kindling-service 0.3.0

//! `KindlingService` — in-process orchestration over the store/provider/filter
//! crates. Ports `KindlingService` from
//! `packages/kindling-core/src/service/kindling-service.ts`.

use std::path::Path;
use std::time::{SystemTime, UNIX_EPOCH};

use crate::filter::mask_secrets;
use kindling_provider::{retrieve_at, LocalFtsProvider};
use kindling_store::{SqliteKindlingStore, StoreError, StoreOptions};
use kindling_types::{
    Capsule, CapsuleInput, CapsuleStatus, CapsuleType, Id, ListObservationsRequest,
    ListObservationsResult, Observation, ObservationInput, Pin, PinInput, PinTargetType,
    RetrieveOptions, RetrieveResult, ScopeIds, Summary, SummaryInput, Timestamp, ValidationError,
};

use crate::context::{PreCompactContext, ResolvedPin, SessionStartContext};
use crate::error::{ServiceError, ServiceResult};
use crate::validation;

/// Options for [`KindlingService::open_capsule`].
///
/// Mirrors `OpenCapsuleOptions` in `packages/kindling-core/src/capsule/types.ts`.
#[derive(Debug, Clone)]
pub struct OpenCapsuleOptions {
    /// Capsule type (`type` in the TS option object).
    pub kind: CapsuleType,
    /// Human-readable intent/purpose.
    pub intent: String,
    /// Scope dimensions for isolation.
    pub scope_ids: ScopeIds,
    /// Optional pre-generated id; defaults to a fresh UUID.
    pub id: Option<Id>,
}

/// Options for [`KindlingService::close_capsule`].
///
/// Mirrors `CloseCapsuleOptions` in the TS service. A summary is generated and
/// persisted only when `generate_summary` is set AND `summary_content` is
/// present.
#[derive(Debug, Clone, Default)]
pub struct CloseCapsuleOptions {
    /// Whether to generate a closing summary.
    pub generate_summary: bool,
    /// Content for the generated summary.
    pub summary_content: Option<String>,
    /// Summary confidence; defaults to `1.0` (the TS service default).
    pub confidence: Option<f64>,
}

/// Options for [`KindlingService::append_observation`].
///
/// Mirrors `AppendObservationOptions` in the TS service. `validate` defaults to
/// `true`; use [`AppendObservationOptions::default`] for the common case.
#[derive(Debug, Clone)]
pub struct AppendObservationOptions {
    /// Capsule to attach the observation to, if any.
    pub capsule_id: Option<Id>,
    /// Run validation before storing (TS default: `true`).
    pub validate: bool,
}

/// Outcome of [`KindlingService::append_observation`].
///
/// Carries the stored observation plus whether the write was deduplicated.
/// When `deduplicated` is `true`, the incoming observation collided with an
/// already-stored id: `observation` is the **existing** stored row (loaded
/// fresh), never the incoming one, and the stored row was left untouched (no
/// re-masking, no overwrite). When `false`, a new row was written and
/// `observation` is that freshly-stored observation.
///
/// This makes spool replay after a crash exactly-once-ish on id: a replayed
/// observation is surfaced as `deduplicated: true` rather than erroring or
/// duplicating.
#[derive(Debug, Clone, PartialEq)]
pub struct AppendOutcome {
    /// The stored observation. On a dedup hit this is the pre-existing row.
    pub observation: Observation,
    /// `true` when the id already existed and the incoming write was ignored.
    pub deduplicated: bool,
}

impl Default for AppendObservationOptions {
    fn default() -> Self {
        Self {
            capsule_id: None,
            validate: true,
        }
    }
}

/// Options for [`KindlingService::pin`].
///
/// Mirrors `CreatePinOptions` in the TS service. `note` becomes the pin's
/// `reason`; `ttl_ms` sets `expires_at = now + ttl_ms`.
#[derive(Debug, Clone)]
pub struct CreatePinOptions {
    /// What kind of entity the pin targets.
    pub target_type: PinTargetType,
    /// Id of the targeted observation or summary.
    pub target_id: Id,
    /// Optional human note (stored as the pin `reason`).
    pub note: Option<String>,
    /// Time-to-live in ms; `None` means the pin never expires.
    pub ttl_ms: Option<i64>,
    /// Scope for the pin; defaults to empty.
    pub scope_ids: Option<ScopeIds>,
}

