wm_memory/

episodic.rs

//! LMDB persistence for the v6 lossless episodic memory lane.

use lmdb::{Cursor, Database, Environment, Transaction, WriteFlags};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::sync::{Arc, RwLock};
use wm_core::{
    CoreError, EpisodicCapturePolicy, EpisodicId, EpisodicKind, EpisodicRecord, MemoryTransition,
    Result, ValidityState,
};

use crate::embedder::Embedder;
use crate::enrichment::VocabularyEnrichment;
use crate::episodic_keys::{AdaptiveAliases, key_index_terms_with_aliases};
use crate::query_planner::QueryPlan;
use crate::search::strip_stopwords;

/// Test-only pause points around the authoritative raw episodic commit.
///
/// Absent from production builds. A no-op unless a child test process sets
/// `WM_Q06_CASE` to the matching boundary, in which case it prints exactly one
/// marker line and blocks on stdin until the parent kills it. It must not
/// write to the store or call sync.
#[cfg(test)]
#[derive(Clone, Copy, PartialEq, Eq)]
enum CommitBoundary {
    BeforeRawCommit,
    AfterRawCommit,
}

#[cfg(test)]
fn commit_boundary_test_hook(boundary: CommitBoundary, records: &[EpisodicRecord]) -> Result<()> {
    use std::io::{Read, Write};
    let Ok(case) = std::env::var("WM_Q06_CASE") else {
        return Ok(());
    };
    let expected = match boundary {
        CommitBoundary::BeforeRawCommit => "before_raw_commit",
        CommitBoundary::AfterRawCommit => "after_raw_commit",
    };
    if case != expected {
        return Ok(());
    }
    let uuid = std::env::var("WM_Q06_UUID")
        .map_err(|_| CoreError::Memory("q06 hook: WM_Q06_UUID is required".into()))?;
    let names: Vec<String> = records.iter().map(|record| record.id.to_string()).collect();
    if names.len() != 1 || names[0] != uuid {
        return Err(CoreError::Memory(
            "q06 hook: candidate set must be the single WM_Q06_UUID record".into(),
        ));
    }
    println!("WM_Q06_BOUNDARY {expected} {uuid}");
    let _ = std::io::stdout().flush();
    let mut release = [0_u8; 1];
    match std::io::stdin().read(&mut release) {
        Ok(0) => Err(CoreError::Memory(
            "q06 hook: stdin closed before release".into(),
        )),
        Ok(_) => Ok(()),
        Err(e) => Err(CoreError::Memory(format!(
            "q06 hook: stdin read failed: {e}"
        ))),
    }
}

/// Deterministic raw episodic search result.
#[derive(Debug, Clone)]
pub struct EpisodicSearchResult {
    pub record: EpisodicRecord,
    pub score: f32,
    pub matched_terms: usize,
}

/// Dedicated persistence view over the episodic-record LMDB database.
pub struct EpisodicStore<'a> {
    env: &'a Environment,
    db: Database,
    term_db: Database,
    term_cache: Arc<RwLock<HashMap<String, Vec<EpisodicId>>>>,
    mutation_count: &'a std::sync::atomic::AtomicU64,
    embedder: Option<Arc<dyn Embedder + Send + Sync>>,
    aliases: Option<AdaptiveAliases>,
    enrichment: Option<VocabularyEnrichment>,
}

impl<'a> EpisodicStore<'a> {
    pub(crate) fn new(
        env: &'a Environment,
        db: Database,
        term_db: Database,
        term_cache: Arc<RwLock<HashMap<String, Vec<EpisodicId>>>>,
        mutation_count: &'a std::sync::atomic::AtomicU64,
    ) -> Self {
        Self {
            env,
            db,
            term_db,
            term_cache,
            mutation_count,
            embedder: None,
            aliases: None,
            enrichment: None,
        }
    }

    /// Attach adaptive aliases for query and ingest-time key expansion.
    #[must_use]
    pub fn with_adaptive_aliases(mut self, aliases: AdaptiveAliases) -> Self {
        if !aliases.is_empty() {
            self.aliases = Some(aliases);
        }
        self
    }

    /// Attach vocabulary enrichment for index-time term expansion.
    #[must_use]
    pub fn with_enrichment(mut self, enrichment: VocabularyEnrichment) -> Self {
        if !enrichment.is_empty() {
            self.enrichment = Some(enrichment);
        }
        self
    }

    /// Attach an embedder for vector reranking.
    #[must_use]
    pub fn with_embedder(mut self, embedder: Arc<dyn Embedder + Send + Sync>) -> Self {
        self.embedder = Some(embedder);
        self
    }

    /// Append a source record without allowing an existing raw ID to be overwritten.
    pub fn append(&self, record: &EpisodicRecord) -> Result<()> {
        self.append_batch(std::slice::from_ref(record))
    }

    /// Append many source records, then project them into the sidecar in one
    /// term-index transaction.
    pub fn append_batch(&self, records: &[EpisodicRecord]) -> Result<()> {
        if records.is_empty() {
            return Ok(());
        }
        let serialized = records
            .iter()
            .map(|record| {
                rmp_serde::to_vec(record)
                    .map(|value| (record, value))
                    .map_err(|e| CoreError::Memory(format!("episodic serialize failed: {e}")))
            })
            .collect::<Result<Vec<_>>>()?;
        let mut tx = self
            .env
            .begin_rw_txn()
            .map_err(|e| CoreError::Memory(format!("episodic rw_txn failed: {e}")))?;
        for (record, value) in &serialized {
            match tx.put(
                self.db,
                record.id.as_bytes(),
                value,
                WriteFlags::NO_OVERWRITE,
            ) {
                Ok(()) => {}
                Err(lmdb::Error::KeyExist) => {
                    tx.abort();
                    return Err(CoreError::InvalidArgs(format!(
                        "episodic record {} already exists",
                        record.id
                    )));
                }
                Err(e) => {
                    tx.abort();
                    return Err(CoreError::Memory(format!("episodic append failed: {e}")));
                }
            }
        }
        #[cfg(test)]
        commit_boundary_test_hook(CommitBoundary::BeforeRawCommit, records)?;
        tx.commit()
            .map_err(|e| CoreError::Memory(format!("episodic commit failed: {e}")))?;
        #[cfg(test)]
        commit_boundary_test_hook(CommitBoundary::AfterRawCommit, records)?;
        self.mutation_count
            .fetch_add(records.len() as u64, std::sync::atomic::Ordering::Relaxed);
        // The raw record is authoritative. A projection failure is returned
        // after the raw commit so callers can rebuild the sidecar without
        // losing the source record.
        self.index_records(records)?;
        self.clear_term_cache();
        Ok(())
    }

    /// Read the posting list for a term from the DUP_SORT sidecar.
    ///
    /// A dup-sorted database stores one (term, id) pair per posting, so a
    /// term's list is materialized by iterating its duplicate values. This
    /// keeps append O(new pairs) instead of rewriting a serialized Vec that
    /// grows with the store.
    fn term_postings(&self, term: &str) -> Result<Vec<EpisodicId>> {
        if let Ok(cache) = self.term_cache.read() {
            if let Some(ids) = cache.get(term) {
                return Ok(ids.clone());
            }
        }

        let tx = self
            .env
            .begin_ro_txn()
            .map_err(|e| CoreError::Memory(format!("episodic index ro_txn failed: {e}")))?;
        let term_key = term.to_string();
        let mut ids: Vec<EpisodicId> = Vec::new();
        {
            // Existence pre-check: iter_from() unwraps MDB_SET_RANGE, which
            // legitimately fails NotFound when the key sorts past every entry.
            match tx.get(self.term_db, &term_key) {
                Ok(_) => {}
                Err(lmdb::Error::NotFound) => {
                    tx.commit().map_err(|e| {
                        CoreError::Memory(format!("episodic index commit failed: {e}"))
                    })?;
                    if let Ok(mut cache) = self.term_cache.write() {
                        cache.insert(term_key, Vec::new());
                    }
                    return Ok(ids);
                }
                Err(e) => {
                    return Err(CoreError::Memory(format!(
                        "episodic index read failed: {e}"
                    )));
                }
            }
            let mut cursor = tx
                .open_ro_cursor(self.term_db)
                .map_err(|e| CoreError::Memory(format!("episodic index cursor failed: {e}")))?;
            for (key, value) in cursor.iter_from(term_key.as_bytes()) {
                if key != term_key.as_bytes() {
                    break;
                }
                if value.len() == std::mem::size_of::<EpisodicId>() {
                    if let Ok(id) = EpisodicId::from_slice(value) {
                        ids.push(id);
                    }
                }
            }
        }
        tx.commit()
            .map_err(|e| CoreError::Memory(format!("episodic index commit failed: {e}")))?;
        if let Ok(mut cache) = self.term_cache.write() {
            cache.insert(term_key, ids.clone());
        }
        Ok(ids)
    }

    fn clear_term_cache(&self) {
        if let Ok(mut cache) = self.term_cache.write() {
            cache.clear();
        }
    }

    fn index_records(&self, records: &[EpisodicRecord]) -> Result<()> {
        let public: Vec<&EpisodicRecord> = records
            .iter()
            .filter(|record| !record.is_private && !record.model_exclude)
            .collect();
        if public.is_empty() {
            return Ok(());
        }
        let mut pending: HashMap<String, Vec<&EpisodicRecord>> = HashMap::new();
        for record in &public {
            let base_terms = index_terms_with_aliases(&record.content, self.aliases.as_ref());
            let enriched: Vec<String> = if let Some(ref enrichment) = self.enrichment {
                let mut all = base_terms.clone();
                let extra = enrichment.enrich(&base_terms);
                all.extend(extra);
                all.sort();
                all.dedup();
                all
            } else {
                base_terms
            };
            for term in enriched {
                pending.entry(term).or_default().push(record);
            }
        }
        let mut tx = self
            .env
            .begin_rw_txn()
            .map_err(|e| CoreError::Memory(format!("episodic index rw_txn failed: {e}")))?;
        for (term, records_for_term) in pending {
            for record in records_for_term {
                // DUP_SORT: inserting an existing (term, id) pair overwrites
                // in place, so re-appends are idempotent and cost O(log n)
                // instead of rewriting the whole posting list.
                if let Err(e) = tx.put(
                    self.term_db,
                    &term.as_bytes().to_vec(),
                    &record.id.as_bytes(),
                    WriteFlags::default(),
                ) {
                    tx.abort();
                    return Err(CoreError::Memory(format!(
                        "episodic term index write failed: {e}"
                    )));
                }
            }
        }
        tx.commit()
            .map_err(|e| CoreError::Memory(format!("episodic term index commit failed: {e}")))?;
        Ok(())
    }

