ai-memory 0.7.0

// Copyright 2026 AlphaOne LLC
// SPDX-License-Identifier: Apache-2.0
//
// v0.7 Track G — Task G2: lifecycle event types + JSON payload structs.
//
// G1 (PR #554) shipped the on-disk hook configuration schema and a
// 20-variant `HookEvent` *stub* in `src/hooks/config.rs`. G2 lifts
// `HookEvent` out of `config.rs` into this module, attaches a
// payload struct to every variant, and pins the JSON wire shape
// the executor (G3) will use to talk to subprocess hooks over
// stdio.
//
// # Wire contract
//
// Every payload type derives `Serialize + Deserialize`. The hook
// pipeline marshals payloads to JSON, writes them to the hook
// child's stdin, and reads a `HookDecision` (G4) back from stdout.
// `Pre*` payloads are *deltas* the hook may mutate before the
// memory operation runs; `Post*` payloads are read-only snapshots
// of the operation's effect and exist for observability /
// telemetry hooks.
//
// # Why payloads live in a separate module from `HookEvent`
//
// The `HookEvent` enum itself is tag-only (Copy, Hash) so a config
// loader can match on a name without depending on every payload
// type. The payload types include owned strings, optional fields,
// and `serde_json::Value` bags, none of which is `Copy`. Splitting
// the tag from the payload is the same shape as `tracing::Event` /
// `tracing::Metadata` and keeps `crate::hooks::config` free of any
// dependency on `crate::models` or `crate::transcripts`.
//
// # Backward compatibility with G1
//
// `crate::hooks::config::HookEvent` is preserved as a `pub use`
// re-export so the G1 call sites (`HookConfig.event: HookEvent`,
// `validate_hook`, the existing tests) keep compiling unchanged.
// The canonical path going forward is `crate::hooks::HookEvent`.
//
// # Where each event will fire (G3-G11)
//
// Each variant carries a `// TODO(G3-G11): wire here at <file>:<line>`
// doc-comment naming the source-code location the executor will
// hook into when later tasks land. The line numbers are
// *approximate* — pinned against the heads of the relevant
// functions on `main` at the time of G2 — and are intended as
// hints for the implementer of G3-G11, not load-bearing
// invariants.

use serde::{Deserialize, Serialize};
use serde_json::Value;

use crate::models::{Memory, MemoryLink, Tier};

// ---------------------------------------------------------------------------
// HookEvent — the 21 lifecycle event tags
// ---------------------------------------------------------------------------

