use actix_web::dev::{ServiceFactory, ServiceRequest};
use actix_web::{App, HttpRequest, HttpResponse, Responder, web};
use chrono::Utc;
use serde::{Deserialize, Serialize};
use std::sync::Mutex;

use crate::data::Claims;
use crate::database::models::{Entity, EntityFact, EntityPhotoLink, InsertEntityFact};
use crate::database::{
    ConsolidationGroup, EntityFilter, EntityPatch, EntitySort, FactFilter, FactPatch, KnowledgeDao,
    PersonaFilter, RecentActivity,
};
use crate::personas::PersonaDaoData;
use crate::state::AppState;

/// Resolve the `X-Persona-Id` header into a `PersonaFilter`. Missing
/// header → `'default'`. If the persona has `include_all_memories=true`,
/// returns `PersonaFilter::All` so reads see the full hive-mind pool.
/// On JWT-parse failure (sub is not a numeric user_id) the resolver
/// falls through to user_id=1 — the operator convention for service
/// tokens — preserving the historical baseline view. Same fallback
/// applies on any persona-lookup error.
fn resolve_persona_filter(
    req: &HttpRequest,
    claims: &Claims,
    persona_dao: &PersonaDaoData,
) -> PersonaFilter {
    let pid = req
        .headers()
        .get("X-Persona-Id")
        .and_then(|v| v.to_str().ok())
        .map(|s| s.to_string())
        .unwrap_or_else(|| "default".to_string());

    let uid = claims.sub.parse::<i32>().unwrap_or(1);

    let cx = opentelemetry::Context::current();
    let mut dao = persona_dao.lock().expect("Unable to lock PersonaDao");
    match dao.get_persona(&cx, uid, &pid) {
        Ok(Some(p)) if p.include_all_memories => PersonaFilter::All { user_id: uid },
        _ => PersonaFilter::Single {
            user_id: uid,
            persona_id: pid,
        },
    }
}

// ---------------------------------------------------------------------------
// Request / Response types
// ---------------------------------------------------------------------------

#[derive(Serialize)]
pub struct EntitySummary {
    pub id: i32,
    pub name: String,
    pub entity_type: String,
    pub description: String,
    pub confidence: f32,
    pub status: String,
    pub created_at: i64,
    pub updated_at: i64,
    /// Persona-scoped count of non-rejected facts about this entity
    /// (subject side). 0 when not provided by the call site, e.g.
    /// PATCH responses return the bare entity without scoping context.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub fact_count: Option<i64>,
    /// Per-persona breakdown of fact counts for this entity, scoped
    /// to the active user. Lets the curation UI surface "this entity
    /// is empty under your active persona but has 12 facts in
    /// journal" so you know which persona owns the existing
    /// knowledge. Skipped on serialization when None.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub persona_breakdown: Option<Vec<PersonaCount>>,
}

#[derive(Serialize)]
pub struct PersonaCount {
    pub persona_id: String,
    pub count: i64,
}

impl From<Entity> for EntitySummary {
    fn from(e: Entity) -> Self {
        EntitySummary {
            id: e.id,
            name: e.name,
            entity_type: e.entity_type,
            description: e.description,
            confidence: e.confidence,
            status: e.status,
            created_at: e.created_at,
            updated_at: e.updated_at,
            fact_count: None,
            persona_breakdown: None,
        }
    }
}

impl EntitySummary {
    fn from_entity_with_count(e: Entity, fact_count: i64) -> Self {
        let mut s = EntitySummary::from(e);
        s.fact_count = Some(fact_count);
        s
    }

    fn with_persona_breakdown(mut self, breakdown: Vec<(String, i64)>) -> Self {
        self.persona_breakdown = Some(
            breakdown
                .into_iter()
                .map(|(persona_id, count)| PersonaCount { persona_id, count })
                .collect(),
        );
        self
    }
}

#[derive(Serialize)]
pub struct EntityListResponse {
    pub entities: Vec<EntitySummary>,
    pub total: i64,
    pub limit: i64,
    pub offset: i64,
}

