//! `/api/state` cold-load snapshot plus the dashboard's live read side:
//! the `StateSnapshot` shape and its view builders, the
//! `/api/dashboard/stream` SSE channel, and the `/api/dashboard/history`
//! backfill. SPA shape + SSE channels: docs/web-ui/shape.md.

use std::convert::Infallible;

use axum::{
    extract::State,
    http::HeaderMap,
    response::{
        IntoResponse, Response,
        sse::{Event, KeepAlive, Sse},
    },
};
use chrono::{DateTime, Utc};
use hive_sh4re::Approval;
use serde::{Deserialize, Serialize};
use tokio_stream::wrappers::BroadcastStream;
use tokio_stream::{Stream, StreamExt};

use crate::container_view::ContainerView;

use super::meta_inputs::{MetaInputView, read_meta_inputs};
use super::tombstones::{TombstoneView, build_tombstone_views};
use super::{AppState, approvals, error_response, scan_validated_paths};

#[allow(clippy::struct_excessive_bools)]
#[derive(Serialize)]
pub(super) struct StateSnapshot {
    /// Broker seq at the moment this snapshot was assembled. Clients
    /// dedupe their buffered SSE traffic against this value: any
    /// `MessageEvent` with `seq <= snapshot.seq` is already reflected in
    /// the snapshot (or pre-dates it); anything with `seq > snapshot.seq`
    /// is post-snapshot and should be applied. Set to 0 in the
    /// pre-emit case (no events ever fired) — clients treat that as
    /// "apply everything you've buffered".
    seq: u64,
    hostname: String,
    any_stale: bool,
    containers: Vec<ContainerView>,
    transients: Vec<TransientView>,
    approvals: Vec<ApprovalView>,
    /// Last 30 resolved approvals (approved / denied / failed), newest-
    /// first. Drives the "history" tab on the approvals section.
    approval_history: Vec<ApprovalHistoryView>,
    /// Pending operator-targeted questions (`target IS NULL`). Any
    /// agent can `ask` the operator and `ask` returns immediately with
    /// the id; on `/answer-question` we mark the row answered and
    /// fire `HelperEvent::QuestionAnswered` back into the asker's
    /// inbox. Peer-to-peer questions live in the same table but never
    /// surface here (see `OperatorQuestions::pending`).
    questions: Vec<QuestionView>,
    /// Last 20 answered questions, newest-first.
    question_history: Vec<QuestionView>,
    /// State dirs (config history + claude creds + /state/ notes) that
    /// survive after a destroy-without-purge. The operator can re-spawn
    /// with the same name to resume, or PURG3 to wipe them.
    tombstones: Vec<TombstoneView>,
    /// Sub-agents whose FNV-1a hashed web UI port collides with at
    /// least one other agent. Operator resolves by renaming. The
    /// dashboard renders a banner at the top listing each cluster.
    port_conflicts: Vec<PortConflict>,
    /// Inputs in `meta/flake.lock` the operator can selectively
    /// `nix flake update`. Hyperhive first, then `agent-<n>` rows.
    meta_inputs: Vec<MetaInputView>,
    /// True while a dashboard-triggered `meta-update` (flake lock bump +
    /// agent rebuild ripple) is running in the background. Lets a
    /// client that cold-loads mid-update render the META INPUTS panel's
    /// disabled "updating…" state; live transitions arrive via the
    /// `MetaUpdateRunning` event.
    meta_update_running: bool,
    /// Current state of the global job queue — pending + running DAGs
    /// (rebuild / meta-update / spawn / power ops) with their per-node
    /// breakdowns, plus the most recent few terminal DAGs the queue
    /// retains for history. Live transitions arrive via the
    /// `RebuildQueueChanged` event. See `job_queue/`. Field name kept
    /// from the old flat queue for wire compatibility.
    rebuild_queue: Vec<crate::job_queue::DagView>,
    /// Whether the hive-forge container is up. When true the dashboard
    /// links each container's config + each approval's commit into the
    /// forge's `agent-configs` repos.
    forge_present: bool,
    /// Whether the matrix GUI is reachable at `/matrix/`. Sourced from
    /// `HIVE_MATRIX_GUI_ENABLED` env var (set by the c0re NixOS module
    /// when `services.hyperhive.matrix.gui.enable` is on). The gateway
    /// (hive-gateway.nix) does the actual `/matrix/` static serving;
    /// this flag is just an availability signal for iris's dashboard
    /// chrome so the `M4TR1X →` tab doesn't flash when the GUI is off.
    matrix_gui_enabled: bool,
    /// Whether `hive-gateway` is in front of this dashboard. Sourced
    /// from the `HIVE_GATEWAY_ENABLED` env var, which the c0re NixOS
    /// module now always sets (the gateway runs unconditionally
    /// alongside hyperhive), so this is effectively always true: the
    /// dashboard frontend builds same-origin `/agent/<name>/` links to
    /// the per-agent web UI (the gateway routes them via the
    /// runtime-generated `agents.conf` include file — see
    /// `gateway_nginx.rs`). The `false` branch (direct
    /// `http://<hostname>:<port>/` TCP links) is retained as a defensive
    /// fallback for the env being unset. See `docs/gateway.md::Vhost map`.
    gateway_enabled: bool,
    /// Public URL of the forge vhost served by hive-gateway (e.g.
    /// `"https://forge.pr1ma.darkest.space"`). Sourced from the
    /// `HIVE_FORGE_PUBLIC_URL` env var, which the c0re NixOS module
    /// sets when `forge.behindGateway = true`. `None` when absent —
    /// the frontend falls back to `http://<hostname>:3000`.
    forge_public_url: Option<String>,
    /// Human name of this single-host hive instance (e.g. `"pr1ma"`).
    /// Sourced from `HYPERHIVE_HIVE_NAME` env var, set by the c0re
    /// NixOS module from `services.hyperhive.hiveName`. `None` when
    /// the option is unset — chrome falls back to `hostname`.
    hive_name: Option<String>,
    /// Human name of the wider swarm this hive belongs to (e.g.
    /// `"constellat1on"`). Sourced from `HYPERHIVE_SWARM_NAME` env
    /// var, set from `services.hyperhive.swarmName`. `None` when
    /// unset — chrome omits the swarm segment of the breadcrumb.
    swarm_name: Option<String>,
    /// Peer hives in the same swarm. Parsed from `HYPERHIVE_PEERS`
    /// (JSON array of `{domain,cert_fingerprint}` objects, emitted by
    /// the c0re NixOS module from `services.hyperhive.swarm.peers`).
    /// Empty on single-hive deploys. Feeds the P33RS dashboard tab.
    peer_hives: Vec<PeerHiveView>,
    /// Server-level warnings for the dashboard's top-of-page banner
    /// (currently host disk-pressure; more producers can be added
    /// backend-side). Empty when all clear. Built by
    /// `host_stats::server_warnings`; the frontend renders this list
    /// generically, so new warning kinds need no frontend change.
    server_warnings: Vec<crate::host_stats::ServerWarning>,
    /// Live running/stopped status for the four hive infra containers
    /// (`hive-ci`, `hive-forge`, `hive-gateway`, `hive-matrix`). Feeds the
    /// C0R3 page's 1NFR4 sub-tab so the operator can start/stop/restart
    /// them without an `infra_admin` agent's `restart` tool.
    infra_containers: Vec<InfraContainerView>,
}