/// In-process kindling orchestration service.
///
/// Owns the [`SqliteKindlingStore`]. The retrieval provider borrows the store
/// connection, so it is constructed per-retrieve rather than held as a field.
pub struct KindlingService {
    store: SqliteKindlingStore,
}

impl KindlingService {
    /// Build a service over an already-open store.
    pub fn new(store: SqliteKindlingStore) -> Self {
        Self { store }
    }

    /// Open (and initialise if fresh) the database at `path`.
    pub fn open(path: &Path) -> ServiceResult<Self> {
        Ok(Self::new(SqliteKindlingStore::open(path)?))
    }

    /// Open the database at `path` with explicit store options.
    pub fn open_with_options(path: &Path, options: &StoreOptions) -> ServiceResult<Self> {
        Ok(Self::new(SqliteKindlingStore::open_with_options(
            path, options,
        )?))
    }

    /// Open a fresh in-memory store (test/scratch use).
    pub fn open_in_memory() -> ServiceResult<Self> {
        Ok(Self::new(SqliteKindlingStore::open_in_memory()?))
    }

    /// Borrow the underlying store (e.g. for read-only callers).
    pub fn store(&self) -> &SqliteKindlingStore {
        &self.store
    }

    // ===== capsule lifecycle =====

    /// Open a new capsule (`status = open`). For `Session` capsules with a
    /// session scope, rejects opening when one is already open for that
    /// session. Ports `openCapsule` lifecycle.
    pub fn open_capsule(&self, options: OpenCapsuleOptions) -> ServiceResult<Capsule> {
        self.open_capsule_at(options, now_ms())
    }

    /// [`Self::open_capsule`] with an explicit clock for deterministic tests.
    pub fn open_capsule_at(
        &self,
        options: OpenCapsuleOptions,
        now: Timestamp,
    ) -> ServiceResult<Capsule> {
        // Duplicate-open guard (session-scoped only), matching the TS lifecycle.
        if options.kind == CapsuleType::Session {
            if let Some(session_id) = options.scope_ids.session_id.as_deref() {
                if let Some(existing) = self.store.get_open_capsule_for_session(session_id)? {
                    return Err(ServiceError::Conflict(format!(
                        "session {session_id} already has an open capsule ({})",
                        existing.id
                    )));
                }
            }
        }

        let capsule = validation::validate_capsule(
            CapsuleInput {
                id: options.id,
                kind: options.kind,
                intent: options.intent,
                status: Some(CapsuleStatus::Open),
                opened_at: None,
                closed_at: None,
                scope_ids: options.scope_ids,
                observation_ids: None,
                summary_id: None,
            },
            now,
        )
        .map_err(ServiceError::Validation)?;

        self.store.create_capsule(&capsule)?;
        Ok(capsule)
    }

    /// Close a capsule, optionally persisting a generated summary first.
    /// Errors if the capsule is missing ([`ServiceError::NotFound`]) or already
    /// closed ([`ServiceError::AlreadyClosed`]). Ports the service `closeCapsule`.
    pub fn close_capsule(
        &self,
        capsule_id: &str,
        options: CloseCapsuleOptions,
    ) -> ServiceResult<Capsule> {
        self.close_capsule_at(capsule_id, options, now_ms())
    }

    /// [`Self::close_capsule`] with an explicit clock for deterministic tests.
    pub fn close_capsule_at(
        &self,
        capsule_id: &str,
        options: CloseCapsuleOptions,
        now: Timestamp,
    ) -> ServiceResult<Capsule> {
        // Distinguish not-found from already-closed up front (the store
        // collapses both into one error; the TS service reports them
        // separately).
        let mut capsule = match self.store.get_capsule(capsule_id)? {
            None => return Err(ServiceError::NotFound(capsule_id.to_string())),
            Some(capsule) => capsule,
        };
        if capsule.status == CapsuleStatus::Closed {
            return Err(ServiceError::AlreadyClosed(capsule_id.to_string()));
        }

