feat: explainable activity log — reasons, subscriber names, snapshot gaps

The live activity feed flagged anomalies with no explanation and showed
opaque session keys. Make events self-describing and clickable.

- Clickable feed rows → read-only event-detail modal: humanized fields,
  entry/exit snapshots, and signed-chain provenance collapsed behind an
  audit disclosure (operator sees the story, auditor expands for crypto).
- Localized reason codes (backend i18n): the signed ledger now carries a
  stable REASON_CODE + params (+ English fallback) instead of free-text
  English. The UI translates via reason.<code> catalogs in sq/en, so an
  Albanian operator reads Albanian — from the same immutable event. Adding
  a language is a catalog change, no re-signing. (@parking/shared
  REASON_CODES, reasonPayload; entry/exit/subscription flows emit codes.)
- Subscriber-name resolution: a SUBSESS-… occurrence now shows the
  subscription holder's name (fallback "Abonent"/"Subscriber"). Resolved
  read-time server-side (events API + WS push) as a non-signed
  subscriberLabel; cached with invalidation on subscription edit/delete.
- Failed-snapshot visibility: a camera that was attempted but unreachable
  now shows a "⚠ camera unreachable" tile instead of a silent gap. The
  snapshots API returns failures[] from telemetry, filtered so a recovered
  capture shows no stale warning.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/server/src/entry-flow.ts

@@ -10,7 +10,7 @@ import {
   type TicketData,
   type TicketHeader,
 } from "@parking/devices";
-import { DEFAULT_VEHICLE_CATEGORY } from "@parking/shared";
+import { DEFAULT_VEHICLE_CATEGORY, reasonPayload } from "@parking/shared";
 import type { FastifyBaseLogger } from "fastify";
 import type { DeviceInputEvent } from "./device-events.js";
 import { getOccupancy } from "./occupancy.js";
@@ -82,7 +82,11 @@ export class EntryFlow {
     if (occ.full) {
       await this.#log.append({
         type: "anomaly",
-        payload: { reason: `transient entry refused — lot full (${occ.count}/${occ.capacity})`, entryRefused: true, full: true },
+        payload: {
+          ...reasonPayload("entry.refused.full", { count: occ.count, capacity: occ.capacity ?? 0 }),
+          entryRefused: true,
+          full: true,
+        },
       });
       this.#logger.warn(`transient entry REFUSED: full (${occ.count}/${occ.capacity})`);
       return;
@@ -107,7 +111,7 @@ export class EntryFlow {
       await this.#log.append({
         type: "anomaly",
         identity: ticketId,
-        payload: { reason: `entry held — ticket not printed: ${reason}`, ticketPrinted: false },
+        payload: { ...reasonPayload("entry.held.noTicket", { detail: reason }), ticketPrinted: false },
       });
       this.#logger.warn(`entry HELD: ${reason} (barrier NOT opened)`);
       return;