/// The 21 lifecycle events the hook pipeline supports.
///
/// `HookEvent` is the *tag* an operator names in `hooks.toml`
/// (`event = "post_store"`) and the discriminator the executor
/// uses when routing a payload to its subscribed hook chain.
///
/// Payload types are defined in this module — see the per-variant
/// payload table in the module-level documentation and the
/// individual variant doc-comments.
///
/// Serde uses snake_case so the on-disk and on-wire spelling
/// matches the table in `docs/v0.7/V0.7-EPIC.md` § Track G2.
///
/// # NSA CSI MCP Security mapping
///
/// Primary defense against **NSA concern (c) Poor approval workflows**
/// and implementation of **NSA recommendation (d) Constrain and
/// sandbox tool execution** + **(f) Filter and monitor output
/// pipelines and chained execution** per U/OO/6030316-26 (May 2026
/// v1.0). 25 lifecycle events (20 baseline + 5 v0.7.0 additions:
/// `PreRecallExpand`, `PreReflect`, `PostReflect`, `PreCompaction`,
/// `OnCompactionRollback`) give operators a substrate-side hook for
/// every memory operation, with the four-way decision contract
/// (`Allow` / `Modify` / `Deny` / `AskUser`) and chain ordering
/// (priority-desc, first-Deny short-circuits). Default-off — a v0.7
/// install with no `~/.config/ai-memory/hooks.toml` behaves
/// identically to v0.6.4. Capability inventory anchor:
/// `track_g_hook_pipeline`. Mapping narrative in
/// `docs/compliance/nsa-csi-mcp.html` §3.3 (concern c), §4.4
/// (recommendation d), and §4.6 (recommendation f).
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum HookEvent {
    /// Fires before a memory is persisted. Payload: [`MemoryDelta`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::insert`.
    PreStore,
    /// Fires after a memory has been persisted. Payload: [`Memory`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::insert` (post-INSERT).
    PostStore,
    /// Fires before a recall query executes. Payload: [`RecallQuery`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::recall`.
    PreRecall,
    /// Fires after a recall query returns. Payload: [`RecallResult`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::recall` (post-return).
    PostRecall,
    /// Fires before a full-text search executes. Payload: [`SearchQuery`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::search`.
    PreSearch,
    /// Fires after a full-text search returns. Payload: [`SearchResult`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::search` (post-return).
    PostSearch,
    /// Fires before a memory is deleted. Payload: [`MemoryRef`] (writable target id).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::delete`.
    PreDelete,
    /// Fires after a memory has been deleted. Payload: [`MemoryRef`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::delete` (post-DELETE).
    PostDelete,
    /// Fires before a tier promotion. Payload: [`PromoteDelta`] (writable target tier).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::promote_to_namespace`.
    PrePromote,
    /// Fires after a tier promotion. Payload: [`PromoteResult`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::promote_to_namespace` (post-UPDATE).
    PostPromote,
    /// Fires before a link is created. Payload: [`LinkDelta`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::create_link`.
    PreLink,
    /// Fires after a link has been created. Payload: [`Link`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::create_link` (post-INSERT).
    PostLink,
    /// Fires before a consolidation pass runs. Payload: [`ConsolidationDelta`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::consolidate`.
    PreConsolidate,
    /// Fires after a consolidation pass completes. Payload: [`ConsolidationResult`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::consolidate` (post-return).
    PostConsolidate,
    /// Fires before a governance gate decision. Payload: [`GovernanceContext`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::enforce_governance`.
    PreGovernanceDecision,
    /// Fires after a governance gate decision. Payload: [`GovernanceDecision`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::enforce_governance` (post-return).
    PostGovernanceDecision,
    /// Fires when the ANN index evicts an entry. Payload: [`EvictionEvent`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::hnsw` (`hnsw.eviction` log site).
    OnIndexEviction,
    /// Fires before a memory is archived. Payload: [`MemoryRef`] (writable target id).
    ///
    /// TODO(G3-G11): wire here at `crate::storage::archive_memory`.
    PreArchive,
    /// Fires before a transcript is stored. Payload: [`TranscriptDelta`] (writable).
    ///
    /// TODO(G3-G11): wire here at `crate::transcripts::store`.
    PreTranscriptStore,
    /// Fires after a transcript has been stored. Payload: [`Transcript`] (read-only).
    ///
    /// TODO(G3-G11): wire here at `crate::transcripts::store` (post-INSERT).
    PostTranscriptStore,
    /// G10: fires *synchronously* on the recall hot path before the
    /// embedder / DB call to allow query expansion (synonyms,
    /// spelling correction, harness-specific normalization). Payload:
    /// [`RecallExpandQuery`] (writable). Distinct from `PreRecall`
    /// because the budget is the recall p95 (50ms) — operators MUST
    /// configure this hook in `mode = "daemon"` to amortize spawn
    /// cost. Classified as [`crate::hooks::EventClass::HotPath`].
    ///
    /// Wires here at `crate::mcp::handle_recall` (top of fn).
    PreRecallExpand,
    /// v0.7.0 recursive-learning Task 6/8 — fires BEFORE the
    /// depth-cap check inside `db::reflect`. **Decision-class** hook:
    /// handlers may VETO the reflection by returning `Deny`, which
    /// propagates an error up to the caller distinct from a cap
    /// refusal (caller-policy refusals like "this agent is
    /// rate-limited" vs the substrate cap refusal Task 5 audits).
    /// Payload: [`ReflectDelta`] (writable — handlers may rewrite the
    /// proposed reflection's tier / tags / priority / metadata before
    /// the cap check evaluates). Classified as
    /// [`crate::hooks::EventClass::Write`].
    ///
    /// Wires here at `crate::storage::reflect` step 4 (after source-load /
    /// depth computation, BEFORE step 5 cap check).
    PreReflect,
    /// v0.7.0 recursive-learning Task 6/8 — fires AFTER the
    /// reflection transaction commits. **Notify-class** hook:
    /// handlers cannot veto; their return value is ignored beyond
    /// logging. Payload: [`ReflectResult`] (read-only — the
    /// post-commit envelope mirrors the `memory_reflect` MCP
    /// response). Classified as [`crate::hooks::EventClass::Write`].
    ///
    /// Wires here at `crate::storage::reflect` step 7 (after COMMIT
    /// succeeds, before returning `ReflectOutcome` to the caller).
    /// Layers on top of the existing `memory_store` webhook event the
    /// MCP handler dispatches — both fire on a successful reflect.
    PostReflect,
    /// v0.7.0 L1-7 compaction pipeline — fires BEFORE a compaction
    /// pass (consolidation, reflection, …) processes a cluster.
    /// **Decision-class** hook: handlers may Allow (default), Modify
    /// (rewrite the cluster's candidate id list), Deny (abort the
    /// cluster — no summarise, no persist, no verify), or AskUser.
    /// Payload: [`CompactionDelta`] (writable — the candidate id list
    /// and the pass name).  Classified as
    /// [`crate::hooks::EventClass::Write`].
    ///
    /// Wires here at `src/curator/compaction.rs` (before
    /// `ConsolidationPass::summarize` is called for each cluster).
    PreCompaction,
    /// v0.7.0 L1-7 compaction pipeline — fires when the verify step
    /// of a compaction pass fails.  **Notify-class** hook: handlers
    /// cannot veto; their return value is ignored beyond logging.
    /// Payload: [`CompactionRollbackEvent`] (read-only — names the
    /// summary id and pass that failed).
    ///
    /// NOTE: actual rollback (re-inserting source rows, invalidating
    /// the summary) is deferred to v0.8.0 Pillar 2.5 (issue #664).
    /// This hook fires NOW so integrations can detect and report
    /// verify failures; the rollback mechanics ship later.
    ///
    /// Classified as [`crate::hooks::EventClass::Write`].
    OnCompactionRollback,
}

// ---------------------------------------------------------------------------
// Pre/Post-store payloads
// ---------------------------------------------------------------------------