#[derive(Serialize)]
pub struct FactDetail {
    pub id: i32,
    pub predicate: String,
    pub object_entity_id: Option<i32>,
    pub object_entity_name: Option<String>,
    pub object_value: Option<String>,
    pub confidence: f32,
    pub status: String,
    pub source_photo: Option<String>,
    pub source_insight_id: Option<i32>,
    pub created_at: i64,
    /// Real-world valid-time interval. NULL on either side means
    /// unbounded; both NULL = "always true" / validity unknown.
    /// Distinct from `created_at` (transaction time — when we
    /// recorded it). See migration 2026-05-10-000100.
    pub valid_from: Option<i64>,
    pub valid_until: Option<i64>,
    /// Points at the entity_facts.id that replaced this one (Phase 2
    /// supersession, migration 2026-05-10-000200). Only set when
    /// status == 'superseded'.
    pub superseded_by: Option<i32>,
    /// Provenance — see migration 2026-05-10-000300. NULL on legacy
    /// rows. `created_by_backend` is "local" / "hybrid" / "manual".
    pub created_by_model: Option<String>,
    pub created_by_backend: Option<String>,
    /// Audit trail — see migration 2026-05-10-000500. Set on any
    /// post-creation mutation. NULL on rows that have never been
    /// touched after they were first written.
    pub last_modified_by_model: Option<String>,
    pub last_modified_by_backend: Option<String>,
    pub last_modified_at: Option<i64>,
    /// Set when another active fact has the same subject+predicate,
    /// a different object, AND their valid-time intervals overlap.
    /// Detected at read time by the get_entity handler grouping
    /// facts by predicate. Some predicates are legitimately
    /// multi-valued ("tagged_in", "friend_of") so this is a *signal*
    /// for the curator, not a hard invariant. The interval check
    /// keeps "lives_in NYC 2018-2020" + "lives_in SF 2020-present"
    /// from false-positive flagging.
    #[serde(skip_serializing_if = "std::ops::Not::not")]
    pub in_conflict: bool,
}

#[derive(Serialize)]
pub struct PhotoLinkDetail {
    pub library_id: i32,
    pub file_path: String,
    pub role: String,
}

impl From<EntityPhotoLink> for PhotoLinkDetail {
    fn from(l: EntityPhotoLink) -> Self {
        PhotoLinkDetail {
            library_id: l.library_id,
            file_path: l.file_path,
            role: l.role,
        }
    }
}

#[derive(Serialize)]
pub struct EntityDetailResponse {
    pub id: i32,
    pub name: String,
    pub entity_type: String,
    pub description: String,
    pub confidence: f32,
    pub status: String,
    pub created_at: i64,
    pub updated_at: i64,
    pub facts: Vec<FactDetail>,
    pub photo_links: Vec<PhotoLinkDetail>,
    /// Per-persona fact counts for the active user. Mirrors the
    /// same field on EntitySummary; the detail panel surfaces a
    /// clickable list so the curator can switch to the persona
    /// that owns existing facts about this entity.
    pub persona_breakdown: Vec<PersonaCount>,
}

#[derive(Serialize)]
pub struct FactSummary {
    pub id: i32,
    pub subject_entity_id: i32,
    pub subject_entity_name: Option<String>,
    pub predicate: String,
    pub object_entity_id: Option<i32>,
    pub object_entity_name: Option<String>,
    pub object_value: Option<String>,
    pub confidence: f32,
    pub status: String,
    pub source_photo: Option<String>,
    pub source_insight_id: Option<i32>,
    pub created_at: i64,
}

#[derive(Serialize)]
pub struct FactListResponse {
    pub facts: Vec<FactSummary>,
    pub total: i64,
    pub limit: i64,
    pub offset: i64,
}

#[derive(Deserialize)]
pub struct MergeRequest {
    pub source_id: i32,
    pub target_id: i32,
}

#[derive(Serialize)]
pub struct MergeResponse {
    pub merged_entity_id: i32,
    pub deleted_entity_id: i32,
    pub facts_transferred: i64,
    pub links_transferred: i64,
}

#[derive(Deserialize)]
pub struct EntityPatchRequest {
    pub name: Option<String>,
    pub description: Option<String>,
    pub status: Option<String>,
    pub confidence: Option<f32>,
}

/// Serde helper for the "tri-state" pattern: distinguish "field
/// omitted" from "field sent as null". Used for nullable columns
/// where we want PATCH to support both "leave alone" and "set NULL".
fn deserialize_optional_nullable_i64<'de, D>(d: D) -> Result<Option<Option<i64>>, D::Error>
where
    D: serde::Deserializer<'de>,
{
    Ok(Some(Option::<i64>::deserialize(d)?))
}

#[derive(Deserialize)]
pub struct FactPatchRequest {
    pub predicate: Option<String>,
    pub object_value: Option<String>,
    pub status: Option<String>,
    pub confidence: Option<f32>,
    /// Tri-state: missing = leave alone, null = clear to NULL, number
    /// = set. See `deserialize_optional_nullable_i64`.
    #[serde(default, deserialize_with = "deserialize_optional_nullable_i64")]
    pub valid_from: Option<Option<i64>>,
    #[serde(default, deserialize_with = "deserialize_optional_nullable_i64")]
    pub valid_until: Option<Option<i64>>,
}

#[derive(Deserialize)]
pub struct SupersedeRequest {
    /// The id of the new fact that replaces the path-params one.
    pub by_fact_id: i32,
}

#[derive(Deserialize)]
pub struct SynthesizeMergeRequest {
    pub source_id: i32,
    pub target_id: i32,
}

#[derive(serde::Serialize)]
pub struct SynthesizeMergeResponse {
    pub proposed_description: String,
    pub model_used: String,
}