    /// Rebuild the DUP_SORT sidecar from the authoritative raw records.
    ///
    /// Used when a store contains records but an empty v2 sidecar (legacy
    /// stores whose postings lived in the retired v1 database, or stores
    /// whose sidecar was lost). The raw lane is never touched; a failure
    /// leaves the sidecar empty and search falls back to the raw scan.
    pub fn rebuild_sidecar(&self) -> Result<usize> {
        let records = self.scan(None, usize::MAX)?;
        let mut indexed = 0usize;
        for chunk in records.chunks(5_000) {
            self.index_records(chunk)?;
            indexed += chunk.len();
        }
        self.clear_term_cache();
        Ok(indexed)
    }

    /// Number of (term, id) postings in the sidecar.
    ///
    /// LMDB 0.8 exposes no per-database stat, so emptiness is checked by
    /// peeking the first entry (cheap; whole-db counts are not needed).
    /// `iter()` (not `iter_start`) is used because `iter_start` unwraps
    /// MDB_FIRST, which fails NotFound on an empty database.
    pub fn sidecar_is_empty(&self) -> Result<bool> {
        let tx = self
            .env
            .begin_ro_txn()
            .map_err(|e| CoreError::Memory(format!("episodic index ro_txn failed: {e}")))?;
        let mut cursor = tx
            .open_ro_cursor(self.term_db)
            .map_err(|e| CoreError::Memory(format!("episodic index cursor failed: {e}")))?;
        Ok(cursor.iter().next().is_none())
    }

    /// Number of raw records in the authoritative lane.
    pub fn record_count(&self) -> Result<u64> {
        let tx = self
            .env
            .begin_ro_txn()
            .map_err(|e| CoreError::Memory(format!("episodic ro_txn failed: {e}")))?;
        let mut cursor = tx
            .open_ro_cursor(self.db)
            .map_err(|e| CoreError::Memory(format!("episodic cursor failed: {e}")))?;
        let mut count = 0u64;
        for _ in cursor.iter() {
            count += 1;
        }
        Ok(count)
    }

    /// Append an explicit record according to the capture policy.
    pub fn append_explicit(
        &self,
        record: &EpisodicRecord,
        policy: EpisodicCapturePolicy,
    ) -> Result<bool> {
        let prepared = record
            .clone()
            .with_content(policy.prepare_content(&record.content));
        self.append(&prepared)?;
        Ok(true)
    }

    /// Append many explicit records according to the capture policy.
    pub fn append_explicit_batch(
        &self,
        records: &[EpisodicRecord],
        policy: EpisodicCapturePolicy,
    ) -> Result<usize> {
        if records.is_empty() {
            return Ok(0);
        }
        let prepared: Vec<EpisodicRecord> = records
            .iter()
            .map(|record| {
                record
                    .clone()
                    .with_content(policy.prepare_content(&record.content))
            })
            .collect();
        self.append_batch(&prepared)?;
        Ok(prepared.len())
    }

    /// Read an episodic record by its canonical ID.
    pub fn get(&self, id: EpisodicId) -> Result<Option<EpisodicRecord>> {
        let tx = self
            .env
            .begin_ro_txn()
            .map_err(|e| CoreError::Memory(format!("episodic ro_txn failed: {e}")))?;
        let result = tx.get(self.db, id.as_bytes());
        match result {
            Ok(bytes) => {
                let record: EpisodicRecord = rmp_serde::from_slice(bytes)
                    .map_err(|e| CoreError::Memory(format!("episodic deserialize failed: {e}")))?;
                tx.commit()
                    .map_err(|e| CoreError::Memory(format!("episodic commit failed: {e}")))?;
                Ok(Some(record))
            }
            Err(lmdb::Error::NotFound) => {
                tx.commit()
                    .map_err(|e| CoreError::Memory(format!("episodic commit failed: {e}")))?;
                Ok(None)
            }
            Err(e) => Err(CoreError::Memory(format!("episodic get failed: {e}"))),
        }
    }

    /// Apply an explicit lifecycle transition to a persisted record.
    pub fn transition(&self, id: EpisodicId, transition: MemoryTransition) -> Result<()> {
        let mut tx = self
            .env
            .begin_rw_txn()
            .map_err(|e| CoreError::Memory(format!("episodic rw_txn failed: {e}")))?;
        let bytes = match tx.get(self.db, id.as_bytes()) {
            Ok(bytes) => bytes,
            Err(lmdb::Error::NotFound) => {
                tx.abort();
                return Err(CoreError::InvalidArgs(format!(
                    "episodic record {id} does not exist"
                )));
            }
            Err(e) => {
                tx.abort();
                return Err(CoreError::Memory(format!("episodic get failed: {e}")));
            }
        };
        let mut record: EpisodicRecord = rmp_serde::from_slice(bytes)
            .map_err(|e| CoreError::Memory(format!("episodic deserialize failed: {e}")))?;
        record
            .transition(transition)
            .map_err(|e| CoreError::InvalidArgs(format!("episodic transition rejected: {e}")))?;
        let value = rmp_serde::to_vec(&record)
            .map_err(|e| CoreError::Memory(format!("episodic serialize failed: {e}")))?;
        tx.put(self.db, id.as_bytes(), &value, WriteFlags::default())
            .map_err(|e| CoreError::Memory(format!("episodic transition write failed: {e}")))?;
        tx.commit()
            .map_err(|e| CoreError::Memory(format!("episodic commit failed: {e}")))?;
        self.mutation_count
            .fetch_add(1, std::sync::atomic::Ordering::Relaxed);
        Ok(())
    }

    /// Return records in sequence order, optionally restricted to a session.
    pub fn scan(
        &self,
        session_id: Option<uuid::Uuid>,
        limit: usize,
    ) -> Result<Vec<EpisodicRecord>> {
        if limit == 0 {
            return Ok(Vec::new());
        }
        let tx = self
            .env
            .begin_ro_txn()
            .map_err(|e| CoreError::Memory(format!("episodic ro_txn failed: {e}")))?;
        let mut cursor = tx
            .open_ro_cursor(self.db)
            .map_err(|e| CoreError::Memory(format!("episodic cursor failed: {e}")))?;
        let mut records = Vec::new();
        for item in cursor.iter() {
            let (_, bytes) = item;
            let record: EpisodicRecord = rmp_serde::from_slice(bytes)
                .map_err(|e| CoreError::Memory(format!("episodic deserialize failed: {e}")))?;
            if session_id.is_none_or(|id| record.session_id == Some(id)) {
                records.push(record);
            }
        }
        drop(cursor);
        tx.commit()
            .map_err(|e| CoreError::Memory(format!("episodic commit failed: {e}")))?;
        records.sort_by_key(|record| (record.sequence, record.created_at, record.id));
        records.truncate(limit);
        Ok(records)
    }

    /// Search current episodic records using deterministic token overlap.
    ///
    /// This is a v6 library path only. It does not alter the v5 MCP search
    /// route and keeps source records attached to every hit.
    ///
    /// When the query asks for the current/latest value of something
    /// (see [`is_current_query`]), the topic cluster is reordered by
    /// deterministic chronology so the most recent statement outranks older
    /// ones — post-retrieval temporal resolution, not a scoring change.
    pub fn search(
        &self,
        query: &str,
        limit: usize,
        include_historical: bool,
    ) -> Result<Vec<EpisodicSearchResult>> {
        self.search_with_limits(query, limit, limit.saturating_mul(2), include_historical)
    }

    /// Search with an explicit candidate budget before selective reranking.
    ///
    /// Uses multi-query pool widening: the original query plus sub-queries
    /// focused on key content words generate candidate IDs. All candidates are
    /// then scored with the primary query's deterministic scoring. This helps
    /// answer turns that match few original query terms but match the key
    /// entity strongly enter the candidate pool.
    pub fn search_with_limits(
        &self,
        query: &str,
        limit: usize,
        candidate_limit: usize,
        include_historical: bool,
    ) -> Result<Vec<EpisodicSearchResult>> {
        if limit == 0 {
            return Ok(Vec::new());
        }
        let mut results = self.search_scored(query, limit, candidate_limit, include_historical)?;
        if is_current_query(query) {
            self.resolve_current(&mut results);
        }
        results.truncate(limit);
        Ok(results)
    }

