khive-runtime 0.10.0

//! RuntimeConfig, BackendId, NamespaceToken, and embedding model helpers.

use std::sync::Arc;

use khive_db::StorageBackend;
pub use khive_db::WalCeilingSource;
use khive_gate::{ActorRef, AllowAllGate, GateRef};
use khive_types::Namespace;
use lattice_embed::EmbeddingModel;

use crate::error::RuntimeResult;

// ---- BackendId ----

/// Identifies a named backend in a multi-backend deployment.
///
/// The `main` backend is the default single-backend name. Multi-backend deployments
/// assign each `[[backends]]` entry a distinct `BackendId`. The
/// `SubstrateCoordinator` in `kkernel`
/// uses `BackendId` for node-to-backend resolution and cross-backend edge routing.
///
/// A single-backend `KhiveRuntime` always has the `main` backend id by default.
/// The boot path in `kkernel` or `khive-mcp` sets the id via `RuntimeConfig::backend_id`
/// when constructing per-pack runtimes.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct BackendId(String);

/// Validation error returned when a backend identifier is rejected.
#[derive(Clone, Debug, PartialEq, Eq, thiserror::Error)]
pub enum BackendIdError {
    /// The supplied identifier was empty or contained only whitespace.
    #[error("backend id must not be empty or whitespace-only")]
    Empty,
}

impl BackendId {
    /// The default single-backend name.
    pub const MAIN: &'static str = "main";

    /// Parse a nonempty backend identifier.
    pub fn parse(name: impl Into<String>) -> Result<Self, BackendIdError> {
        let name = name.into();
        if name.trim().is_empty() {
            return Err(BackendIdError::Empty);
        }
        Ok(Self(name))
    }

    /// The default `main` backend id.
    pub fn main() -> Self {
        Self(Self::MAIN.to_string())
    }

    /// Return the backend name as a `&str`.
    pub fn as_str(&self) -> &str {
        &self.0
    }
}

impl TryFrom<String> for BackendId {
    type Error = BackendIdError;

    fn try_from(value: String) -> Result<Self, Self::Error> {
        Self::parse(value)
    }
}

impl TryFrom<&str> for BackendId {
    type Error = BackendIdError;

    fn try_from(value: &str) -> Result<Self, Self::Error> {
        Self::parse(value)
    }
}

impl std::str::FromStr for BackendId {
    type Err = BackendIdError;

    fn from_str(value: &str) -> Result<Self, Self::Err> {
        Self::parse(value)
    }
}

impl std::fmt::Display for BackendId {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.0)
    }
}

#[cfg(test)]
mod backend_id_tests {
    use super::BackendId;

    #[test]
    fn empty_and_whitespace_only_backend_ids_are_rejected() {
        for invalid in ["", " ", "\t\n"] {
            assert!(
                BackendId::parse(invalid).is_err(),
                "backend id {invalid:?} must be rejected"
            );
        }
    }

    #[test]
    fn nonempty_backend_id_round_trips() {
        let id = BackendId::parse("archive").expect("valid backend id");
        assert_eq!(id.as_str(), "archive");
        assert_eq!(id.to_string(), "archive");
    }
}

// ---- Sealed token ----

mod private {
    #[derive(Clone, Debug)]
    pub(crate) struct Sealed;
}

/// Authorization proof that a caller is permitted to access a specific namespace.
///
/// Created by [`crate::VerbRegistry::dispatch`] after the gate approves the request.
/// The sealed inner field prevents external code from constructing a token
/// without going through the authorization path.
///
/// The `namespace` field is the **write namespace**: all records created via
/// this token land in that namespace. `visible` is the **read visibility set**:
/// list/search/get operations will return records from any namespace in this
/// set. The write namespace is always a member of the visible set.
///
/// Single-namespace behaviour (backward-compatible default): `visible` contains
/// exactly `[namespace]` — identical to the old strict-equality checks.
#[derive(Clone, Debug)]
pub struct NamespaceToken {
    namespace: Namespace,
    gate_namespace: Namespace,
    gate_explicit_namespace: Option<String>,
    request_id: Option<u64>,
    visible: Vec<Namespace>,
    actor: ActorRef,
    process_ref: Option<String>,
    _sealed: private::Sealed,
}

impl NamespaceToken {
    /// Mint an authorized token with an extended visibility set.
    ///
    /// `extra_visible` lists namespaces beyond the primary that the token may
    /// read. The primary namespace is always included in the visible set
    /// regardless of what `extra_visible` contains. Duplicates are removed.
    pub(crate) fn mint_with_visibility(
        namespace: Namespace,
        extra_visible: Vec<Namespace>,
        actor: ActorRef,
    ) -> Self {
        let mut visible = vec![namespace.clone()];
        for ns in extra_visible {
            if !visible.contains(&ns) {
                visible.push(ns);
            }
        }
        debug_assert!(!visible.is_empty(), "visible set must be non-empty");
        Self {
            gate_namespace: namespace.clone(),
            gate_explicit_namespace: None,
            request_id: None,
            namespace,
            visible,
            actor,
            process_ref: None,
            _sealed: private::Sealed,
        }
    }

    /// Mint an authorized token. Only callable from within `khive-runtime`.
    ///
    /// The visible set defaults to `[namespace]` — backward-compatible with
    /// single-namespace enforcement.
    pub(crate) fn mint_authorized(namespace: Namespace, actor: ActorRef) -> Self {
        Self::mint_with_visibility(namespace, vec![], actor)
    }

    /// Convenience constructor for the local namespace with an anonymous actor.
    ///
    /// Only callable from within `khive-runtime`. External callers must use
    /// [`KhiveRuntime::authorize`] to mint tokens.
    // Used only in #[cfg(test)] blocks within this crate's src/ files.
    #[allow(dead_code)]
    pub(crate) fn local() -> Self {
        Self::mint_authorized(Namespace::local(), ActorRef::anonymous())
    }

    /// Convenience constructor for a specific namespace with an anonymous actor.
    ///
    /// Only callable from within `khive-runtime`. External callers must use
    /// [`KhiveRuntime::authorize`] to mint tokens.
    // Used only in #[cfg(test)] blocks within this crate's src/ files.
    #[allow(dead_code)]
    pub(crate) fn for_namespace(ns: Namespace) -> Self {
        Self::mint_authorized(ns, ActorRef::anonymous())
    }

    /// Return the write namespace this token authorises.
    ///
    /// All records created via this token land in this namespace.
    pub fn namespace(&self) -> &Namespace {
        &self.namespace
    }

    /// Return the namespace used by the originating dispatch's Gate check.
    /// It can differ from the primary storage namespace on an implicit request.
    /// Tokens minted directly, or reminted by `with_namespace`, use their primary.
    pub fn gate_namespace(&self) -> &Namespace {
        &self.gate_namespace
    }

    pub(crate) fn with_gate_namespace(mut self, namespace: Namespace) -> Self {
        self.gate_namespace = namespace;
        self
    }

    /// The exact submitted namespace argument, if the caller supplied one.
    /// Pack handlers normally receive params after dispatch strips this key.
    pub(crate) fn gate_explicit_namespace(&self) -> Option<&str> {
        self.gate_explicit_namespace.as_deref()
    }

    pub(crate) fn with_gate_explicit_namespace(mut self, namespace: Option<String>) -> Self {
        self.gate_explicit_namespace = namespace;
        self
    }

