crtx-memory 0.1.1

//! Memory candidate acceptance rules.
//!
//! The store layer owns durable writes; this module owns the memory-domain gate
//! before those writes are attempted.

use std::error::Error;
use std::fmt;

use chrono::{DateTime, Utc};
use cortex_core::{MemoryId, PolicyDecision, ProofClosureReport, ProofState};
use cortex_store::repo::{MemoryAcceptanceAudit, MemoryCandidate, MemoryRepo};
use cortex_store::StoreError;

/// Stable invariant key surfaced when the lifecycle layer refuses an accept
/// because the supplied [`ProofClosureReport`] is not fully verified.
///
/// ADR 0036 forbids a durable candidate -> active mutation when the proof
/// closure is `Partial` or `Broken`. The lifecycle layer fails closed before
/// any store boundary work happens, so any caller (CLI, future API, tests)
/// inherits the gate.
pub const LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT: &str =
    "cortex_memory.lifecycle.accept.proof_closure";

/// Result type for memory lifecycle operations.
pub type LifecycleResult<T> = Result<T, LifecycleError>;

/// Errors raised by memory lifecycle domain logic.
#[derive(Debug)]
pub enum LifecycleError {
    /// Store boundary failed.
    Store(StoreError),
    /// Candidate lineage or state is invalid.
    Validation(String),
    /// ADR 0036 proof closure refusal: the supplied [`ProofClosureReport`]
    /// was not [`ProofState::FullChainVerified`] and the lifecycle layer
    /// will not promote a partial- or broken-proof candidate to Active.
    /// The associated [`ProofState`] is the observed state.
    ProofClosureRefusal(ProofState),
}

impl fmt::Display for LifecycleError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Store(err) => write!(f, "store error: {err}"),
            Self::Validation(message) => write!(f, "validation failed: {message}"),
            Self::ProofClosureRefusal(state) => write!(
                f,
                "invariant={LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT} proof closure must be FullChainVerified for durable accept; observed {state:?}"
            ),
        }
    }
}

impl Error for LifecycleError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            Self::Store(err) => Some(err),
            Self::Validation(_) | Self::ProofClosureRefusal(_) => None,
        }
    }
}

impl From<StoreError> for LifecycleError {
    fn from(err: StoreError) -> Self {
        Self::Store(err)
    }
}

/// Request to accept a candidate already materialized by the caller.
///
/// ADR 0026 §2 requires every candidate -> active mutation to compose through
/// the policy lattice. The composed [`PolicyDecision`] is supplied by the
/// caller (lifecycle layer assembles AXIOM admission, proof closure, conflict
/// resolution, and operator temporal-authority contributors) and forwarded to
/// the store boundary.
///
/// ADR 0036 also requires the caller to supply a typed
/// [`ProofClosureReport`] for the candidate's lineage. The lifecycle layer
/// refuses durable promotion when the report is not
/// [`ProofState::FullChainVerified`]; the gate fires under the stable
/// invariant [`LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT`].
#[derive(Debug, Clone, Copy)]
pub struct AcceptCandidateRequest<'a> {
    /// Candidate row to insert and activate.
    pub candidate: &'a MemoryCandidate,
    /// Required audit row supplied by the caller.
    pub audit: &'a MemoryAcceptanceAudit,
    /// Composed acceptance policy decision (ADR 0026 §2). Must satisfy
    /// [`MemoryRepo::accept_candidate`]'s contributor envelope.
    pub policy: &'a PolicyDecision,
    /// Typed proof closure report (ADR 0036 §3). The lifecycle layer fails
    /// closed when this is not [`ProofState::FullChainVerified`]. The
    /// caller is responsible for computing the report from real lineage
    /// (e.g. `cortex_store::verify_memory_proof_closure`) — the lifecycle
    /// layer never invents a "trusted" report on the caller's behalf.
    pub proof_closure: &'a ProofClosureReport,
}