    /// Deterministic scoring pipeline without temporal resolution or
    /// truncation: candidates → scoring → boosts → score sort. `limit` is
    /// used only for query-class planning (candidate budgets); the caller
    /// truncates.
    fn search_scored(
        &self,
        query: &str,
        limit: usize,
        candidate_limit: usize,
        include_historical: bool,
    ) -> Result<Vec<EpisodicSearchResult>> {
        let plan = QueryPlan::plan(query, limit);
        let candidate_limit = candidate_limit.max(plan.candidate_limit);
        let query_terms = tokenize(query);
        let query_keys = key_index_terms_with_aliases(query, self.aliases.as_ref());
        if query_terms.is_empty() && query_keys.is_empty() || limit == 0 {
            return Ok(Vec::new());
        }
        let mut candidate_scores: HashMap<EpisodicId, usize> = HashMap::new();
        for term in query_terms.iter().chain(query_keys.iter()) {
            for id in self.term_postings(term)? {
                *candidate_scores.entry(id).or_default() += 1;
            }
        }

        let records = if candidate_scores.is_empty() {
            // A populated sidecar with no postings for any query term means
            // the query genuinely matches nothing public — do not fall back
            // to an O(store) raw scan. The scan fallback exists only for
            // degraded or legacy stores whose sidecar is empty/missing.
            if !matches!(self.sidecar_is_empty(), Ok(true)) {
                return Ok(Vec::new());
            }
            // Existing stores or a degraded projection can still be searched.
            self.scan(None, usize::MAX)?
        } else {
            let mut ranked_candidates: Vec<(EpisodicId, usize)> =
                candidate_scores.into_iter().collect();
            ranked_candidates.sort_by(|(left_id, left_count), (right_id, right_count)| {
                right_count
                    .cmp(left_count)
                    .then_with(|| left_id.cmp(right_id))
            });
            ranked_candidates.truncate(candidate_limit);
            self.load_records(
                &ranked_candidates
                    .into_iter()
                    .map(|(id, _)| id)
                    .collect::<Vec<_>>(),
            )?
        };

        let mut results = Vec::new();
        for record in records {
            if !include_historical && !matches!(record.validity, ValidityState::Active) {
                continue;
            }
            let content_terms = tokenize(&record.content);
            let content_keys = key_index_terms_with_aliases(&record.content, self.aliases.as_ref());
            // For UserStatement records, also count reverse-enrichment matches:
            // if the query has "play" and the content has "production", count
            // it as a match. This bridges the vocabulary gap for answer turns
            // without boosting competing Assistant turns.
            let reverse_map: HashMap<&String, Vec<String>> =
                if let Some(ref enrichment) = self.enrichment {
                    if matches!(record.kind, EpisodicKind::UserStatement) {
                        query_terms
                            .iter()
                            .map(|qt| (qt, enrichment.reverse_enrich(qt)))
                            .collect()
                    } else {
                        HashMap::new()
                    }
                } else {
                    HashMap::new()
                };
            let mut reverse_match_count = 0usize;
            let matched_terms = query_terms
                .iter()
                .filter(|term| {
                    if content_terms.iter().any(|candidate| candidate == *term)
                        || content_keys.iter().any(|candidate| candidate == *term)
                    {
                        return true;
                    }
                    // Check reverse enrichment: does the content have any term
                    // that maps to this query term?
                    if let Some(reverse_terms) = reverse_map.get(term) {
                        let found = reverse_terms.iter().any(|rt| {
                            content_terms.iter().any(|candidate| candidate == rt)
                                || content_keys.iter().any(|candidate| candidate == rt)
                        });
                        if found {
                            reverse_match_count += 1;
                        }
                        return found;
                    }
                    false
                })
                .count();
            let matched_keys = query_keys
                .iter()
                .filter(|term| {
                    content_keys.iter().any(|candidate| candidate == *term)
                        || content_terms.iter().any(|candidate| candidate == *term)
                })
                .count();
            if matched_terms == 0 && matched_keys == 0 {
                continue;
            }
            let key_bonus = if query_keys.is_empty() {
                0.0
            } else {
                matched_keys as f32 / query_keys.len() as f32 * plan.key_weight
            };
            let role_boost = match record.kind {
                EpisodicKind::UserStatement => 0.12,
                _ => 0.0,
            };
            let effective_matched = if matches!(record.kind, EpisodicKind::UserStatement) {
                (matched_terms + 2).min(query_terms.len())
            } else {
                matched_terms
            };
            let coverage = if query_terms.is_empty() {
                0.0
            } else {
                effective_matched as f32 / query_terms.len() as f32
            };
            let number_bonus = if plan.number_query {
                let has_digit = content_terms
                    .iter()
                    .any(|term| term.chars().any(|c| c.is_ascii_digit()));
                if has_digit || contains_number_word(&record.content) {
                    0.03
                } else {
                    0.0
                }
            } else {
                0.0
            };
            let density = matched_terms as f32 / content_terms.len().max(1) as f32;
            results.push(EpisodicSearchResult {
                record,
                score: coverage
                    + key_bonus
                    + role_boost
                    + number_bonus
                    + (reverse_match_count as f32).mul_add(0.05, density * 0.03),
                matched_terms: matched_terms.max(matched_keys),
            });
        }
        // Session-aware RRF boost: turns from sessions with multiple matching
        // turns get a small score boost. This is a simplified RRF that preserves
        // the deterministic score scale for the reranking pipeline.
        let mut session_counts: HashMap<Option<uuid::Uuid>, usize> = HashMap::new();
        for r in &results {
            *session_counts.entry(r.record.session_id).or_default() += 1;
        }
        for r in &mut results {
            let count = session_counts
                .get(&r.record.session_id)
                .copied()
                .unwrap_or(1);
            if count > 1 {
                r.score = 0.02f32.mul_add((count - 1).min(3) as f32, r.score);
            }
        }
        // Content-frequency boost (consolidation): if the same content hash
        // appears multiple times in the result set, boost all instances. This
        // simulates consolidation — facts mentioned repeatedly are more
        // important. The boost is small (0.03 per duplicate, max 0.09) to
        // avoid distorting the score scale.
        let mut hash_counts: HashMap<&str, usize> = HashMap::new();
        for r in &results {
            *hash_counts
                .entry(r.record.content_hash.as_str())
                .or_default() += 1;
        }
        let hash_boosts: HashMap<String, f32> = results
            .iter()
            .map(|r| {
                let count = hash_counts
                    .get(r.record.content_hash.as_str())
                    .copied()
                    .unwrap_or(1);
                let boost = if count > 1 {
                    0.03 * (count - 1).min(3) as f32
                } else {
                    0.0
                };
                (r.record.id.to_string(), boost)
            })
            .collect();
        for r in &mut results {
            if let Some(boost) = hash_boosts.get(&r.record.id.to_string()) {
                r.score += boost;
            }
        }
        results.sort_by(|a, b| {
            b.score
                .partial_cmp(&a.score)
                .unwrap_or(std::cmp::Ordering::Equal)
                .then_with(|| b.matched_terms.cmp(&a.matched_terms))
                .then_with(|| a.record.content.len().cmp(&b.record.content.len()))
                .then_with(|| a.record.sequence.cmp(&b.record.sequence))
                .then_with(|| a.record.id.cmp(&b.record.id))
        });
        Ok(results)
    }

    /// Search with vector reranking on top of deterministic scoring.
    ///
    /// Pipeline: deterministic scoring → top-N candidates → embed query +
    /// candidates → reranking → top-K.
    ///
    /// Modes by `alpha`:
    /// - `alpha >= 2.0` — **protected top-K** (ConvMemory v2 pattern):
    ///   fully reorder only the deterministic top-`limit` set by cosine
    ///   similarity. Membership is fixed, so recall@limit is preserved by
    ///   construction; only ordering (R@1/MRR) can change.
    /// - `1.0 <= alpha < 2.0` — **tiebreaker mode**: only reorder adjacent
    ///   candidates whose deterministic scores are within δ=0.05, using
    ///   cosine as the tiebreaker.
    /// - `alpha < 1.0` — **hybrid blending**: score = α·det_norm + (1-α)·cosine.
    ///
    /// Falls back to `search_with_limits()` when no embedder is attached.
    pub fn search_with_rerank(
        &self,
        query: &str,
        limit: usize,
        candidate_limit: usize,
        include_historical: bool,
        alpha: f32,
        rerank_pool: usize,
    ) -> Result<Vec<EpisodicSearchResult>> {
        let Some(ref embedder) = self.embedder else {
            return self.search_with_limits(query, limit, candidate_limit, include_historical);
        };
        if !embedder.is_available() || limit == 0 {
            return self.search_with_limits(query, limit, candidate_limit, include_historical);
        }

        // `candidate_limit` is the deterministic retrieval width (how deep
        // the scorer looks); `rerank_pool` bounds only how many of those
        // candidates are embedded and reordered (0 = auto). Decoupled so a
        // wide deterministic membership can back a small embed pool — the
        // old shared value also shrank the deterministic set, which broke
        // protected mode's fixed-membership claim against the baseline
        // (T0 finding F-T0-1).
        let rerank_pool = if rerank_pool == 0 {
            limit.max(candidate_limit).min(50)
        } else {
            rerank_pool.max(limit).min(50)
        };
        // `search_scored` does not truncate (its limit arg is planning-only),
        // so the pool is enforced here explicitly.
        let deterministic: Vec<EpisodicSearchResult> = self
            .search_scored(query, rerank_pool, candidate_limit, include_historical)?
            .into_iter()
            .take(rerank_pool)
            .collect();
        if deterministic.is_empty() {
            return Ok(Vec::new());
        }

