auths-transparency 0.1.3

//! Offline bundle verification logic.
//!
//! Provides [`verify_bundle`] — a synchronous, I/O-free function that verifies
//! an [`OfflineBundle`] against a [`TrustRoot`].

use chrono::{DateTime, Duration, Utc};
use ring::signature::{ECDSA_P256_SHA256_ASN1, ED25519, UnparsedPublicKey};

use crate::bundle::{
    BundleVerificationReport, CheckpointStatus, DelegationStatus, InclusionStatus, NamespaceStatus,
    SignatureStatus, WitnessStatus,
};
use crate::checkpoint::SignedCheckpoint;
use crate::entry::{EntryBody, EntryType};
use crate::merkle::hash_leaf;
use crate::{OfflineBundle, TrustRoot};
use auths_verifier::{Capability, IdentityDID};

const STALE_BUNDLE_DAYS: i64 = 90;

/// Verifies an offline transparency bundle against a trust root.
///
/// Each verification dimension (signature, inclusion, checkpoint, witnesses,
/// namespace, delegation) is evaluated independently so callers can make
/// nuanced trust decisions.
///
/// Args:
/// * `bundle` — The offline bundle to verify.
/// * `trust_root` — Trusted log public key and witness set.
/// * `now` — Current wall-clock time (injected, never read from system clock).
///
/// Usage:
/// ```ignore
/// let report = verify_bundle(&bundle, &trust_root, now);
/// if report.is_valid() {
///     // bundle is trustworthy
/// }
/// ```
pub fn verify_bundle(
    bundle: &OfflineBundle,
    trust_root: &TrustRoot,
    now: DateTime<Utc>,
) -> BundleVerificationReport {
    let signature = verify_signature(bundle);
    let inclusion = verify_inclusion_proof(bundle);
    let checkpoint = verify_checkpoint(&bundle.signed_checkpoint, trust_root);
    let witnesses = verify_witnesses(&bundle.signed_checkpoint, trust_root);
    let delegation = verify_delegation_chain(bundle);
    let namespace = derive_namespace_status(&delegation, bundle);

    let mut warnings = Vec::new();
    check_staleness(&bundle.signed_checkpoint, now, &mut warnings);

    BundleVerificationReport {
        signature,
        inclusion,
        checkpoint,
        witnesses,
        namespace,
        delegation,
        warnings,
    }
}

fn resolve_actor_public_key(bundle: &OfflineBundle) -> Option<[u8; 32]> {
    let actor_did = bundle.entry.content.actor_did.as_str();

    if actor_did.starts_with("did:key:z") {
        return auths_crypto::did_key_decode(actor_did)
            .ok()
            .and_then(|decoded| match decoded {
                auths_crypto::DecodedDidKey::Ed25519(pk) => Some(pk),
                auths_crypto::DecodedDidKey::P256(_) => None,
            });
    }

    if actor_did.starts_with("did:keri:") {
        for link in &bundle.delegation_chain {
            if link.link_type == EntryType::DeviceBind
                && let EntryBody::DeviceBind {
                    ref device_did,
                    ref public_key,
                } = link.entry.content.body
                && device_did.as_str() == actor_did
            {
                return Some(*public_key.as_bytes());
            }
        }
    }

    None
}

fn verify_signature(bundle: &OfflineBundle) -> SignatureStatus {
    let public_key_bytes = match resolve_actor_public_key(bundle) {
        Some(pk) => pk,
        None => {
            return SignatureStatus::Failed {
                reason: format!(
                    "could not resolve public key for actor DID: {}",
                    bundle.entry.content.actor_did
                ),
            };
        }
    };

    let canonical = match bundle.entry.content.canonicalize() {
        Ok(c) => c,
        Err(e) => {
            return SignatureStatus::Failed {
                reason: format!("canonicalization failed: {e}"),
            };
        }
    };

    let peer_key = UnparsedPublicKey::new(&ED25519, &public_key_bytes);
    match peer_key.verify(&canonical, bundle.entry.actor_sig.as_bytes()) {
        Ok(()) => SignatureStatus::Verified,
        Err(_) => SignatureStatus::Failed {
            reason: "Ed25519 signature verification failed".into(),
        },
    }
}

fn verify_inclusion_proof(bundle: &OfflineBundle) -> InclusionStatus {
    let leaf_data = match bundle.entry.leaf_data() {
        Ok(d) => d,
        Err(e) => {
            return InclusionStatus::Failed {
                reason: format!("leaf data serialization failed: {e}"),
            };
        }
    };
    let leaf_hash = hash_leaf(&leaf_data);

    let proof = &bundle.inclusion_proof;
    if let Err(e) = crate::merkle::verify_inclusion(
        &leaf_hash,
        proof.index,
        proof.size,
        &proof.hashes,
        &proof.root,
    ) {
        return InclusionStatus::Failed {
            reason: format!("Merkle inclusion failed: {e}"),
        };
    }

    if proof.root != bundle.signed_checkpoint.checkpoint.root {
        return InclusionStatus::Failed {
            reason: "inclusion proof root does not match checkpoint root".into(),
        };
    }