/// Accept a previously persisted candidate by id after validating stored
/// lineage and composing the ADR 0026 acceptance policy.
///
/// `proof_closure` MUST be [`ProofState::FullChainVerified`]; the lifecycle
/// layer refuses with [`LifecycleError::ProofClosureRefusal`] otherwise and
/// no store boundary call is made. The stable invariant
/// [`LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT`] documents the refusal.
pub fn accept(
    memories: &MemoryRepo<'_>,
    candidate_id: &MemoryId,
    updated_at: DateTime<Utc>,
    audit: &MemoryAcceptanceAudit,
    policy: &PolicyDecision,
    proof_closure: &ProofClosureReport,
) -> LifecycleResult<MemoryId> {
    require_full_proof_closure(proof_closure)?;

    let candidate = memories.get_candidate_by_id(candidate_id)?.ok_or_else(|| {
        LifecycleError::Validation(format!("memory {candidate_id} is not a candidate"))
    })?;

    if candidate
        .source_episodes_json
        .as_array()
        .is_some_and(|items| !items.is_empty())
        || candidate
            .source_events_json
            .as_array()
            .is_some_and(|items| !items.is_empty())
    {
        let accepted = memories.accept_candidate(candidate_id, updated_at, audit, policy)?;
        return Ok(accepted.id);
    }

    Err(LifecycleError::Validation(
        "memory candidate requires non-empty episode or event lineage".into(),
    ))
}

/// Accept a candidate after validating lineage before any store write.
///
/// The durable candidate -> active transition and audit write are delegated to
/// `cortex-store` so the two effects occur in one transaction, and the
/// composed [`PolicyDecision`] is forwarded to the store boundary so the
/// ADR 0026 contributor envelope fails closed on `Reject` / `Quarantine`.
///
/// `request.proof_closure` MUST be [`ProofState::FullChainVerified`]; the
/// lifecycle layer refuses with [`LifecycleError::ProofClosureRefusal`]
/// otherwise and no insert or accept is attempted. The stable invariant
/// [`LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT`] documents the refusal.
pub fn accept_candidate(
    memories: &MemoryRepo<'_>,
    request: AcceptCandidateRequest<'_>,
) -> LifecycleResult<MemoryId> {
    require_full_proof_closure(request.proof_closure)?;
    validate_candidate_lineage(request.candidate)?;

    memories.insert_candidate(request.candidate)?;
    memories.accept_candidate(
        &request.candidate.id,
        request.candidate.updated_at,
        request.audit,
        request.policy,
    )?;

    Ok(request.candidate.id)
}

/// Fail closed before any durable write if the proof closure is not
/// [`ProofState::FullChainVerified`]. The lifecycle layer is the
/// fail-closed line for ADR 0036 at the memory candidate -> active surface.
fn require_full_proof_closure(report: &ProofClosureReport) -> LifecycleResult<()> {
    if report.is_full_chain_verified() {
        Ok(())
    } else {
        Err(LifecycleError::ProofClosureRefusal(report.state()))
    }
}

/// Validate the minimum lineage invariant for a memory candidate.
///
/// At least one of `source_episodes_json` or `source_events_json` must be a
/// non-empty JSON array. Missing (`null`) or empty lineage fails closed.
pub fn validate_candidate_lineage(candidate: &MemoryCandidate) -> LifecycleResult<()> {
    if candidate
        .source_episodes_json
        .as_array()
        .is_some_and(|items| !items.is_empty())
        || candidate
            .source_events_json
            .as_array()
            .is_some_and(|items| !items.is_empty())
    {
        return Ok(());
    }

    Err(LifecycleError::Validation(
        "memory candidate requires non-empty episode or event lineage".into(),
    ))
}

#[cfg(test)]
mod tests {
    use super::*;
    use cortex_core::{
        AuditRecordId, FailingEdge, ProofClosureReport, ProofEdgeFailure, ProofEdgeKind,
    };
    use cortex_store::repo::memories::accept_candidate_policy_decision_test_allow;
    use cortex_store::{Pool, INITIAL_MIGRATION_SQL};
    use serde_json::json;

    fn full_proof_closure() -> ProofClosureReport {
        // Test fixture: a fully-verified report with no failing edges.
        // Production callers compute this via
        // `cortex_store::verify_memory_proof_closure`.
        ProofClosureReport::full_chain_verified(Vec::new())
    }

    fn partial_proof_closure() -> ProofClosureReport {
        ProofClosureReport::from_edges(
            Vec::new(),
            vec![FailingEdge::missing(
                ProofEdgeKind::LineageClosure,
                "memory:test",
                "test fixture: lineage axis observed but unresolved",
            )],
        )
    }