        // Batch-embed query + all candidate contents in one call.
        let contents: Vec<&str> = std::iter::once(query)
            .chain(deterministic.iter().map(|r| r.record.content.as_str()))
            .collect();
        let embeddings = embedder.embed_batch(&contents)?;
        if embeddings.len() != deterministic.len() + 1 {
            return Err(CoreError::Memory(format!(
                "embedder returned {} vectors, expected {}",
                embeddings.len(),
                deterministic.len() + 1
            )));
        }
        let query_vec = &embeddings[0];
        let candidate_vecs = &embeddings[1..];

        if alpha >= 2.0 {
            // Protected top-K rerank (ConvMemory v2 pattern): fully reorder
            // ONLY the deterministic top-`limit` set by cosine similarity.
            // Set membership is fixed, so recall@limit is preserved by
            // construction — only the ordering (R@1/MRR) can change.
            let protected: Vec<EpisodicSearchResult> =
                deterministic.into_iter().take(limit).collect();
            let cosines: Vec<f32> = protected
                .iter()
                .enumerate()
                .map(|(i, _)| cosine_sim(query_vec, &candidate_vecs[i]))
                .collect();
            let mut order: Vec<usize> = (0..protected.len()).collect();
            order.sort_by(|&a, &b| {
                cosines[b]
                    .partial_cmp(&cosines[a])
                    .unwrap_or(std::cmp::Ordering::Equal)
                    // Stable within equal cosine: keep deterministic order.
                    .then_with(|| a.cmp(&b))
            });
            let mut slots: Vec<Option<EpisodicSearchResult>> =
                protected.into_iter().map(Some).collect();
            let reranked: Vec<EpisodicSearchResult> =
                order.into_iter().filter_map(|i| slots[i].take()).collect();
            Ok(reranked)
        } else if alpha >= 1.0 {
            // Tiebreaker mode: only reorder adjacent candidates with close det scores.
            let delta = 0.05;
            let mut reranked = deterministic;
            let cosines: Vec<f32> = candidate_vecs
                .iter()
                .map(|v| cosine_sim(query_vec, v))
                .collect();
            // Bubble-sort adjacent swaps only when det scores are within delta.
            let n = reranked.len();
            for _ in 0..n {
                let mut swapped = false;
                for i in 0..n.saturating_sub(1) {
                    let det_gap = (reranked[i].score - reranked[i + 1].score).abs();
                    if det_gap < delta && cosines[i + 1] > cosines[i] {
                        reranked.swap(i, i + 1);
                        swapped = true;
                    }
                }
                if !swapped {
                    break;
                }
            }
            if is_current_query(query) {
                self.resolve_current(&mut reranked);
            }
            reranked.truncate(limit);
            Ok(reranked)
        } else {
            // Hybrid blending mode.
            let max_det = deterministic
                .iter()
                .map(|r| r.score)
                .fold(0.0f32, f32::max)
                .max(1e-9);

            let mut reranked: Vec<EpisodicSearchResult> = deterministic
                .into_iter()
                .enumerate()
                .map(|(i, mut r)| {
                    let cosine = cosine_sim(query_vec, &candidate_vecs[i]);
                    let det_norm = r.score / max_det;
                    r.score = alpha.mul_add(det_norm, (1.0 - alpha) * cosine);
                    r
                })
                .collect();

            reranked.sort_by(|a, b| {
                b.score
                    .partial_cmp(&a.score)
                    .unwrap_or(std::cmp::Ordering::Equal)
                    .then_with(|| b.matched_terms.cmp(&a.matched_terms))
                    .then_with(|| a.record.content.len().cmp(&b.record.content.len()))
                    .then_with(|| a.record.sequence.cmp(&b.record.sequence))
                    .then_with(|| a.record.id.cmp(&b.record.id))
            });
            if is_current_query(query) {
                self.resolve_current(&mut reranked);
            }
            reranked.truncate(limit);
            Ok(reranked)
        }
    }

    /// Post-retrieval temporal resolution for "current value" queries.
    ///
    /// When the user asks "What's my current favorite X?", the current-value
    /// statement often matches *fewer* query terms than an older statement
    /// ("my favorite coffee is dark roast" matches favorite+coffee, while
    /// "I switched to cold brew for coffee" matches only coffee), so pure
    /// score order prefers the stale fact. This layer instead promotes the
    /// currency signal directly:
    ///
    /// 1. Anchor set: `UserStatement` records containing a change marker
    ///    ("switched to", "changed my", "now prefer", "used to", ...) — the
    ///    user's own words that a value moved. Only user statements anchor:
    ///    the user's own statement is the authority for their current state,
    ///    and assistant echoes must not hijack chronology.
    /// 2. Anchors are ordered by deterministic chronology — `(created_at,
    ///    sequence)` descending — so the most recent change outranks earlier
    ///    ones (v1→v2→v3 chains resolve to v3).
    /// 3. Remaining results keep their deterministic score order behind the
    ///    anchors.
    ///
    /// Scoring is untouched and non-current queries take the identical path,
    /// so behavior for historical questions is unchanged by construction
    /// (see `docs/notes/research-2026-08-20-agent-memory.md`: the
    /// Post-Retrieval Assembly paper found the LongMemEval effect of
    /// temporal machinery insignificant, p=0.45 — the gain is on
    /// current-value questions, which is exactly what this targets).
    fn resolve_current(&self, results: &mut Vec<EpisodicSearchResult>) {
        if results.len() < 2 {
            return;
        }
        let mut anchors: Vec<EpisodicSearchResult> = Vec::new();
        let mut rest: Vec<EpisodicSearchResult> = Vec::new();
        for result in results.drain(..) {
            let is_anchor = matches!(result.record.kind, EpisodicKind::UserStatement)
                && contains_change_marker(&result.record.content);
            if is_anchor {
                anchors.push(result);
            } else {
                rest.push(result);
            }
        }
        if anchors.is_empty() {
            // No currency signal — keep the deterministic score order.
            *results = rest;
            return;
        }
        anchors.sort_by(|a, b| {
            b.record
                .created_at
                .cmp(&a.record.created_at)
                .then_with(|| b.record.sequence.cmp(&a.record.sequence))
                .then_with(|| a.record.id.cmp(&b.record.id))
        });
        anchors.extend(rest);
        *results = anchors;
    }

    fn load_records(&self, ids: &[EpisodicId]) -> Result<Vec<EpisodicRecord>> {
        let tx = self
            .env
            .begin_ro_txn()
            .map_err(|e| CoreError::Memory(format!("episodic ro_txn failed: {e}")))?;
        let mut records = Vec::with_capacity(ids.len());
        for id in ids {
            match tx.get(self.db, id.as_bytes()) {
                Ok(bytes) => {
                    records.push(rmp_serde::from_slice(bytes).map_err(|e| {
                        CoreError::Memory(format!("episodic deserialize failed: {e}"))
                    })?);
                }
                Err(lmdb::Error::NotFound) => {}
                Err(e) => return Err(CoreError::Memory(format!("episodic get failed: {e}"))),
            }
        }
        tx.commit()
            .map_err(|e| CoreError::Memory(format!("episodic commit failed: {e}")))?;
        Ok(records)
    }
}

fn index_terms_with_aliases(text: &str, aliases: Option<&AdaptiveAliases>) -> Vec<String> {
    tokenize(text)
        .into_iter()
        .chain(key_index_terms_with_aliases(text, aliases))
        .fold(Vec::new(), |mut terms, term| {
            if !terms.contains(&term) {
                terms.push(term);
            }
            terms
        })
}

fn tokenize(text: &str) -> Vec<String> {
    strip_stopwords(text)
        .split(|c: char| !c.is_alphanumeric())
        .filter(|term| term.len() > 1)
        .map(|term| simple_stem(&term.to_ascii_lowercase()))
        .fold(Vec::new(), |mut terms, term| {
            if !terms.contains(&term) {
                terms.push(term);
            }
            terms
        })
}

/// Single-word cues that ask for the current value of something.
const CURRENT_QUERY_WORD_CUES: &[&str] = &["current", "currently", "latest", "nowadays"];

/// Multi-word cues that ask for the current value of something.
const CURRENT_QUERY_PHRASE_CUES: &[&str] = &["these days", "right now", "at the moment"];

/// True when the query asks for the current/latest value of something,
/// e.g. "What's my current favorite coffee?".
///
/// Only such queries trigger post-retrieval temporal resolution
/// ([`EpisodicStore::resolve_current`]); all other queries take the
/// deterministic score order unchanged.
#[must_use]
pub fn is_current_query(query: &str) -> bool {
    let lowered = query.to_ascii_lowercase();
    let has_word = lowered
        .split(|c: char| !c.is_alphanumeric())
        .any(|token| CURRENT_QUERY_WORD_CUES.contains(&token));
    has_word
        || CURRENT_QUERY_PHRASE_CUES
            .iter()
            .any(|cue| lowered.contains(cue))
}

/// Phrase markers that a stated value has changed — the currency signal
/// used by [`EpisodicStore::resolve_current`]. Kept deliberately specific:
/// these phrases indicate a *transition*, not merely a preference
/// statement, so plain "my favorite X is Y" statements never anchor.
const CHANGE_MARKERS: &[&str] = &[
    "switched to",
    "switch to",
    "switching to",
    "switched from",
    "changed my",
    "change my",
    "changed from",
    "now prefer",
    "now i prefer",
    "now i'm",
    "now im",
    "no longer",
    "used to",
    "moved to",
    "not anymore",
    "instead of",
    "replaced",
    "gave up",
];

/// True when the content contains a phrase marking a value transition.
fn contains_change_marker(content: &str) -> bool {
    let lowered = content.to_ascii_lowercase();
    CHANGE_MARKERS.iter().any(|marker| lowered.contains(marker))
}

/// Markers that explicitly contradict a previously stated value — signals
/// that two retrieved statements may conflict and should be surfaced
/// together (TANGLE semantics: preserve both, never silently resolve).
const CONTRADICTION_MARKERS: &[&str] = &[
    "no longer",
    "anymore",
    "changed my mind",
    "changed my",
    "used to",
    "gave up",
    "just a phase",
    "not really",
    "but i",
];