/// Writable delta a `pre_store` hook may mutate before the row is
/// persisted.
///
/// Mirrors the user-controllable fields of `crate::models::CreateMemory`
/// — but as a JSON-friendly bag with every field optional so a hook
/// can return a partial diff (e.g. just rewriting `tags`) without
/// echoing the whole memory back over stdio. The executor (G3)
/// merges `Some(_)` fields onto the in-flight `CreateMemory`
/// before calling `db::insert`.
// #969 — `PartialEq` derive enables direct equality in `ChainResult`,
// `HookDecision`, and `Decision` enums that wrap a `MemoryDelta`.
// Pre-#969 those enums hand-rolled equality via
// `serde_json::to_value(a).ok() == serde_json::to_value(b).ok()` on
// the (mistaken) premise that `serde_json::Value` was not
// `PartialEq` — it IS (`serde_json-1.0/src/value/mod.rs:115` derives
// `Eq, PartialEq, Hash`). The real blocker is `Option<f64>` below,
// which is `PartialEq` but not `Eq`; that blocks `derive(Eq)` but
// not `derive(PartialEq)`.
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct MemoryDelta {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tier: Option<Tier>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub namespace: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub title: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub content: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tags: Option<Vec<String>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub priority: Option<i32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub confidence: Option<f64>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub source: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub expires_at: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub metadata: Option<Value>,
}

// ---------------------------------------------------------------------------
// Pre/Post-recall payloads
// ---------------------------------------------------------------------------

/// Writable recall query a `pre_recall` hook may rewrite before
/// the recall executes. Mirrors the public `memory_recall` MCP /
/// HTTP request shape; fields are optional so a hook may rewrite
/// only the parts it cares about (e.g. injecting a `namespace`
/// filter for tenant isolation).
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RecallQuery {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub query: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub namespace: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub limit: Option<usize>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tier: Option<Tier>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tags: Option<Vec<String>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub budget_tokens: Option<usize>,
}

/// G10 hot-path payload for [`HookEvent::PreRecallExpand`]. Carries
/// only the three fields a query-expansion hook needs to make a
/// rewrite decision — the original `query` text, the recall
/// `namespace` filter (empty string when the caller did not pass
/// one), and `k`, the recall limit. Kept narrow on purpose: the
/// hook fires inside the 50ms recall budget, so the wire payload
/// stays small to keep daemon-mode round-trip latency in the low
/// micros.
///
/// All three fields are required (no `Option<…>`) because the hot
/// path calls this hook with concrete values — the caller has
/// already resolved namespace defaults and limit clamping.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RecallExpandQuery {
    pub query: String,
    pub namespace: String,
    pub k: u32,
}

/// Read-only snapshot of a recall's result returned to a
/// `post_recall` hook. The `memories` vector reuses
/// [`crate::models::Memory`] verbatim so post-hooks can inspect
/// every field the recall surfaced (tier, score-driving
/// metadata, etc.) without an additional translation layer.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RecallResult {
    pub query: String,
    pub memories: Vec<Memory>,
    /// Total cl100k_base tokens (or `len/4` byte estimate when
    /// the budget path was skipped) the recall consumed. Mirrors
    /// the v0.6.3 `tokens_used` field on the wire envelope.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tokens_used: Option<usize>,
}

// ---------------------------------------------------------------------------
// Pre/Post-search payloads
// ---------------------------------------------------------------------------

/// Writable FTS search query for `pre_search` hooks. Same shape
/// as [`RecallQuery`] minus the budget knob — search is the
/// uncapped FTS surface; the budget machinery is recall-only.
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct SearchQuery {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub query: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub namespace: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub limit: Option<usize>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tags: Option<Vec<String>>,
}

/// Read-only result returned to `post_search` hooks.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SearchResult {
    pub query: String,
    pub memories: Vec<Memory>,
}

// ---------------------------------------------------------------------------
// Pre/Post-delete + pre-archive payloads
// ---------------------------------------------------------------------------

/// Pointer at a single memory by id. Used by `pre_delete`,
/// `post_delete`, and `pre_archive` — operations that take an id
/// and don't need the full row to make a decision.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MemoryRef {
    pub id: String,
}

// ---------------------------------------------------------------------------
// Pre/Post-promote payloads
// ---------------------------------------------------------------------------

/// Writable delta for `pre_promote` — a hook may rewrite the
/// target tier before the promotion runs, e.g. to refuse
/// promotion to `long` tier for transient agent output.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PromoteDelta {
    pub id: String,
    pub from_tier: Tier,
    pub to_tier: Tier,
}

/// Read-only result for `post_promote` — the resolved tier
/// transition after the operation completed.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PromoteResult {
    pub id: String,
    pub from_tier: Tier,
    pub to_tier: Tier,
}

// ---------------------------------------------------------------------------
// Pre/Post-link payloads
// ---------------------------------------------------------------------------

/// Writable delta for `pre_link`. Mirrors the user-controllable
/// surface of `MemoryLink` so hooks can rewrite the relation
/// (e.g. demote `contradicts` → `related_to` if the source
/// confidence is low) before the row is inserted.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LinkDelta {
    pub source_id: String,
    pub target_id: String,
    pub relation: String,
}

/// Read-only `post_link` payload. Re-uses
/// [`crate::models::MemoryLink`] so the wire shape matches the
/// existing v0.6.3 link surface and downstream consumers don't
/// need a translation table.
pub type Link = MemoryLink;