    /// Correlates handler-internal Gate consultations with their dispatch audit.
    pub(crate) fn request_id(&self) -> Option<u64> {
        self.request_id
    }

    pub(crate) fn with_request_id(mut self, request_id: Option<u64>) -> Self {
        self.request_id = request_id;
        self
    }

    /// Return the read-visibility set.
    ///
    /// List, search, and get operations must accept records whose namespace is
    /// a member of this set. The write namespace is always included.
    pub fn visible_namespaces(&self) -> &[Namespace] {
        &self.visible
    }

    /// Return a deduplicated list of visible namespace strings (borrowed).
    ///
    /// Convenience for passing directly to storage layer filters.
    pub fn visible_namespace_strs(&self) -> Vec<&str> {
        self.visible.iter().map(|ns| ns.as_str()).collect()
    }

    /// Return the actor reference embedded in this token.
    pub fn actor(&self) -> &ActorRef {
        &self.actor
    }

    /// Return the originating process's opaque attribution reference, when set.
    ///
    /// This is request metadata only. It never participates in gate checks,
    /// namespace visibility, or actor identity.
    pub fn process_ref(&self) -> Option<&str> {
        self.process_ref.as_deref()
    }

    pub(crate) fn with_process_ref(mut self, process_ref: Option<String>) -> Self {
        self.process_ref = process_ref;
        self
    }

    /// Return a new token with the same actor but a different namespace.
    /// The Gate namespace metadata is reset to the new primary namespace.
    ///
    /// The visible set is replaced with `[ns]`: this is a full read+write token
    /// for `ns`, not a type-enforced write-only or append-only capability. It is
    /// a capability-transfer primitive, not a policy gate: callers must enforce
    /// any ACL check before calling this and use the minted token only within
    /// the intended narrow scope (e.g. a single `create_note` call). A future
    /// security model should replace this pattern with a type-enforced
    /// append-only capability that goes through the Gate.
    pub fn with_namespace(&self, ns: Namespace) -> Self {
        Self::mint_authorized(ns, self.actor.clone()).with_process_ref(self.process_ref.clone())
    }
}

/// Read the optional request-origin process reference without normalization.
///
/// A non-Unicode environment value cannot be represented in JSON and is
/// treated as absent after emitting a warning that does not expose its bytes.
pub fn process_ref_from_env() -> Option<String> {
    match std::env::var("KHIVE_PROCESS_REF") {
        Ok(value) => Some(value),
        Err(std::env::VarError::NotPresent) => None,
        Err(std::env::VarError::NotUnicode(_)) => {
            tracing::warn!(
                "KHIVE_PROCESS_REF is not valid Unicode and cannot be represented in request metadata"
            );
            None
        }
    }
}

// ---- RuntimeConfig ----

/// Runtime configuration.
///
/// The `db_path` field remains for backward compatibility and as input to the
/// supported async khive-mcp/kkernel host builders. Direct backend assembly is
/// reserved for an already-coordinated database; use
/// [`crate::KhiveRuntime::from_prepared_backend`] when that precondition has
/// been established. `embedding_model` remains as the primary-model config
/// shorthand beside the provider registry.
#[derive(Clone, Debug)]
pub struct RuntimeConfig {
    /// Named custody references; secret material stays inside credential providers.
    pub credentials: Vec<crate::credentials::CredentialConfig>,
    /// Configured receipt key ring. Absence never generates a replacement key.
    pub visibility_receipts: Option<crate::credentials::VisibilityReceiptConfig>,