/// A read-time contradiction between two retrieved user statements.
///
/// Detection is deliberately conservative: one statement must carry an
/// explicit contradiction marker, and the pair must share at least two
/// content terms (the topic cluster). The report preserves both sides with
/// full provenance — it never adjudicates.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct EpisodicConflict {
    /// The chronologically later statement (carries the contradiction
    /// marker in the common case).
    pub later_record: EpisodicId,
    /// The statement it appears to contradict.
    pub earlier_record: EpisodicId,
    /// The contradiction phrase that triggered the detection.
    pub marker: String,
    /// Content terms shared by the pair (the topic cluster).
    pub shared_terms: Vec<String>,
    /// Full content of the later statement (provenance).
    pub later_content: String,
    /// Full content of the earlier statement (provenance).
    pub earlier_content: String,
}

/// Detect contradictions among retrieved results.
///
/// For every `UserStatement` carrying an explicit contradiction marker,
/// pair it with other `UserStatement` results sharing at least two content
/// terms. Statements with identical content hashes (the same fact seen
/// twice) are not conflicts. Results are capped to keep tool output
/// bounded.
#[must_use]
pub fn detect_conflicts(results: &[EpisodicSearchResult]) -> Vec<EpisodicConflict> {
    const MAX_CONFLICTS: usize = 10;
    let mut conflicts: Vec<EpisodicConflict> = Vec::new();
    let mut seen_pairs: Vec<(EpisodicId, EpisodicId)> = Vec::new();
    for (i, marked) in results.iter().enumerate() {
        if !matches!(marked.record.kind, EpisodicKind::UserStatement) {
            continue;
        }
        let lowered = marked.record.content.to_ascii_lowercase();
        let Some(marker) = CONTRADICTION_MARKERS
            .iter()
            .find(|m| lowered.contains(*m))
            .copied()
        else {
            continue;
        };
        let marked_terms = tokenize(&marked.record.content);
        for (j, other) in results.iter().enumerate() {
            if i == j || !matches!(other.record.kind, EpisodicKind::UserStatement) {
                continue;
            }
            if other.record.content_hash == marked.record.content_hash {
                continue;
            }
            let other_terms = tokenize(&other.record.content);
            let shared: Vec<String> = marked_terms
                .iter()
                .filter(|t| other_terms.contains(t))
                .cloned()
                .collect();
            if shared.len() < 2 {
                continue;
            }
            // Label by deterministic chronology: the later statement is the
            // one the user said most recently.
            let (later, earlier) = if (marked.record.created_at, marked.record.sequence)
                > (other.record.created_at, other.record.sequence)
            {
                (&marked.record, &other.record)
            } else {
                (&other.record, &marked.record)
            };
            let pair_key = if later.id < earlier.id {
                (later.id, earlier.id)
            } else {
                (earlier.id, later.id)
            };
            if seen_pairs.contains(&pair_key) {
                continue;
            }
            seen_pairs.push(pair_key);
            conflicts.push(EpisodicConflict {
                later_record: later.id,
                earlier_record: earlier.id,
                marker: marker.to_string(),
                shared_terms: shared,
                later_content: later.content.clone(),
                earlier_content: earlier.content.clone(),
            });
            if conflicts.len() >= MAX_CONFLICTS {
                return conflicts;
            }
        }
    }
    conflicts
}

fn simple_stem(word: &str) -> String {
    if word.len() <= 3 {
        return word.to_string();
    }
    for suffix in ["ies", "ied", "ing", "edly", "ed", "ly", "es", "s"] {
        if let Some(stem) = word.strip_suffix(suffix) {
            if suffix == "ies" || suffix == "ied" {
                return format!("{stem}y");
            }
            if stem.len() >= 2 {
                return stem.to_string();
            }
        }
    }
    word.to_string()
}

fn cosine_sim(a: &[f32], b: &[f32]) -> f32 {
    let dot = a.iter().zip(b.iter()).map(|(x, y)| x * y).sum::<f32>();
    let norm_a = a.iter().map(|x| x * x).sum::<f32>().sqrt();
    let norm_b = b.iter().map(|x| x * x).sum::<f32>().sqrt();
    if norm_a < 1e-9 || norm_b < 1e-9 {
        0.0
    } else {
        dot / (norm_a * norm_b)
    }
}

fn contains_number_word(text: &str) -> bool {
    const NUMBER_WORDS: &[&str] = &[
        "one",
        "two",
        "three",
        "four",
        "five",
        "six",
        "seven",
        "eight",
        "nine",
        "ten",
        "eleven",
        "twelve",
        "thirteen",
        "fourteen",
        "fifteen",
        "sixteen",
        "seventeen",
        "eighteen",
        "nineteen",
        "twenty",
        "thirty",
        "forty",
        "fifty",
        "sixty",
        "seventy",
        "eighty",
        "ninety",
        "hundred",
        "thousand",
        "million",
        "billion",
        "dozen",
        "couple",
        "half",
        "quarter",
        "double",
        "triple",
        "twice",
    ];
    for word in text.split(|c: char| !c.is_alphanumeric()) {
        if word.len() >= 3 && NUMBER_WORDS.iter().any(|nw| word.eq_ignore_ascii_case(nw)) {
            return true;
        }
    }
    false
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::MemoryStore;
    // Used only by the Q06 commit-boundary experiment, which is Unix-only
    // (SIGKILL semantics); ungated imports are unused on Windows and fail the
    // CI `-D warnings` build.
    #[cfg(unix)]
    use chrono::{DateTime, Utc};
    use tempfile::tempdir;
    #[cfg(unix)]
    use uuid::Uuid;
    use wm_core::{EpisodicKind, Provenance, ProvenanceSource, ValidityState};

    fn sample_record(sequence: u64, content: &str) -> EpisodicRecord {
        EpisodicRecord::new(
            None,
            sequence,
            EpisodicKind::Observation,
            content,
            Provenance::new(ProvenanceSource::User),
        )
    }

    fn user_statement(sequence: u64, content: &str) -> EpisodicRecord {
        EpisodicRecord::new(
            None,
            sequence,
            EpisodicKind::UserStatement,
            content,
            Provenance::new(ProvenanceSource::User),
        )
    }

    fn assistant_response(sequence: u64, content: &str) -> EpisodicRecord {
        EpisodicRecord::new(
            None,
            sequence,
            EpisodicKind::AssistantResponse,
            content,
            Provenance::new(ProvenanceSource::Agent),
        )
    }

    // ── Q06 commit-boundary subprocess experiment ──────────────────────────
    // Design: docs/V9_3_Q06_COMMIT_BOUNDARY_EXPERIMENT.md. One parent test plus
    // a child branch selected by WM_Q06_CASE. The parent re-executes its own
    // test binary, kills the child at an exact commit-boundary hook, reopens
    // the store, and classifies the candidate. SIGKILL models abrupt process
    // termination only — not power loss.

    #[cfg(unix)]
    fn q06_record(id: u128, sequence: u64, content: &str, created_at: &str) -> EpisodicRecord {
        let mut record = EpisodicRecord::new(
            None,
            sequence,
            EpisodicKind::Observation,
            content,
            Provenance::new(ProvenanceSource::User),
        )
        .with_id(Uuid::from_u128(id));
        record.created_at = DateTime::parse_from_rfc3339(created_at)
            .unwrap()
            .with_timezone(&Utc);
        record
    }

    #[cfg(unix)]
    fn q06_acknowledged() -> EpisodicRecord {
        q06_record(601, 601, "q06 acknowledged control", "2026-01-01T00:10:01Z")
    }

    #[cfg(unix)]
    fn run_q06_child(case: &str, store_path: &std::path::Path) {
        use std::io::Write;
        let expected_uuid = std::env::var("WM_Q06_UUID").expect("WM_Q06_UUID");
        let uuid = Uuid::parse_str(&expected_uuid).expect("WM_Q06_UUID must parse");
        let (sequence, content, created_at) = match case {
            "before_raw_commit" => (602, "q06 precommit candidate", "2026-01-01T00:10:02Z"),
            "after_raw_commit" => (603, "q06 uncertain candidate", "2026-01-01T00:10:03Z"),
            other => panic!("q06 child: unknown case {other}"),
        };
        let record = q06_record(uuid.as_u128(), sequence, content, created_at);
        let store = MemoryStore::open_default(store_path).expect("q06 child store");
        match store.episodic().append(&record) {
            Ok(()) => {
                // Only legal when the termination window was missed; the
                // parent treats this line as a hard failure.
                println!("WM_Q06_CALLER_ACK {uuid}");
                let _ = std::io::stdout().flush();
            }
            Err(e) => {
                eprintln!("q06 child append failed: {e}");
                std::process::exit(2);
            }
        }
    }