/// One row for the C0R3 page's 1NFR4 sub-tab.
#[derive(Serialize)]
struct InfraContainerView {
    /// Container / systemd-unit name (e.g. `"hive-ci"`).
    name: &'static str,
    running: bool,
}

/// Live running/stopped status for all four hive infra containers.
/// Extracted out of [`api_state`] to keep it under clippy's
/// `too_many_lines` limit.
async fn infra_container_views() -> Vec<InfraContainerView> {
    let mut infra_containers = Vec::with_capacity(hive_priv_sock::InfraContainer::ALL.len());
    for container in hive_priv_sock::InfraContainer::ALL {
        infra_containers.push(InfraContainerView {
            name: container.unit_name(),
            running: crate::lifecycle::infra_is_running(container).await,
        });
    }
    infra_containers
}

/// One peer hive for the P33RS dashboard tab. Derived from
/// `HYPERHIVE_PEERS` env; `url` is the peer's HTTPS dashboard root.
/// `cert_fingerprint` is `Some("sha256:<hex64>")` when the peer uses a
/// self-signed cert and the operator pinned its fingerprint in
/// `services.hyperhive.swarm.peers`.
#[derive(Serialize)]
struct PeerHiveView {
    name: String,
    url: String,
    cert_fingerprint: Option<String>,
}