    pub mounts: Vec<crate::mount_config::MountConfig>,

    /// Path to the SQLite database file. `None` = in-memory (tests).
    ///
    /// Production boot passes this value to the async khive-mcp/kkernel host
    /// builders, which coordinate V21 before constructing runtimes. Tests and
    /// already-current single-backend callers may still use it directly.
    pub db_path: Option<std::path::PathBuf>,
    /// The WAL ceiling applied to this runtime's implicit main backend.
    /// Zero means disabled, including for a read-only backend that retains a
    /// nonzero configured value only for operator reporting.
    pub wal_ceiling_bytes: u64,
    /// The configured value before read-only writer-policy suppression.
    pub wal_ceiling_configured_bytes: u64,
    /// Where the configured ceiling came from.
    pub wal_ceiling_source: WalCeilingSource,
    /// Construction-time snapshot of the environment fallback. The host uses
    /// this same value to resolve every named backend before forwarding or
    /// opening it, without rereading mutable process environment.
    pub wal_ceiling_env_raw: Option<String>,
    /// One snapshot for named backend resolution and daemon compatibility.
    pub disk_guard_environment: khive_db::DiskGuardEnvironment,
    /// Captured implicit-main policy, or an explicit caller-supplied policy.
    pub disk_guard_config: Option<khive_db::EffectiveDiskGuardConfig>,
    /// Directory for the SQLite volume lock files, captured with the rest of
    /// boot configuration from [`crate::daemon::volume_lock_dir`]. `None` means
    /// no directory could be resolved; every writable file-backed open then
    /// fails with a configuration error naming `KHIVE_VOLUME_LOCK_DIR`.
    pub volume_lock_dir: Option<std::path::PathBuf>,
    /// Namespace used when no explicit namespace is provided.
    pub default_namespace: Namespace,
    /// Local embedding model. `None` alone does not disable embedding: setting
    /// only this field to `None` while `additional_embedding_models` is
    /// non-empty still registers those models. Both `embedding_model` and
    /// `additional_embedding_models` must be empty to disable built-in
    /// embedding model registration, at which point `hybrid_search` falls back
    /// to text-only. Use [`RuntimeConfig::no_embeddings`] to clear both fields
    /// together — it is the canonical constructor for this. Custom embedder
    /// providers registered later by packs are not affected by this field.
    ///
    /// Deprecated: embedding engines move to a per-pack `EmbedderRegistry`.
    /// This field persists for backward compatibility until the embedder registry
    /// is fully plumbed.
    pub embedding_model: Option<EmbeddingModel>,
    /// Additional embedding models to make available by request name.
    ///
    /// `embedding_model` remains the default used by existing `embed()` and
    /// `embed_batch()` callers. This list adds non-default models that can be
    /// selected with `embedder(name)`, `embed_with_model(...)`, memory
    /// `remember.embedding_model`, and memory `recall.embedding_model`.
    pub additional_embedding_models: Vec<EmbeddingModel>,
    /// Authorization gate consulted before each verb dispatch.
    /// Default: `AllowAllGate` (permissive). For production policy enforcement,
    /// plug in a Rego- or capability-witness-backed impl.
    pub gate: GateRef,
    /// Names of packs the transport layer should register into the VerbRegistry.
    /// The transport layer (e.g. `khive-mcp`) reads this list and instantiates
    /// the matching concrete pack types. Unknown names are reported as errors
    /// by the transport, not silently ignored.
    /// Defaults to the shipped production set returned by
    /// [`RuntimeConfig::built_in_packs`].
    pub packs: Vec<String>,
    /// Resolved aggregate admission budget for resident digest-verified blob
    /// buffers (ADR-160 D3), in raw bytes.
    ///
    /// `[runtime].blob_hydration_bytes` may raise or lower the built-in 256 MiB
    /// value, but config validation guarantees enough room for one maximum-size
    /// whole-blob read.
    pub blob_hydration_bytes: u64,
    /// Identifies this runtime's backend in a multi-backend deployment.
    ///
    /// Set by the boot path when constructing per-pack runtimes from `khive.toml`.
    /// Single-backend deployments use the default `BackendId::MAIN`.
    pub backend_id: BackendId,
    /// Brain profile to use for `memory.feedback` / `knowledge.feedback` and
    /// recall-time score boosting (ADR-035 §Brain profile configuration).
    ///
    /// Resolution order (highest to lowest, ADR-035): CLI flag, then
    /// `runtime.brain_profile` in project/global `khive.toml`, then the
    /// `KHIVE_BRAIN_PROFILE` env var as fallback default. Callers must keep
    /// env OUT of the base config they pass in (see `khive-mcp` serve.rs).
    /// 1. `--brain-profile` CLI flag (explicit only)
    /// 2. Namespace-bound profile resolved via `brain.resolve` at feedback time
    /// 3. Pack-local global tuning prior (default fallback)
    pub brain_profile: Option<String>,
    /// Operator-configured read-visibility set (ADR-007 Rev 4 Rule 3b).
    ///
    /// OSS dispatch widens the DEFAULT multi-record read scope to
    /// `['local'] ∪ visible_namespaces`. Writes remain pinned to `'local'`.
    /// An explicit `namespace=` request param is a precise single-namespace
    /// escape and is not widened. Populated from `actor.visible_namespaces`
    /// in `khive.toml`.
    pub visible_namespaces: Vec<Namespace>,
    /// Namespaces this actor's comm.send/reply may deliver messages INTO
    /// (outbound, sender-side). Populated from `actor.allowed_outbound_namespaces`
    /// in `khive.toml`. Empty by default — cross-namespace delivery denied
    /// unless explicitly declared. The comm handler uses an ordinary
    /// `NamespaceToken` (minted via `with_namespace`) in an append-only manner;
    /// the token itself is NOT type-enforced write-only. The recipient-side
    /// `allowed_inbound_namespaces` (bilateral mutual opt-in) is reserved for
    /// a future cloud-path authorization ADR (not yet written).
    pub allowed_outbound_namespaces: Vec<Namespace>,
    /// Configured actor identity label (ADR-057). Populated from `[actor] id` in
    /// `khive.toml`. When `Some`, `authorize()` mints tokens carrying this actor
    /// label so that `comm.inbox` filters by `to_actor` instead of falling back to
    /// the party-line "local" behavior. When `None` (default), tokens carry
    /// `ActorRef::anonymous()` and inbox is scoped to party-line messages —
    /// those addressed to `"local"` or carrying no `to_actor` stamp.
    pub actor_id: Option<String>,
    /// Resolved `[brain]` policy from the serving process's configuration.
    pub brain: crate::engine_config::BrainSectionConfig,
    /// Resolved `[git_write]` policy allowlist (ADR-108 Amendment), populated
    /// from `khive.toml`'s `[[git_write.allowed]]` entries by
    /// [`runtime_config_from_khive_config`]. Threaded through so
    /// `khive-pack-git`'s write-verb handlers read an already-resolved policy
    /// instead of re-running config discovery (which would ignore an
    /// explicit `--config` path not also exported as `KHIVE_CONFIG`).
    pub git_write: crate::engine_config::GitWriteSectionConfig,
    /// Effective `[blob]` file-transfer opt-in, resolved with the exact environment
    /// opt-in during construction and retained by the blob pack.
    pub blob: crate::engine_config::BlobSectionConfig,
    /// Resolved `[exec]` sandbox section (ADR-181), threaded through like
    /// `git_write` so the exec pack reads an already-resolved config.
    pub exec: crate::engine_config::ExecSectionConfig,
    /// Resolved carrier and failure policy for telemetry emission.
    pub telemetry: crate::telemetry_config::TelemetryConfig,
    /// Resolved rendering timezone (ADR-169), consumed today by date-only
    /// `parse_due` anchoring. Populated from `[display] timezone` in
    /// `khive.toml` by [`runtime_config_from_khive_config`]; when absent,
    /// resolves once to the host's local IANA zone (falling back to UTC when
    /// the host zone cannot be determined) via [`resolve_default_display_timezone`].
    pub display_timezone: chrono_tz::Tz,
    /// Events-daemon split (ADR-170). `None` = legacy behavior: events persist
    /// in the main store. `Some` routes event persistence to the events database —
    /// forwarded over the events daemon socket in daemon deployments, opened
    /// directly in embedded/one-shot contexts. Populated by the transport
    /// hosts (khive-mcp serve, kkernel exec); tests and in-memory runtimes
    /// leave it `None`.
    pub events_split: Option<crate::events_split::EventsSplitConfig>,
    /// Resolved `[web]` policy (ADR-175 Amendment 1), threaded through like
    /// `exec`/`git_write` so `khive-pack-web` reads an already-resolved config.
    pub web: crate::engine_config::WebSectionConfig,
}

/// Parse a comma- or whitespace-separated pack list from a single string.
///
/// Empty entries are dropped, surrounding whitespace is trimmed.
pub fn parse_pack_list(s: &str) -> Vec<String> {
    s.split(|c: char| c == ',' || c.is_whitespace())
        .map(str::trim)
        .filter(|s| !s.is_empty())
        .map(str::to_owned)
        .collect()
}

const ANN_REBUILD_THRESHOLD_DEFAULT: f64 = 0.20;

/// Read the ANN tail-rebuild fraction on each invocation (ADR-079 Amendment 2).
///
/// ADR-079's `ann_rebuild_threshold` default rationale describes the raw-row
/// policy, its workload assumptions and its coupled maintenance/visibility roles.
///
/// The exact environment value must parse as `f64` and lie in `(0, 1]`;
/// unset, non-Unicode, malformed and out-of-range values use `0.20`.
/// This reader deliberately does not trim or cache the value.
pub fn ann_rebuild_threshold_from_env() -> f64 {
    std::env::var("KHIVE_ANN_REBUILD_THRESHOLD")
        .ok()
        .and_then(|v| v.parse::<f64>().ok())
        .filter(|v| *v > 0.0 && *v <= 1.0)
        .unwrap_or(ANN_REBUILD_THRESHOLD_DEFAULT)
}

#[cfg(test)]
#[path = "config/ann_rebuild_threshold_tests.rs"]
mod ann_rebuild_threshold_tests;

/// Interpret the construction-time `KHIVE_ANN_FRESH_TAIL` value.
///
/// Preserve the escape hatch's existing semantics while moving its read out of
/// request serving: only `0` disables; unset and every other value enable.
fn ann_fresh_tail_enabled_from_value(value: Option<&str>) -> bool {
    value != Some("0")
}

/// Sample ADR-118's fresh-tail escape hatch for runtime construction.
///
/// Callers must retain the returned value for the runtime's lifetime instead
/// of re-reading the environment on a serving path. Only the exact value `0`
/// disables; unset and every other value enable.
pub fn ann_fresh_tail_enabled_from_env() -> bool {
    let value = std::env::var("KHIVE_ANN_FRESH_TAIL").ok();
    ann_fresh_tail_enabled_from_value(value.as_deref())
}