    InclusionStatus::Verified
}

fn verify_checkpoint(signed: &SignedCheckpoint, trust_root: &TrustRoot) -> CheckpointStatus {
    if signed.checkpoint.origin != trust_root.log_origin {
        return CheckpointStatus::InvalidSignature;
    }

    let note_body = signed.checkpoint.to_note_body();

    match trust_root.signature_algorithm {
        auths_verifier::SignatureAlgorithm::Ed25519 => {
            let peer_key = UnparsedPublicKey::new(&ED25519, trust_root.log_public_key.as_bytes());
            match peer_key.verify(note_body.as_bytes(), signed.log_signature.as_bytes()) {
                Ok(()) => CheckpointStatus::Verified,
                Err(_) => CheckpointStatus::InvalidSignature,
            }
        }
        auths_verifier::SignatureAlgorithm::EcdsaP256 => {
            // For ECDSA P-256, the C2SP signed-note `log_signature` field
            // is Ed25519-pinned by spec (64-byte fixed). We carry the
            // ECDSA DER signature + key in sibling
            // `ecdsa_checkpoint_signature` / `ecdsa_checkpoint_key`
            // fields that the Rekor adapter populates. Spec link:
            // https://c2sp.org/signed-note.
            //
            // Missing fields are a STRUCTURAL error — operators
            // investigating log misbehavior need to tell "the signature
            // didn't verify" apart from "the signature doesn't exist in
            // the bundle at all". Falling through to InvalidSignature
            // conflates these and hides the real cause.
            let Some(ecdsa_sig) = &signed.ecdsa_checkpoint_signature else {
                return CheckpointStatus::MissingEcdsaSignature;
            };
            let Some(ecdsa_pk) = &signed.ecdsa_checkpoint_key else {
                return CheckpointStatus::MissingEcdsaKey;
            };
            // Bundle-carried key must match the pinned key from the
            // trust root byte-for-byte — otherwise the verifier is
            // just checking "did this key sign this message" which
            // is trivially forgeable.
            if let Some(pinned) = trust_root.ecdsa_log_public_key_der.as_deref()
                && pinned != ecdsa_pk.as_der()
            {
                return CheckpointStatus::InvalidSignature;
            }
            // ring's ECDSA verifier consumes the raw uncompressed SEC1 point,
            // not the DER SPKI we carry — convert before verifying.
            let Some(point) = ecdsa_pk.as_sec1_uncompressed() else {
                return CheckpointStatus::InvalidSignature;
            };
            let peer_key = UnparsedPublicKey::new(&ECDSA_P256_SHA256_ASN1, point);
            match peer_key.verify(note_body.as_bytes(), ecdsa_sig.as_der()) {
                Ok(()) => CheckpointStatus::Verified,
                Err(_) => CheckpointStatus::InvalidSignature,
            }
        }
    }
}

/// Verify only the checkpoint-signature dimension of a [`SignedCheckpoint`]
/// against a [`TrustRoot`], dispatching on the trust root's signature algorithm
/// (Ed25519 or ECDSA-P256). Exposed for the submit/verify flow, which holds a
/// checkpoint without assembling a full [`OfflineBundle`].
///
/// Args:
/// * `signed` — The signed checkpoint to verify.
/// * `trust_root` — The pinned trust root for the log that produced it.
///
/// Usage:
/// ```ignore
/// let status = verify_checkpoint_signature(&signed, &trust_root);
/// ```
pub fn verify_checkpoint_signature(
    signed: &SignedCheckpoint,
    trust_root: &TrustRoot,
) -> CheckpointStatus {
    verify_checkpoint(signed, trust_root)
}