#[derive(Deserialize)]
pub struct FactCreateRequest {
    pub subject_entity_id: i32,
    pub predicate: String,
    pub object_entity_id: Option<i32>,
    pub object_value: Option<String>,
    pub source_photo: Option<String>,
    pub confidence: Option<f32>,
    pub valid_from: Option<i64>,
    pub valid_until: Option<i64>,
}

#[derive(Deserialize)]
pub struct EntityListQuery {
    #[serde(rename = "type")]
    pub entity_type: Option<String>,
    pub status: Option<String>,
    pub search: Option<String>,
    /// "updated" (default) | "name" | "count". `count` is persona-scoped
    /// via the X-Persona-Id header.
    pub sort: Option<String>,
    pub limit: Option<i64>,
    pub offset: Option<i64>,
}

#[derive(Deserialize)]
pub struct FactListQuery {
    pub entity_id: Option<i32>,
    pub status: Option<String>,
    pub predicate: Option<String>,
    pub limit: Option<i64>,
    pub offset: Option<i64>,
}

#[derive(Deserialize)]
pub struct RecentQuery {
    pub since: Option<i64>,
    pub limit: Option<i64>,
}

#[derive(Deserialize)]
pub struct ConsolidationQuery {
    /// Cosine threshold for clustering. Default 0.85 — looser than
    /// the upsert-time guard (0.92) so this view surfaces "probably
    /// same" pairs for human review.
    pub threshold: Option<f32>,
    pub limit: Option<i64>,
}

#[derive(Serialize)]
pub struct ConsolidationGroupView {
    pub entities: Vec<EntitySummary>,
    pub min_cosine: f32,
    pub max_cosine: f32,
}

#[derive(Serialize)]
pub struct ConsolidationResponse {
    pub groups: Vec<ConsolidationGroupView>,
}

// ---------------------------------------------------------------------------
// Service registration
// ---------------------------------------------------------------------------

pub fn add_knowledge_services<T, D: KnowledgeDao + 'static>(app: App<T>) -> App<T>
where
    T: ServiceFactory<ServiceRequest, Config = (), Error = actix_web::Error, InitError = ()>,
{
    app.service(
        web::scope("/knowledge")
            .service(web::resource("/entities").route(web::get().to(list_entities::<D>)))
            .service(web::resource("/entities/merge").route(web::post().to(merge_entities::<D>)))
            .service(
                web::resource("/entities/synthesize-merge")
                    .route(web::post().to(synthesize_merge::<D>)),
            )
            .service(
                web::resource("/entities/{id}")
                    .route(web::get().to(get_entity::<D>))
                    .route(web::patch().to(patch_entity::<D>))
                    .route(web::delete().to(delete_entity::<D>)),
            )
            .service(
                web::resource("/facts")
                    .route(web::get().to(list_facts::<D>))
                    .route(web::post().to(create_fact::<D>)),
            )
            .service(
                web::resource("/facts/{id}")
                    .route(web::patch().to(patch_fact::<D>))
                    .route(web::delete().to(delete_fact::<D>)),
            )
            .service(
                web::resource("/facts/{id}/supersede").route(web::post().to(supersede_fact::<D>)),
            )
            .service(web::resource("/facts/{id}/restore").route(web::post().to(restore_fact::<D>)))
            .service(web::resource("/recent").route(web::get().to(get_recent::<D>)))
            .service(
                web::resource("/consolidation-proposals")
                    .route(web::get().to(get_consolidation_proposals::<D>)),
            ),
    )
}

// ---------------------------------------------------------------------------
// Handlers
// ---------------------------------------------------------------------------

async fn list_entities<D: KnowledgeDao + 'static>(
    req: HttpRequest,
    claims: Claims,
    query: web::Query<EntityListQuery>,
    dao: web::Data<Mutex<D>>,
    persona_dao: PersonaDaoData,
) -> impl Responder {
    let limit = query.limit.unwrap_or(50).min(200);
    let offset = query.offset.unwrap_or(0);

    let status_filter = match query.status.as_deref() {
        None | Some("active") => Some("active".to_string()),
        Some("all") => None,
        Some(s) => Some(s.to_string()),
    };

    let sort = match query.sort.as_deref() {
        Some("name") => EntitySort::NameAsc,
        Some("count") => EntitySort::FactCountDesc,
        // "updated" or anything else falls through to the default.
        _ => EntitySort::UpdatedDesc,
    };

    let persona = resolve_persona_filter(&req, &claims, &persona_dao);

    let filter = EntityFilter {
        entity_type: query.entity_type.clone(),
        status: status_filter,
        search: query.search.clone(),
        limit,
        offset,
    };