/// Resolve the host's local IANA zone name once, for [`RuntimeConfig`]'s
/// default `display_timezone` (ADR-169). Falls back to UTC when the host
/// zone cannot be determined (e.g. `TZ`/`/etc/localtime` unreadable) or does
/// not parse as a known `chrono_tz::Tz` — this must never panic or block
/// construction of a default `RuntimeConfig`.
pub fn resolve_default_display_timezone() -> chrono_tz::Tz {
    iana_time_zone::get_timezone()
        .ok()
        .and_then(|name| name.parse::<chrono_tz::Tz>().ok())
        .unwrap_or(chrono_tz::Tz::UTC)
}

impl Default for RuntimeConfig {
    fn default() -> Self {
        let db_path = std::env::var("HOME")
            .ok()
            .map(|h| std::path::PathBuf::from(h).join(".khive/khive.db"));
        let embedding_model = std::env::var("KHIVE_EMBEDDING_MODEL")
            .ok()
            .and_then(|s| s.parse().ok())
            .or(Some(EmbeddingModel::AllMiniLmL6V2));
        // Ships single-engine. A second engine is embedded on every write and
        // searched on every read, which is cost a deployment should opt into
        // rather than inherit: set KHIVE_ADDITIONAL_EMBEDDING_MODELS to add one.
        let additional_embedding_models = std::env::var("KHIVE_ADDITIONAL_EMBEDDING_MODELS")
            .ok()
            .map(|s| parse_embedding_model_list(&s))
            .unwrap_or_default();
        let packs = std::env::var("KHIVE_PACKS")
            .ok()
            .map(|s| parse_pack_list(&s))
            .filter(|v| !v.is_empty())
            .unwrap_or_else(Self::built_in_packs);
        let brain_profile = std::env::var("KHIVE_BRAIN_PROFILE")
            .ok()
            .filter(|s| !s.trim().is_empty());
        let actor_id = std::env::var("KHIVE_ACTOR")
            .ok()
            .filter(|s| !s.trim().is_empty());
        Self {
            credentials: Vec::new(),
            visibility_receipts: None,
            db_path,
            wal_ceiling_bytes: 0,
            wal_ceiling_configured_bytes: 0,
            wal_ceiling_source: WalCeilingSource::Default,
            wal_ceiling_env_raw: std::env::var_os("KHIVE_SQLITE_WAL_CEILING_BYTES")
                .map(|value| value.to_string_lossy().into_owned()),
            disk_guard_environment: khive_db::DiskGuardEnvironment::capture(),
            disk_guard_config: None,
            volume_lock_dir: crate::daemon::volume_lock_dir().ok(),
            default_namespace: Namespace::local(),
            embedding_model,
            additional_embedding_models,
            gate: Arc::new(AllowAllGate),
            packs,
            blob_hydration_bytes: crate::blob::DEFAULT_BLOB_HYDRATION_BYTES,
            backend_id: BackendId::main(),
            brain_profile,
            visible_namespaces: vec![],
            allowed_outbound_namespaces: vec![],
            actor_id,
            brain: crate::engine_config::BrainSectionConfig::default(),
            git_write: crate::engine_config::GitWriteSectionConfig::default(),
            blob: crate::engine_config::BlobSectionConfig {
                file_transfers: std::env::var("KHIVE_FILE_TRANSFERS")
                    .map(|value| value == "1")
                    .unwrap_or(false),
            },
            exec: crate::engine_config::ExecSectionConfig::default(),
            telemetry: crate::telemetry_config::TelemetryConfig::default(),
            mounts: Vec::new(),
            display_timezone: resolve_default_display_timezone(),
            events_split: None,
            web: crate::engine_config::WebSectionConfig::default(),
        }
    }
}

impl RuntimeConfig {
    /// The WAL ceiling policy this config asks its implicit main backend to
    /// open with. Preserves a configured ceiling for read-only reporting while
    /// ensuring a directly constructed config cannot silently drop a nonzero
    /// effective value: when the configured value is zero, the effective
    /// `wal_ceiling_bytes` is used. Host openers validate the captured
    /// environment through [`Self::resolve_wal_ceiling_policy`] first.
    pub fn wal_ceiling_policy(&self) -> khive_db::WalCeilingPolicy {
        khive_db::WalCeilingPolicy {
            bytes: if self.wal_ceiling_configured_bytes == 0 {
                self.wal_ceiling_bytes
            } else {
                self.wal_ceiling_configured_bytes
            },
            source: self.wal_ceiling_source,
        }
    }

    /// Resolve the implicit backend against the config's captured environment,
    /// retaining configured bytes separately from a read-only writer policy.
    pub fn resolve_wal_ceiling_policy(
        &mut self,
        read_only: bool,
    ) -> RuntimeResult<khive_db::WalCeilingPolicy> {
        let policy = self.wal_ceiling_policy();
        let backend_field = match self.wal_ceiling_source {
            WalCeilingSource::BackendField => Some(policy.bytes),
            WalCeilingSource::Environment if self.wal_ceiling_env_raw.is_some() => None,
            _ if policy.bytes != 0 => Some(policy.bytes),
            _ => None,
        };
        let kind = if self.db_path.is_some() {
            crate::BackendKind::Sqlite
        } else {
            crate::BackendKind::Memory
        };
        let resolved = crate::resolve_wal_ceiling(
            backend_field,
            self.wal_ceiling_env_raw.as_deref(),
            self.backend_id.as_str(),
            kind,
            true,
            read_only,
        )
        .map_err(|error| khive_db::SqliteError::InvalidConfig(error.to_string()))?;
        self.wal_ceiling_configured_bytes = resolved.configured_bytes;
        self.wal_ceiling_bytes = resolved.effective_bytes;
        self.wal_ceiling_source = resolved.source;
        Ok(self.wal_ceiling_policy())
    }

    /// Resolve the implicit backend's disk reserve and guard deadline from the
    /// config's captured environment, unless a caller already supplied a policy.
    /// Read-only and in-memory backends have no writer to guard.
    pub fn resolve_disk_guard_policy(
        &mut self,
        read_only: bool,
    ) -> RuntimeResult<Option<khive_db::EffectiveDiskGuardConfig>> {
        if self.db_path.is_none() {
            if self
                .disk_guard_config
                .is_some_and(|policy| policy.reserve_bytes != 0)
            {
                return Err(khive_db::SqliteError::InvalidConfig(
                    "nonzero disk_reserve_bytes requires a file-backed SQLite backend".into(),
                )
                .into());
            }
            return Ok(None);
        }
        if read_only {
            return Ok(None);
        }
        let policy = match self.disk_guard_config {
            Some(policy) => {
                policy.validate()?;
                policy
            }
            None => self.disk_guard_environment.resolve(None, None)?,
        };
        self.disk_guard_config = Some(policy);
        Ok(Some(policy))
    }

    /// Pack-registry discovery has no file-backed writer to govern.
    pub fn for_metadata_registry(mut self) -> Self {
        self.db_path = None;
        self.wal_ceiling_bytes = 0;
        self.wal_ceiling_configured_bytes = 0;
        self.wal_ceiling_source = WalCeilingSource::BackendField;
        self.disk_guard_config = None;
        self.embedding_model = None;
        self.additional_embedding_models.clear();
        self
    }

    /// Return the shipped pack set used when no CLI, environment, or
    /// configuration-file selection is present.
    pub fn built_in_packs() -> Vec<String> {
        [
            "kg",
            "gtd",
            "memory",
            "brain",
            "comm",
            "schedule",
            "knowledge",
            "session",
            "tool",
            "exec",
            "git",
            "code",
            "workspace",
            "blob",
        ]
        .into_iter()
        .map(String::from)
        .collect()
    }