// ---------------------------------------------------------------------------
// Pre/Post-consolidate payloads
// ---------------------------------------------------------------------------

/// Writable delta for `pre_consolidate`. Names the namespace and
/// candidate memory ids the consolidator is about to operate on.
/// A hook may shrink (or veto via `HookDecision::Deny` in G4) the
/// candidate set before the consolidation runs.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ConsolidationDelta {
    pub namespace: String,
    pub candidate_ids: Vec<String>,
}

/// Read-only `post_consolidate` payload. Reports the resolved
/// merge / supersede outcome so observability hooks can surface
/// consolidation activity to operators.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ConsolidationResult {
    pub namespace: String,
    /// Memory ids that were merged into a consolidated row.
    pub merged_ids: Vec<String>,
    /// The id of the consolidated row, when one was produced.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub result_id: Option<String>,
}

// ---------------------------------------------------------------------------
// Pre/Post-governance-decision payloads
// ---------------------------------------------------------------------------

/// Writable governance context passed to `pre_governance_decision`
/// hooks. Hooks see the namespace, the action under review, and
/// the requesting agent identity, and may augment / rewrite any
/// of these before `enforce_governance` runs.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GovernanceContext {
    pub namespace: String,
    pub action: String,
    pub agent_id: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub memory_id: Option<String>,
}

/// Read-only outcome of a governance gate decision. Mirrors the
/// allow/deny/pending shape `enforce_governance` returns; the
/// optional `pending_id` correlates an `Ask` outcome with the
/// row in `pending_actions`.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum GovernanceOutcome {
    Allow,
    Deny,
    Ask,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GovernanceDecision {
    pub namespace: String,
    pub action: String,
    pub agent_id: String,
    pub outcome: GovernanceOutcome,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub reason: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub pending_id: Option<String>,
}

// ---------------------------------------------------------------------------
// Index eviction payload
// ---------------------------------------------------------------------------

/// `on_index_eviction` payload — fired when the HNSW index
/// evicts an entry under capacity pressure. Lets observability
/// hooks (datadog, prometheus pushgateway, etc.) surface the
/// eviction without polling the `index_evictions_total` counter.
///
/// G8 (v0.7) widened the wire shape from `{ memory_id }` to the
/// full `{ memory_id, namespace, evicted_at, reason }` so a hook
/// can re-index, archive, or notify with enough context to do
/// its job without re-querying the DB. Older `{ memory_id }`-only
/// payloads still parse — `namespace`, `evicted_at`, and `reason`
/// default to empty strings on the decode side via
/// `serde(default)` so v0.7 hooks remain backward-compatible with
/// any v0.7-rc / G2-stub fixtures that might still be on disk.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EvictionEvent {
    /// Stringified id of the memory whose embedding was evicted
    /// from the HNSW hot index. Matches the `evicted_id` field in
    /// the `hnsw.eviction` tracing event so log + hook payloads
    /// correlate.
    pub memory_id: String,
    /// Namespace the evicted memory lived in. The current HNSW
    /// fire site (G8) does not have the namespace in scope at
    /// eviction time; G9+ will plumb it through. Empty string
    /// today; populated from the test-only `fire_on_index_eviction`
    /// helper so the wire contract is exercised.
    #[serde(default)]
    pub namespace: String,
    /// RFC-3339 wall-clock timestamp of the eviction. Matches the
    /// format used by `Memory.created_at` so hook authors can
    /// reuse the same date parser.
    #[serde(default)]
    pub evicted_at: String,
    /// Free-form machine-tag for *why* the eviction happened.
    /// Today the only fire site uses `"max_entries_reached"`
    /// (matching the existing `hnsw.eviction` tracing event); G9+
    /// may add `"ttl_expired"`, `"manual"`, etc.
    #[serde(default)]
    pub reason: String,
}

impl EvictionEvent {
    /// Construct an eviction payload tagged with the current
    /// wall-clock time (RFC-3339, matching the rest of the
    /// codebase's timestamp shape).
    #[must_use]
    pub fn new(
        memory_id: impl Into<String>,
        namespace: impl Into<String>,
        reason: impl Into<String>,
    ) -> Self {
        Self {
            memory_id: memory_id.into(),
            namespace: namespace.into(),
            evicted_at: rfc3339_now(),
            reason: reason.into(),
        }
    }
}

/// Tiny RFC-3339 formatter used by `EvictionEvent::new`. Keeps
/// the chrono dep out of `events.rs` — a UNIX-seconds → ISO 8601
/// projection is cheap and lossless for the second-precision
/// timestamps every other model in this crate uses.
fn rfc3339_now() -> String {
    use std::time::{SystemTime, UNIX_EPOCH};
    // The hooks subsystem already pulls chrono in transitively via
    // `crate::models`; reach for it here too so the wire shape
    // matches `Memory.created_at` byte-for-byte.
    let secs = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|d| d.as_secs())
        .unwrap_or(0);
    // chrono is already a workspace dep — see Cargo.toml.
    chrono::DateTime::<chrono::Utc>::from_timestamp(secs as i64, 0)
        .map(|dt| dt.to_rfc3339_opts(chrono::SecondsFormat::Secs, true))
        .unwrap_or_default()
}