        // Generate + persist the summary before closing, matching TS ordering.
        if options.generate_summary {
            if let Some(content) = options.summary_content {
                let summary = validation::validate_summary(
                    SummaryInput {
                        id: None,
                        capsule_id: capsule_id.to_string(),
                        content,
                        confidence: options.confidence.unwrap_or(1.0),
                        created_at: Some(now),
                        evidence_refs: Vec::new(),
                    },
                    now,
                )
                .map_err(ServiceError::Validation)?;
                self.store.insert_summary(&summary)?;
            }
        }

        // Close in the store. The summary (if any) is linked via
        // summaries.capsule_id, so no summary_id is threaded here.
        match self.store.close_capsule(capsule_id, Some(now), None) {
            Ok(()) => {}
            // Lost a race: someone closed it between our read and this write.
            Err(StoreError::CapsuleNotOpen(_)) => {
                return Err(ServiceError::AlreadyClosed(capsule_id.to_string()))
            }
            Err(err) => return Err(err.into()),
        }

        capsule.status = CapsuleStatus::Closed;
        capsule.closed_at = Some(now);
        Ok(capsule)
    }

    // ===== observations =====

    /// Validate/normalise, secret-mask, store, and (optionally) attach an
    /// observation. Returns an [`AppendOutcome`] carrying the stored
    /// observation and whether the write was deduplicated. Ports
    /// `appendObservation`, plus the service-boundary secret masking that has
    /// no TS equivalent.
    pub fn append_observation(
        &self,
        input: ObservationInput,
        options: AppendObservationOptions,
    ) -> ServiceResult<AppendOutcome> {
        self.append_observation_at(input, options, now_ms())
    }

    /// [`Self::append_observation`] with an explicit clock for deterministic
    /// tests.
    ///
    /// Dedup contract: if an observation with the same id already exists, the
    /// incoming write is ignored — the stored row is **not** overwritten and
    /// the (already-masked) incoming content is discarded. The existing row is
    /// loaded fresh and returned with `deduplicated: true`. This keeps spool
    /// replay idempotent on id.
    pub fn append_observation_at(
        &self,
        input: ObservationInput,
        options: AppendObservationOptions,
        now: Timestamp,
    ) -> ServiceResult<AppendOutcome> {
        let mut observation = if options.validate {
            validation::validate_observation(input, now).map_err(ServiceError::Validation)?
        } else {
            validation::normalize_observation(input, now)
        };

        // Service-boundary secret masking: mask (do NOT truncate — truncation
        // is a hook-layer concern owned by PORT-009) so no consumer can route
        // around secret filtering. Applies on both the validated and the
        // validate:false path.
        observation.content = mask_secrets(&observation.content);

        let written = self.store.insert_observation(&observation)?;

        // On a dedup hit, the stored row wins: load it fresh and return THAT,
        // never the incoming (masked) observation. Re-masking or overwriting a
        // previously stored row must never happen on replay.
        let (observation, deduplicated) = if written {
            (observation, false)
        } else {
            let existing = self
                .store
                .get_observation_by_id(&observation.id)?
                .ok_or_else(|| {
                    // INSERT OR IGNORE reported "not written" yet no row exists:
                    // this is an internal invariant violation, not a dedup hit.
                    ServiceError::Store(StoreError::ObservationNotFound(observation.id.clone()))
                })?;
            (existing, true)
        };

        // Attach is idempotent (INSERT OR IGNORE on the link's primary key), so
        // re-attaching a deduplicated observation to the same capsule is a
        // safe no-op.
        if let Some(capsule_id) = options.capsule_id.as_deref() {
            self.store
                .attach_observation_to_capsule(capsule_id, &observation.id)?;
        }

        Ok(AppendOutcome {
            observation,
            deduplicated,
        })
    }

    // ===== retrieval =====

    /// Retrieve relevant context, scored as of the current time.
    pub fn retrieve(&self, options: RetrieveOptions) -> ServiceResult<RetrieveResult> {
        self.retrieve_at(options, now_ms())
    }

    /// [`Self::retrieve`] with an explicit clock for deterministic tests.
    pub fn retrieve_at(
        &self,
        options: RetrieveOptions,
        now: Timestamp,
    ) -> ServiceResult<RetrieveResult> {
        let provider = LocalFtsProvider::from_store(&self.store);
        Ok(retrieve_at(&self.store, &provider, &options, now)?)
    }