    /// Build a `RuntimeConfig` with embedding disabled entirely.
    ///
    /// `embedding_model` and `additional_embedding_models` are computed
    /// independently inside [`Default::default`], so `RuntimeConfig {
    /// embedding_model: None, ..RuntimeConfig::default() }` does NOT produce a
    /// model-less runtime: `additional_embedding_models` still carries its
    /// env-driven fallback seed, and the note-write path fans out embedding to
    /// every registered model regardless of `embedding_model`: so the first
    /// `memory.remember` on a machine without local model files hard-fails
    /// instead of degrading to FTS-only.
    ///
    /// This constructor clears both fields together and ignores
    /// `KHIVE_ADDITIONAL_EMBEDDING_MODELS` unconditionally: the caller wants
    /// zero embedders, not "zero unless the environment disagrees". Use it on
    /// model-less machines (CI runners, fresh installs without local model
    /// files) instead of the two-field struct-update form.
    pub fn no_embeddings() -> Self {
        Self {
            embedding_model: None,
            additional_embedding_models: Vec::new(),
            ..Self::default()
        }
    }
}

/// Expand a leading `~` to `$HOME` in a path.
///
/// This is the single shared expansion point for every `RuntimeConfig.db_path`
/// construction site (CLI `--db`, `KHIVE_DB`, declared `[[backends]].path`).
/// [`resolve_db_anchor`] calls it so a `~`-prefixed override is expanded once,
/// at resolution, before the path ever reaches boot (single- or multi-backend),
/// `compute_config_id` fingerprinting, or the `--db` override equivalence
/// guard — those consumers then agree on one expanded path instead of a raw
/// `~` diverging from its already-expanded equivalent.
pub fn expand_tilde(path: &std::path::Path) -> std::path::PathBuf {
    let s = path.to_string_lossy();
    if let Some(rest) = s.strip_prefix("~/") {
        let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
        std::path::PathBuf::from(format!("{home}/{rest}"))
    } else if s == "~" {
        let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
        std::path::PathBuf::from(home)
    } else {
        path.to_path_buf()
    }
}

/// Resolve the `--db`/`KHIVE_DB` value into the anchor path used for tier-3
/// project-local `.khive/config.toml` discovery, mirroring the precedence
/// `kkernel mcp` and `kkernel exec` use to open the database itself:
/// `:memory:` has no file to anchor on (`None`); an explicit path anchors on
/// that path (with a leading `~` expanded via [`expand_tilde`]); an unset
/// value falls back to `$HOME/.khive/khive.db`, or `./.khive/khive.db` when
/// `HOME` is unset.
///
/// Always resolves to a concrete anchor (unlike a 2-arm "override the
/// default?" resolver): when `HOME` is unset this falls back to
/// `./.khive/khive.db` rather than `None`, deliberately diverging from
/// `RuntimeConfig::default()`: a caller anchoring config discovery needs a
/// concrete directory to search even without `HOME`.
pub fn resolve_db_anchor(db: Option<&str>) -> Option<std::path::PathBuf> {
    match db {
        Some(":memory:") => None,
        Some(path) => Some(expand_tilde(std::path::Path::new(path))),
        None => {
            let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
            Some(std::path::PathBuf::from(format!("{home}/.khive/khive.db")))
        }
    }
}

/// Assert that a resolved `db_path`: which `compute_config_id` folds into a
/// process's `config_id`: agrees with what [`resolve_db_anchor`] derives from
/// the same raw `--db`/`KHIVE_DB` input.
///
/// This compatibility entry point preserves the raw-string API. Construction
/// paths that already captured the anchor should call
/// [`assert_captured_db_anchor_consistent`] so they do not re-read mutable
/// process environment.
pub fn assert_db_anchor_consistent(
    resolved_db_path: Option<&std::path::Path>,
    args_db: Option<&str>,
) -> anyhow::Result<()> {
    let db_anchor = resolve_db_anchor(args_db);
    assert_captured_db_anchor_consistent(resolved_db_path, db_anchor.as_deref())
}

/// Assert that a resolved `db_path`: which `compute_config_id` folds into a
/// process's `config_id`: agrees with the database anchor captured from the
/// same `--db`/`KHIVE_DB` input at the construction boundary.
///
/// Guards against a construction path recomputing `db_path` independently of
/// `resolve_db_anchor`: left unchecked, that would silently desync `config_id`
/// from a daemon or peer sharing the same database instead of failing loud.
/// The caller passes the captured anchor so validation never re-reads mutable
/// process environment. Inert (`Ok(())`) when the anchor itself is `None` (the
/// `:memory:` sentinel) since there is nothing to compare against.
pub fn assert_captured_db_anchor_consistent(
    resolved_db_path: Option<&std::path::Path>,
    db_anchor: Option<&std::path::Path>,
) -> anyhow::Result<()> {
    let Some(anchor) = db_anchor else {
        return Ok(());
    };
    if resolved_db_path != Some(anchor) {
        anyhow::bail!(
            "db-path resolution drift at server construction: resolved db_path {:?} \
             does not match the canonical anchor {:?} computed by resolve_db_anchor \
             from the same --db input; this construction path likely recomputed the \
             db path independently instead of routing through the shared resolver, \
             which would desynchronize config_id from other processes sharing the \
             same database",
            resolved_db_path,
            anchor
        );
    }
    Ok(())
}

/// Resolve the per-connection attribution actor from the project/cwd-anchored
/// config tier, independently of the database-anchored config load that
/// governs `config_id`.
///
/// The database-anchored config load keeps `config_id` coherent between a
/// short-lived client and a long-running daemon sharing one database, but
/// when many per-project connections share one database under a single
/// `HOME` (the daemon-multiplexed fleet case), that shared config carries no
/// `[actor]` block, so every connection's write-stamp attribution collapses
/// to the default identity.
///
/// This performs a separate, cwd-anchored lookup (`db_path: None`) and reads
/// only `[actor].id`: it must not perturb `config_id` or `default_namespace`,
/// which remain governed exclusively by the database-anchored load.
///
/// `config_path` is the same explicit `--config`/`KHIVE_CONFIG` override the
/// caller's database-anchored load receives, so an explicit override wins
/// here too.
///
/// Returns `Ok(None)` when no project-anchored config exists, or it exists
/// but carries no non-empty `[actor].id`: callers fall through to their own
/// env/anonymous tiers in that case. A `config_path` naming a file that does
/// not exist is a loud error (`ExplicitConfigMissing`), matching the
/// database-anchored load's explicit-tier contract (ADR-035) — in production
/// that load errors first, so this lookup only ever sees an existing file.
pub fn resolve_project_actor_id(
    config_path: Option<&std::path::Path>,
) -> Result<Option<String>, crate::engine_config::ConfigError> {
    let khive_cfg = crate::engine_config::KhiveConfig::load_with_home_fallback(config_path, None)?;
    Ok(khive_cfg
        .and_then(|cfg| cfg.actor.id)
        .filter(|s| !s.trim().is_empty()))
}