/// `OpQuestion` + computed `question_refs` / `answer_refs`. Built
/// from the snapshot read; the live channel attaches the same
/// fields directly on `QuestionAdded` / `QuestionResolved`.
#[derive(Serialize)]
struct QuestionView {
    #[serde(flatten)]
    inner: crate::operator_questions::OpQuestion,
    #[serde(skip_serializing_if = "Vec::is_empty")]
    question_refs: Vec<String>,
    #[serde(skip_serializing_if = "Vec::is_empty")]
    answer_refs: Vec<String>,
}

impl QuestionView {
    fn from_question(q: crate::operator_questions::OpQuestion) -> Self {
        let question_refs = scan_validated_paths(&q.question);
        let answer_refs = q
            .answer
            .as_deref()
            .map(scan_validated_paths)
            .unwrap_or_default();
        Self {
            inner: q,
            question_refs,
            answer_refs,
        }
    }
}

#[derive(Serialize)]
struct PortConflict {
    port: u16,
    /// All agent names sharing this port (sorted, ≥2 entries).
    agents: Vec<String>,
}

#[derive(Serialize)]
struct TransientView {
    name: String,
    kind: &'static str,
    secs: u64,
}

#[derive(Serialize)]
struct ApprovalHistoryView {
    id: i64,
    agent: String,
    kind: &'static str,
    /// First 12 chars of the canonical sha (preferred) or
    /// manager-supplied ref. None for resolved spawn approvals.
    sha_short: Option<String>,
    /// `approved` / `denied` / `failed`.
    status: &'static str,
    /// RFC 3339 UTC. Renders as a relative time on the dashboard.
    resolved_at: DateTime<Utc>,
    /// Operator-supplied deny reason (for `denied`) or build error
    /// (for `failed`). None on `approved`.
    #[serde(skip_serializing_if = "Option::is_none")]
    note: Option<String>,
}

#[derive(Serialize)]
struct ApprovalView {
    id: i64,
    agent: String,
    kind: &'static str,
    /// First 12 chars of the reviewed PR head sha, for `MergeConfigPr`
    /// only. Display-only (the short chip on the card).
    sha_short: Option<String>,
    /// Manager-supplied description shown on the approval card.
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
    /// Forge PR number, for `MergeConfigPr` only. Lets the frontend
    /// build a "review PR on forge" link
    /// (`{forgeBase}/agent-configs/{agent}/pulls/{pr_number}`). `None`
    /// for every other kind.
    #[serde(skip_serializing_if = "Option::is_none")]
    pr_number: Option<u64>,
    /// Raw `commit_ref` payload for `UpdateMetaInputs` (JSON-encoded
    /// `Vec<String>` of input names; `"[]"` = all inputs) and
    /// `SchedulePrompt` (JSON-encoded `SchedulePromptPayload`). The
    /// frontend parses this to render a human-readable card body.
    /// `None` for every other kind.
    #[serde(skip_serializing_if = "Option::is_none")]
    commit_ref: Option<String>,
    /// RFC 3339 UTC time the approval was queued. Rendered as a
    /// relative time on the card so the operator can spot a stale
    /// request.
    requested_at: DateTime<Utc>,
}

/// Replace silent `.unwrap_or_default()` on the data sources behind
/// `/api/state` so that whichever query degrades surfaces in journald
/// instead of leaving the operator staring at an empty list. The
/// dashboard still degrades to a sensible default value; the warn
/// is just the diagnostic breadcrumb the old code swallowed.
fn log_default<T, E>(what: &str, result: std::result::Result<T, E>) -> T
where
    T: Default,
    E: std::fmt::Debug,
{
    match result {
        Ok(v) => v,
        Err(e) => {
            tracing::warn!(target: "api_state", source = %what, error = ?e, "snapshot source failed; using default");
            T::default()
        }
    }
}

/// Window over which container crashes count toward the `agents_crashing`
/// banner warning. Wide enough that a crash-looping container (restarted
/// by `Restart=on-failure` every few seconds) keeps the warning lit
/// between flaps, short enough that a single recovered crash clears within
/// minutes.
const CRASH_WARNING_WINDOW: std::time::Duration = std::time::Duration::from_mins(10);

pub(super) async fn api_state(
    headers: HeaderMap,
    State(state): State<AppState>,
) -> axum::Json<StateSnapshot> {
    let host = headers
        .get("host")
        .and_then(|h| h.to_str().ok())
        .unwrap_or("localhost");
    let hostname = host.split(':').next().unwrap_or(host).to_owned();