// ---------------------------------------------------------------------------
// Pre/Post-reflect payloads (v0.7.0 recursive-learning Task 6/8)
// ---------------------------------------------------------------------------

/// Writable delta a `pre_reflect` hook may mutate before `db::reflect`
/// evaluates the depth-cap. Mirrors the user-controllable fields of
/// `crate::db::ReflectInput` — but as a JSON-friendly bag with every
/// field optional so a hook may return a partial diff (e.g. just
/// rewriting `tags` or `priority`) without echoing the whole input
/// back over stdio. Fields a `pre_reflect` hook may not safely
/// override (`source_ids`, `agent_id`) are intentionally absent here —
/// rewriting either would silently change the audit provenance of a
/// downstream refusal, which is the wrong shape for a hook contract.
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct ReflectDelta {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tier: Option<Tier>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub namespace: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub title: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub content: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tags: Option<Vec<String>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub priority: Option<i32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub confidence: Option<f64>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub metadata: Option<Value>,
}

/// Read-only result returned to a `post_reflect` hook. Mirrors the
/// `crate::db::ReflectOutcome` wire shape (id, reflection_depth,
/// reflects_on, namespace) so the post-hook can correlate the new
/// reflection memory with the sources it was derived from. The new
/// memory is already durable at hook-fire time — the hook may read it
/// back via the same connection without racing the writer.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReflectResult {
    pub id: String,
    pub reflection_depth: i32,
    pub reflects_on: Vec<String>,
    pub namespace: String,
}

// ---------------------------------------------------------------------------
// Compaction payloads (v0.7.0 L1-7)
// ---------------------------------------------------------------------------

/// Writable delta for [`HookEvent::PreCompaction`]. Names the compaction
/// pass and the candidate memory ids it is about to operate on.  A hook
/// may shrink (or veto via `HookDecision::Deny`) the candidate set before
/// the pass summarises.
///
/// `pass_name` matches [`crate::curator::pipeline::CompactionPass::name`]
/// so a hook can filter by strategy (`"consolidation"`, `"reflection"`, …).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CompactionDelta {
    /// Name of the compaction pass (e.g. `"consolidation"`).
    pub pass_name: String,
    /// Memory ids in the cluster about to be compacted.  A hook may
    /// return a `Modify` delta with a shorter list to reduce the cluster.
    pub candidate_ids: Vec<String>,
    /// Namespace all candidates share.
    pub namespace: String,
}

/// Read-only payload for [`HookEvent::OnCompactionRollback`]. Carries
/// enough context for an observability hook to log, page, or re-index
/// without re-querying the database.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CompactionRollbackEvent {
    /// Name of the compaction pass that failed the verify step.
    pub pass_name: String,
    /// Id of the summary memory whose verify step failed.
    pub summary_id: String,
    /// Namespace the cluster belonged to.
    pub namespace: String,
    /// Human-readable description of the verify failure.
    pub reason: String,
}

// ---------------------------------------------------------------------------
// Transcript payloads (I-track interop)
// ---------------------------------------------------------------------------

/// Writable delta for `pre_transcript_store`. Hooks may rewrite
/// the namespace, the raw content, or the TTL before the
/// transcript blob is compressed and persisted. Content is
/// passed in clear text — compression happens server-side.
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct TranscriptDelta {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub namespace: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub content: Option<String>,
    /// TTL in seconds from "now"; `None` means no expiry.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub ttl_secs: Option<i64>,
}

/// Read-only handle returned to `post_transcript_store` hooks.
///
/// Mirrors `crate::transcripts::Transcript` field-for-field
/// (which is *not* `Serialize` itself — it's an internal storage
/// handle). The executor (G3) will project from the internal
/// type into this wire-shaped struct before fanning out to hook
/// subscribers.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Transcript {
    pub id: String,
    pub namespace: String,
    pub created_at: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub expires_at: Option<String>,
    pub compressed_size: i64,
    pub original_size: i64,
}

impl From<&crate::transcripts::Transcript> for Transcript {
    fn from(t: &crate::transcripts::Transcript) -> Self {
        Self {
            id: t.id.clone(),
            namespace: t.namespace.clone(),
            created_at: t.created_at.clone(),
            expires_at: t.expires_at.clone(),
            compressed_size: t.compressed_size,
            original_size: t.original_size,
        }
    }
}

// ---------------------------------------------------------------------------
// Tests — JSON round-trip per representative variant
// ---------------------------------------------------------------------------
//
// Per the G2 prompt: aim for ~5-10 representative tests, not 20
// individual ones. We cover (a) the `HookEvent` tag itself for
// every variant in one pass and (b) a JSON round-trip per payload
// *family*: store / recall / search / delete / promote / link /
// consolidate / governance / eviction / transcript.