// ---- Embedding model helpers ----

/// Sanitize an embedding model name into a valid SQL table suffix.
/// e.g. `bge-small-en-v1.5` -> `bge_small_en_v1_5`
pub(crate) fn vec_model_key(model: EmbeddingModel) -> String {
    sanitize_key(&model.to_string())
}

pub(crate) fn sanitize_key(s: &str) -> String {
    s.chars()
        .map(|c| if c.is_ascii_alphanumeric() { c } else { '_' })
        .collect()
}

pub(crate) fn build_embedder_registry(
    config: &RuntimeConfig,
) -> (crate::embedder_registry::EmbedderRegistry, Arc<str>) {
    use crate::embedder_registry::{EmbedderRegistry, LatticeEmbedderProvider};
    let mut registry = EmbedderRegistry::new();
    for model in configured_embedding_models(config) {
        registry.register_builtin(LatticeEmbedderProvider::new(model));
    }
    let default_embedder_name = config
        .embedding_model
        .map(|model| Arc::<str>::from(model.to_string()))
        .unwrap_or_else(|| Arc::<str>::from(""));
    (registry, default_embedder_name)
}

fn configured_embedding_models(config: &RuntimeConfig) -> Vec<EmbeddingModel> {
    let mut models: Vec<EmbeddingModel> = Vec::new();
    if let Some(model) = config.embedding_model {
        models.push(model);
    }
    for model in config.additional_embedding_models.iter().copied() {
        if !models.contains(&model) {
            models.push(model);
        }
    }
    models
}

pub(crate) fn register_configured_embedding_models(
    backend: &StorageBackend,
    config: &RuntimeConfig,
) -> RuntimeResult<()> {
    for model in configured_embedding_models(config) {
        backend.register_embedding_model(
            &model.to_string(),
            model.model_id(),
            model.key_version(),
            model.dimensions() as u32,
        )?;
    }
    Ok(())
}

/// Build a `RuntimeConfig` from a parsed `KhiveConfig`.
///
/// For each `[[engines]]` entry:
/// - The engine flagged `default = true` becomes `RuntimeConfig::embedding_model`.
/// - All other engines become `RuntimeConfig::additional_embedding_models`.
///
/// `KhiveConfig::validate()` rejects an unrecognized engine model at load time.
/// A caller-constructed config that bypasses validation still skips an invalid
/// engine with a warning here.
///
/// If `khive_cfg.engines` is empty, the returned `RuntimeConfig` uses the
/// env-var-derived defaults from `RuntimeConfig::default()`.
///
/// When both a config file and `KHIVE_EMBEDDING_MODEL` env var are present,
/// the caller is responsible for emitting a warning that env vars are overridden.
/// This function purely converts `KhiveConfig` to `RuntimeConfig` fields.
pub fn runtime_config_from_khive_config(
    khive_cfg: &crate::engine_config::KhiveConfig,
    base: RuntimeConfig,
) -> RuntimeConfig {
    // `[actor] id` never becomes the storage namespace (writes always pin to
    // `local`); it only widens the read visible-set below.
    let default_namespace = base.default_namespace.clone();
    let mounts = khive_cfg.mounts.clone();
    let credentials = khive_cfg.credentials.clone();
    let visibility_receipts = khive_cfg.visibility_receipts.clone();

    // base.brain_profile must carry only the explicit CLI tier, never an env
    // value: env sits below toml in precedence and is applied later by the MCP resolver.
    let brain_profile = base.brain_profile.clone().or_else(|| {
        khive_cfg
            .runtime
            .brain_profile
            .clone()
            .filter(|s| !s.trim().is_empty())
    });

    let visible_namespaces: Vec<Namespace> = khive_cfg
        .actor
        .visible_namespaces
        .as_deref()
        .unwrap_or_default()
        .iter()
        .filter_map(|s| match Namespace::parse(s) {
            Ok(ns) => Some(ns),
            Err(e) => {
                tracing::warn!(ns = %s, error = %e, "actor.visible_namespaces: invalid namespace; skipped");
                None
            }
        })
        .collect();

    // Fold actor.id's namespace into visible_namespaces so default reads widen
    // to {local} ∪ {actor namespace}; skipped when it parses to `local` (would
    // duplicate the primary namespace already minted) or is already present.
    let visible_namespaces = if let Some(id) = khive_cfg.actor.id.as_deref() {
        match Namespace::parse(id) {
            Ok(actor_ns) if actor_ns != Namespace::local() => {
                let mut v = visible_namespaces;
                if !v.contains(&actor_ns) {
                    v.push(actor_ns);
                }
                v
            }
            _ => visible_namespaces,
        }
    } else {
        visible_namespaces
    };

    // KhiveConfig::validate() guarantees these are valid Namespace strings, so
    // parse failures here are unreachable for validated configs; filter_map+warn
    // guards against a validation bug panicking instead.
    let allowed_outbound_namespaces: Vec<Namespace> = khive_cfg
        .actor
        .allowed_outbound_namespaces
        .iter()
        .filter_map(|s| match Namespace::parse(s) {
            Ok(ns) => Some(ns),
            Err(e) => {
                tracing::warn!(ns = %s, error = %e, "actor.allowed_outbound_namespaces: invalid namespace; skipped");
                None
            }
        })
        .collect();

    // Precedence: TOML `[actor] id` > `base.actor_id` (env/CLI-resolved) >
    // anonymous. Falls back to `base.actor_id` rather than `None` when
    // `[actor] id` is absent: otherwise an env-resolved actor like
    // `KHIVE_ACTOR` is silently dropped whenever a project config exists
    // without an `[actor]` block.
    let actor_id = khive_cfg
        .actor
        .id
        .clone()
        .filter(|s| !s.trim().is_empty())
        .or_else(|| base.actor_id.clone());

    let gate = khive_cfg
        .gate
        .as_ref()
        .map(|gate| {
            Arc::new(khive_gate::CallerEnrollmentGate::with_write_denials(
                gate.granted_actors.clone(),
                gate.grant_unattributed,
                gate.deny_writes_for.clone(),
            )) as GateRef
        })
        .unwrap_or_else(|| base.gate.clone());
    let gate = crate::mailbox_view::configured_mailbox_gate(&khive_cfg.actor, gate);

    let brain = khive_cfg.brain.clone();
    let git_write = khive_cfg.git_write.clone();
    let blob = crate::engine_config::BlobSectionConfig {
        file_transfers: khive_cfg.blob.file_transfers || base.blob.file_transfers,
    };
    let exec = khive_cfg.exec.clone();
    let telemetry = khive_cfg.telemetry.clone();
    let web = khive_cfg.web.clone();
    let blob_hydration_bytes = khive_cfg
        .runtime
        .blob_hydration_bytes
        .unwrap_or(base.blob_hydration_bytes);

    // KhiveConfig::validate() guarantees a present timezone parses as a valid
    // chrono_tz::Tz, so the fallback to base.display_timezone below is only
    // reachable for an unvalidated caller-constructed KhiveConfig, not a
    // config loaded via KhiveConfig::load.
    let display_timezone = khive_cfg
        .display
        .timezone
        .as_deref()
        .and_then(|s| s.parse::<chrono_tz::Tz>().ok())
        .unwrap_or(base.display_timezone);

    if khive_cfg.engines.is_empty() {
        return RuntimeConfig {
            credentials,
            visibility_receipts,
            default_namespace,
            brain_profile,
            visible_namespaces,
            allowed_outbound_namespaces,
            actor_id,
            gate,
            brain,
            git_write,
            blob,
            exec,
            telemetry,
            mounts,
            blob_hydration_bytes,
            display_timezone,
            web,
            ..base
        };
    }

    let mut embedding_model: Option<EmbeddingModel> = None;
    let mut additional: Vec<EmbeddingModel> = Vec::new();

    for engine in &khive_cfg.engines {
        match parse_embedding_model_alias(&engine.model) {
            Some(model) => {
                if engine.default {
                    embedding_model = Some(model);
                } else {
                    additional.push(model);
                }
            }
            None => {
                tracing::warn!(
                    engine = %engine.name,
                    model = %engine.model,
                    "engine config: unknown model name; engine will be skipped"
                );
            }
        }
    }