    // Capture the unified dashboard-channel seq *before* any read so the
    // dedupe contract is "events with seq > snapshot.seq are
    // post-snapshot, never missed." An event landing during snapshot
    // construction may be doubly applied (snapshot caught the write +
    // client also applies the SSE frame) — that's a renderer's problem
    // to make idempotent, not ours to avoid here.
    let seq = state.coord.current_seq();

    // Refresh the coordinator's cached container snapshot before
    // reading. Cold-load clients then see whatever the latest rescan
    // produced; live clients converge via the matching
    // `ContainerStateChanged` / `ContainerRemoved` events the rescan
    // emits.
    //
    // Bound the rescan: it shells out (`nixos-container list` etc.), so a
    // saturated/wedged build backend — e.g. hive-c0re mid-startup-sweep
    // hammering slow `nixos-container update` subprocesses — can stall it
    // long enough that `/api/state` hangs for the whole request (the
    // ~minute-long /state reported in the field). On timeout we skip the
    // fresh rescan and serve the last cached snapshot instead; live
    // clients still converge via the SSE events a later successful rescan
    // emits, and the next /state call retries the refresh. Introspection
    // stays responsive regardless of the build backend's health.
    if tokio::time::timeout(
        std::time::Duration::from_secs(3),
        state.coord.rescan_containers_and_emit(),
    )
    .await
    .is_err()
    {
        tracing::warn!(
            "api_state: container rescan exceeded 3s (build backend likely saturated); \
             serving last cached snapshot"
        );
    }
    let containers = state.coord.containers_snapshot().await;
    let any_stale = containers.iter().any(|c| c.needs_update);
    let transient_snapshot = state.coord.transient_snapshot();
    let pending_approvals = approvals::gc_orphans(
        &state.coord,
        log_default("approvals.pending", state.coord.approvals.pending()),
    );
    let transients = build_transient_views(&containers, &transient_snapshot);
    let approvals = build_approval_views(pending_approvals);
    let approval_history = log_default(
        "approvals.recent_resolved",
        state.coord.approvals.recent_resolved(30),
    )
    .into_iter()
    .map(history_view)
    .collect();
    let tombstones = build_tombstone_views(&state.coord, &containers, &transient_snapshot);
    let port_conflicts = build_port_conflicts(&containers);

    // Both operator-targeted and peer threads surface on the dashboard
    // (the client filters by target). Each row is wrapped in QuestionView
    // so the snapshot carries the same file_refs the live event variants
    // attach.
    let questions: Vec<QuestionView> =
        log_default("questions.pending_all", state.coord.questions.pending_all())
            .into_iter()
            .map(QuestionView::from_question)
            .collect();
    let question_history: Vec<QuestionView> = log_default(
        "questions.recent_answered_all",
        state.coord.questions.recent_answered_all(20),
    )
    .into_iter()
    .map(QuestionView::from_question)
    .collect();

    // Banner warnings: host probes (disk) + agent-state (pending logins,
    // crashing agents). Built before the response struct because the
    // agent-state producer borrows `containers`, which moves in below.
    let server_warnings = {
        let mut w = crate::host_stats::server_warnings();
        w.extend(crate::host_stats::agent_state_warnings(
            &containers,
            &state.coord.recent_crash_counts(CRASH_WARNING_WINDOW),
        ));
        w
    };

    let infra_containers = infra_container_views().await;