    /// Exhaustive, deterministically-paginated observation list — the
    /// FTS-independent read path (no BM25 query string). Filters by kind, scope,
    /// and a half-open `[since, until)` time window; paginates with an opaque
    /// keyset cursor over the store's stable `(ts ASC, id ASC)` order.
    ///
    /// `limit` is clamped to `[1, 1000]` (default 100). A malformed `cursor`
    /// yields a validation error (`400`). `scope_ids.task_id` is ignored — task
    /// id is not a retrieval-filterable dimension.
    pub fn list_observations(
        &self,
        request: ListObservationsRequest,
    ) -> ServiceResult<ListObservationsResult> {
        const DEFAULT_LIMIT: u32 = 100;
        const MAX_LIMIT: u32 = 1000;

        let limit = request.limit.unwrap_or(DEFAULT_LIMIT).clamp(1, MAX_LIMIT);

        let cursor = match request.cursor.as_deref() {
            Some(raw) => Some(cursor::decode(raw).map_err(|()| {
                ServiceError::Validation(vec![ValidationError {
                    field: "cursor".to_string(),
                    message: "malformed pagination cursor".to_string(),
                    value: None,
                }])
            })?),
            None => None,
        };

        // task_id is carried for provenance only; never a filter dimension.
        let mut scope = request.scope_ids.clone();
        scope.task_id = None;

        let include_redacted = request.include_redacted.unwrap_or(false);
        let cursor_ref = cursor.as_ref().map(|(ts, id)| (*ts, id.as_str()));

        // Fetch one extra row to detect (and anchor) the next page.
        let fetch = limit.saturating_add(1);
        let mut observations = self.store.list_observations(
            Some(&scope),
            &request.kinds,
            request.since,
            request.until,
            cursor_ref,
            include_redacted,
            fetch,
        )?;

        let next_cursor = if observations.len() as u32 > limit {
            observations.truncate(limit as usize);
            observations.last().map(|o| cursor::encode(o.ts, &o.id))
        } else {
            None
        };

        Ok(ListObservationsResult {
            observations,
            next_cursor,
        })
    }

    // ===== pins =====

    /// Create a pin. `note` → reason; `ttl_ms` → `expires_at = now + ttl_ms`.
    /// Ports `pin`.
    pub fn pin(&self, options: CreatePinOptions) -> ServiceResult<Pin> {
        self.pin_at(options, now_ms())
    }

    /// [`Self::pin`] with an explicit clock for deterministic tests.
    pub fn pin_at(&self, options: CreatePinOptions, now: Timestamp) -> ServiceResult<Pin> {
        let expires_at = options.ttl_ms.map(|ttl| now + ttl);
        let pin = validation::validate_pin(
            PinInput {
                id: None,
                target_type: options.target_type,
                target_id: options.target_id,
                reason: options.note,
                created_at: Some(now),
                expires_at,
                scope_ids: options.scope_ids.unwrap_or_default(),
            },
            now,
        )
        .map_err(ServiceError::Validation)?;

        self.store.insert_pin(&pin)?;
        Ok(pin)
    }

    /// Remove a pin. Errors with [`ServiceError::Store`] if it does not exist.
    /// Ports `unpin`.
    pub fn unpin(&self, pin_id: &str) -> ServiceResult<()> {
        self.store.delete_pin(pin_id)?;
        Ok(())
    }

    // ===== read accessors =====

    /// Redact an observation (content replaced, `redacted` set). Ports `forget`.
    pub fn forget(&self, observation_id: &str) -> ServiceResult<()> {
        self.store.redact_observation(observation_id)?;
        Ok(())
    }

    /// Capsule by id. Ports `getCapsule`.
    pub fn get_capsule(&self, capsule_id: &str) -> ServiceResult<Option<Capsule>> {
        Ok(self.store.get_capsule(capsule_id)?)
    }

    /// Open capsule for a session, if any. Ports `getOpenCapsule`.
    pub fn get_open_capsule(&self, session_id: &str) -> ServiceResult<Option<Capsule>> {
        Ok(self.store.get_open_capsule_for_session(session_id)?)
    }

    /// Observation by id. Ports `getObservation`.
    pub fn get_observation(&self, observation_id: &str) -> ServiceResult<Option<Observation>> {
        Ok(self.store.get_observation_by_id(observation_id)?)
    }