    #[cfg(unix)]
    fn run_q06_killed_case(
        test_filter: &str,
        store_path: &std::path::Path,
        case: &str,
        uuid: Uuid,
    ) -> Vec<String> {
        use std::io::{BufRead, BufReader};
        let exe = std::env::current_exe().expect("q06 current_exe");
        let mut child = std::process::Command::new(exe)
            .arg(test_filter)
            .arg("--exact")
            .arg("--nocapture")
            .env("WM_Q06_CASE", case)
            .env("WM_Q06_STORE", store_path)
            .env("WM_Q06_UUID", uuid.to_string())
            .stdout(std::process::Stdio::piped())
            .stdin(std::process::Stdio::piped())
            .stderr(std::process::Stdio::inherit())
            .spawn()
            .expect("q06 spawn child");

        let stdout = child.stdout.take().expect("q06 child stdout");
        let (tx, rx) = std::sync::mpsc::channel::<String>();
        let reader = std::thread::spawn(move || {
            for line in BufReader::new(stdout).lines() {
                match line {
                    Ok(line) => {
                        if tx.send(line).is_err() {
                            break;
                        }
                    }
                    Err(_) => break,
                }
            }
        });

        let expected = format!("WM_Q06_BOUNDARY {case} {uuid}");
        let deadline = std::time::Instant::now() + std::time::Duration::from_secs(5);
        let mut lines = Vec::new();
        let mut seen = false;
        while !seen {
            let remaining = deadline.saturating_duration_since(std::time::Instant::now());
            if remaining.is_zero() {
                break;
            }
            match rx.recv_timeout(remaining) {
                Ok(line) if line == expected => seen = true,
                Ok(line) => lines.push(line),
                Err(_) => break,
            }
        }
        if !seen {
            let _ = child.kill();
            let _ = child.wait();
            reader.join().ok();
            panic!("q06 case {case}: boundary {expected:?} not observed; lines={lines:?}");
        }

        child.kill().expect("q06 kill blocked child");
        let status = child.wait().expect("q06 reap child");
        assert!(
            !status.success(),
            "q06 case {case}: killed child must not exit successfully: {status:?}"
        );
        reader.join().ok();
        while let Ok(line) = rx.try_recv() {
            lines.push(line);
        }
        assert!(
            !lines.iter().any(|line| line.contains("WM_Q06_CALLER_ACK")),
            "q06 case {case}: caller acknowledgement in a killed case invalidates the experiment: {lines:?}"
        );
        lines
    }

    #[cfg(unix)]
    #[test]
    fn q06_commit_boundary_sigkill_classification() {
        if let Ok(case) = std::env::var("WM_Q06_CASE") {
            let store_path = std::env::var("WM_Q06_STORE").expect("WM_Q06_STORE");
            run_q06_child(&case, std::path::Path::new(&store_path));
            return;
        }

        let dir = tempdir().unwrap();
        let store_path = dir.path().join("lmdb");
        let acknowledged = q06_acknowledged();

        // Acknowledged pre-state: normal append, exact read, store dropped.
        {
            let store = MemoryStore::open_default(&store_path).unwrap();
            store.episodic().append(&acknowledged).unwrap();
            let read = store
                .episodic()
                .get(acknowledged.id)
                .unwrap()
                .expect("acknowledged record");
            assert_eq!(read, acknowledged);
        }

        let test_filter = "episodic::tests::q06_commit_boundary_sigkill_classification";

        // Case A — killed immediately before the raw commit: rejected/uncommitted.
        let candidate_before =
            q06_record(602, 602, "q06 precommit candidate", "2026-01-01T00:10:02Z");
        run_q06_killed_case(
            test_filter,
            &store_path,
            "before_raw_commit",
            candidate_before.id,
        );
        {
            let store = MemoryStore::open_default(&store_path).unwrap();
            assert_eq!(
                store.episodic().get(acknowledged.id).unwrap(),
                Some(acknowledged.clone()),
                "acknowledged record must survive a pre-commit kill unchanged"
            );
            assert_eq!(
                store.episodic().get(candidate_before.id).unwrap(),
                None,
                "pre-commit candidate must be absent after reopen"
            );
        }

        // Case B — killed after the raw commit, before acknowledgement:
        // storage committed, caller outcome uncertain.
        let candidate_after =
            q06_record(603, 603, "q06 uncertain candidate", "2026-01-01T00:10:03Z");
        run_q06_killed_case(
            test_filter,
            &store_path,
            "after_raw_commit",
            candidate_after.id,
        );
        {
            let store = MemoryStore::open_default(&store_path).unwrap();
            assert_eq!(
                store.episodic().get(acknowledged.id).unwrap(),
                Some(acknowledged),
                "acknowledged record must survive a post-commit kill unchanged"
            );
            assert_eq!(
                store.episodic().get(candidate_before.id).unwrap(),
                None,
                "pre-commit candidate must stay absent"
            );
            assert_eq!(
                store.episodic().get(candidate_after.id).unwrap(),
                Some(candidate_after),
                "post-commit candidate must be present and byte-equal after reopen"
            );
        }
    }

    #[test]
    fn current_query_detection() {
        assert!(is_current_query("What's my current favorite coffee?"));
        assert!(is_current_query("What am I currently reading these days?"));
        assert!(is_current_query("What's the latest book I mentioned?"));
        assert!(is_current_query("What's my job right now?"));
        assert!(is_current_query("What am I eating at the moment?"));
        assert!(!is_current_query("What's my favorite coffee?"));
        assert!(!is_current_query("Where did I volunteer in February?"));
        assert!(!is_current_query("What did I say about the trip?"));
        // Word-boundary match: "current" inside another word must not fire.
        assert!(!is_current_query("What currency did I use in Japan?"));
    }

    #[test]
    fn protected_rerank_preserves_membership_with_a_small_pool() {
        // T0 F-T0-1: `rerank_pool` bounds only the embedded/reordered set;
        // `candidate_limit` stays the deterministic retrieval width. The old
        // code used the pool for both, so shrinking the pool also shrank the
        // candidate set and protected mode lost baseline membership.
        use crate::embedder::Embedder;
        use std::sync::Arc;
        use std::sync::atomic::{AtomicUsize, Ordering};

        struct CountingEmbedder(Arc<AtomicUsize>);
        impl Embedder for CountingEmbedder {
            fn embed_batch(&self, texts: &[&str]) -> wm_core::Result<Vec<Vec<f32>>> {
                self.0.store(texts.len(), Ordering::Relaxed);
                Ok(texts
                    .iter()
                    .map(|t| {
                        let mut v = vec![0.0_f32; 8];
                        for (i, b) in t.bytes().enumerate() {
                            v[i % 8] += f32::from(b) / 255.0;
                        }
                        v
                    })
                    .collect())
            }
            fn dimension(&self) -> usize {
                8
            }
            fn is_available(&self) -> bool {
                true
            }
            fn backend_name(&self) -> &'static str {
                "counting-test"
            }
        }

        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        for i in 0..20 {
            store
                .episodic()
                .append(&user_statement(
                    i,
                    &format!("Record {i} discusses topic alpha beta gamma delta epsilon"),
                ))
                .unwrap();
        }

        let query = "topic alpha beta gamma delta epsilon";
        // Deterministic top-5 from a 20-wide candidate scoring — the
        // membership protected mode must preserve.
        let expected: Vec<uuid::Uuid> = store
            .episodic()
            .search_scored(query, 5, 20, false)
            .unwrap()
            .iter()
            .take(5)
            .map(|r| r.record.id)
            .collect();
        assert_eq!(expected.len(), 5);

        let batches = Arc::new(AtomicUsize::new(0));
        store.set_episodic_embedder(Arc::new(CountingEmbedder(batches.clone())));
        let reranked = store
            .episodic()
            .search_with_rerank(query, 5, 20, false, 2.0, 5)
            .unwrap();
        assert_eq!(
            batches.load(Ordering::Relaxed),
            6,
            "small rerank pool must embed pool + query only"
        );
        let mut got: Vec<uuid::Uuid> = reranked.iter().map(|r| r.record.id).collect();
        let mut want = expected;
        got.sort();
        want.sort();
        assert_eq!(
            got, want,
            "protected mode must keep the deterministic candidate set (membership), only reorder it"
        );
    }

    #[test]
    fn current_query_resolution_prefers_latest_statement() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        // Old-value statements match MORE query terms (favorite + coffee)
        // than the change statement (coffee only), so pure score order
        // prefers the stale fact — the exact T1 failure mode.
        episodic
            .append(&user_statement(1, "My favorite coffee is dark roast."))
            .unwrap();
        episodic
            .append(&user_statement(
                2,
                "I really love dark roast when it comes to coffee.",
            ))
            .unwrap();
        episodic
            .append(&user_statement(3, "I've been jogging lately."))
            .unwrap();
        episodic
            .append(&user_statement(4, "I've switched to cold brew for coffee."))
            .unwrap();

        let results = episodic
            .search("What's my current favorite coffee?", 5, false)
            .unwrap();
        assert!(!results.is_empty());
        assert!(
            results[0].record.content.contains("cold brew"),
            "current query must rank the latest statement first, got: {}",
            results[0].record.content
        );
    }

    #[test]
    fn current_query_anchors_switched_from_template() {
        // Regression: "I've actually switched from X to Y" (MemoraStrict
        // change-template 1) contains "switched from", which was missing
        // from CHANGE_MARKERS — the anchor set stayed empty and the stale
        // value won on score order. Found by static miss analysis
        // 2026-08-20: 12/40 T1+T6 questions failed on exactly this phrase.
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        episodic
            .append(&user_statement(1, "My favorite coffee is espresso."))
            .unwrap();
        episodic
            .append(&user_statement(
                2,
                "I've actually switched from espresso to latte for coffee.",
            ))
            .unwrap();
        episodic
            .append(&user_statement(3, "My favorite coffee is latte."))
            .unwrap();

        let results = episodic
            .search("What's my current favorite coffee?", 5, false)
            .unwrap();
        assert!(!results.is_empty());
        assert!(
            results[0].record.content.contains("latte"),
            "'switched from' must anchor the current value, got: {}",
            results[0].record.content
        );
    }

    #[test]
    fn non_current_query_keeps_score_order() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        episodic
            .append(&user_statement(1, "My favorite coffee is dark roast."))
            .unwrap();
        episodic
            .append(&user_statement(2, "I've switched to cold brew for coffee."))
            .unwrap();