apps/server/src/event-enrich.ts

@@ -0,0 +1,56 @@
+import { eq, subscriptions, type Db } from "@parking/db";
+import type { LedgerEvent } from "@parking/shared";
+
+// READ-TIME event enrichment. The signed ledger stays minimal and stable; some fields
+// are nice to SHOW but must not be signed (they can change, or depend on other tables).
+// We resolve them when serializing an event for the API / WS feed — never on the
+// signed record itself.
+//
+// Today: a subscription occurrence's identity is an opaque `SUBSESS-…` key. The human
+// who matters is the subscription HOLDER, whose name lives on the subscriptions row
+// (mutable master data — NOT signed into the event). We resolve payload.permitId →
+// holder_name so the feed reads "Aqif Kopertoni" rather than "SUBSESS-08cd1c52e219".
+
+/** Fallback label when a subscription has no holder name (or was deleted). Matches the
+ *  i18n key `booth.subscriberFallback`; kept here in English for the API/log layer. */
+const SUBSCRIBER_FALLBACK = "Subscriber";
+
+/** Tiny holder-name cache. Single-writer SQLite; a subscription rename is rare and the
+ *  feed is not security-sensitive, so a short-lived cache is plenty. Invalidate by
+ *  process lifetime — restart picks up renames; for live correctness the lookup is
+ *  cheap enough that we just read per miss. */
+const holderCache = new Map<string, string | null>();
+
+/** Resolve a subscription id to its holder name (or null), memoized. */
+function holderName(db: Db, permitId: string): string | null {
+  if (holderCache.has(permitId)) return holderCache.get(permitId) ?? null;
+  const row = db
+    .select({ holderName: subscriptions.holderName })
+    .from(subscriptions)
+    .where(eq(subscriptions.id, permitId))
+    .get();
+  const name = row?.holderName?.trim() || null;
+  holderCache.set(permitId, name);
+  return name;
+}
+
+/** Drop a cached holder name (call after a subscription create/update/delete). */
+export function invalidateHolder(permitId: string): void {
+  holderCache.delete(permitId);
+}
+
+/** Clear the whole holder cache (call on bulk subscription changes). */
+export function clearHolderCache(): void {
+  holderCache.clear();
+}
+
+/**
+ * Attach read-time display fields to a raw ledger row before it goes to a client.
+ * Currently: `subscriberLabel` for subscription occurrences. Idempotent and cheap;
+ * non-subscription events pass through unchanged (no `subscriberLabel`).
+ */
+export function enrichEvent<T extends LedgerEvent>(db: Db, event: T): T {
+  const permitId = event.payload && typeof event.payload.permitId === "string" ? event.payload.permitId : null;
+  if (!permitId) return event;
+  return { ...event, subscriberLabel: holderName(db, permitId) ?? SUBSCRIBER_FALLBACK };
+}

apps/server/src/exit-flow.ts

@@ -2,7 +2,7 @@ import { desc, eq, ledgerEvents, sessions, tariffVersions, tariffs, type Db, typ
 import { registry, type AccessControlDevice } from "@parking/devices";
 import { firstRelayByDirection, type ResolvedRelay } from "./device-resolve.js";
 import { snapshotAsync } from "./snapshot.js";
-import { computeFee, type LedgerPayload, type TariffStructure } from "@parking/shared";
+import { computeFee, reasonPayload, renderReasonEn, type LedgerPayload, type TariffStructure } from "@parking/shared";
 import type { FastifyBaseLogger } from "fastify";
 import type { DeviceReadEvent, ReadOutcome } from "./device-events.js";
 import type { EventLog } from "./event-log.js";
@@ -97,10 +97,10 @@ export class ExitFlow {
       // No open session — unknown/closed ticket. Sign an anomaly (same as the reader
       // path) so a booth attempt on a bad ticket is auditable.
       if (!view || !view.open) {
-        const reason = view ? "exit refused — session already closed" : "exit refused — no open session for ticket";
-        await this.#log.append({ type: "anomaly", identity: id, payload: { reason, exitRefused: true, source: "booth" } });
-        this.#logger.warn(`booth exit refused (${id}): ${reason}`);
-        return { ok: false, status: view ? "closed" : "no_session", reason };
+        const rp = reasonPayload(view ? "exit.refused.closed" : "exit.refused.noSession");
+        await this.#log.append({ type: "anomaly", identity: id, payload: { ...rp, exitRefused: true, source: "booth" } });
+        this.#logger.warn(`booth exit refused (${id}): ${rp.reason}`);
+        return { ok: false, status: view ? "closed" : "no_session", reason: rp.reason };
       }
 
       // PAID + within grace, OR free entry-grace — the same checks the reader uses.
@@ -110,12 +110,10 @@ export class ExitFlow {
         paid && view.graceExitMin != null && Date.now() - Date.parse(view.paidAt!) <= view.graceExitMin * 60_000;
 
       if (!freeGrace && (!paid || !withinGrace)) {
-        const reason = !paid
-          ? "exit refused — not paid (take payment first)"
-          : "exit refused — walk-back grace expired (top-up required)";
-        await this.#log.append({ type: "anomaly", identity: id, payload: { reason, exitRefused: true, source: "booth" } });
-        this.#logger.warn(`booth exit refused (${id}): ${reason}`);
-        return { ok: false, status: paid ? "grace_expired" : "unpaid", reason };
+        const rp = reasonPayload(paid ? "exit.refused.graceExpired" : "exit.refused.unpaid");
+        await this.#log.append({ type: "anomaly", identity: id, payload: { ...rp, exitRefused: true, source: "booth" } });
+        this.#logger.warn(`booth exit refused (${id}): ${rp.reason}`);
+        return { ok: false, status: paid ? "grace_expired" : "unpaid", reason: rp.reason };
       }
 