    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    match dao.list_entities_with_fact_counts(&cx, filter, sort, &persona) {
        Ok((pairs, total)) => {
            // Batch fetch persona breakdowns so the list-row tooltip
            // and detail panel can show "0 here · 12 in journal".
            // One extra query for the visible page.
            let entity_ids: Vec<i32> = pairs.iter().map(|(e, _)| e.id).collect();
            let breakdowns = dao
                .get_persona_breakdowns_for_entities(&cx, &entity_ids, persona.user_id())
                .unwrap_or_default();
            let summaries: Vec<EntitySummary> = pairs
                .into_iter()
                .map(|(e, c)| {
                    let entity_id = e.id;
                    let summary = EntitySummary::from_entity_with_count(e, c);
                    match breakdowns.get(&entity_id) {
                        Some(bd) => summary.with_persona_breakdown(bd.clone()),
                        None => summary,
                    }
                })
                .collect();
            HttpResponse::Ok().json(EntityListResponse {
                entities: summaries,
                total,
                limit,
                offset,
            })
        }
        Err(e) => {
            log::error!("list_entities error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn get_entity<D: KnowledgeDao + 'static>(
    req: HttpRequest,
    claims: Claims,
    id: web::Path<i32>,
    dao: web::Data<Mutex<D>>,
    persona_dao: PersonaDaoData,
) -> impl Responder {
    let persona = resolve_persona_filter(&req, &claims, &persona_dao);
    let cx = opentelemetry::Context::current();
    let entity_id = id.into_inner();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");

    let entity = match dao.get_entity_by_id(&cx, entity_id) {
        Ok(Some(e)) => e,
        Ok(None) => {
            return HttpResponse::NotFound().json(serde_json::json!({"error": "Entity not found"}));
        }
        Err(e) => {
            log::error!("get_entity error: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
    };

    // Fetch all facts (all statuses for audit), scoped to the active persona.
    let raw_facts: Vec<EntityFact> = match dao.get_facts_for_entity(&cx, entity_id, &persona) {
        Ok(f) => f,
        Err(e) => {
            log::error!("get_facts_for_entity error: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
    };

    // Resolve object entity names
    let mut facts = Vec::with_capacity(raw_facts.len());
    for f in raw_facts {
        let object_entity_name = if let Some(oid) = f.object_entity_id {
            dao.get_entity_by_id(&cx, oid)
                .ok()
                .flatten()
                .map(|e| e.name)
        } else {
            None
        };
        facts.push(FactDetail {
            id: f.id,
            predicate: f.predicate,
            object_entity_id: f.object_entity_id,
            object_entity_name,
            object_value: f.object_value,
            confidence: f.confidence,
            status: f.status,
            source_photo: f.source_photo,
            source_insight_id: f.source_insight_id,
            created_at: f.created_at,
            valid_from: f.valid_from,
            valid_until: f.valid_until,
            superseded_by: f.superseded_by,
            created_by_model: f.created_by_model,
            created_by_backend: f.created_by_backend,
            last_modified_by_model: f.last_modified_by_model,
            last_modified_by_backend: f.last_modified_by_backend,
            last_modified_at: f.last_modified_at,
            in_conflict: false,
        });
    }

    // Conflict detection: within the active set, group by predicate;
    // for each pair within a group that disagrees on the object,
    // flag both only if their valid-time intervals overlap. NULL on
    // either bound treats that side as unbounded — a fact with no
    // valid-time data still flags against any time period (worst case
    // for legacy data; user adds dates to suppress).
    fn intervals_overlap(a: (Option<i64>, Option<i64>), b: (Option<i64>, Option<i64>)) -> bool {
        let a_lo = a.0.unwrap_or(i64::MIN);
        let a_hi = a.1.unwrap_or(i64::MAX);
        let b_lo = b.0.unwrap_or(i64::MIN);
        let b_hi = b.1.unwrap_or(i64::MAX);
        a_lo < b_hi && b_lo < a_hi
    }
    {
        use std::collections::{HashMap, HashSet};
        let mut by_predicate: HashMap<String, Vec<usize>> = HashMap::new();
        for (idx, f) in facts.iter().enumerate() {
            if f.status == "active" {
                by_predicate
                    .entry(f.predicate.clone())
                    .or_default()
                    .push(idx);
            }
        }
        let mut to_flag: HashSet<usize> = HashSet::new();
        for indices in by_predicate.values() {
            if indices.len() < 2 {
                continue;
            }
            for (a_pos, &i) in indices.iter().enumerate() {
                for &j in &indices[a_pos + 1..] {
                    let same_object = facts[i].object_entity_id == facts[j].object_entity_id
                        && facts[i].object_value == facts[j].object_value;
                    if same_object {
                        continue;
                    }
                    if intervals_overlap(
                        (facts[i].valid_from, facts[i].valid_until),
                        (facts[j].valid_from, facts[j].valid_until),
                    ) {
                        to_flag.insert(i);
                        to_flag.insert(j);
                    }
                }
            }
        }
        for i in to_flag {
            facts[i].in_conflict = true;
        }
    }

    // Fetch photo links
    let photo_links: Vec<PhotoLinkDetail> = match dao.get_links_for_entity(&cx, entity_id) {
        Ok(links) => links.into_iter().map(PhotoLinkDetail::from).collect(),
        Err(e) => {
            log::error!("get_links_for_entity error: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
    };