        // Without a current-value cue the deterministic score order holds:
        // the statement matching more query terms (favorite + coffee) wins.
        let results = episodic
            .search("What's my favorite coffee?", 5, false)
            .unwrap();
        assert!(!results.is_empty());
        assert!(
            results[0].record.content.contains("dark roast"),
            "non-current query must keep score order, got: {}",
            results[0].record.content
        );
    }

    #[test]
    fn current_resolution_anchors_on_user_statements_only() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        episodic
            .append(&user_statement(1, "My favorite coffee is dark roast."))
            .unwrap();
        // An assistant echo created LATER must not hijack the anchor set.
        episodic
            .append(&assistant_response(
                2,
                "Got it, dark roast is your favorite coffee!",
            ))
            .unwrap();
        episodic
            .append(&user_statement(3, "I've switched to cold brew for coffee."))
            .unwrap();

        let results = episodic
            .search("What's my current favorite coffee?", 5, false)
            .unwrap();
        assert!(
            results[0].record.content.contains("cold brew"),
            "user statements anchor chronology, got: {}",
            results[0].record.content
        );
        assert_eq!(results[0].record.kind, EpisodicKind::UserStatement);
    }

    #[test]
    fn current_query_without_change_markers_keeps_score_order() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        // No change markers anywhere: resolution must not reorder anything.
        episodic
            .append(&user_statement(
                1,
                "My favorite hiking trail is Eagle Ridge.",
            ))
            .unwrap();
        episodic
            .append(&user_statement(2, "I go hiking every weekend."))
            .unwrap();

        let results = episodic
            .search("What's my current favorite hiking trail?", 5, false)
            .unwrap();
        assert!(!results.is_empty());
        assert!(
            results[0].record.content.contains("Eagle Ridge"),
            "no change markers → deterministic score order, got: {}",
            results[0].record.content
        );
    }

    #[test]
    fn detect_conflicts_flags_contradiction_with_shared_topic() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        episodic
            .append(&user_statement(
                1,
                "I'm vegetarian now. I decided to stop eating animal products.",
            ))
            .unwrap();
        episodic
            .append(&user_statement(
                2,
                "I'm not really vegetarian anymore, I eat steak now.",
            ))
            .unwrap();
        episodic
            .append(&user_statement(3, "I went hiking yesterday."))
            .unwrap();

        let results = episodic
            .search("vegetarian steak eating", 10, false)
            .unwrap();
        let conflicts = detect_conflicts(&results);
        assert_eq!(
            conflicts.len(),
            1,
            "the vegetarian/steak pair must be flagged, got {conflicts:?}"
        );
        let conflict = &conflicts[0];
        assert!(conflict.later_content.contains("steak"));
        assert!(conflict.earlier_content.contains("animal products"));
        assert!(
            conflict.shared_terms.iter().any(|t| t == "vegetarian"),
            "shared terms must include the topic: {:?}",
            conflict.shared_terms
        );
    }

    #[test]
    fn detect_conflicts_ignores_plain_statements_and_assistant_turns() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        // Two statements about the same topic, but neither contradicts.
        episodic
            .append(&user_statement(1, "My favorite coffee is dark roast."))
            .unwrap();
        episodic
            .append(&user_statement(2, "I love coffee with breakfast."))
            .unwrap();
        // An assistant echo with a contradiction marker must not initiate.
        episodic
            .append(&assistant_response(
                3,
                "You mentioned you no longer like tea!",
            ))
            .unwrap();

        let results = episodic.search("coffee tea breakfast", 10, false).unwrap();
        assert!(detect_conflicts(&results).is_empty());
    }

    #[test]
    fn detect_conflicts_skips_identical_content() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = store.episodic();
        let record = user_statement(1, "I'm vegetarian now, but I changed my mind.");
        let duplicate = user_statement(2, "I'm vegetarian now, but I changed my mind.");
        episodic.append(&record).unwrap();
        episodic.append(&duplicate).unwrap();

        let results = episodic.search("vegetarian", 10, false).unwrap();
        // Same fact seen twice is a duplicate, not a conflict.
        assert!(detect_conflicts(&results).is_empty());
    }

    #[test]
    fn append_get_transition_and_reopen_roundtrip() {
        let tmp = tempdir().unwrap();
        let session = uuid::Uuid::new_v4();
        let record = EpisodicRecord::new(
            Some(session),
            2,
            EpisodicKind::Decision,
            "use the raw episodic lane",
            Provenance::new(ProvenanceSource::User).with_actor("test"),
        );
        let id = record.id;
        {
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            let episodic = store.episodic();
            episodic.append(&record).unwrap();
            assert_eq!(episodic.get(id).unwrap().unwrap(), record);
            episodic
                .transition(
                    id,
                    MemoryTransition::Supersede {
                        replacement: uuid::Uuid::new_v4(),
                    },
                )
                .unwrap();
            assert!(matches!(
                episodic.get(id).unwrap().unwrap().validity,
                ValidityState::Superseded { .. }
            ));
        }
        let reopened = MemoryStore::open_default(tmp.path()).unwrap();
        let records = reopened.episodic().scan(Some(session), 10).unwrap();
        assert_eq!(records.len(), 1);
        assert_eq!(records[0].id, id);
    }

    #[test]
    fn duplicate_append_is_rejected() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let record = sample_record(1, "once");
        store.episodic().append(&record).unwrap();
        let error = store.episodic().append(&record).unwrap_err();
        assert!(error.to_string().contains("already exists"));
    }

    #[test]
    fn raw_search_returns_canonical_records_and_skips_revoked_by_default() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let active = sample_record(1, "Rust memory retrieval");
        let revoked = sample_record(2, "Rust memory retrieval old");
        let revoked_id = revoked.id;
        store.episodic().append(&active).unwrap();
        store.episodic().append(&revoked).unwrap();
        store
            .episodic()
            .transition(
                revoked_id,
                MemoryTransition::Revoke {
                    reason: "stale".into(),
                },
            )
            .unwrap();

        let current = store
            .episodic()
            .search("memory retrieval", 10, false)
            .unwrap();
        assert_eq!(current.len(), 1);
        assert_eq!(current[0].record.id, active.id);

        let all = store
            .episodic()
            .search("memory retrieval", 10, true)
            .unwrap();
        assert_eq!(all.len(), 2);
    }

    #[test]
    fn append_batch_indexes_once_and_preserves_search() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let first = sample_record(1, "Dr. Patel scheduled a follow-up appointment");
        let second = sample_record(2, "unrelated grocery list");
        let first_id = first.id;
        store.episodic().append_batch(&[first, second]).unwrap();
        let hits = store
            .episodic()
            .search("patel appointment", 10, false)
            .unwrap();
        assert_eq!(hits.len(), 1);
        assert_eq!(hits[0].record.id, first_id);
    }

    #[test]
    fn rejected_append_batch_preserves_prior_state_after_reopen() {
        // Exercise the real NO_OVERWRITE transaction with a disposable LMDB
        // directory.  The new record is queued before the duplicate so this
        // proves the transaction aborts rather than leaving an early write.
        let tmp = tempdir().unwrap();
        let original = sample_record(1, "acknowledged original record");
        let rejected_new = sample_record(2, "must not survive rejected batch");
        {
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            store.episodic().append(&original).unwrap();
            let error = store
                .episodic()
                .append_batch(&[rejected_new.clone(), original.clone()])
                .unwrap_err();
            assert!(error.to_string().contains("already exists"));
            assert_eq!(
                store.episodic().get(original.id).unwrap(),
                Some(original.clone())
            );
            assert_eq!(store.episodic().get(rejected_new.id).unwrap(), None);
        }

        let reopened = MemoryStore::open_default(tmp.path()).unwrap();
        assert_eq!(
            reopened.episodic().get(original.id).unwrap(),
            Some(original)
        );
        assert_eq!(reopened.episodic().get(rejected_new.id).unwrap(), None);
    }

    #[test]
    fn lost_episodic_sidecar_rebuilds_from_raw_records_after_reopen() {
        // This models loss of a *derived* sidecar only.  It deliberately does
        // not model an LMDB/process crash or make a filesystem-durability
        // claim; the authoritative raw records remain in the same temporary
        // store and the next process rebuilds the projection from them.
        let tmp = tempdir().unwrap();
        let record = sample_record(1, "sidecar recovery preserves searchable evidence");
        {
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            let episodic = store.episodic();
            episodic.append(&record).unwrap();
            assert!(!episodic.sidecar_is_empty().unwrap());

            let mut tx = store.env().begin_rw_txn().unwrap();
            tx.clear_db(episodic.term_db).unwrap();
            tx.commit().unwrap();
            assert!(episodic.sidecar_is_empty().unwrap());
        }

        let reopened = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = reopened.episodic();
        assert_eq!(episodic.get(record.id).unwrap(), Some(record.clone()));
        assert!(!episodic.sidecar_is_empty().unwrap());
        let hits = episodic
            .search("sidecar searchable evidence", 10, false)
            .unwrap();
        assert_eq!(hits.len(), 1);
        assert_eq!(hits[0].record.id, record.id);
    }

    #[test]
    fn append_explicit_batch_redacts_and_skips_private() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let public = sample_record(1, "api_key=supersecret rust retrieval");
        let private = sample_record(2, "private rust retrieval").with_visibility(true, false);
        let public_id = public.id;
        store
            .episodic()
            .append_explicit_batch(&[public, private], EpisodicCapturePolicy::explicit_only())
            .unwrap();
        let stored = store.episodic().get(public_id).unwrap().unwrap();
        assert!(stored.content.contains("<REDACTED>"));
        let hits = store
            .episodic()
            .search("rust retrieval", 10, false)
            .unwrap();
        assert_eq!(hits.len(), 1);
        assert_eq!(hits[0].record.id, public_id);
    }