       // Free entry-grace path: mint the $0 payment first (ledger invariant), as the
@@ -130,7 +128,7 @@ export class ExitFlow {
             currency: view.freeGrace.currency,
             tariffVersionId: view.freeGrace.tariffVersionId,
             graceExitMin: view.freeGrace.graceExitMin,
-            reason: "free entry-grace (no charge)",
+            ...reasonPayload("exit.freeGrace"),
           },
         });
       }
@@ -144,18 +142,18 @@ export class ExitFlow {
 
       if (!resolved) {
         await this.#openFailedAnomaly(id, "no exit relay configured");
-        return { ok: true, opened: false, reason: "exit recorded, but no exit barrier is configured — open manually" };
+        return { ok: true, opened: false, reason: renderReasonEn("exit.open.noBarrier") };
       }
       const access = this.#buildAccess(resolved.controller);
       if (!access) {
         await this.#openFailedAnomaly(id, "exit controller would not build");
-        return { ok: true, opened: false, reason: "exit recorded, but the barrier is unavailable — open manually" };
+        return { ok: true, opened: false, reason: renderReasonEn("exit.open.unavailable") };
       }
       try {
         await access.pulseOpen(resolved.relay);
       } catch (err) {
         await this.#openFailedAnomaly(id, `pulseOpen failed: ${(err as Error).message}`);
-        return { ok: true, opened: false, reason: "exit recorded, but the barrier did not open — open manually" };
+        return { ok: true, opened: false, reason: renderReasonEn("exit.open.failed") };
       }
 
       this.#fireExitSnapshot(id);
@@ -210,7 +208,7 @@ export class ExitFlow {
         type: "anomaly",
         identity: id,
         payload: {
-          reason: "manual barrier open (human intervention)",
+          ...reasonPayload("exit.manualOpen"),
           source: "booth",
           barrierReopen: true,
           ...(operator ? { operator } : {}),
@@ -229,18 +227,18 @@ export class ExitFlow {
 
       if (!resolved) {
         this.#logger.warn(`barrier re-open for ${id}: no exit relay configured`);
-        return { ok: true, opened: false, reason: "no exit barrier configured — open manually" };
+        return { ok: true, opened: false, reason: renderReasonEn("exit.open.noBarrier") };
       }
       const access = this.#buildAccess(resolved.controller);
       if (!access) {
         this.#logger.warn(`barrier re-open for ${id}: exit controller would not build`);
-        return { ok: true, opened: false, reason: "barrier unavailable — open manually" };
+        return { ok: true, opened: false, reason: renderReasonEn("exit.open.unavailable") };
       }
       try {
         await access.pulseOpen(resolved.relay);
       } catch (err) {
         this.#logger.error(`barrier re-open pulseOpen failed (${id}): ${(err as Error).message}`);
-        return { ok: true, opened: false, reason: "barrier did not open — open manually" };
+        return { ok: true, opened: false, reason: renderReasonEn("exit.open.failed") };
       }
       this.#logger.info(`manual barrier open for ${id}${operator ? ` by ${operator}` : ""}`);
       return { ok: true, opened: true };
@@ -270,14 +268,14 @@ export class ExitFlow {
 
     // No matching open session — unknown/duplicate ticket. Reject + log.
     if (!view || !view.open) {
-      const reason = view ? "exit refused — session already closed" : "exit refused — no open session for credential";
+      const rp = reasonPayload(view ? "exit.refused.closed" : "exit.refused.noSession");
       await this.#log.append({
         type: "anomaly",
         identity: e.value,
-        payload: { reason, exitRefused: true },
+        payload: { ...rp, exitRefused: true },
       });
       this.#logger.warn(`exit refused: no open session for ${e.value}`);
-      return { accepted: false, direction: "exit", reason };
+      return { accepted: false, direction: "exit", reason: rp.reason };
     }
 