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

    /// Every `HookEvent` variant must round-trip through JSON
    /// with snake_case spelling. A single table-driven test keeps
    /// the assertion surface compact.
    #[test]
    fn hook_event_all_variants_round_trip() {
        let table = [
            (HookEvent::PreStore, "\"pre_store\""),
            (HookEvent::PostStore, "\"post_store\""),
            (HookEvent::PreRecall, "\"pre_recall\""),
            (HookEvent::PostRecall, "\"post_recall\""),
            (HookEvent::PreSearch, "\"pre_search\""),
            (HookEvent::PostSearch, "\"post_search\""),
            (HookEvent::PreDelete, "\"pre_delete\""),
            (HookEvent::PostDelete, "\"post_delete\""),
            (HookEvent::PrePromote, "\"pre_promote\""),
            (HookEvent::PostPromote, "\"post_promote\""),
            (HookEvent::PreLink, "\"pre_link\""),
            (HookEvent::PostLink, "\"post_link\""),
            (HookEvent::PreConsolidate, "\"pre_consolidate\""),
            (HookEvent::PostConsolidate, "\"post_consolidate\""),
            (
                HookEvent::PreGovernanceDecision,
                "\"pre_governance_decision\"",
            ),
            (
                HookEvent::PostGovernanceDecision,
                "\"post_governance_decision\"",
            ),
            (HookEvent::OnIndexEviction, "\"on_index_eviction\""),
            (HookEvent::PreArchive, "\"pre_archive\""),
            (HookEvent::PreTranscriptStore, "\"pre_transcript_store\""),
            (HookEvent::PostTranscriptStore, "\"post_transcript_store\""),
            (HookEvent::PreRecallExpand, "\"pre_recall_expand\""),
            (HookEvent::PreReflect, "\"pre_reflect\""),
            (HookEvent::PostReflect, "\"post_reflect\""),
            // v0.7.0 L1-7: compaction pipeline events (24th + 25th).
            (HookEvent::PreCompaction, "\"pre_compaction\""),
            (
                HookEvent::OnCompactionRollback,
                "\"on_compaction_rollback\"",
            ),
        ];

        // Pin the count at the type boundary so adding a 26th
        // variant without updating the table fails this test. G2
        // shipped 20; G10 added the 21st (`pre_recall_expand`);
        // v0.7.0 recursive-learning Task 6/8 added the 22nd +
        // 23rd (`pre_reflect`, `post_reflect`); L1-7 adds the
        // 24th + 25th (`pre_compaction`, `on_compaction_rollback`).
        assert_eq!(
            table.len(),
            25,
            "L1-7 raises the count from 23 to 25 (adds pre_compaction + on_compaction_rollback)"
        );

        for (variant, expected_json) in table {
            let encoded = serde_json::to_string(&variant).expect("variant encodes");
            assert_eq!(encoded, expected_json, "variant {variant:?} mis-encoded");
            let decoded: HookEvent = serde_json::from_str(&encoded).expect("variant decodes");
            assert_eq!(decoded, variant, "variant {variant:?} did not round-trip");
        }
    }

    #[test]
    fn memory_delta_partial_serialization_omits_none_fields() {
        let delta = MemoryDelta {
            tags: Some(vec!["urgent".into(), "v0.7".into()]),
            priority: Some(80),
            ..Default::default()
        };
        let v: Value = serde_json::to_value(&delta).expect("encode");
        // Only the fields the hook touched should appear on the wire.
        assert_eq!(v["tags"], serde_json::json!(["urgent", "v0.7"]));
        assert_eq!(v["priority"], serde_json::json!(80));
        assert!(v.get("title").is_none());
        assert!(v.get("content").is_none());
        assert!(v.get("metadata").is_none());

        // And the partial round-trips.
        let back: MemoryDelta = serde_json::from_value(v).expect("decode");
        assert_eq!(
            back.tags.as_deref(),
            Some(&["urgent".into(), "v0.7".into()][..])
        );
        assert_eq!(back.priority, Some(80));
        assert!(back.title.is_none());
    }

    #[test]
    fn recall_query_round_trips() {
        let q = RecallQuery {
            query: Some("auth tokens".into()),
            namespace: Some("team/security".into()),
            limit: Some(10),
            tier: Some(Tier::Long),
            tags: Some(vec!["secrets".into()]),
            budget_tokens: Some(2_048),
        };
        let json = serde_json::to_string(&q).expect("encode");
        let back: RecallQuery = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.query.as_deref(), Some("auth tokens"));
        assert_eq!(back.namespace.as_deref(), Some("team/security"));
        assert_eq!(back.limit, Some(10));
        assert_eq!(back.tier, Some(Tier::Long));
        assert_eq!(back.budget_tokens, Some(2_048));
    }

    #[test]
    fn recall_expand_query_round_trips() {
        // G10 hot-path payload: the wire shape MUST stay narrow
        // (just `query`, `namespace`, `k`) so daemon-mode hooks can
        // round-trip inside the 50ms recall budget.
        let q = RecallExpandQuery {
            query: "auht tokn".into(),
            namespace: "team/security".into(),
            k: 10,
        };
        let json = serde_json::to_string(&q).expect("encode");
        let back: RecallExpandQuery = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.query, "auht tokn");
        assert_eq!(back.namespace, "team/security");
        assert_eq!(back.k, 10);
        // Sanity: no unexpected fields snuck onto the wire.
        let v: Value = serde_json::from_str(&json).expect("parse");
        let obj = v.as_object().expect("object");
        assert_eq!(obj.len(), 3, "RecallExpandQuery is exactly 3 wire fields");
    }