    #[test]
    fn typed_keys_retrieve_vocabulary_mismatch() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let dog = sample_record(1, "My Golden Retriever loves the park");
        let other = sample_record(2, "I bought a yellow dress");
        let dog_id = dog.id;
        store.episodic().append_batch(&[dog, other]).unwrap();
        let hits = store
            .episodic()
            .search("What breed is my dog?", 5, false)
            .unwrap();
        assert_eq!(hits[0].record.id, dog_id);
    }

    #[test]
    fn planner_boosts_temporal_date_match() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let dated = sample_record(1, "I volunteered on February 14th at the animal shelter");
        let other = sample_record(2, "I volunteered at the community garden last summer");
        let dated_id = dated.id;
        store.episodic().append_batch(&[dated, other]).unwrap();
        let hits = store
            .episodic()
            .search("When did I volunteer at the animal shelter?", 5, false)
            .unwrap();
        assert_eq!(hits[0].record.id, dated_id);
    }

    #[test]
    #[ignore = "manual in-process latency profile"]
    fn profile_ingest_and_search_latency() {
        fn timed_ms(label: &str, repeats: u32, mut work: impl FnMut()) {
            let start = std::time::Instant::now();
            for _ in 0..repeats {
                work();
            }
            let elapsed = start.elapsed();
            println!(
                "{label}: {:.3} ms (n={repeats})",
                elapsed.as_secs_f64() * 1000.0 / f64::from(repeats)
            );
        }

        let search_records: Vec<EpisodicRecord> = (0..10_000)
            .map(|n| {
                sample_record(
                    n,
                    if n % 5 == 0 {
                        "Rust memory retrieval benchmark item"
                    } else {
                        "Unrelated episodic record"
                    },
                )
            })
            .collect();

        timed_ms("append_single_1000", 1, || {
            let tmp = tempdir().unwrap();
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            for n in 0..1_000 {
                store.episodic().append(&sample_record(n, "once")).unwrap();
            }
        });
        timed_ms("append_batch_1000", 1, || {
            let tmp = tempdir().unwrap();
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            let records: Vec<EpisodicRecord> =
                (0..1_000).map(|n| sample_record(n, "once")).collect();
            store.episodic().append_batch(&records).unwrap();
        });

        let tmp = tempdir().unwrap();
        {
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            store.episodic().append_batch(&search_records).unwrap();
        }
        let cold = MemoryStore::open_default(tmp.path()).unwrap();
        timed_ms("cold_search_10000", 1, || {
            let hits = cold
                .episodic()
                .search("rust memory retrieval", 10, false)
                .unwrap();
            assert!(!hits.is_empty());
        });
        timed_ms("warm_search_10000", 50, || {
            let hits = cold
                .episodic()
                .search("rust memory retrieval", 10, false)
                .unwrap();
            assert!(!hits.is_empty());
        });
    }

    /// Realistic-scale profile: 25k records of sentence-length content with
    /// per-session entity diversity (mimics a persistent server accumulating
    /// 50 LongMemEval haystacks). Measures whether episodic search stays
    /// bounded as the store grows, warm and cold, and whether queries that
    /// miss the sidecar entirely (full-scan fallback) degrade differently.
    #[test]
    #[ignore = "manual in-process latency profile at realistic scale"]
    fn profile_search_latency_25k_realistic() {
        const TOTAL: u64 = 25_000;
        const SESSIONS: u64 = 50;
        let topics = [
            "bookshelf",
            "guitar",
            "vegetarian",
            "portfolio",
            "commute",
            "grandmother",
            "chemistry",
            "marathon",
            "internship",
            "yoga",
            "spam filter",
            "projector",
            "swimming",
            "cousin",
            "bank account",
            "book club",
            "recipe",
            "journal subscription",
            "laptop",
            "hiking",
        ];
        let fillers = [
            "We discussed the plan for the weekend and agreed on the schedule.",
            "The meeting notes were circulated and everyone acknowledged them.",
            "I explained my reasoning and the group considered the proposal.",
            "After the presentation we reviewed the feedback together.",
            "She mentioned the deadline and we adjusted the timeline accordingly.",
        ];

        let records: Vec<EpisodicRecord> = (0..TOTAL)
            .map(|n| {
                let session = n * SESSIONS / TOTAL;
                let topic = topics[(n as usize) % topics.len()];
                let filler = fillers[(n as usize) % fillers.len()];
                let content = format!(
                    "Session {session} note {n}: my friend Alice mentioned {topic} while {filler}"
                );
                let session_id = if n % 4 == 0 {
                    None
                } else {
                    Some(uuid::Uuid::new_v4())
                };
                EpisodicRecord::new(
                    session_id,
                    n,
                    if n % 3 == 0 {
                        EpisodicKind::UserStatement
                    } else {
                        EpisodicKind::AssistantResponse
                    },
                    content,
                    Provenance::new(ProvenanceSource::User),
                )
            })
            .collect();

        let tmp = tempdir().unwrap();
        {
            let store = MemoryStore::open_default(tmp.path()).unwrap();
            let t = std::time::Instant::now();
            store.episodic().append_batch(&records).unwrap();
            println!("ingest 25k: {:.1} ms", t.elapsed().as_secs_f64() * 1000.0);
        }

        // Cold process semantics: reopen, then a query.
        let cold = MemoryStore::open_default(tmp.path()).unwrap();
        let episodic = cold.episodic();
        let t = std::time::Instant::now();
        let hits = episodic
            .search("guitar grandmother recipe", 10, false)
            .unwrap();
        println!(
            "cold_search: {:.1} ms (hits={})",
            t.elapsed().as_secs_f64() * 1000.0,
            hits.len()
        );

        // Warm varied queries: topics rotate so postings cache does not hide
        // per-term loads, and one no-match query to time the full-scan fallback.
        let queries: Vec<String> = (0..20)
            .map(|i| {
                let a = topics[i * 7 % topics.len()];
                let b = topics[(i * 7 + 5) % topics.len()];
                format!("{a} {b} weekend plan")
            })
            .collect();
        let start = std::time::Instant::now();
        for q in &queries {
            let hits = episodic.search(q, 10, false).unwrap();
            assert!(!hits.is_empty(), "no hits for {q}");
        }
        println!(
            "warm_search varied p50: {:.2} ms/query",
            start.elapsed().as_secs_f64() * 1000.0 / queries.len() as f64
        );

        let t = std::time::Instant::now();
        let hits = episodic
            .search("zzzterm zzzother zzzthird", 10, false)
            .unwrap();
        println!(
            "no_match_query (full-scan fallback path): {:.1} ms (hits={})",
            t.elapsed().as_secs_f64() * 1000.0,
            hits.len()
        );
    }

    #[test]
    fn enrichment_bridges_vocabulary_gap_for_theater() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        store.set_episodic_enrichment(crate::enrichment::VocabularyEnrichment::with_defaults());
        // Answer turn says "production" not "play" — enrichment bridges this
        let answer = sample_record(1, "The production I attended was The Glass Menagerie");
        let competing = sample_record(2, "I went to a play at the local community theater");
        let answer_id = answer.id;
        store.episodic().append_batch(&[answer, competing]).unwrap();
        let hits = store
            .episodic()
            .search(
                "What play did I attend at the local community theater?",
                5,
                false,
            )
            .unwrap();
        // With enrichment, "production" in the answer turn gets postings for
        // "play", "theater", "performance" — so it should now match more terms
        assert!(hits.iter().any(|h| h.record.id == answer_id));
    }

    #[test]
    fn enrichment_bridges_vocabulary_gap_for_shelter() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        store.set_episodic_enrichment(crate::enrichment::VocabularyEnrichment::with_defaults());
        let answer = sample_record(1, "I rescued a dog from the humane society last week");
        let other = sample_record(2, "I bought groceries at the store");
        let answer_id = answer.id;
        store.episodic().append_batch(&[answer, other]).unwrap();
        let hits = store
            .episodic()
            .search("When did I volunteer at the animal shelter?", 5, false)
            .unwrap();
        assert!(hits.iter().any(|h| h.record.id == answer_id));
    }

    #[test]
    fn session_boost_favors_sessions_with_multiple_matches() {
        let tmp = tempdir().unwrap();
        let store = MemoryStore::open_default(tmp.path()).unwrap();
        let session_a = uuid::Uuid::new_v4();
        let session_b = uuid::Uuid::new_v4();
        // Session A has two matching turns (same kind to isolate session boost)
        let a1 = EpisodicRecord::new(
            Some(session_a),
            1,
            EpisodicKind::Observation,
            "I love hiking in the mountains",
            Provenance::new(ProvenanceSource::User),
        );
        let a2 = EpisodicRecord::new(
            Some(session_a),
            2,
            EpisodicKind::Observation,
            "Hiking in the mountains is great exercise",
            Provenance::new(ProvenanceSource::User),
        );
        // Session B has one matching turn with same kind
        let b1 = EpisodicRecord::new(
            Some(session_b),
            1,
            EpisodicKind::Observation,
            "Hiking is fun",
            Provenance::new(ProvenanceSource::User),
        );
        store.episodic().append_batch(&[a1, a2, b1]).unwrap();
        let hits = store
            .episodic()
            .search("hiking mountains", 10, false)
            .unwrap();
        // Session A turns should be boosted over session B turn because
        // session A has 2 matching turns vs 1 for session B
        let a_ranks: Vec<usize> = hits
            .iter()
            .enumerate()
            .filter(|(_, h)| h.record.session_id == Some(session_a))
            .map(|(i, _)| i)
            .collect();
        let b_rank = hits
            .iter()
            .position(|h| h.record.session_id == Some(session_b));
        if let Some(br) = b_rank {
            assert!(a_ranks.iter().all(|&ar| ar < br));
        }
    }
}