —
    /// as a single queue node. `moves` is typed `(Ident, Option<Ident>)`
    /// pairs, applied in order under one `META_LOCK` acquisition.
    Reparent {
        moves: Vec<(hive_types::Ident, Option<hive_types::Ident>)>,
    },
    /// Group root of the approval-deploy (`MergeConfigPr`) subtree — the
    /// **brace** that owns the deploy window. See _Braces_ and _Approvals_.
    DeployWindow { agent: String, approval_id: i64 },
    /// Group root of a rebuild subtree — the **brace**, scoped to one
    /// agent. Why braces exist and what they cost: _Braces_.
    AgentWindow { agent: String },
    /// Deploy phase 1 — **verify only, mutates nothing.**
    MergeVerify { agent: String, approval_id: i64 },
    /// Deploy phase 2 — the irreversible fast-forward plus the *opening*
    /// half of the two-phase meta deploy. Does **not** build the container
    /// itself; grows the ordinary rebuild subgraph in as its own children
    /// (see the rebuild-path section's approval-deploy paragraph).
    DeployApply { agent: String, approval_id: i64 },
    /// Deploy phase 3 — closes the two-phase meta deploy once
    /// [`NodeKind::DeployApply`]'s rebuild subgraph comes up clean.
    FinalizeDeploy { agent: String, approval_id: i64 },
    /// Deploy compensation **and bookkeeping** tail. See the `DeployTail`
    /// node-inventory row for its three responsibilities and why it isn't
    /// named `AbortDeploy`.
    DeployTail { agent: String, approval_id: i64 },
    /// Tail node of an approval-carrying DAG (spawn / opaque deploy /
    /// config-PR merge): resolve the approval row from how the work ended.
    ResolveApproval {
        approval_id: i64,
        /// Which outcome this node reports. A template emits **one per
        /// outcome**, each edged to accept only that one, so exactly one is
        /// ever runnable. The `Cancelled` one is also the node
        /// [`super::JobQueue::cancel`] spares, since its edge is the only
        /// one that accepts a dropped dependency.
        outcome: TerminalState,
    },
    /// Tail node of a rebuild / perm-change: emit this agent's `Rebuilt`
    /// manager event. One node per agent *and* per outcome; no cancel
    /// variant (a cancelled DAG never ran, so there is no rebuild to
    /// report).
    EmitRebuilt { agent: String, ok: bool },
    /// Write the agent's durable power intent (`wanted = Up` when `up`,
    /// else `Offline`) as the head node of a power-op DAG.
    SetWanted { agent: String, up: bool },
    /// One-shot boot-time forge user/token sweep for every existing
    /// container (`forge::ensure_all`). Agentless.
    ForgeSweep,
    /// One-shot boot-time matrix user/space sweep (`matrix::ensure_all`).
    /// Agentless.
    MatrixSweep,
    /// One-shot boot-time Forgejo webhook registration. Agentless.
    WebhookRegister,
    /// One-shot boot-time `/knowledge` pull (`knowledge::pull`). Agentless.
    KnowledgePull,
    /// One-shot boot-time pull of the agent set the swarm controller
    /// declares for this hive (`wanted::pull`). Agentless.
    WantedPull,
}

/// How a hive-c0re node describes itself to a generic graph viewer.
///
/// Every field in the wire node's `data` representation here used to be a named column on
/// `NodeView`, meaningful for one node kind and `null` on all the others. As
/// free-form data it costs the wire type nothing, and a generic consumer
/// renders it without knowing what any of it means.
impl hive_jobq_wire::WireNode for NodeKind {
    fn label(&self) -> String {
        self.as_str().to_owned()
    }

    fn data(&self, id: hive_jobq_wire::WireId) -> serde_json::Value {
        let mut data = serde_json::Map::new();
        let agent = self.agent();
        if !agent.is_empty() {
            data.insert("agent".to_owned(), agent.into());
        }
        if let NodeKind::DeployWindow { approval_id, .. } = self {
            data.insert("approval_id".to_owned(), (*approval_id).into());
        }
        if let NodeKind::MetaLock { inputs, .. } = self
            && !inputs.is_empty()
        {
            data.insert("inputs".to_owned(), inputs.clone().into());
        }
        // Not in the payload at all — the build log is keyed on node identity
        // in a side table, which is why `data` is handed the id.
        if let Some(log) = crate::build_logs::global().and_then(|h| h.id_for_node(id)) {
            data.insert("build_log_id".to_owned(), log.into());
        }
        if data.is_empty() {
            serde_json::Value::Null
        } else {
            serde_json::Value::Object(data)
        }
    }
}