    RuntimeConfig {
        credentials,
        visibility_receipts,
        embedding_model,
        additional_embedding_models: additional,
        default_namespace,
        brain_profile,
        visible_namespaces,
        allowed_outbound_namespaces,
        actor_id,
        gate,
        brain,
        git_write,
        blob,
        exec,
        telemetry,
        mounts,
        blob_hydration_bytes,
        display_timezone,
        web,
        ..base
    }
}

#[cfg(test)]
mod display_timezone_tests {
    use super::resolve_default_display_timezone;

    // The host's actual zone is environment-dependent (CI runners are
    // typically UTC), so this only asserts the resolver always produces some
    // valid, non-panicking Tz — never that it matches a specific zone.
    #[test]
    fn resolve_default_display_timezone_never_panics() {
        let _tz = resolve_default_display_timezone();
    }
}

/// Parse a comma- or whitespace-separated list of embedding model names.
fn parse_embedding_model_list(s: &str) -> Vec<EmbeddingModel> {
    parse_pack_list(s)
        .into_iter()
        .filter_map(|raw| {
            let parsed = parse_embedding_model_alias(&raw);
            if parsed.is_none() && !raw.trim().is_empty() {
                tracing::warn!(
                    model = %raw,
                    "KHIVE_ADDITIONAL_EMBEDDING_MODELS contains unknown model name; ignored. \
                     Valid forms: short alias like 'paraphrase' or a fully-qualified key \
                     from lattice_embed::EmbeddingModel::from_str."
                );
            }
            parsed
        })
        .collect()
}

pub(crate) fn parse_embedding_model_alias(name: &str) -> Option<EmbeddingModel> {
    let normalized = name.trim().to_ascii_lowercase().replace('_', "-");
    match normalized.as_str() {
        "paraphrase" => Some(EmbeddingModel::ParaphraseMultilingualMiniLmL12V2),
        _ => normalized.parse().ok(),
    }
}

#[cfg(test)]
mod resolve_db_anchor_tests {
    use super::resolve_db_anchor;

    #[test]
    fn memory_sentinel_maps_to_none() {
        assert_eq!(resolve_db_anchor(Some(":memory:")), None);
    }

    #[test]
    fn explicit_path_maps_to_some() {
        assert_eq!(
            resolve_db_anchor(Some("/tmp/khive-anchor-test.db")),
            Some(std::path::PathBuf::from("/tmp/khive-anchor-test.db"))
        );
    }

    #[test]
    fn absent_maps_to_home_default() {
        let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
        let expected = std::path::PathBuf::from(format!("{home}/.khive/khive.db"));
        assert_eq!(resolve_db_anchor(None), Some(expected));
    }
}

#[cfg(test)]
mod assert_db_anchor_consistent_tests {
    use super::{assert_captured_db_anchor_consistent, resolve_db_anchor};
    use crate::assert_db_anchor_consistent;

    #[test]
    fn diverging_db_path_is_rejected_naming_both_paths() {
        let args_db = "/tmp/khive-anchor-guard-real.db";
        let anchor = resolve_db_anchor(Some(args_db)).expect("explicit path always anchors");
        let wrong = std::path::PathBuf::from("/tmp/khive-anchor-guard-wrong.db");

        let err =
            assert_captured_db_anchor_consistent(Some(wrong.as_path()), Some(anchor.as_path()))
                .expect_err("a resolved db_path diverging from the anchor must be rejected");

        let msg = err.to_string();
        assert!(
            msg.contains(&wrong.display().to_string()),
            "error must name the resolved (wrong) path: {msg}"
        );
        assert!(
            msg.contains(&anchor.display().to_string()),
            "error must name the canonical anchor path: {msg}"
        );
    }

    #[test]
    fn matching_explicit_db_path_passes() {
        let args_db = "/tmp/khive-anchor-guard-consistent.db";
        let anchor = resolve_db_anchor(Some(args_db)).expect("explicit path always anchors");
        assert!(assert_captured_db_anchor_consistent(
            Some(anchor.as_path()),
            Some(anchor.as_path())
        )
        .is_ok());
    }

    #[test]
    fn memory_sentinel_anchor_is_inert() {
        // `resolve_db_anchor(":memory:")` yields `None` — there is no canonical
        // path to assert against, so the guard passes regardless of what
        // `resolved_db_path` happens to carry.
        let bogus = std::path::PathBuf::from("/tmp/should-not-matter.db");
        assert!(assert_captured_db_anchor_consistent(Some(bogus.as_path()), None).is_ok());
        assert!(assert_captured_db_anchor_consistent(None, None).is_ok());
    }

    #[test]
    fn normal_boot_with_db_unset_passes_silently() {
        // Mirrors a normal boot with `--db` unset: `resolve_db_anchor(None)`
        // always resolves to `Some(..)` (HOME-set or -unset both produce a
        // concrete anchor), so a runtime whose resolved `db_path` matches
        // passes silently.
        let anchor = resolve_db_anchor(None);
        assert!(assert_captured_db_anchor_consistent(anchor.as_deref(), anchor.as_deref()).is_ok());
    }

    #[test]
    fn public_compatibility_wrapper_accepts_path_and_memory_sentinel() {
        let args_db = "/tmp/khive-anchor-guard-public-api.db";
        let anchor = resolve_db_anchor(Some(args_db)).expect("explicit path always anchors");
        assert!(assert_db_anchor_consistent(Some(anchor.as_path()), Some(args_db)).is_ok());

        let unrelated = std::path::Path::new("/tmp/khive-anchor-guard-unrelated.db");
        assert!(assert_db_anchor_consistent(Some(unrelated), Some(":memory:")).is_ok());
    }
}

#[cfg(test)]
mod resolve_project_actor_id_tests {
    use super::resolve_project_actor_id;

    fn write_toml(dir: &tempfile::TempDir, body: &str) -> std::path::PathBuf {
        let path = dir.path().join("config.toml");
        std::fs::write(&path, body).expect("write config.toml");
        path
    }

    #[test]
    fn extracts_non_empty_actor_id_from_explicit_path() {
        let dir = tempfile::tempdir().expect("tempdir");
        let path = write_toml(&dir, "[actor]\nid = \"lambda:explicit-actor\"\n");

        assert_eq!(
            resolve_project_actor_id(Some(&path)).expect("no error"),
            Some("lambda:explicit-actor".to_string())
        );
    }

    #[test]
    fn missing_explicit_path_fails_loud() {
        // The explicit tier is enforced inside the loader
        // (`KhiveConfig::load_with_home_fallback_and_source` returns
        // `ExplicitConfigMissing`): a nonexistent explicit path is an error,
        // never a silent `None` (ADR-035).
        let missing = std::path::PathBuf::from("/nonexistent/khive-project-actor-test/config.toml");
        let err = resolve_project_actor_id(Some(&missing))
            .expect_err("a missing explicit path must fail loud");
        assert!(
            matches!(
                err,
                crate::engine_config::ConfigError::ExplicitConfigMissing { .. }
            ),
            "expected ExplicitConfigMissing, got {err:?}"
        );
    }