    fn broken_proof_closure() -> ProofClosureReport {
        ProofClosureReport::from_edges(
            Vec::new(),
            vec![FailingEdge::broken(
                ProofEdgeKind::HashChain,
                "event:a",
                "event:b",
                ProofEdgeFailure::Mismatch,
                "test fixture: hash chain mismatch",
            )],
        )
    }

    fn test_pool() -> Pool {
        let pool = Pool::open_in_memory().expect("open in-memory sqlite");
        pool.execute_batch(INITIAL_MIGRATION_SQL)
            .expect("run initial migration");
        pool
    }

    fn candidate(has_event_lineage: bool) -> MemoryCandidate {
        MemoryCandidate {
            id: "mem_01ARZ3NDEKTSV4RRFFQ69G5FAV".parse().unwrap(),
            memory_type: "semantic".into(),
            claim: "Cortex memories require lineage.".into(),
            source_episodes_json: Default::default(),
            source_events_json: if has_event_lineage {
                "[\"evt_01ARZ3NDEKTSV4RRFFQ69G5FAV\"]".parse().unwrap()
            } else {
                Default::default()
            },
            domains_json: Default::default(),
            salience_json: Default::default(),
            confidence: 0.7,
            authority: "candidate".into(),
            applies_when_json: Default::default(),
            does_not_apply_when_json: Default::default(),
            created_at: "1970-01-01T00:00:00Z".parse().unwrap(),
            updated_at: "1970-01-01T00:00:00Z".parse().unwrap(),
        }
    }

    #[test]
    fn lineage_validation_rejects_missing_or_empty_sources() {
        assert!(validate_candidate_lineage(&candidate(false)).is_err());
        assert!(validate_candidate_lineage(&candidate(true)).is_ok());
    }

    #[test]
    fn accept_candidate_rejects_empty_lineage_before_any_write() {
        let pool = test_pool();
        let memories = MemoryRepo::new(&pool);
        let policy = accept_candidate_policy_decision_test_allow();
        let proof_closure = full_proof_closure();
        let request = AcceptCandidateRequest {
            candidate: &candidate(false),
            audit: &acceptance_audit(),
            policy: &policy,
            proof_closure: &proof_closure,
        };

        assert!(accept_candidate(&memories, request).is_err());

        let count: i64 = pool
            .query_row("SELECT COUNT(*) FROM memories;", [], |row| row.get(0))
            .unwrap();
        assert_eq!(count, 0);
    }

    fn acceptance_audit() -> MemoryAcceptanceAudit {
        MemoryAcceptanceAudit {
            id: AuditRecordId::new(),
            actor_json: json!({"kind": "test"}),
            reason: "unit test accept".into(),
            source_refs_json: json!(["evt_01ARZ3NDEKTSV4RRFFQ69G5FAV"]),
            created_at: "1970-01-01T00:00:05Z".parse().unwrap(),
        }
    }

    #[test]
    fn accept_candidate_inserts_active_memory_and_optional_audit() {
        let pool = test_pool();
        let memories = MemoryRepo::new(&pool);
        let mut candidate = candidate(true);
        candidate.updated_at = "1970-01-01T00:00:05Z".parse().unwrap();
        let audit = acceptance_audit();
        let policy = accept_candidate_policy_decision_test_allow();
        let proof_closure = full_proof_closure();

        let accepted = accept_candidate(
            &memories,
            AcceptCandidateRequest {
                candidate: &candidate,
                audit: &audit,
                policy: &policy,
                proof_closure: &proof_closure,
            },
        )
        .expect("accept candidate with lineage");

        assert_eq!(accepted, candidate.id);
        let status: String = pool
            .query_row(
                "SELECT status FROM memories WHERE id = ?1;",
                [candidate.id.to_string()],
                |row| row.get(0),
            )
            .unwrap();
        assert_eq!(status, "active");
        let audit_count: i64 = pool
            .query_row(
                "SELECT COUNT(*) FROM audit_records WHERE target_ref = ?1;",
                [candidate.id.to_string()],
                |row| row.get(0),
            )
            .unwrap();
        assert_eq!(audit_count, 1);
    }