/// Verify only the witness-cosignature dimension of a [`SignedCheckpoint`] against a
/// [`TrustRoot`], returning the quorum + independence verdict.
///
/// Each cosignature is checked against a trusted witness (matched in constant time)
/// and the present cosigning quorum is evaluated for independence under the trust
/// root's policy. Exposed for the monitor, which holds a checkpoint without
/// assembling a full [`OfflineBundle`] and must not re-implement Ed25519 cosignature
/// verification itself.
///
/// Args:
/// * `signed` — The signed checkpoint whose witness cosignatures to verify.
/// * `trust_root` — The pinned trust root (witness roster + independence policy).
///
/// Usage:
/// ```ignore
/// let status = verify_witness_cosignatures(&signed, &trust_root);
/// ```
pub fn verify_witness_cosignatures(
    signed: &SignedCheckpoint,
    trust_root: &TrustRoot,
) -> WitnessStatus {
    verify_witnesses(signed, trust_root)
}

fn verify_witnesses(signed: &SignedCheckpoint, trust_root: &TrustRoot) -> WitnessStatus {
    if trust_root.witnesses.is_empty() {
        return WitnessStatus::NotProvided;
    }

    let note_body = signed.checkpoint.to_note_body();
    let required = trust_root.witnesses.len() / 2 + 1;
    let mut verified = 0usize;
    // Independence is evaluated over the ACTUAL cosigning quorum — the witnesses
    // whose cosignatures verify here — not the configured roster. A diverse roster
    // with a correlated quorum must still fail.
    let mut cosigner_attrs = Vec::new();

    for cosig in &signed.witnesses {
        let trusted = trust_root.witnesses.iter().find(|w| {
            use subtle::ConstantTimeEq;
            w.public_key
                .as_bytes()
                .ct_eq(cosig.witness_public_key.as_bytes())
                .into()
        });

        if let Some(witness) = trusted {
            let peer_key = UnparsedPublicKey::new(&ED25519, cosig.witness_public_key.as_bytes());
            if peer_key
                .verify(note_body.as_bytes(), cosig.signature.as_bytes())
                .is_ok()
            {
                verified += 1;
                // A verified cosigner without pinned attributes cannot contribute
                // to diversity (fail closed under a real policy).
                if let Some(attrs) = witness.operator_attributes() {
                    cosigner_attrs.push(attrs);
                }
            }
        }
    }

    if verified < required {
        return WitnessStatus::Insufficient { verified, required };
    }

    // Count met — require the present cosigners to be independent. Under the
    // unconstrained default policy this passes trivially (0 ≥ 0), preserving
    // legacy behavior; under a pinned commons policy it enforces diversity.
    let independence = auths_keri::witness::independence::spans_distinct(
        &cosigner_attrs,
        &trust_root.independence_policy,
    );
    if independence.independent {
        WitnessStatus::Quorum { verified, required }
    } else {
        WitnessStatus::NotIndependent {
            verified,
            required,
            shortfalls: independence.shortfalls,
        }
    }
}

fn check_staleness(signed: &SignedCheckpoint, now: DateTime<Utc>, warnings: &mut Vec<String>) {
    #[allow(clippy::expect_used)] // INVARIANT: 90 days always fits in Duration
    let stale_threshold =
        Duration::try_days(STALE_BUNDLE_DAYS).expect("STALE_BUNDLE_DAYS is a small constant");
    if now - signed.checkpoint.timestamp > stale_threshold {
        warnings.push(format!(
            "bundle checkpoint is older than {} days",
            STALE_BUNDLE_DAYS
        ));
    }
}

fn validate_chain_link_order(
    chain: &[crate::bundle::DelegationChainLink],
) -> Option<DelegationStatus> {
    if chain[0].link_type != EntryType::DeviceBind {
        return Some(DelegationStatus::ChainBroken {
            reason: format!(
                "link[0] expected type {:?}, got {:?}",
                EntryType::DeviceBind,
                chain[0].link_type
            ),
        });
    }

    let allowed_order = [
        EntryType::OrgAddMember,
        EntryType::NamespaceClaim,
        EntryType::NamespaceDelegate,
    ];

    let mut order_idx = 0;
    for (i, link) in chain.iter().enumerate().skip(1) {
        while order_idx < allowed_order.len() && link.link_type != allowed_order[order_idx] {
            order_idx += 1;
        }
        if order_idx >= allowed_order.len() {
            return Some(DelegationStatus::ChainBroken {
                reason: format!(
                    "link[{i}] unexpected type {:?} at this position",
                    link.link_type
                ),
            });
        }
        if link.link_type == EntryType::NamespaceDelegate {
            // NamespaceDelegate can repeat (multi-hop delegation)
        } else {
            order_idx += 1;
        }
    }

    let has_namespace_claim = chain
        .iter()
        .any(|l| l.link_type == EntryType::NamespaceClaim);
    let has_namespace_delegate = chain
        .iter()
        .any(|l| l.link_type == EntryType::NamespaceDelegate);
    if has_namespace_delegate && !has_namespace_claim {
        return Some(DelegationStatus::ChainBroken {
            reason: "NamespaceDelegate requires a preceding NamespaceClaim".into(),
        });
    }

    if !has_namespace_claim
        && !chain
            .iter()
            .skip(1)
            .any(|l| l.link_type == EntryType::OrgAddMember)
    {
        return Some(DelegationStatus::ChainBroken {
            reason: "chain must contain at least OrgAddMember or NamespaceClaim after DeviceBind"
                .into(),
        });
    }