    #[test]
    fn search_query_and_result_round_trip() {
        let sq = SearchQuery {
            query: Some("postgres".into()),
            namespace: Some("eng".into()),
            limit: Some(5),
            tags: None,
        };
        let json = serde_json::to_string(&sq).expect("encode SearchQuery");
        let back: SearchQuery = serde_json::from_str(&json).expect("decode SearchQuery");
        assert_eq!(back.query.as_deref(), Some("postgres"));
        assert!(back.tags.is_none());

        let sr = SearchResult {
            query: "postgres".into(),
            memories: vec![],
        };
        let json = serde_json::to_string(&sr).expect("encode SearchResult");
        let back: SearchResult = serde_json::from_str(&json).expect("decode SearchResult");
        assert_eq!(back.query, "postgres");
        assert!(back.memories.is_empty());
    }

    #[test]
    fn memory_ref_round_trips() {
        let r = MemoryRef {
            id: "01HZX0R5GZ8R3KJYV1Y3M9YW2T".into(),
        };
        let json = serde_json::to_string(&r).expect("encode");
        let back: MemoryRef = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.id, r.id);

        // Same payload backs PreDelete / PostDelete / PreArchive.
        // The variant tag is independent so it's fine to reuse.
        assert_eq!(
            serde_json::to_string(&HookEvent::PreArchive).unwrap(),
            "\"pre_archive\""
        );
    }

    #[test]
    fn promote_delta_and_result_round_trip() {
        let d = PromoteDelta {
            id: "abc".into(),
            from_tier: Tier::Short,
            to_tier: Tier::Long,
        };
        let json = serde_json::to_string(&d).expect("encode");
        let back: PromoteDelta = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.from_tier, Tier::Short);
        assert_eq!(back.to_tier, Tier::Long);

        let r = PromoteResult {
            id: "abc".into(),
            from_tier: Tier::Short,
            to_tier: Tier::Mid,
        };
        let back: PromoteResult =
            serde_json::from_str(&serde_json::to_string(&r).unwrap()).expect("decode");
        assert_eq!(back.to_tier, Tier::Mid);
    }

    #[test]
    fn link_delta_and_post_link_round_trip() {
        let d = LinkDelta {
            source_id: "src".into(),
            target_id: "tgt".into(),
            relation: "related_to".into(),
        };
        let json = serde_json::to_string(&d).expect("encode");
        let back: LinkDelta = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.relation, "related_to");

        // Link is a re-export of MemoryLink — exercise its serde path.
        let post = Link {
            source_id: "src".into(),
            target_id: "tgt".into(),
            relation: crate::models::MemoryLinkRelation::RelatedTo,
            created_at: "2026-05-05T00:00:00Z".into(),
            signature: None,
            observed_by: None,
            valid_from: None,
            valid_until: None,
            attest_level: None,
        };
        let json = serde_json::to_string(&post).expect("encode Link");
        let back: Link = serde_json::from_str(&json).expect("decode Link");
        assert_eq!(back.source_id, "src");
        assert_eq!(back.created_at, "2026-05-05T00:00:00Z");
    }

    #[test]
    fn consolidation_payloads_round_trip() {
        let d = ConsolidationDelta {
            namespace: "team/ops".into(),
            candidate_ids: vec!["a".into(), "b".into(), "c".into()],
        };
        let back: ConsolidationDelta =
            serde_json::from_str(&serde_json::to_string(&d).unwrap()).expect("decode");
        assert_eq!(back.candidate_ids.len(), 3);

        let r = ConsolidationResult {
            namespace: "team/ops".into(),
            merged_ids: vec!["a".into(), "b".into()],
            result_id: Some("merged-1".into()),
        };
        let json = serde_json::to_string(&r).expect("encode");
        let v: Value = serde_json::from_str(&json).expect("parse");
        assert_eq!(v["result_id"], serde_json::json!("merged-1"));

        // Verify the skip-if-none bites.
        let r_no_result = ConsolidationResult {
            namespace: "team/ops".into(),
            merged_ids: vec![],
            result_id: None,
        };
        let v: Value = serde_json::to_value(&r_no_result).expect("encode");
        assert!(v.get("result_id").is_none());
    }

    #[test]
    fn governance_payloads_round_trip() {
        let ctx = GovernanceContext {
            namespace: "team/security".into(),
            action: "memory_store".into(),
            agent_id: "agent-1".into(),
            memory_id: None,
        };
        let back: GovernanceContext =
            serde_json::from_str(&serde_json::to_string(&ctx).unwrap()).expect("decode");
        assert_eq!(back.action, "memory_store");
        assert!(back.memory_id.is_none());

        let dec = GovernanceDecision {
            namespace: "team/security".into(),
            action: "memory_store".into(),
            agent_id: "agent-1".into(),
            outcome: GovernanceOutcome::Ask,
            reason: Some("requires human review".into()),
            pending_id: Some("pending-1".into()),
        };
        let json = serde_json::to_string(&dec).expect("encode");
        let v: Value = serde_json::from_str(&json).expect("parse");
        assert_eq!(v["outcome"], serde_json::json!("ask"));
        let back: GovernanceDecision = serde_json::from_value(v).expect("decode");
        assert!(matches!(back.outcome, GovernanceOutcome::Ask));
        assert_eq!(back.pending_id.as_deref(), Some("pending-1"));
    }