    /// Summary by id. Ports `getSummary`.
    pub fn get_summary(&self, summary_id: &str) -> ServiceResult<Option<Summary>> {
        Ok(self.store.get_summary_by_id(summary_id)?)
    }

    /// Latest summary for a capsule, if any. (Read helper used by callers and
    /// tests; the TS service exposes the same via the store.)
    pub fn get_latest_summary(&self, capsule_id: &str) -> ServiceResult<Option<Summary>> {
        Ok(self.store.get_latest_summary_for_capsule(capsule_id)?)
    }

    /// Active pins for a scope, as of the current time. Ports `listPins`.
    pub fn list_pins(&self, scope: Option<&ScopeIds>) -> ServiceResult<Vec<Pin>> {
        self.list_pins_at(scope, now_ms())
    }

    /// [`Self::list_pins`] with an explicit clock for deterministic tests.
    pub fn list_pins_at(
        &self,
        scope: Option<&ScopeIds>,
        now: Timestamp,
    ) -> ServiceResult<Vec<Pin>> {
        Ok(self.store.list_active_pins(scope, Some(now))?)
    }

    // ===== injection context (hook support) =====

    /// Assemble the structured data for the SessionStart injection, scored as
    /// of the current time.
    pub fn session_start_context(
        &self,
        scope: &ScopeIds,
        max_results: u32,
    ) -> ServiceResult<SessionStartContext> {
        self.session_start_context_at(scope, max_results, now_ms())
    }

    /// [`Self::session_start_context`] with an explicit clock for deterministic
    /// tests (controls active-pin expiry).
    ///
    /// Ports the inline queries in
    /// `plugins/kindling-claude-code/hooks/session-start.js`:
    /// active pins for the scope (resolved to target content) plus the most
    /// recent non-redacted observations for the scope, capped at `max_results`.
    pub fn session_start_context_at(
        &self,
        scope: &ScopeIds,
        max_results: u32,
        now: Timestamp,
    ) -> ServiceResult<SessionStartContext> {
        let pins = self.resolved_active_pins(scope, now)?;
        // The Node hook orders by `ts DESC LIMIT maxResults`, excluding
        // redacted rows — exactly `query_observations` with no time bounds.
        let recent = self
            .store
            .query_observations(Some(scope), None, None, max_results)?;
        Ok(SessionStartContext { pins, recent })
    }

    /// Assemble the structured data for the PreCompact injection, scored as of
    /// the current time.
    pub fn pre_compact_context(&self, scope: &ScopeIds) -> ServiceResult<PreCompactContext> {
        self.pre_compact_context_at(scope, now_ms())
    }

    /// [`Self::pre_compact_context`] with an explicit clock for deterministic
    /// tests (controls active-pin expiry).
    ///
    /// Ports the inline queries in
    /// `plugins/kindling-claude-code/hooks/pre-compact.js`: active pins for the
    /// scope (resolved to target content) plus the single latest summary across
    /// the scope's capsules. An empty-content summary is normalised to `None`
    /// here, matching the Node hook's `latestSummary.content` truthiness gate,
    /// so the server never has to second-guess it.
    pub fn pre_compact_context_at(
        &self,
        scope: &ScopeIds,
        now: Timestamp,
    ) -> ServiceResult<PreCompactContext> {
        let pins = self.resolved_active_pins(scope, now)?;
        let latest_summary = self
            .store
            .latest_summary_for_scope(Some(scope))?
            .filter(|s| !s.content.is_empty());
        Ok(PreCompactContext {
            pins,
            latest_summary,
        })
    }

    /// Active pins for `scope` at `now`, each resolved to its target's content.
    ///
    /// Mirrors the TS `listActivePins` join: `note` is the pin reason, `content`
    /// is the target observation/summary content (redacted observations carry
    /// their `[redacted]` placeholder; missing targets resolve to `None`).
    fn resolved_active_pins(
        &self,
        scope: &ScopeIds,
        now: Timestamp,
    ) -> ServiceResult<Vec<ResolvedPin>> {
        let pins = self.store.list_active_pins(Some(scope), Some(now))?;
        pins.into_iter()
            .map(|pin| {
                let content = match pin.target_type {
                    PinTargetType::Observation => self
                        .store
                        .get_observation_by_id(&pin.target_id)?
                        .map(|o| o.content),
                    PinTargetType::Summary => self
                        .store
                        .get_summary_by_id(&pin.target_id)?
                        .map(|s| s.content),
                };
                Ok(ResolvedPin {
                    note: pin.reason,
                    content,
                })
            })
            .collect()
    }
}