    None
}

fn verify_link_inclusion_proofs(
    chain: &[crate::bundle::DelegationChainLink],
    checkpoint_root: &crate::types::MerkleHash,
) -> Option<DelegationStatus> {
    let mut sequences: Vec<u128> = chain.iter().map(|l| l.entry.sequence).collect();
    sequences.sort_unstable();
    sequences.dedup();
    if sequences.len() != chain.len() {
        return Some(DelegationStatus::ChainBroken {
            reason: "duplicate sequence numbers in delegation chain".into(),
        });
    }

    for (i, link) in chain.iter().enumerate() {
        let leaf_data = match link.entry.leaf_data() {
            Ok(d) => d,
            Err(e) => {
                return Some(DelegationStatus::ChainBroken {
                    reason: format!("link[{i}] leaf data failed: {e}"),
                });
            }
        };
        let leaf_hash = hash_leaf(&leaf_data);
        let proof = &link.inclusion_proof;
        if let Err(e) = crate::merkle::verify_inclusion(
            &leaf_hash,
            proof.index,
            proof.size,
            &proof.hashes,
            &proof.root,
        ) {
            return Some(DelegationStatus::ChainBroken {
                reason: format!("link[{i}] inclusion proof failed: {e}"),
            });
        }
        if &proof.root != checkpoint_root {
            return Some(DelegationStatus::ChainBroken {
                reason: format!("link[{i}] proof root does not match checkpoint"),
            });
        }
    }

    None
}

fn extract_namespace_from_entry(body: &EntryBody) -> Option<(&str, &str)> {
    match body {
        EntryBody::NamespaceClaim {
            ecosystem,
            package_name,
            ..
        }
        | EntryBody::NamespaceDelegate {
            ecosystem,
            package_name,
            ..
        }
        | EntryBody::NamespaceTransfer {
            ecosystem,
            package_name,
            ..
        } => Some((ecosystem.as_str(), package_name.as_str())),
        _ => None,
    }
}

fn verify_delegation_chain(bundle: &OfflineBundle) -> DelegationStatus {
    if bundle.delegation_chain.is_empty() {
        return DelegationStatus::NoDelegationData;
    }

    let chain = &bundle.delegation_chain;

    if chain.len() < 2 {
        return DelegationStatus::ChainBroken {
            reason: format!("chain must have at least 2 links, got {}", chain.len()),
        };
    }

    if let Some(broken) = validate_chain_link_order(chain) {
        return broken;
    }

    let checkpoint_root = &bundle.signed_checkpoint.checkpoint.root;
    if let Some(broken) = verify_link_inclusion_proofs(chain, checkpoint_root) {
        return broken;
    }

    let device_did = match &chain[0].entry.content.body {
        EntryBody::DeviceBind { device_did, .. } => device_did.clone(),
        _ => {
            return DelegationStatus::ChainBroken {
                reason: "link[0] body is not DeviceBind".into(),
            };
        }
    };

    #[allow(clippy::disallowed_methods)]
    // INVARIANT: actor_did from a parsed Entry is already valid
    let identity_did = IdentityDID::new_unchecked(chain[0].entry.content.actor_did.as_str());

    let org_add_member = chain
        .iter()
        .enumerate()
        .find(|(_, l)| l.link_type == EntryType::OrgAddMember);

    let namespace_claim = chain
        .iter()
        .enumerate()
        .find(|(_, l)| l.link_type == EntryType::NamespaceClaim);

    let (member_did, member_role, org_did) = if let Some((idx, link)) = org_add_member {
        match &link.entry.content.body {
            EntryBody::OrgAddMember {
                member_did,
                role,
                capabilities,
                ..
            } => {
                let bundle_is_namespace_op =
                    extract_namespace_from_entry(&bundle.entry.content.body).is_some();
                if bundle_is_namespace_op && !capabilities.contains(&Capability::sign_release()) {
                    return DelegationStatus::ChainBroken {
                        reason: format!(
                            "link[{idx}] OrgAddMember lacks sign_release capability required for namespace operations"
                        ),
                    };
                }