impl NodeKind {
    /// Wire string for the node's label on the graph wire
    /// ([`hive_jobq_wire::WireNode::label`]).
    pub fn as_str(&self) -> &'static str {
        match self {
            NodeKind::MetaSync { .. } => "meta_sync",
            NodeKind::Prebuild { .. } => "prebuild",
            NodeKind::Swap { .. } => "swap",
            NodeKind::RebuildBookkeeping { .. } => "rebuild_bookkeeping",
            NodeKind::Provision { .. } => "provision",
            NodeKind::Create { .. } => "create",
            NodeKind::DestroyContainer { .. } => "destroy_container",
            NodeKind::PurgeState { .. } => "purge_state",
            NodeKind::DestroyBookkeeping { .. } => "destroy_bookkeeping",
            NodeKind::MetaLock { .. } => "meta_lock",
            NodeKind::Reconcile { .. } => "reconcile",
            NodeKind::Start { .. } => "start",
            NodeKind::Stop { .. } => "stop",
            NodeKind::StopForUpdate { .. } => "stop_for_update",
            NodeKind::Signal { .. } => "signal",
            NodeKind::Drain { .. } => "drain",
            NodeKind::PauseSignal { .. } => "pause_signal",
            NodeKind::PauseDrain { .. } => "pause_drain",
            NodeKind::WriteDropin { .. } => "write_dropin",
            NodeKind::WritePermFile { .. } => "write_perm_file",
            NodeKind::Reparent { .. } => "reparent",
            NodeKind::DeployWindow { .. } => "deploy_window",
            NodeKind::AgentWindow { .. } => "agent_window",
            NodeKind::MergeVerify { .. } => "merge_verify",
            NodeKind::DeployApply { .. } => "deploy_apply",
            NodeKind::FinalizeDeploy { .. } => "finalize_deploy",
            NodeKind::DeployTail { .. } => "deploy_tail",
            NodeKind::ResolveApproval { .. } => "resolve_approval",
            NodeKind::EmitRebuilt { .. } => "emit_rebuilt",
            NodeKind::SetWanted { .. } => "set_wanted",
            NodeKind::ForgeSweep => "forge_sweep",
            NodeKind::MatrixSweep => "matrix_sweep",
            NodeKind::WebhookRegister => "webhook_register",
            NodeKind::KnowledgePull => "knowledge_pull",
            NodeKind::WantedPull => "wanted_pull",
        }
    }

    /// The agent this node targets, or `""` for agentless kinds
    /// ([`NodeKind::MetaLock`] on the `hyperhive` pseudo-agent,
    /// [`NodeKind::Reparent`] which can span multiple agents, and
    /// [`NodeKind::ResolveApproval`] which acts on an approval row).
    #[must_use]
    pub fn agent(&self) -> &str {
        match self {
            NodeKind::MetaSync { agent, .. }
            | NodeKind::Prebuild { agent }
            | NodeKind::Swap { agent }
            | NodeKind::RebuildBookkeeping { agent }
            | NodeKind::Provision { agent }
            | NodeKind::Create { agent }
            | NodeKind::DestroyContainer { agent }
            | NodeKind::PurgeState { agent }
            | NodeKind::DestroyBookkeeping { agent, .. }
            | NodeKind::Reconcile { agent }
            | NodeKind::Start { agent }
            | NodeKind::Stop { agent }
            | NodeKind::StopForUpdate { agent }
            | NodeKind::Signal { agent }
            | NodeKind::Drain { agent }
            | NodeKind::PauseSignal { agent }
            | NodeKind::PauseDrain { agent }
            | NodeKind::WriteDropin { agent }
            | NodeKind::WritePermFile { agent, .. }
            | NodeKind::DeployWindow { agent, .. }
            | NodeKind::AgentWindow { agent }
            | NodeKind::MergeVerify { agent, .. }
            | NodeKind::DeployApply { agent, .. }
            | NodeKind::FinalizeDeploy { agent, .. }
            | NodeKind::DeployTail { agent, .. }
            | NodeKind::EmitRebuilt { agent, .. }
            | NodeKind::SetWanted { agent, .. } => agent,
            NodeKind::MetaLock { .. }
            | NodeKind::Reparent { .. }
            | NodeKind::ResolveApproval { .. }
            | NodeKind::ForgeSweep
            | NodeKind::MatrixSweep
            | NodeKind::WebhookRegister
            | NodeKind::KnowledgePull
            | NodeKind::WantedPull => "",
        }
    }

    /// Whether running this node is *expected* to take the agent's container
    /// down. Feeds `RunningTransient::takes_container_down`, which the crash watcher
    /// reads to tell an intentional stop from a crash.
    ///
    /// This is a **safety** question, not a display one — it decides whether a
    /// vanished container raises an alert. It is deliberately not derived from
    /// the pill label: a label is free to be renamed or added without moving
    /// the alerting boundary, and only the operation itself knows its intent.
    ///
    /// Default is `false`, and that asymmetry is the point. A wrong `false`
    /// costs a spurious crash event; a wrong `true` **swallows a real crash**
    /// silently. So a kind earns `true` by being listed here, and anything new
    /// is noisy-but-safe until someone decides otherwise.
    #[must_use]
    pub fn takes_container_down(&self) -> bool {
        matches!(
            self,
            // Explicit stops, and the quiesce steps that precede one.
            NodeKind::Stop { .. }
                | NodeKind::StopForUpdate { .. }
                | NodeKind::Signal { .. }
                | NodeKind::Drain { .. }
                | NodeKind::SetWanted { up: false, .. }
                // The rebuild's own machinery: the container is down across the
                // swap and the drop-in write that reconfigures it.
                | NodeKind::Swap { .. }
                | NodeKind::WriteDropin { .. }
        )
        // Everything else is `false` on purpose, including the ones that would
        // be easy to wave through:
        // - `Create` / `Start` / `SetWanted{up}` bring a container UP. A
        //   container disappearing *while starting* is a genuine crash and has
        //   to keep reporting as one.
        // - `DestroyContainer` looks like the most obvious `true` on this list
        //   and is the one that must stay `false`. It is edged downstream of a
        //   `Stop`, so the container is already down when it claims; the stop
        //   that the operator asked for is accounted for by the node that
        //   performs it. A container found alive at destroy time is a genuine
        //   bug, and a `true` here would suppress the alert that says so.
        // - `Reconcile` is a planner; it fans out `Start` / `Stop`, which carry
        //   their own answer.
        // - `DeployWindow` brackets a deploy without itself stopping anything.
        // - `AgentWindow` likewise, though it *parents* nodes that answer
        //   `true`. This is per-node, not per-subtree, and each of those
        //   children reports for itself — so `true` here would only widen
        //   suppression over the build and tail, where a vanished container is
        //   still a real crash.
    }
}