    // Per-persona breakdown for the detail panel's "facts live in
    // {persona}" block — same data the list-row tooltip reads. One
    // query, single entity in scope.
    let persona_breakdown: Vec<PersonaCount> = dao
        .get_persona_breakdowns_for_entities(&cx, &[entity_id], persona.user_id())
        .ok()
        .and_then(|mut map| map.remove(&entity_id))
        .unwrap_or_default()
        .into_iter()
        .map(|(persona_id, count)| PersonaCount { persona_id, count })
        .collect();

    HttpResponse::Ok().json(EntityDetailResponse {
        id: entity.id,
        name: entity.name,
        entity_type: entity.entity_type,
        description: entity.description,
        confidence: entity.confidence,
        status: entity.status,
        created_at: entity.created_at,
        updated_at: entity.updated_at,
        facts,
        photo_links,
        persona_breakdown,
    })
}

async fn patch_entity<D: KnowledgeDao + 'static>(
    _claims: Claims,
    id: web::Path<i32>,
    body: web::Json<EntityPatchRequest>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    let cx = opentelemetry::Context::current();
    let entity_id = id.into_inner();
    let patch = EntityPatch {
        name: body.name.clone(),
        description: body.description.clone(),
        status: body.status.clone(),
        confidence: body.confidence,
    };

    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    match dao.update_entity(&cx, entity_id, patch) {
        Ok(Some(entity)) => HttpResponse::Ok().json(EntitySummary::from(entity)),
        Ok(None) => HttpResponse::NotFound().json(serde_json::json!({"error": "Entity not found"})),
        Err(e) => {
            log::error!("patch_entity error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn delete_entity<D: KnowledgeDao + 'static>(
    _claims: Claims,
    id: web::Path<i32>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    let cx = opentelemetry::Context::current();
    let entity_id = id.into_inner();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");

    // Verify entity exists before deleting
    match dao.get_entity_by_id(&cx, entity_id) {
        Ok(None) => {
            return HttpResponse::NotFound().json(serde_json::json!({"error": "Entity not found"}));
        }
        Err(e) => {
            log::error!("delete_entity lookup error: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
        Ok(Some(_)) => {}
    }

    match dao.delete_entity(&cx, entity_id) {
        Ok(()) => HttpResponse::NoContent().finish(),
        Err(e) => {
            log::error!("delete_entity error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn merge_entities<D: KnowledgeDao + 'static>(
    _claims: Claims,
    body: web::Json<MergeRequest>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    if body.source_id == body.target_id {
        return HttpResponse::BadRequest()
            .json(serde_json::json!({"error": "source_id and target_id must be different"}));
    }

    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");

    // Verify both entities exist
    for id in [body.source_id, body.target_id] {
        match dao.get_entity_by_id(&cx, id) {
            Ok(None) => {
                return HttpResponse::BadRequest()
                    .json(serde_json::json!({"error": format!("Entity {} not found", id)}));
            }
            Err(e) => {
                log::error!("merge_entities lookup error: {:?}", e);
                return HttpResponse::InternalServerError()
                    .json(serde_json::json!({"error": "Database error"}));
            }
            Ok(Some(_)) => {}
        }
    }

    match dao.merge_entities(&cx, body.source_id, body.target_id) {
        Ok((facts_transferred, links_transferred)) => HttpResponse::Ok().json(MergeResponse {
            merged_entity_id: body.target_id,
            deleted_entity_id: body.source_id,
            facts_transferred,
            links_transferred,
        }),
        Err(e) => {
            log::error!("merge_entities error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

/// Preview a merged-description before the actual merge fires. Calls
/// the local Ollama with both entities' names + descriptions and
/// returns a synthesized rewrite that combines them. The curator
/// previews, edits, and either accepts (PATCH target's description
/// then POST /merge) or skips (just /merge as-is).
///
/// Deliberately doesn't touch the database — read-only on entities,
/// no LLM call gets to write anything. If the model is unavailable
/// the handler returns 503 so the UI can degrade gracefully (skip
/// the preview, fall back to the existing merge action).
async fn synthesize_merge<D: KnowledgeDao + 'static>(
    _claims: Claims,
    body: web::Json<SynthesizeMergeRequest>,
    dao: web::Data<Mutex<D>>,
    app_state: web::Data<AppState>,
) -> impl Responder {
    if body.source_id == body.target_id {
        return HttpResponse::BadRequest()
            .json(serde_json::json!({"error": "source_id and target_id must differ"}));
    }

    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");

    let source = match dao.get_entity_by_id(&cx, body.source_id) {
        Ok(Some(e)) => e,
        Ok(None) => {
            return HttpResponse::BadRequest()
                .json(serde_json::json!({"error": "source entity not found"}));
        }
        Err(e) => {
            log::error!("synthesize_merge source lookup: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
    };
    let target = match dao.get_entity_by_id(&cx, body.target_id) {
        Ok(Some(e)) => e,
        Ok(None) => {
            return HttpResponse::BadRequest()
                .json(serde_json::json!({"error": "target entity not found"}));
        }
        Err(e) => {
            log::error!("synthesize_merge target lookup: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
    };