    #[test]
    fn propagates_load_error_for_invalid_actor_id() {
        // `KhiveConfig::load`'s `validate()` rejects an empty `[actor] id` before
        // the emptiness filter in `resolve_project_actor_id` ever sees it; this
        // asserts the error surfaces rather than being swallowed into `Ok(None)`.
        let dir = tempfile::tempdir().expect("tempdir");
        let path = write_toml(&dir, "[actor]\nid = \"\"\n");

        let err = resolve_project_actor_id(Some(&path)).expect_err("invalid actor.id must error");
        let root = match &err {
            crate::engine_config::ConfigError::InFile { source, .. } => source.as_ref(),
            other => other,
        };
        assert!(
            matches!(
                root,
                crate::engine_config::ConfigError::InvalidActorId { .. }
            ),
            "expected InvalidActorId, got {err:?}"
        );
    }

    #[test]
    fn returns_none_when_config_has_no_actor_section() {
        let dir = tempfile::tempdir().expect("tempdir");
        let path = write_toml(
            &dir,
            "[[engines]]\nname = \"primary\"\nmodel = \"bge-small-en-v1.5\"\ndefault = true\n",
        );

        assert_eq!(
            resolve_project_actor_id(Some(&path)).expect("no error"),
            None,
            "a config file with no [actor] section must resolve to None"
        );
    }
}

#[cfg(test)]
mod no_embeddings_tests {
    use super::*;
    use serial_test::serial;

    #[test]
    fn no_embeddings_clears_both_fields() {
        let config = RuntimeConfig::no_embeddings();
        assert_eq!(config.embedding_model, None);
        assert!(config.additional_embedding_models.is_empty());
        assert!(
            configured_embedding_models(&config).is_empty(),
            "no_embeddings() must yield zero configured embedders"
        );
    }

    #[test]
    fn blob_hydration_default_is_four_portable_whole_objects() {
        assert_eq!(
            RuntimeConfig::default().blob_hydration_bytes,
            4 * khive_storage::MAX_BLOB_WHOLE_BYTES
        );
    }

    #[test]
    #[serial]
    fn no_embeddings_ignores_additional_env_override() {
        // no_embeddings() is an unconditional opt-out: even if the caller's
        // environment sets KHIVE_ADDITIONAL_EMBEDDING_MODELS, the resulting
        // config must still report zero embedders.
        std::env::set_var("KHIVE_ADDITIONAL_EMBEDDING_MODELS", "paraphrase");
        let config = RuntimeConfig::no_embeddings();
        std::env::remove_var("KHIVE_ADDITIONAL_EMBEDDING_MODELS");

        assert!(config.additional_embedding_models.is_empty());
        assert!(configured_embedding_models(&config).is_empty());
    }

    #[test]
    #[serial]
    fn default_computes_additional_models_independently_of_no_embeddings() {
        // `Default` must keep computing `embedding_model` and
        // `additional_embedding_models` independently; `no_embeddings()` is a
        // separate opt-out constructor, not a change to `Default`'s seeding.
        // The env var is SET here rather than cleared: since Default now ships
        // no secondary engine, an unset env would make Default and
        // no_embeddings() indistinguishable and the test would stop
        // discriminating the thing it exists to discriminate.
        std::env::set_var("KHIVE_ADDITIONAL_EMBEDDING_MODELS", "paraphrase");
        let config = RuntimeConfig::default();
        let buggy_form = RuntimeConfig {
            embedding_model: None,
            ..RuntimeConfig::default()
        };
        std::env::remove_var("KHIVE_ADDITIONAL_EMBEDDING_MODELS");

        assert_eq!(
            config.additional_embedding_models,
            vec![EmbeddingModel::ParaphraseMultilingualMiniLmL12V2]
        );

        // Overriding only `embedding_model` via struct-update syntax does not
        // clear `additional_embedding_models`.
        assert!(
            !buggy_form.additional_embedding_models.is_empty(),
            "Default's independent-field seeding must remain unchanged; \
             no_embeddings() is the fix, not a change to Default"
        );
    }

    #[test]
    #[serial]
    fn default_ships_a_single_engine_when_env_unset() {
        // A secondary engine is embedded on every write and searched on every
        // read. That cost is opted into, not inherited.
        std::env::remove_var("KHIVE_ADDITIONAL_EMBEDDING_MODELS");
        let config = RuntimeConfig::default();

        assert!(
            config.additional_embedding_models.is_empty(),
            "shipped default must register one engine; a second is opt-in via \
             KHIVE_ADDITIONAL_EMBEDDING_MODELS"
        );
        assert_eq!(
            configured_embedding_models(&config),
            vec![EmbeddingModel::AllMiniLmL6V2]
        );
    }
}

#[cfg(test)]
mod ann_fresh_tail_config_tests {
    use super::ann_fresh_tail_enabled_from_value;

    #[test]
    fn only_exact_zero_disables_fresh_tail() {
        assert!(ann_fresh_tail_enabled_from_value(None));
        assert!(!ann_fresh_tail_enabled_from_value(Some("0")));
        assert!(ann_fresh_tail_enabled_from_value(Some("1")));
        assert!(ann_fresh_tail_enabled_from_value(Some("false")));
        assert!(ann_fresh_tail_enabled_from_value(Some(" 0")));
    }
}

#[cfg(test)]
mod configured_embedding_models_order_tests {
    use super::*;

    /// Issue #1115: the configured engine list must preserve declaration
    /// order (primary first, then `additional_embedding_models` in order)
    /// instead of alphabetizing — any consumer that treats the list as
    /// ordered (e.g. recall fan-out) otherwise gets the wrong primary.
    #[test]
    fn preserves_primary_first_then_additional_in_declared_order() {
        let config = RuntimeConfig {
            embedding_model: Some(EmbeddingModel::AllMiniLmL6V2),
            additional_embedding_models: vec![
                EmbeddingModel::Qwen3Embedding4B,
                EmbeddingModel::BgeSmallEnV15,
            ],
            ..RuntimeConfig::default()
        };

        assert_eq!(
            configured_embedding_models(&config),
            vec![
                EmbeddingModel::AllMiniLmL6V2,
                EmbeddingModel::Qwen3Embedding4B,
                EmbeddingModel::BgeSmallEnV15,
            ],
            "order must be primary-first, then additional models as declared, \
             not alphabetized"
        );
    }

    /// A model repeated in both `embedding_model` and `additional_embedding_models`
    /// must be deduped to a single entry, keeping its first (primary) position.
    #[test]
    fn dedupes_model_shared_between_primary_and_additional() {
        let config = RuntimeConfig {
            embedding_model: Some(EmbeddingModel::AllMiniLmL6V2),
            additional_embedding_models: vec![
                EmbeddingModel::AllMiniLmL6V2,
                EmbeddingModel::BgeSmallEnV15,
            ],
            ..RuntimeConfig::default()
        };

        assert_eq!(
            configured_embedding_models(&config),
            vec![EmbeddingModel::AllMiniLmL6V2, EmbeddingModel::BgeSmallEnV15],
            "the shared model must appear once, in its primary position"
        );
    }
}