                #[allow(clippy::disallowed_methods)]
                // INVARIANT: actor_did from a parsed Entry is already valid
                let org = IdentityDID::new_unchecked(link.entry.content.actor_did.as_str());
                (member_did.clone(), *role, org)
            }
            _ => {
                return DelegationStatus::ChainBroken {
                    reason: format!("link[{idx}] body is not OrgAddMember"),
                };
            }
        }
    } else {
        // 2-link chain: [DeviceBind, NamespaceClaim] — direct ownership, no org
        #[allow(clippy::disallowed_methods)]
        // INVARIANT: actor_did from a parsed Entry is already valid
        let owner_did = IdentityDID::new_unchecked(chain[0].entry.content.actor_did.as_str());
        (owner_did.clone(), auths_verifier::Role::Admin, owner_did)
    };

    if member_did.as_str() != identity_did.as_str() {
        return DelegationStatus::ChainBroken {
            reason: format!(
                "DID connectivity broken: OrgAddMember member_did ({}) != DeviceBind actor_did ({})",
                member_did, identity_did
            ),
        };
    }

    if let Some((ns_idx, ns_link)) = namespace_claim {
        if let EntryBody::NamespaceClaim {
            ecosystem: claim_ecosystem,
            package_name: claim_package,
            ..
        } = &ns_link.entry.content.body
        {
            if org_add_member.is_some() {
                #[allow(clippy::disallowed_methods)]
                // INVARIANT: actor_did from a parsed Entry is already valid
                let claim_actor =
                    IdentityDID::new_unchecked(ns_link.entry.content.actor_did.as_str());
                if claim_actor.as_str() != org_did.as_str() {
                    return DelegationStatus::ChainBroken {
                        reason: format!(
                            "link[{ns_idx}] NamespaceClaim actor_did ({}) != org_did ({})",
                            claim_actor, org_did
                        ),
                    };
                }
            }

            if let Some((bundle_ecosystem, bundle_package)) =
                extract_namespace_from_entry(&bundle.entry.content.body)
                && (claim_ecosystem != bundle_ecosystem || claim_package != bundle_package)
            {
                return DelegationStatus::ChainBroken {
                    reason: format!(
                        "link[{ns_idx}] NamespaceClaim namespace ({}/{}) does not match bundle entry ({}/{})",
                        claim_ecosystem, claim_package, bundle_ecosystem, bundle_package
                    ),
                };
            }
        } else {
            return DelegationStatus::ChainBroken {
                reason: format!("link[{ns_idx}] body is not NamespaceClaim"),
            };
        }
    }

    DelegationStatus::ChainVerified {
        org_did,
        member_did,
        member_role,
        device_did,
    }
}

fn derive_namespace_status(
    delegation: &DelegationStatus,
    bundle: &OfflineBundle,
) -> NamespaceStatus {
    match delegation {
        DelegationStatus::ChainVerified { .. } => {
            let has_namespace_delegate = bundle
                .delegation_chain
                .iter()
                .any(|link| link.link_type == EntryType::NamespaceDelegate);
            let has_namespace_claim = bundle
                .delegation_chain
                .iter()
                .any(|link| link.link_type == EntryType::NamespaceClaim);
            if has_namespace_delegate || has_namespace_claim {
                NamespaceStatus::Authorized
            } else {
                NamespaceStatus::Owned
            }
        }
        DelegationStatus::Direct => NamespaceStatus::Owned,
        DelegationStatus::NoDelegationData => NamespaceStatus::Owned,
        DelegationStatus::ChainBroken { .. } => NamespaceStatus::Unauthorized,
    }
}

#[cfg(test)]
#[allow(clippy::disallowed_methods)]
mod tests {
    use super::*;
    use crate::TrustRootWitness;
    use crate::bundle::DelegationChainLink;
    use crate::checkpoint::{Checkpoint, WitnessCosignature};
    use crate::entry::{Entry, EntryContent};
    use crate::merkle::compute_root;
    use crate::proof::InclusionProof;
    use crate::types::LogOrigin;
    use auths_verifier::{CanonicalDid, Ed25519PublicKey, Ed25519Signature};
    use ring::signature::{Ed25519KeyPair, KeyPair};

    fn fixed_now() -> DateTime<Utc> {
        chrono::DateTime::parse_from_rfc3339("2025-07-01T00:00:00Z")
            .unwrap()
            .with_timezone(&Utc)
    }

    fn fixed_ts() -> DateTime<Utc> {
        chrono::DateTime::parse_from_rfc3339("2025-06-15T00:00:00Z")
            .unwrap()
            .with_timezone(&Utc)
    }

    struct TestFixture {
        log_keypair: Ed25519KeyPair,
        log_public_key: [u8; 32],
        actor_keypair: Ed25519KeyPair,
        actor_public_key: [u8; 32],
        actor_did: String,
        trust_root: TrustRoot,
    }