     // FREE entry-grace: a quick in-and-out the tariff prices at 0 exits at the gate
@@ -295,7 +293,7 @@ export class ExitFlow {
           currency: view.freeGrace.currency,
           tariffVersionId: view.freeGrace.tariffVersionId,
           graceExitMin: view.freeGrace.graceExitMin,
-          reason: "free entry-grace (no charge)",
+          ...reasonPayload("exit.freeGrace"),
         },
       });
       this.#logger.info(`exit free within entry-grace (${e.value})`);
@@ -310,16 +308,14 @@ export class ExitFlow {
       Date.now() - Date.parse(view.paidAt!) <= view.graceExitMin * 60_000;
 
     if (!paid || !withinGrace) {
-      const reason = !paid
-        ? "exit refused — not paid (pay at the station)"
-        : "exit refused — walk-back grace expired (top-up required)";
+      const rp = reasonPayload(paid ? "exit.refused.graceExpired" : "exit.refused.unpaid");
       await this.#log.append({
         type: "anomaly",
         identity: e.value,
-        payload: { reason, exitRefused: true, sessionRef: e.value },
+        payload: { ...rp, exitRefused: true, sessionRef: e.value },
       });
-      this.#logger.warn(`exit refused (${e.value}): ${reason}`);
-      return { accepted: false, direction: "exit", reason };
+      this.#logger.warn(`exit refused (${e.value}): ${rp.reason}`);
+      return { accepted: false, direction: "exit", reason: rp.reason };
     }
 
     // Valid (a real payment within walk-back grace): sign + open.
@@ -352,7 +348,7 @@ export class ExitFlow {
       identity,
       payload: {
         sessionRef: identity,
-        ...(source === "manual" ? { reason: "human-intervention exit (manual barrier open)" } : {}),
+        ...(source === "manual" ? reasonPayload("exit.manualOpen") : {}),
       },
     });
   }
@@ -386,7 +382,7 @@ export class ExitFlow {
     await this.#log.append({
       type: "anomaly",
       identity,
-      payload: { reason: "exit signed but barrier open failed", detail, source: "booth", exitOpenFailed: true },
+      payload: { ...reasonPayload("exit.open.failed"), detail, source: "booth", exitOpenFailed: true },
     });
     this.#logger.error(`booth exit open failed (${identity}): ${detail}`);
   }

apps/server/src/routes/events.ts

@@ -1,6 +1,8 @@
 import type { FastifyInstance } from "fastify";
 import { desc, gte, ledgerEvents, type Db } from "@parking/db";
+import type { LedgerEvent } from "@parking/shared";
 import { requirePermission } from "../auth.js";
+import { enrichEvent } from "../event-enrich.js";
 import type { EventLog } from "../event-log.js";
 
 // Read access to the append-only signed event log. NO write/update/delete routes
@@ -33,7 +35,10 @@ export async function eventRoutes(
         .orderBy(desc(ledgerEvents.index))
         .limit(limit)
         .all();
-      return { events: rows };
+      // Attach read-time display fields (e.g. subscriber name) without touching the
+      // signed record. The cast bridges the Drizzle row to the shared LedgerEvent.
+      const events = rows.map((r) => enrichEvent(db, r as unknown as LedgerEvent));
+      return { events };
     },
   );
 

apps/server/src/routes/snapshots.ts

@@ -1,5 +1,5 @@
 import type { FastifyInstance } from "fastify";
-import { desc, eq, snapshots, type Db } from "@parking/db";
+import { and, desc, eq, deviceEvents, snapshots, type Db } from "@parking/db";
 import { requirePermission } from "../auth.js";
 
 // Read access to captured entry/exit snapshots (the BLOB-in-DB image store, see
@@ -12,11 +12,15 @@ export async function snapshotRoutes(app: FastifyInstance, db: Db): Promise<void
   const guard = requirePermission("session:read");
 