    #[test]
    fn id_only_accept_uses_stored_candidate_and_audit_transaction() {
        let pool = test_pool();
        let memories = MemoryRepo::new(&pool);
        let mut candidate = candidate(true);
        candidate.updated_at = "1970-01-01T00:00:03Z".parse().unwrap();
        memories
            .insert_candidate(&candidate)
            .expect("insert candidate");
        let audit = acceptance_audit();
        let proof_closure = full_proof_closure();

        let accepted = accept(
            &memories,
            &candidate.id,
            "1970-01-01T00:00:06Z".parse().unwrap(),
            &audit,
            &accept_candidate_policy_decision_test_allow(),
            &proof_closure,
        )
        .expect("accept stored candidate by id");

        assert_eq!(accepted, candidate.id);
        assert_eq!(
            memories
                .get_by_id(&candidate.id)
                .unwrap()
                .expect("accepted memory exists")
                .status,
            "active"
        );
    }

    // =========================================================================
    // Commit B — ADR 0036 library-level proof closure gate (lifecycle::accept)
    //
    // The lifecycle layer is the fail-closed line for ADR 0036 at the
    // candidate -> active surface. Any caller (CLI, future API, tests) that
    // routes through `accept` or `accept_candidate` MUST supply a
    // `ProofClosureReport`; the lifecycle layer refuses with the stable
    // invariant `LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT` when the report
    // is not FullChainVerified, and no store boundary call is attempted.
    // =========================================================================

    #[test]
    fn accept_candidate_refuses_partial_proof_closure_before_any_write() {
        let pool = test_pool();
        let memories = MemoryRepo::new(&pool);
        let candidate = candidate(true);
        let policy = accept_candidate_policy_decision_test_allow();
        let proof_closure = partial_proof_closure();

        let err = accept_candidate(
            &memories,
            AcceptCandidateRequest {
                candidate: &candidate,
                audit: &acceptance_audit(),
                policy: &policy,
                proof_closure: &proof_closure,
            },
        )
        .expect_err("partial proof closure must refuse");

        match err {
            LifecycleError::ProofClosureRefusal(state) => {
                assert_eq!(state, ProofState::Partial);
                assert!(err
                    .to_string()
                    .contains(LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT));
            }
            other => panic!("expected ProofClosureRefusal, got {other:?}"),
        }

        let count: i64 = pool
            .query_row("SELECT COUNT(*) FROM memories;", [], |row| row.get(0))
            .unwrap();
        assert_eq!(count, 0, "no row may be written on proof closure refusal");
    }

    #[test]
    fn accept_candidate_refuses_broken_proof_closure_before_any_write() {
        let pool = test_pool();
        let memories = MemoryRepo::new(&pool);
        let candidate = candidate(true);
        let policy = accept_candidate_policy_decision_test_allow();
        let proof_closure = broken_proof_closure();

        let err = accept_candidate(
            &memories,
            AcceptCandidateRequest {
                candidate: &candidate,
                audit: &acceptance_audit(),
                policy: &policy,
                proof_closure: &proof_closure,
            },
        )
        .expect_err("broken proof closure must refuse");

        match err {
            LifecycleError::ProofClosureRefusal(state) => {
                assert_eq!(state, ProofState::Broken);
            }
            other => panic!("expected ProofClosureRefusal, got {other:?}"),
        }
    }

    #[test]
    fn id_only_accept_refuses_partial_proof_closure_before_any_write() {
        let pool = test_pool();
        let memories = MemoryRepo::new(&pool);
        let candidate = candidate(true);
        memories
            .insert_candidate(&candidate)
            .expect("insert candidate");
        let audit = acceptance_audit();
        let proof_closure = partial_proof_closure();

        let err = accept(
            &memories,
            &candidate.id,
            "1970-01-01T00:00:06Z".parse().unwrap(),
            &audit,
            &accept_candidate_policy_decision_test_allow(),
            &proof_closure,
        )
        .expect_err("partial proof closure must refuse");

        match err {
            LifecycleError::ProofClosureRefusal(state) => {
                assert_eq!(state, ProofState::Partial);
            }
            other => panic!("expected ProofClosureRefusal, got {other:?}"),
        }
        assert_eq!(
            memories
                .get_by_id(&candidate.id)
                .unwrap()
                .expect("candidate still exists")
                .status,
            "candidate",
            "candidate must remain in candidate state after refusal"
        );
    }

    #[test]
    fn lifecycle_accept_proof_closure_invariant_key_is_stable() {
        assert_eq!(
            LIFECYCLE_ACCEPT_PROOF_CLOSURE_INVARIANT,
            "cortex_memory.lifecycle.accept.proof_closure"
        );
    }
}