/// Current time in epoch milliseconds.
fn now_ms() -> Timestamp {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .expect("system clock before Unix epoch")
        .as_millis() as Timestamp
}

/// Opaque keyset cursor for [`KindlingService::list_observations`].
///
/// Encodes `(ts, id)` as URL-safe base64 (no padding) of `"<ts>:<id>"`. Kept
/// dependency-free and opaque so the wire token is stable and consumers cannot
/// usefully parse or forge it. `id` (a UUID) never contains `:`.
mod cursor {
    use kindling_types::Timestamp;

    const ALPHABET: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";

    fn b64_encode(input: &[u8]) -> String {
        let mut out = String::with_capacity(input.len().div_ceil(3) * 4);
        for chunk in input.chunks(3) {
            let b0 = chunk[0] as u32;
            let b1 = *chunk.get(1).unwrap_or(&0) as u32;
            let b2 = *chunk.get(2).unwrap_or(&0) as u32;
            let n = (b0 << 16) | (b1 << 8) | b2;
            out.push(ALPHABET[((n >> 18) & 0x3f) as usize] as char);
            out.push(ALPHABET[((n >> 12) & 0x3f) as usize] as char);
            if chunk.len() > 1 {
                out.push(ALPHABET[((n >> 6) & 0x3f) as usize] as char);
            }
            if chunk.len() > 2 {
                out.push(ALPHABET[(n & 0x3f) as usize] as char);
            }
        }
        out
    }

    fn b64_decode(input: &str) -> Result<Vec<u8>, ()> {
        fn val(c: u8) -> Result<u32, ()> {
            match c {
                b'A'..=b'Z' => Ok((c - b'A') as u32),
                b'a'..=b'z' => Ok((c - b'a' + 26) as u32),
                b'0'..=b'9' => Ok((c - b'0' + 52) as u32),
                b'-' => Ok(62),
                b'_' => Ok(63),
                _ => Err(()),
            }
        }
        let bytes = input.as_bytes();
        let mut out = Vec::with_capacity(input.len() / 4 * 3);
        for chunk in bytes.chunks(4) {
            if chunk.len() < 2 {
                return Err(());
            }
            let mut n = 0u32;
            for (i, &c) in chunk.iter().enumerate() {
                n |= val(c)? << (18 - 6 * i);
            }
            out.push((n >> 16) as u8);
            if chunk.len() > 2 {
                out.push((n >> 8) as u8);
            }
            if chunk.len() > 3 {
                out.push(n as u8);
            }
        }
        Ok(out)
    }

    /// Encode a `(ts, id)` anchor into an opaque cursor token.
    pub(crate) fn encode(ts: Timestamp, id: &str) -> String {
        b64_encode(format!("{ts}:{id}").as_bytes())
    }

    /// Decode a cursor token back to `(ts, id)`. `Err(())` on any malformed input.
    pub(crate) fn decode(raw: &str) -> Result<(Timestamp, String), ()> {
        let s = String::from_utf8(b64_decode(raw)?).map_err(|_| ())?;
        let (ts_str, id) = s.split_once(':').ok_or(())?;
        let ts = ts_str.parse::<Timestamp>().map_err(|_| ())?;
        if id.is_empty() {
            return Err(());
        }
        Ok((ts, id.to_string()))
    }

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

        #[test]
        fn round_trips_various_lengths() {
            for id in [
                "a",
                "ab",
                "abc",
                "abcd",
                "550e8400-e29b-41d4-a716-446655440000",
            ] {
                let token = encode(1_750_000_000_123, id);
                assert_eq!(decode(&token).unwrap(), (1_750_000_000_123, id.to_string()));
            }
        }

        #[test]
        fn rejects_malformed() {
            assert!(decode("").is_err()); // empty
            assert!(decode("####").is_err()); // non-alphabet chars
            assert!(decode(&b64_encode(b"no-colon-here")).is_err()); // missing ':'
            assert!(decode(&b64_encode(b"notanumber:abc")).is_err()); // bad ts
            assert!(decode(&b64_encode(b"123:")).is_err()); // empty id
        }
    }
}