    // Drop the DAO lock before the LLM call — the generate request
    // is the slow part (seconds) and we don't want to block other
    // knowledge reads while it runs.
    drop(dao);

    let source_desc = if source.description.trim().is_empty() {
        "(none)".to_string()
    } else {
        source.description.clone()
    };
    let target_desc = if target.description.trim().is_empty() {
        "(none)".to_string()
    } else {
        target.description.clone()
    };

    let system = "You are condensing two stored entity descriptions into one. The two \
        entities refer to the same real-world thing and are about to be merged. Write a \
        single neutral third-person description (1-2 sentences, max 300 chars) that \
        preserves any concrete facts in either source. Do not invent details. Do not \
        editorialize. Plain prose only — no markdown, no bold, no italics, no headings, \
        no bullets, no lists, no code fences. Return ONLY the merged description — no \
        preamble, no labels, no quotes.";
    let prompt = format!(
        "Entity A: {} [{}]\nDescription: {}\n\nEntity B: {} [{}]\nDescription: {}\n\nMerged description:",
        source.name, source.entity_type, source_desc, target.name, target.entity_type, target_desc,
    );

    let ollama = app_state.ollama.clone();
    let model_used = ollama.primary_model.clone();
    let proposed = match ollama.generate(&prompt, Some(system)).await {
        Ok(out) => {
            // Strip the framing models reach for even with explicit
            // "no preamble" guidance: leading "Merged description:"
            // labels, wrapping quotes, ``` code fences, leading
            // bullets / hash headings. Belt-and-braces against the
            // system prompt's plain-text directive.
            let mut s = out.trim().to_string();
            s = s
                .trim_start_matches("Merged description:")
                .trim_start_matches("Merged Description:")
                .trim()
                .to_string();
            // Code fences (``` or ```text)
            s = s
                .trim_start_matches("```text")
                .trim_start_matches("```markdown")
                .trim_start_matches("```")
                .trim_end_matches("```")
                .trim()
                .to_string();
            // Markdown headings / bullets at the very start
            while let Some(stripped) = s
                .strip_prefix('#')
                .or_else(|| s.strip_prefix('*'))
                .or_else(|| s.strip_prefix('-'))
                .or_else(|| s.strip_prefix('>'))
            {
                s = stripped.trim_start().to_string();
            }
            // Wrapping quotes
            s = s.trim_matches(|c| c == '"' || c == '\'').to_string();
            // Inline emphasis: drop standalone `**` / `*` / `__` /
            // `_` markers without trying to parse markdown — just
            // remove the punctuation. Rare enough that this naive
            // replace is fine.
            s = s.replace("**", "").replace("__", "");
            s
        }
        Err(e) => {
            log::warn!("synthesize_merge generate failed: {:?}", e);
            return HttpResponse::ServiceUnavailable().json(serde_json::json!({
                "error": "LLM unavailable; the merge picker should fall back to skip-synthesis."
            }));
        }
    };

    HttpResponse::Ok().json(SynthesizeMergeResponse {
        proposed_description: proposed,
        model_used,
    })
}

async fn list_facts<D: KnowledgeDao + 'static>(
    req: HttpRequest,
    claims: Claims,
    query: web::Query<FactListQuery>,
    dao: web::Data<Mutex<D>>,
    persona_dao: PersonaDaoData,
) -> impl Responder {
    let limit = query.limit.unwrap_or(50).min(200);
    let offset = query.offset.unwrap_or(0);

    let status_filter = match query.status.as_deref() {
        None | Some("active") => Some("active".to_string()),
        Some("all") => None,
        Some(s) => Some(s.to_string()),
    };
    let persona = resolve_persona_filter(&req, &claims, &persona_dao);

    let filter = FactFilter {
        entity_id: query.entity_id,
        status: status_filter,
        predicate: query.predicate.clone(),
        persona,
        limit,
        offset,
    };

    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    match dao.list_facts(&cx, filter) {
        Ok((facts, total)) => {
            let mut summaries = Vec::with_capacity(facts.len());
            for f in facts {
                let subject_entity_name = dao
                    .get_entity_by_id(&cx, f.subject_entity_id)
                    .ok()
                    .flatten()
                    .map(|e| e.name);
                let object_entity_name = if let Some(oid) = f.object_entity_id {
                    dao.get_entity_by_id(&cx, oid)
                        .ok()
                        .flatten()
                        .map(|e| e.name)
                } else {
                    None
                };
                summaries.push(FactSummary {
                    id: f.id,
                    subject_entity_id: f.subject_entity_id,
                    subject_entity_name,
                    predicate: f.predicate,
                    object_entity_id: f.object_entity_id,
                    object_entity_name,
                    object_value: f.object_value,
                    confidence: f.confidence,
                    status: f.status,
                    source_photo: f.source_photo,
                    source_insight_id: f.source_insight_id,
                    created_at: f.created_at,
                });
            }
            HttpResponse::Ok().json(FactListResponse {
                facts: summaries,
                total,
                limit,
                offset,
            })
        }
        Err(e) => {
            log::error!("list_facts error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn create_fact<D: KnowledgeDao + 'static>(
    req: HttpRequest,
    claims: Claims,
    body: web::Json<FactCreateRequest>,
    dao: web::Data<Mutex<D>>,
    persona_dao: PersonaDaoData,
) -> impl Responder {
    if body.object_entity_id.is_none() && body.object_value.is_none() {
        return HttpResponse::BadRequest().json(serde_json::json!({
            "error": "object_entity_id or object_value is required"
        }));
    }
    if body.predicate.trim().is_empty() {
        return HttpResponse::BadRequest()
            .json(serde_json::json!({"error": "predicate must not be empty"}));
    }