    fn setup() -> TestFixture {
        let log_keypair = Ed25519KeyPair::from_seed_unchecked(&[1u8; 32]).unwrap();
        let log_public_key: [u8; 32] = log_keypair.public_key().as_ref().try_into().unwrap();

        let actor_keypair = Ed25519KeyPair::from_seed_unchecked(&[2u8; 32]).unwrap();
        let actor_public_key: [u8; 32] = actor_keypair.public_key().as_ref().try_into().unwrap();
        let actor_did = CanonicalDid::from_public_key_did_key(
            &actor_public_key,
            auths_crypto::CurveType::Ed25519,
        )
        .to_string();

        let trust_root = TrustRoot {
            log_public_key: Ed25519PublicKey::from_bytes(log_public_key),
            log_origin: LogOrigin::new("test.dev/log").unwrap(),
            witnesses: vec![],
            signature_algorithm: Default::default(),
            ecdsa_log_public_key_der: None,
            independence_policy:
                auths_keri::witness::independence::IndependencePolicy::unconstrained(),
        };

        TestFixture {
            log_keypair,
            log_public_key,
            actor_keypair,
            actor_public_key,
            actor_did,
            trust_root,
        }
    }

    fn make_entry(fixture: &TestFixture) -> Entry {
        let content = EntryContent {
            entry_type: EntryType::DeviceBind,
            body: EntryBody::DeviceBind {
                device_did: CanonicalDid::new_unchecked(&fixture.actor_did),
                public_key: Ed25519PublicKey::from_bytes(fixture.actor_public_key),
            },
            actor_did: CanonicalDid::new_unchecked(&fixture.actor_did),
        };
        let canonical = content.canonicalize().unwrap();
        let sig_bytes = fixture.actor_keypair.sign(&canonical);
        let actor_sig = Ed25519Signature::try_from_slice(sig_bytes.as_ref()).unwrap();

        Entry {
            sequence: 0,
            timestamp: fixed_ts(),
            content,
            actor_sig,
        }
    }

    fn make_signed_checkpoint(
        entry: &Entry,
        fixture: &TestFixture,
    ) -> (SignedCheckpoint, InclusionProof) {
        let leaf_data = entry.leaf_data().unwrap();
        let leaf_hash = hash_leaf(&leaf_data);
        let root = compute_root(&[leaf_hash]);

        let checkpoint = Checkpoint {
            origin: LogOrigin::new("test.dev/log").unwrap(),
            size: 1,
            root,
            timestamp: fixed_ts(),
        };

        let note_body = checkpoint.to_note_body();
        let log_sig_bytes = fixture.log_keypair.sign(note_body.as_bytes());
        let log_signature = Ed25519Signature::try_from_slice(log_sig_bytes.as_ref()).unwrap();

        let signed = SignedCheckpoint {
            checkpoint,
            log_signature,
            log_public_key: Ed25519PublicKey::from_bytes(fixture.log_public_key),
            witnesses: vec![],
            ecdsa_checkpoint_signature: None,
            ecdsa_checkpoint_key: None,
        };

        let proof = InclusionProof {
            index: 0,
            size: 1,
            root,
            hashes: vec![],
        };

        (signed, proof)
    }

    fn make_valid_bundle(fixture: &TestFixture) -> OfflineBundle {
        let entry = make_entry(fixture);
        let (signed_checkpoint, inclusion_proof) = make_signed_checkpoint(&entry, fixture);

        OfflineBundle {
            entry,
            inclusion_proof,
            signed_checkpoint,
            delegation_chain: vec![],
        }
    }

    #[test]
    fn valid_bundle_all_verified() {
        let fixture = setup();
        let bundle = make_valid_bundle(&fixture);
        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());

        assert_eq!(report.signature, SignatureStatus::Verified);
        assert_eq!(report.inclusion, InclusionStatus::Verified);
        assert_eq!(report.checkpoint, CheckpointStatus::Verified);
        assert_eq!(report.witnesses, WitnessStatus::NotProvided);
        assert!(report.is_valid());
        assert!(report.warnings.is_empty());
    }

    #[test]
    fn bad_signature_fails() {
        let fixture = setup();
        let mut bundle = make_valid_bundle(&fixture);
        bundle.entry.actor_sig = Ed25519Signature::from_bytes([0xaa; 64]);

        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());

        assert!(matches!(report.signature, SignatureStatus::Failed { .. }));
        assert!(!report.is_valid());
    }