    axum::Json(StateSnapshot {
        seq,
        hostname,
        any_stale,
        containers,
        transients,
        approvals,
        approval_history,
        meta_inputs: read_meta_inputs(),
        meta_update_running: state.coord.meta_update_in_progress(),
        questions,
        question_history,
        tombstones,
        port_conflicts,
        rebuild_queue: state.coord.job_queue.snapshot(),
        forge_present: crate::forge::is_present().await,
        matrix_gui_enabled: std::env::var_os("HIVE_MATRIX_GUI_ENABLED").is_some_and(|v| {
            // Accept any truthy string ("1", "true", "yes") since the
            // env var is set by NixOS module wiring with the literal
            // "1"; defensive parse so manual overrides also work.
            let s = v.to_string_lossy().to_ascii_lowercase();
            matches!(s.as_str(), "1" | "true" | "yes")
        }),
        gateway_enabled: std::env::var_os("HIVE_GATEWAY_ENABLED").is_some_and(|v| {
            // Same truthy-string parse as `matrix_gui_enabled`; the
            // env var is set by the c0re NixOS module to the literal
            // "1" — the gateway always runs alongside hyperhive.
            let s = v.to_string_lossy().to_ascii_lowercase();
            matches!(s.as_str(), "1" | "true" | "yes")
        }),
        forge_public_url: std::env::var("HIVE_FORGE_PUBLIC_URL")
            .ok()
            .filter(|s| !s.is_empty()),
        hive_name: std::env::var("HYPERHIVE_HIVE_NAME")
            .ok()
            .filter(|s| !s.is_empty()),
        swarm_name: std::env::var("HYPERHIVE_SWARM_NAME")
            .ok()
            .filter(|s| !s.is_empty()),
        peer_hives: parse_peer_hives(),
        server_warnings,
        infra_containers,
    })
}

/// Parse `HYPERHIVE_PEERS` env var into dashboard-ready `PeerHiveView`
/// entries. The env var is a JSON array of `{domain, cert_fingerprint}`
/// objects emitted by the c0re NixOS module from
/// `services.hyperhive.swarm.peers`. Each entry becomes
/// `{ name: domain, url: "https://domain/" }` for the P33RS tab.
/// Returns empty vec when unset (single-hive deploy).
fn parse_peer_hives() -> Vec<PeerHiveView> {
    #[derive(serde::Deserialize)]
    struct Raw {
        domain: String,
        cert_fingerprint: Option<String>,
    }
    let Ok(json) = std::env::var("HYPERHIVE_PEERS") else {
        return Vec::new();
    };
    let Ok(raw): Result<Vec<Raw>, _> = serde_json::from_str(&json) else {
        tracing::warn!("HYPERHIVE_PEERS is not valid JSON; ignoring");
        return Vec::new();
    };
    raw.into_iter()
        .map(|r| {
            let cert_fingerprint = r.cert_fingerprint.and_then(|fp| {
                if validate_cert_fingerprint(&fp) {
                    Some(fp)
                } else {
                    tracing::warn!(
                        domain = %r.domain,
                        fingerprint = %fp,
                        "HYPERHIVE_PEERS: invalid cert_fingerprint format \
                         (expected `sha256:<64 hex chars>`); ignoring fingerprint"
                    );
                    None
                }
            });
            PeerHiveView {
                name: r.domain.clone(),
                url: format!("https://{}/", r.domain),
                cert_fingerprint,
            }
        })
        .collect()
}

/// Validate a TLS certificate fingerprint string from `HYPERHIVE_PEERS`.
/// Accepts `sha256:<64 hex chars>` (upper or lower case).
fn validate_cert_fingerprint(fp: &str) -> bool {
    let Some(hex) = fp.strip_prefix("sha256:") else {
        return false;
    };
    hex.len() == 64 && hex.chars().all(|c| c.is_ascii_hexdigit())
}

/// Group live containers by their assigned web UI port; clusters with
/// more than one member are port-hash collisions the operator needs
/// to resolve by renaming. Manager (fixed at 8000) and sub-agents
/// (8100..8999) can't collide with each other — collisions are
/// strictly between sub-agents.
fn build_port_conflicts(containers: &[ContainerView]) -> Vec<PortConflict> {
    let mut by_port: std::collections::BTreeMap<u16, Vec<String>> =
        std::collections::BTreeMap::new();
    for c in containers {
        by_port.entry(c.port).or_default().push(c.name.clone());
    }
    by_port
        .into_iter()
        .filter(|(_, agents)| agents.len() > 1)
        .map(|(port, mut agents)| {
            agents.sort();
            PortConflict { port, agents }
        })
        .collect()
}