    // Persona scoping: facts are written under the active single persona.
    // PersonaFilter::All is read-only ("hive-mind" view); callers should
    // pin a specific persona for writes via X-Persona-Id.
    let persona = resolve_persona_filter(&req, &claims, &persona_dao);
    let (user_id, persona_id) = match &persona {
        PersonaFilter::Single {
            user_id,
            persona_id,
        } => (*user_id, persona_id.clone()),
        PersonaFilter::All { user_id } => (*user_id, "default".to_string()),
    };

    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");

    // Verify subject entity exists.
    match dao.get_entity_by_id(&cx, body.subject_entity_id) {
        Ok(None) => {
            return HttpResponse::BadRequest().json(serde_json::json!({
                "error": format!("Subject entity {} not found", body.subject_entity_id)
            }));
        }
        Err(e) => {
            log::error!("create_fact subject lookup error: {:?}", e);
            return HttpResponse::InternalServerError()
                .json(serde_json::json!({"error": "Database error"}));
        }
        Ok(Some(_)) => {}
    }

    // Optional object entity validation when supplied.
    if let Some(oid) = body.object_entity_id {
        match dao.get_entity_by_id(&cx, oid) {
            Ok(None) => {
                return HttpResponse::BadRequest().json(serde_json::json!({
                    "error": format!("Object entity {} not found", oid)
                }));
            }
            Err(e) => {
                log::error!("create_fact object lookup error: {:?}", e);
                return HttpResponse::InternalServerError()
                    .json(serde_json::json!({"error": "Database error"}));
            }
            Ok(Some(_)) => {}
        }
    }

    let now = Utc::now().timestamp();
    let confidence = body.confidence.unwrap_or(0.6).clamp(0.0, 0.95);

    let insert = InsertEntityFact {
        subject_entity_id: body.subject_entity_id,
        predicate: body.predicate.trim().to_string(),
        object_entity_id: body.object_entity_id,
        object_value: body.object_value.clone(),
        source_photo: body.source_photo.clone(),
        source_insight_id: None,
        confidence,
        status: "active".to_string(),
        created_at: now,
        persona_id,
        user_id,
        valid_from: body.valid_from,
        valid_until: body.valid_until,
        superseded_by: None,
        // Manual creation via curation UI — provenance recorded as
        // "manual" with no model, distinguishing user-entered facts
        // from agent-generated ones in the audit view.
        created_by_model: None,
        created_by_backend: Some("manual".to_string()),
        last_modified_by_model: None,
        last_modified_by_backend: None,
        last_modified_at: None,
    };

    match dao.upsert_fact(&cx, insert) {
        Ok((fact, is_new)) => {
            let status = if is_new {
                actix_web::http::StatusCode::CREATED
            } else {
                actix_web::http::StatusCode::OK
            };
            HttpResponse::build(status).json(fact)
        }
        Err(e) => {
            log::error!("create_fact upsert error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn patch_fact<D: KnowledgeDao + 'static>(
    _claims: Claims,
    id: web::Path<i32>,
    body: web::Json<FactPatchRequest>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    let cx = opentelemetry::Context::current();
    let fact_id = id.into_inner();
    let patch = FactPatch {
        predicate: body.predicate.clone(),
        object_value: body.object_value.clone(),
        status: body.status.clone(),
        confidence: body.confidence,
        valid_from: body.valid_from,
        valid_until: body.valid_until,
    };

    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    // Manual PATCH from the curation UI — provenance stamped as
    // "manual" so the audit feed can distinguish human edits from
    // agent corrections.
    match dao.update_fact(&cx, fact_id, patch, Some(("manual", "manual"))) {
        Ok(Some(fact)) => HttpResponse::Ok().json(fact),
        Ok(None) => HttpResponse::NotFound().json(serde_json::json!({"error": "Fact not found"})),
        Err(e) => {
            log::error!("patch_fact error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn delete_fact<D: KnowledgeDao + 'static>(
    _claims: Claims,
    id: web::Path<i32>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    let cx = opentelemetry::Context::current();
    let fact_id = id.into_inner();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    match dao.delete_fact(&cx, fact_id) {
        Ok(()) => HttpResponse::NoContent().finish(),
        Err(e) => {
            log::warn!("delete_fact({}) error: {:?}", fact_id, e);
            HttpResponse::NotFound().json(serde_json::json!({"error": "Fact not found"}))
        }
    }
}