    #[test]
    fn bad_inclusion_proof_fails() {
        let fixture = setup();
        let mut bundle = make_valid_bundle(&fixture);
        bundle
            .inclusion_proof
            .hashes
            .push(crate::types::MerkleHash::from_bytes([0xff; 32]));

        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());

        assert!(matches!(report.inclusion, InclusionStatus::Failed { .. }));
    }

    #[test]
    fn stale_checkpoint_produces_warning() {
        let fixture = setup();
        let mut bundle = make_valid_bundle(&fixture);

        let old_ts = chrono::DateTime::parse_from_rfc3339("2025-01-01T00:00:00Z")
            .unwrap()
            .with_timezone(&Utc);
        bundle.signed_checkpoint.checkpoint.timestamp = old_ts;

        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());

        assert!(!report.warnings.is_empty());
        assert!(report.warnings[0].contains("older than 90 days"));
    }

    #[test]
    fn witness_quorum_met() {
        let w1_keypair = Ed25519KeyPair::from_seed_unchecked(&[10u8; 32]).unwrap();
        let w1_pk: [u8; 32] = w1_keypair.public_key().as_ref().try_into().unwrap();
        let w2_keypair = Ed25519KeyPair::from_seed_unchecked(&[11u8; 32]).unwrap();
        let w2_pk: [u8; 32] = w2_keypair.public_key().as_ref().try_into().unwrap();

        let fixture = setup();
        let bundle = make_valid_bundle(&fixture);

        let note_body = bundle.signed_checkpoint.checkpoint.to_note_body();
        let w1_sig = w1_keypair.sign(note_body.as_bytes());
        let w2_sig = w2_keypair.sign(note_body.as_bytes());

        let mut bundle = bundle;
        bundle.signed_checkpoint.witnesses = vec![
            WitnessCosignature {
                witness_name: "w1".into(),
                witness_public_key: Ed25519PublicKey::from_bytes(w1_pk),
                signature: Ed25519Signature::try_from_slice(w1_sig.as_ref()).unwrap(),
                timestamp: fixed_ts(),
            },
            WitnessCosignature {
                witness_name: "w2".into(),
                witness_public_key: Ed25519PublicKey::from_bytes(w2_pk),
                signature: Ed25519Signature::try_from_slice(w2_sig.as_ref()).unwrap(),
                timestamp: fixed_ts(),
            },
        ];

        let trust_root = TrustRoot {
            log_public_key: Ed25519PublicKey::from_bytes(fixture.log_public_key),
            log_origin: LogOrigin::new("test.dev/log").unwrap(),
            witnesses: vec![
                TrustRootWitness {
                    witness_did: CanonicalDid::from_public_key_did_key(
                        &w1_pk,
                        auths_crypto::CurveType::Ed25519,
                    ),
                    name: "w1".into(),
                    public_key: Ed25519PublicKey::from_bytes(w1_pk),
                    operator_info: None,
                },
                TrustRootWitness {
                    witness_did: CanonicalDid::from_public_key_did_key(
                        &w2_pk,
                        auths_crypto::CurveType::Ed25519,
                    ),
                    name: "w2".into(),
                    public_key: Ed25519PublicKey::from_bytes(w2_pk),
                    operator_info: None,
                },
            ],
            signature_algorithm: Default::default(),
            ecdsa_log_public_key_der: None,
            independence_policy:
                auths_keri::witness::independence::IndependencePolicy::unconstrained(),
        };

        let report = verify_bundle(&bundle, &trust_root, fixed_now());
        assert!(matches!(
            report.witnesses,
            WitnessStatus::Quorum {
                verified: 2,
                required: 2,
            }
        ));
    }

    /// Build a 2-witness checkpoint cosigned by both, with the given operator
    /// organizations and diversity thresholds, and return the witness verdict.
    fn witness_status_for_orgs(
        org1: &str,
        org2: &str,
        min_org: usize,
        min_jur: usize,
        min_infra: usize,
    ) -> WitnessStatus {
        use auths_keri::witness::independence::{
            IndependencePolicy, Infrastructure, Jurisdiction, OperatorId, Organization,
            WitnessOperatorInfo,
        };

        let w1_keypair = Ed25519KeyPair::from_seed_unchecked(&[10u8; 32]).unwrap();
        let w1_pk: [u8; 32] = w1_keypair.public_key().as_ref().try_into().unwrap();
        let w2_keypair = Ed25519KeyPair::from_seed_unchecked(&[11u8; 32]).unwrap();
        let w2_pk: [u8; 32] = w2_keypair.public_key().as_ref().try_into().unwrap();