/// Transient state for agents whose container does NOT yet exist
/// (`Spawning`). Lifecycle ops on existing containers surface as
/// `ContainerView.pending` inline; this list only catches pre-creation.
fn build_transient_views(
    containers: &[ContainerView],
    transient_snapshot: &std::collections::HashMap<String, crate::coordinator::TransientState>,
) -> Vec<TransientView> {
    transient_snapshot
        .iter()
        .filter(|(name, _)| !containers.iter().any(|c| &c.name == *name))
        .map(|(name, st)| TransientView {
            name: name.clone(),
            kind: transient_label(st.kind),
            secs: st.since.elapsed().as_secs(),
        })
        .collect()
}

fn transient_label(k: crate::coordinator::TransientKind) -> &'static str {
    use crate::coordinator::TransientKind::{
        Destroying, Rebuilding, Restarting, Spawning, Starting, Stopping,
    };
    match k {
        Spawning => "spawning",
        Starting => "starting",
        Stopping => "stopping",
        Restarting => "restarting",
        Rebuilding => "rebuilding",
        Destroying => "destroying",
    }
}

/// Render each pending approval into its dashboard view (short sha for
/// `MergeConfigPr`, just the name for `Spawn`).
/// Project a resolved sqlite row into the lean shape the dashboard
/// history tab consumes — no `diff_html` (rendering 30 of them
/// per /api/state poll would mean 30 git diffs per refresh).
fn history_view(a: Approval) -> ApprovalHistoryView {
    let displayed = a.fetched_sha.as_deref().unwrap_or(&a.commit_ref);
    let sha_short = if displayed.is_empty() {
        None
    } else {
        Some(displayed[..displayed.len().min(12)].to_owned())
    };
    let status = match a.status {
        hive_sh4re::ApprovalStatus::Approved => "approved",
        hive_sh4re::ApprovalStatus::Denied => "denied",
        hive_sh4re::ApprovalStatus::Failed => "failed",
        hive_sh4re::ApprovalStatus::Cancelled => "cancelled",
        // Pending shouldn't appear in recent_resolved, but be defensive.
        hive_sh4re::ApprovalStatus::Pending => "pending",
    };
    let kind = a.kind.as_str();
    ApprovalHistoryView {
        id: a.id,
        agent: a.agent,
        kind,
        sha_short,
        status,
        resolved_at: a.resolved_at.unwrap_or_default(),
        note: a.note,
    }
}

fn build_approval_views(approvals: Vec<Approval>) -> Vec<ApprovalView> {
    let mut out = Vec::with_capacity(approvals.len());
    for a in approvals {
        out.push(match a.kind {
            hive_sh4re::ApprovalKind::Spawn => ApprovalView {
                id: a.id,
                agent: a.agent,
                kind: "spawn",
                sha_short: None,
                description: a.description,
                pr_number: None,
                commit_ref: None,
                requested_at: a.requested_at,
            },
            hive_sh4re::ApprovalKind::InitConfig => ApprovalView {
                id: a.id,
                agent: a.agent,
                kind: "init_config",
                sha_short: None,
                description: a.description,
                pr_number: None,
                commit_ref: None,
                requested_at: a.requested_at,
            },
            hive_sh4re::ApprovalKind::UpdateMetaInputs => ApprovalView {
                id: a.id,
                agent: a.agent,
                kind: "update_meta_inputs",
                sha_short: None,
                description: a.description,
                pr_number: None,
                commit_ref: Some(a.commit_ref),
                requested_at: a.requested_at,
            },
            hive_sh4re::ApprovalKind::SchedulePrompt => ApprovalView {
                id: a.id,
                agent: a.agent,
                kind: "schedule_prompt",
                sha_short: None,
                description: a.description,
                pr_number: None,
                commit_ref: Some(a.commit_ref),
                requested_at: a.requested_at,
            },
            hive_sh4re::ApprovalKind::MergeConfigPr => {
                // commit_ref = PR number; fetched_sha = the reviewed PR
                // head. Show the head sha; the config diff surface lives
                // on the forge PR itself.
                let sha = a
                    .fetched_sha
                    .as_deref()
                    .map(|s| s[..s.len().min(12)].to_owned());
                // Surface the PR number so the frontend can link to the
                // PR on the forge. commit_ref holds the number as text.
                let pr_number = a.commit_ref.parse::<u64>().ok();
                ApprovalView {
                    id: a.id,
                    agent: a.agent,
                    kind: "merge_config_pr",
                    sha_short: sha,
                    description: a.description,
                    pr_number,
                    commit_ref: None,
                    requested_at: a.requested_at,
                }
            }
        });
    }
    out
}