async fn supersede_fact<D: KnowledgeDao + 'static>(
    _claims: Claims,
    id: web::Path<i32>,
    body: web::Json<SupersedeRequest>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    let cx = opentelemetry::Context::current();
    let old_id = id.into_inner();
    if old_id == body.by_fact_id {
        return HttpResponse::BadRequest()
            .json(serde_json::json!({"error": "old_id and by_fact_id must differ"}));
    }
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    // Manual supersede from the curation UI — same stamping rule as
    // the PATCH path.
    match dao.supersede_fact(&cx, old_id, body.by_fact_id, Some(("manual", "manual"))) {
        Ok(Some(fact)) => HttpResponse::Ok().json(fact),
        Ok(None) => {
            HttpResponse::NotFound().json(serde_json::json!({"error": "Old or new fact not found"}))
        }
        Err(e) => {
            log::error!("supersede_fact error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn restore_fact<D: KnowledgeDao + 'static>(
    _claims: Claims,
    id: web::Path<i32>,
    dao: web::Data<Mutex<D>>,
) -> impl Responder {
    let cx = opentelemetry::Context::current();
    let fact_id = id.into_inner();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    match dao.revert_supersession(&cx, fact_id, Some(("manual", "manual"))) {
        Ok(Some(fact)) => HttpResponse::Ok().json(fact),
        Ok(None) => HttpResponse::NotFound().json(serde_json::json!({"error": "Fact not found"})),
        Err(e) => {
            log::error!("restore_fact error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn get_recent<D: KnowledgeDao + 'static>(
    req: HttpRequest,
    claims: Claims,
    query: web::Query<RecentQuery>,
    dao: web::Data<Mutex<D>>,
    persona_dao: PersonaDaoData,
) -> impl Responder {
    let since = query
        .since
        .unwrap_or_else(|| Utc::now().timestamp() - 86400);
    let limit = query.limit.unwrap_or(20).min(100);

    let persona = resolve_persona_filter(&req, &claims, &persona_dao);
    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    match dao.get_recent_activity(&cx, since, limit, &persona) {
        Ok(RecentActivity { entities, facts }) => {
            let entity_summaries: Vec<EntitySummary> =
                entities.into_iter().map(EntitySummary::from).collect();
            HttpResponse::Ok().json(serde_json::json!({
                "entities": entity_summaries,
                "facts": facts
            }))
        }
        Err(e) => {
            log::error!("get_recent error: {:?}", e);
            HttpResponse::InternalServerError().json(serde_json::json!({"error": "Database error"}))
        }
    }
}

async fn get_consolidation_proposals<D: KnowledgeDao + 'static>(
    req: HttpRequest,
    claims: Claims,
    query: web::Query<ConsolidationQuery>,
    dao: web::Data<Mutex<D>>,
    persona_dao: PersonaDaoData,
) -> impl Responder {
    // Clamp threshold so a curious client can't drag the cosine
    // floor to 0 and pull every entity into one giant cluster.
    let threshold = query.threshold.unwrap_or(0.85).clamp(0.5, 0.99);
    let max_groups = query.limit.unwrap_or(50).clamp(1, 200) as usize;

    let persona = resolve_persona_filter(&req, &claims, &persona_dao);
    let cx = opentelemetry::Context::current();
    let mut dao = dao.lock().expect("Unable to lock KnowledgeDao");
    let groups: Vec<ConsolidationGroup> =
        match dao.find_consolidation_proposals(&cx, threshold, max_groups) {
            Ok(g) => g,
            Err(e) => {
                log::error!("find_consolidation_proposals: {:?}", e);
                return HttpResponse::InternalServerError()
                    .json(serde_json::json!({"error": "Database error"}));
            }
        };

    // Decorate with per-persona fact counts so the curation UI can
    // show "default 8 · journal 3" inline and the curator can pick
    // which entity is the strongest target.
    let entity_ids: Vec<i32> = groups
        .iter()
        .flat_map(|g| g.entities.iter().map(|e| e.id))
        .collect();
    let breakdowns = dao
        .get_persona_breakdowns_for_entities(&cx, &entity_ids, persona.user_id())
        .unwrap_or_default();

    let groups_view: Vec<ConsolidationGroupView> = groups
        .into_iter()
        .map(|g| ConsolidationGroupView {
            entities: g
                .entities
                .into_iter()
                .map(|e| {
                    let id = e.id;
                    let summary = EntitySummary::from(e);
                    match breakdowns.get(&id) {
                        Some(bd) => summary.with_persona_breakdown(bd.clone()),
                        None => summary,
                    }
                })
                .collect(),
            min_cosine: g.min_cosine,
            max_cosine: g.max_cosine,
        })
        .collect();

    HttpResponse::Ok().json(ConsolidationResponse {
        groups: groups_view,
    })
}