        let fixture = setup();
        let mut bundle = make_valid_bundle(&fixture);
        let note_body = bundle.signed_checkpoint.checkpoint.to_note_body();
        let w1_sig = w1_keypair.sign(note_body.as_bytes());
        let w2_sig = w2_keypair.sign(note_body.as_bytes());
        bundle.signed_checkpoint.witnesses = vec![
            WitnessCosignature {
                witness_name: "w1".into(),
                witness_public_key: Ed25519PublicKey::from_bytes(w1_pk),
                signature: Ed25519Signature::try_from_slice(w1_sig.as_ref()).unwrap(),
                timestamp: fixed_ts(),
            },
            WitnessCosignature {
                witness_name: "w2".into(),
                witness_public_key: Ed25519PublicKey::from_bytes(w2_pk),
                signature: Ed25519Signature::try_from_slice(w2_sig.as_ref()).unwrap(),
                timestamp: fixed_ts(),
            },
        ];

        let info = |op: &str, org: &str, jur: &str, infra: &str| WitnessOperatorInfo {
            operator: OperatorId::new(op).unwrap(),
            organization: Organization::new(org).unwrap(),
            jurisdiction: Jurisdiction::new(jur).unwrap(),
            infrastructure: Infrastructure::new(infra).unwrap(),
        };

        let trust_root = TrustRoot {
            log_public_key: Ed25519PublicKey::from_bytes(fixture.log_public_key),
            log_origin: LogOrigin::new("test.dev/log").unwrap(),
            witnesses: vec![
                TrustRootWitness {
                    witness_did: CanonicalDid::from_public_key_did_key(
                        &w1_pk,
                        auths_crypto::CurveType::Ed25519,
                    ),
                    name: "w1".into(),
                    public_key: Ed25519PublicKey::from_bytes(w1_pk),
                    operator_info: Some(info("w1", org1, "US", "aws/us-east-1")),
                },
                TrustRootWitness {
                    witness_did: CanonicalDid::from_public_key_did_key(
                        &w2_pk,
                        auths_crypto::CurveType::Ed25519,
                    ),
                    name: "w2".into(),
                    public_key: Ed25519PublicKey::from_bytes(w2_pk),
                    operator_info: Some(info("w2", org2, "DE", "gcp/eu-west-1")),
                },
            ],
            signature_algorithm: Default::default(),
            ecdsa_log_public_key_der: None,
            independence_policy: IndependencePolicy {
                min_organizations: min_org,
                min_jurisdictions: min_jur,
                min_infra_zones: min_infra,
            },
        };

        verify_bundle(&bundle, &trust_root, fixed_now()).witnesses
    }

    #[test]
    fn witness_quorum_diverse_passes() {
        // 2 orgs / 2 jurisdictions / 2 infra zones meets a 2/2/2 policy.
        let status = witness_status_for_orgs("org-a", "org-b", 2, 2, 2);
        assert!(
            matches!(status, WitnessStatus::Quorum { verified: 2, .. }),
            "got {status:?}"
        );
    }

    #[test]
    fn witness_quorum_same_org_not_independent() {
        // Count is met (2 ≥ 2) but both cosigners share an org → NotIndependent.
        let status = witness_status_for_orgs("acme", "acme", 2, 1, 1);
        assert!(
            matches!(status, WitnessStatus::NotIndependent { .. }),
            "got {status:?}"
        );
    }

    #[test]
    fn empty_delegation_yields_no_delegation_data() {
        let fixture = setup();
        let bundle = make_valid_bundle(&fixture);
        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());
        assert_eq!(report.delegation, DelegationStatus::NoDelegationData);
    }

    #[test]
    fn delegation_chain_wrong_length_is_broken() {
        let fixture = setup();
        let mut bundle = make_valid_bundle(&fixture);

        let entry = make_entry(&fixture);
        let root = bundle.signed_checkpoint.checkpoint.root;

        bundle.delegation_chain = vec![DelegationChainLink {
            link_type: EntryType::DeviceBind,
            entry,
            inclusion_proof: InclusionProof {
                index: 0,
                size: 1,
                root,
                hashes: vec![],
            },
        }];

        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());
        assert!(matches!(
            report.delegation,
            DelegationStatus::ChainBroken { .. }
        ));
    }

    #[test]
    fn checkpoint_origin_mismatch_fails() {
        let fixture = setup();
        let mut bundle = make_valid_bundle(&fixture);
        bundle.signed_checkpoint.checkpoint.origin = LogOrigin::new("other.dev/log").unwrap();

        let report = verify_bundle(&bundle, &fixture.trust_root, fixed_now());
        assert_eq!(report.checkpoint, CheckpointStatus::InvalidSignature);
    }
}