pub(super) async fn dashboard_history(State(state): State<AppState>) -> Response {
    // Backfill source for the dashboard terminal. Returns up to ~200
    // historical broker messages (no other event kinds are persisted)
    // converted to `DashboardEvent::Sent` JSON so the client can replay
    // through the same dispatch path as live frames. Wrapped in
    // `{ seq, events }`: the seq is the dashboard channel's high-water
    // mark at fetch time. Clients use it to dedupe their buffered live
    // SSE traffic (drop anything with `seq <= history_seq`) so a frame
    // that lands between SSE-subscribe and history-fetch isn't shown
    // twice and isn't lost. Historical rows carry `seq = 0`; the
    // boundary seq is what closes the dedupe window.
    const HISTORY_LIMIT: u64 = 200;
    let seq = state.coord.current_seq();
    match state.coord.broker.recent_all(HISTORY_LIMIT) {
        Ok(mut messages) => {
            messages.reverse();
            let events: Vec<crate::dashboard_events::DashboardEvent> = messages
                .into_iter()
                .map(|m| match m {
                    crate::broker::MessageEvent::Sent {
                        id,
                        from,
                        to,
                        body,
                        at,
                        in_reply_to,
                    } => {
                        let file_refs = scan_validated_paths(&body);
                        crate::dashboard_events::DashboardEvent::Sent {
                            seq: 0,
                            id,
                            from,
                            to,
                            body,
                            at: hive_sh4re::wire_time::from_secs(at),
                            in_reply_to,
                            file_refs,
                        }
                    }
                    crate::broker::MessageEvent::Delivered {
                        id,
                        from,
                        to,
                        body,
                        at,
                        in_reply_to,
                    } => {
                        let file_refs = scan_validated_paths(&body);
                        crate::dashboard_events::DashboardEvent::Delivered {
                            seq: 0,
                            id,
                            from,
                            to,
                            body,
                            at: hive_sh4re::wire_time::from_secs(at),
                            in_reply_to,
                            file_refs,
                        }
                    }
                })
                .collect();
            axum::Json(serde_json::json!({ "seq": seq, "events": events })).into_response()
        }
        Err(e) => error_response(&format!("dashboard/history failed: {e:#}")),
    }
}

/// `/dashboard/stream` query string. Today's only field is `kinds`:
/// a comma-separated allow-list of event-`kind` strings.
/// Empty / absent ⇒ no filter (current behaviour, all variants
/// forwarded). Set ⇒ only the named kinds reach the subscriber,
/// non-matches are skipped before the JSON serialise cost.
///
/// Useful for narrow pages (e.g. `flow.js` only cares about `sent`
/// / `delivered` / `container_state_changed` / `container_removed`)
/// that want to drop the dispatch overhead on every unrelated mutation.
#[derive(Deserialize, Default)]
pub(super) struct DashboardStreamQuery {
    /// Comma-separated event kinds to forward. Each token is
    /// trimmed; unknown kinds are silently ignored on lookup
    /// (subscriber sees nothing instead of an error).
    kinds: Option<String>,
}

pub(super) async fn dashboard_stream(
    State(state): State<AppState>,
    axum::extract::Query(q): axum::extract::Query<DashboardStreamQuery>,
) -> Sse<impl Stream<Item = Result<Event, Infallible>>> {
    let rx = state.coord.dashboard_subscribe();
    // Pre-parse the allow-list once at subscription time, so the
    // per-event hot path is just a `HashSet::contains` on a
    // `&'static str` — no string churn per frame.
    let kind_filter: Option<std::collections::HashSet<String>> = q.kinds.and_then(|raw| {
        let set: std::collections::HashSet<String> = raw
            .split(',')
            .map(str::trim)
            .filter(|s| !s.is_empty())
            .map(str::to_owned)
            .collect();
        if set.is_empty() { None } else { Some(set) }
    });
    let stream = BroadcastStream::new(rx).filter_map(move |res| {
        // Drop lagged frames. Browsers reconnect; the seq dedupe on
        // reconnect skips any frame already reflected in the snapshot.
        let event = res.ok()?;
        if let Some(filter) = kind_filter.as_ref()
            && !filter.contains(event.kind_tag())
        {
            return None;
        }
        let json = serde_json::to_string(&event).ok()?;
        Some(Ok(Event::default().data(json)))
    });
    Sse::new(stream).keep_alive(KeepAlive::default())
}