   // Snapshot metadata for one session/credential identity (NOT the bytes), newest
-  // first — lets the UI show "entry/exit image" links beside an event.
+  // first — lets the UI show "entry/exit image" links beside an event. We also return
+  // FAILED capture attempts (from snapshot telemetry) so the operator can tell a
+  // camera that was offline from a direction that simply has no camera — otherwise a
+  // missing shot is a silent gap. See snapshot.ts (recordFailure).
   app.get<{ Params: { identity: string } }>(
     "/api/snapshots/by-identity/:identity",
     { preHandler: guard },
     async (req) => {
+      const identity = req.params.identity;
       const rows = db
         .select({
           id: snapshots.id,
@@ -27,10 +31,44 @@ export async function snapshotRoutes(app: FastifyInstance, db: Db): Promise<void
           capturedAt: snapshots.capturedAt,
         })
         .from(snapshots)
-        .where(eq(snapshots.identity, req.params.identity))
+        .where(eq(snapshots.identity, identity))
         .orderBy(desc(snapshots.capturedAt))
         .all();
-      return { snapshots: rows };
+
+      // Failed attempts: kind="snapshot" telemetry whose detail.identity matches and
+      // detail.ok === false. There may be both a failure and (on a retry) a success
+      // for the same direction; we keep only failures with NO successful shot in the
+      // same direction, so a recovered capture doesn't show a stale warning.
+      const haveDir = new Set<string | null>(rows.map((r) => r.direction));
+      const telemetry = db
+        .select({ detail: deviceEvents.detail, deviceId: deviceEvents.deviceId, occurredAt: deviceEvents.occurredAt })
+        .from(deviceEvents)
+        .where(and(eq(deviceEvents.category, "camera"), eq(deviceEvents.kind, "snapshot")))
+        .orderBy(desc(deviceEvents.occurredAt))
+        .all();
+      const failures: {
+        direction: "entry" | "exit" | null;
+        deviceId: string;
+        error: string;
+        occurredAt: string;
+      }[] = [];
+      const seenFailDir = new Set<string>();
+      for (const row of telemetry) {
+        const d = (row.detail ?? {}) as { identity?: string; ok?: boolean; error?: string; direction?: string };
+        if (d.identity !== identity || d.ok !== false) continue;
+        const dir = d.direction === "entry" || d.direction === "exit" ? d.direction : null;
+        const dirKey = dir ?? "both";
+        if (haveDir.has(dir) || seenFailDir.has(dirKey)) continue; // a success exists, or already shown
+        seenFailDir.add(dirKey);
+        failures.push({
+          direction: dir,
+          deviceId: row.deviceId ?? "",
+          error: d.error ?? "capture failed",
+          occurredAt: row.occurredAt ?? "",
+        });
+      }
+
+      return { snapshots: rows, failures };
     },
   );
 

apps/server/src/routes/subscriptions.ts

@@ -3,6 +3,7 @@ import type { FastifyInstance } from "fastify";
 import { eq, devices, subscriptionCredentials, subscriptionPlates, subscriptions, type Db } from "@parking/db";
 import { NoPrinterAvailableError } from "@parking/devices";
 import { requirePermission } from "../auth.js";
+import { invalidateHolder } from "../event-enrich.js";
 import { printSubscriptionCard } from "../booth-print.js";
 import type { CredentialCapture } from "../credential-capture.js";
 import { directionOf } from "../device-resolve.js";
@@ -310,6 +311,8 @@ export async function subscriptionRoutes(
         .where(eq(subscriptions.id, req.params.id))
         .run();
       writeChildren(req.params.id, b);
+      // The holder name may have changed — drop the feed-label cache for this sub.
+      invalidateHolder(req.params.id);
       return loadAggregate(req.params.id);
     },
   );
@@ -362,6 +365,7 @@ export async function subscriptionRoutes(
       if (r.changes === 0) return reply.code(404).send({ error: "subscription not found" });
       db.delete(subscriptionCredentials).where(eq(subscriptionCredentials.subscriptionId, req.params.id)).run();
       db.delete(subscriptionPlates).where(eq(subscriptionPlates.subscriptionId, req.params.id)).run();
+      invalidateHolder(req.params.id);
       return reply.code(204).send();
     },
   );

apps/server/src/routes/ws.ts

@@ -1,7 +1,9 @@
 import type { FastifyInstance } from "fastify";
 import type { Db } from "@parking/db";
+import type { LedgerEvent } from "@parking/shared";
 import { roleHasPermissions } from "../auth.js";
 import { deviceEvents } from "../device-events.js";
+import { enrichEvent } from "../event-enrich.js";
 import type { DeviceMonitor } from "../device-monitor.js";
 import { getOccupancy } from "../occupancy.js";
 