    #[test]
    fn eviction_event_round_trips() {
        // G8 widened the payload to carry the namespace, the
        // RFC-3339 wall-clock eviction time, and a machine-tag
        // for the reason. The full wire shape must round-trip
        // verbatim.
        let ev = EvictionEvent {
            memory_id: "m-1".into(),
            namespace: "team/ops".into(),
            evicted_at: "2026-05-05T12:34:56Z".into(),
            reason: "max_entries_reached".into(),
        };
        let json = serde_json::to_string(&ev).expect("encode");
        let back: EvictionEvent = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.memory_id, "m-1");
        assert_eq!(back.namespace, "team/ops");
        assert_eq!(back.evicted_at, "2026-05-05T12:34:56Z");
        assert_eq!(back.reason, "max_entries_reached");
    }

    #[test]
    fn eviction_event_decodes_legacy_memory_id_only_payload() {
        // G2 shipped `EvictionEvent { memory_id }`; G8 widened it.
        // Backward compatibility: a legacy `{ memory_id }`-only
        // fixture must still parse so any v0.7-rc on-disk hook
        // payloads keep loading. `serde(default)` on the new fields
        // gives empty-string defaults.
        let legacy = r#"{"memory_id":"m-legacy"}"#;
        let back: EvictionEvent = serde_json::from_str(legacy).expect("decode legacy");
        assert_eq!(back.memory_id, "m-legacy");
        assert!(back.namespace.is_empty());
        assert!(back.evicted_at.is_empty());
        assert!(back.reason.is_empty());
    }

    #[test]
    fn eviction_event_new_stamps_rfc3339_timestamp() {
        let ev = EvictionEvent::new("m-1", "team/ops", "max_entries_reached");
        assert_eq!(ev.memory_id, "m-1");
        assert_eq!(ev.namespace, "team/ops");
        assert_eq!(ev.reason, "max_entries_reached");
        // RFC-3339 second-precision UTC: `YYYY-MM-DDTHH:MM:SSZ`.
        // The cheapest invariant to assert without freezing the
        // clock: trailing `Z`, length 20, all ASCII.
        assert_eq!(ev.evicted_at.len(), 20, "got {:?}", ev.evicted_at);
        assert!(
            ev.evicted_at.ends_with('Z'),
            "expected trailing Z, got {:?}",
            ev.evicted_at
        );
    }

    #[test]
    fn reflect_delta_partial_serialization_omits_none_fields() {
        // v0.7.0 Task 6/8 — ReflectDelta wire shape sanity. Only
        // hook-touched fields should surface on the wire.
        let delta = ReflectDelta {
            tags: Some(vec!["rate-limited".into(), "policy".into()]),
            priority: Some(2),
            ..Default::default()
        };
        let v: Value = serde_json::to_value(&delta).expect("encode");
        assert_eq!(v["tags"], serde_json::json!(["rate-limited", "policy"]));
        assert_eq!(v["priority"], serde_json::json!(2));
        assert!(v.get("title").is_none());
        assert!(v.get("content").is_none());
        assert!(v.get("metadata").is_none());

        let back: ReflectDelta = serde_json::from_value(v).expect("decode");
        assert_eq!(back.priority, Some(2));
        assert_eq!(
            back.tags.as_deref(),
            Some(&["rate-limited".to_string(), "policy".to_string()][..])
        );
    }

    #[test]
    fn reflect_result_round_trips() {
        // v0.7.0 Task 6/8 — ReflectResult is the post-commit envelope
        // a post_reflect hook receives. Mirrors db::ReflectOutcome
        // (id, reflection_depth, reflects_on, namespace) field-for-
        // field so a hook author doesn't have to learn a second shape.
        let r = ReflectResult {
            id: "01HZX0R5GZ8R3KJYV1Y3M9YW2T".into(),
            reflection_depth: 2,
            reflects_on: vec!["src-a".into(), "src-b".into()],
            namespace: "team/ops".into(),
        };
        let json = serde_json::to_string(&r).expect("encode");
        let back: ReflectResult = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.id, r.id);
        assert_eq!(back.reflection_depth, 2);
        assert_eq!(back.reflects_on, vec!["src-a".to_string(), "src-b".into()]);
        assert_eq!(back.namespace, "team/ops");
    }

    #[test]
    fn transcript_payloads_round_trip_and_project_from_internal() {
        let delta = TranscriptDelta {
            namespace: Some("agent/claude".into()),
            content: Some("hello world".into()),
            ttl_secs: Some(crate::SECS_PER_HOUR),
        };
        let json = serde_json::to_string(&delta).expect("encode");
        let back: TranscriptDelta = serde_json::from_str(&json).expect("decode");
        assert_eq!(back.namespace.as_deref(), Some("agent/claude"));
        assert_eq!(back.ttl_secs, Some(crate::SECS_PER_HOUR));

        // Project from the internal storage handle to the wire shape.
        let internal = crate::transcripts::Transcript {
            id: "tr-1".into(),
            namespace: "agent/claude".into(),
            created_at: "2026-05-05T00:00:00Z".into(),
            expires_at: None,
            compressed_size: 42,
            original_size: 256,
        };
        let wire: Transcript = (&internal).into();
        let json = serde_json::to_string(&wire).expect("encode wire");
        let back: Transcript = serde_json::from_str(&json).expect("decode wire");
        assert_eq!(back.id, "tr-1");
        assert_eq!(back.compressed_size, 42);
        assert_eq!(back.original_size, 256);
        assert!(back.expires_at.is_none());
    }
}