@@ -92,7 +94,9 @@ export async function wsRoutes(app: FastifyInstance, db: Db, deviceMonitor: Devi
       // Subscribe to the live buses. Each handler recomputes occupancy from the
       // ledger (cheap fold) so the pushed count is always authoritative.
       const offLedger = deviceEvents.onLedger((event) => {
-        send({ kind: "ledger", event, occupancy: getOccupancy(db) });
+        // Enrich with read-time display fields (subscriber name) before fan-out.
+        const enriched = enrichEvent(db, event as unknown as LedgerEvent);
+        send({ kind: "ledger", event: enriched, occupancy: getOccupancy(db) });
       });
       const offPrinter = deviceEvents.onPrinterStatus((event) => {
         send({ kind: "printer-status", event });

apps/server/src/subscription-flow.ts

@@ -10,6 +10,7 @@ import {
   type DeviceRow,
 } from "@parking/db";
 import { registry, type AccessControlDevice } from "@parking/devices";
+import { reasonPayload, type ReasonCode } from "@parking/shared";
 import type { FastifyBaseLogger } from "fastify";
 import type { DeviceReadEvent, ReadOutcome } from "./device-events.js";
 import type { EventLog } from "./event-log.js";
@@ -98,7 +99,7 @@ export class SubscriptionFlow {
 
   async #run(resolved: ResolvedRelay, e: DeviceReadEvent, m: SubscriptionMatch): Promise<ReadOutcome> {
     const sub = this.#db.select().from(subscriptions).where(eq(subscriptions.id, m.subscriptionId)).get();
-    if (!sub) return { accepted: false, reason: "subscription not found" };
+    if (!sub) return { accepted: false, reason: await this.#reject(m, "sub.refused.notFound") };
 
     // Validity: active + within the coverage window.
     const now = new Date().toISOString();
@@ -107,8 +108,7 @@ export class SubscriptionFlow {
       (sub.validFrom != null && now < sub.validFrom) ||
       (sub.validTo != null && now > sub.validTo);
     if (invalid) {
-      const reason = `subscription ${sub.status}/out-of-window`;
-      await this.#reject(m, reason);
+      const reason = await this.#reject(m, "sub.refused.outOfWindow", { status: sub.status });
       return { accepted: false, reason };
     }
 
@@ -136,8 +136,7 @@ export class SubscriptionFlow {
       // subscription has NOTHING open, an exit read is a no-op anti-passback signal.
       const oldest = open[0];
       if (!oldest) {
-        const reason = "subscription exit with no open session (already out / never entered)";
-        await this.#reject(m, reason);
+        const reason = await this.#reject(m, "sub.refused.noSession");
         return { accepted: false, direction: "exit", reason };
       }
       const occurrenceId = oldest.identity;
@@ -157,8 +156,10 @@ export class SubscriptionFlow {
     // ENTRY: enforce the car-count binding (maxConcurrent), then sign + open. Mint a
     // fresh per-occurrence id so a fleet can have several open at once.
     if (sub.maxConcurrent != null && open.length >= sub.maxConcurrent) {
-      const reason = `subscription at capacity (${open.length}/${sub.maxConcurrent} cars in)`;
-      await this.#reject(m, reason);
+      const reason = await this.#reject(m, "sub.refused.atCapacity", {
+        inUse: open.length,
+        max: sub.maxConcurrent,
+      });
       return { accepted: false, direction: "entry", reason };
     }
 
@@ -226,14 +227,22 @@ export class SubscriptionFlow {
     return open;
   }
 
-  async #reject(m: SubscriptionMatch, reason: string): Promise<void> {
+  /** Sign a refused-subscription anomaly with a localizable reason code, and return
+   *  the rendered English reason for the caller's ReadOutcome. */
+  async #reject(
+    m: SubscriptionMatch,
+    code: ReasonCode,
+    params?: Record<string, string | number>,
+  ): Promise<string> {
+    const rp = reasonPayload(code, params);
     await this.#log.append({
       type: "anomaly",
       identity: m.carKey,
       // `permitId`/`permitRefused` are the on-chain field names (immutable).
-      payload: { reason: `subscription refused — ${reason}`, permitId: m.subscriptionId, permitRefused: true },
+      payload: { ...rp, permitId: m.subscriptionId, permitRefused: true },
     });
-    this.#logger.warn(`subscription refused (${m.carKey}): ${reason}`);
+    this.#logger.warn(`subscription refused (${m.carKey}): ${rp.reason}`);
+    return rp.reason;
   }
 
   async #open(resolved: ResolvedRelay, dir: FlowDirection, carKey: string, what: string): Promise<void> {