feat: show recognized plate in live feed + active sessions

Surface the advisory ANPR plate (device_events kind="read", keyed by session identity — unsigned, prunable, never an access decision) next to entry/exit events in the live feed and on active-session rows. Resolved at serialize time (new plate-lookup.ts; prefers an entry read; one device_events scan per page) like subscriber-name enrichment — the signed ledger is untouched. Adds plate? to the shared LedgerEvent and to ActiveSession/SessionLookup; a small amber badge in the UI. Caveat: a vehicle_entry is signed + pushed over WS before the async ANPR read lands, so a fresh feed row may show no plate until reload; always present on active sessions. Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
2026-06-20 15:45:57 +02:00
parent b0c9ba0f8c
commit cdb55a8652
10 changed files with 171 additions and 11 deletions
@@ -0,0 +1,85 @@
+import { and, desc, deviceEvents, eq, type Db } from "@parking/db";
+
+// READ-TIME plate resolution. A recognized licence plate is ADVISORY evidence — it
+// lives in the unsigned, prunable `device_events` (kind="read") stream written by the
+// ANPR-on-snapshot path (snapshot.ts → recognizePlate), keyed to the session `identity`.
+// It is deliberately NOT on the signed ledger (a fuzzy camera read must never become a
+// signed fact). To SHOW it next to a feed event or an active session we resolve it here,
+// at serialize time, the same way subscriber names are resolved (see event-enrich.ts).
+//
+// Preference: an ENTRY read over an exit read (the plate as it arrived identifies the
+// session); within a direction, the newest read wins. Returns the plate text only —
+// confidence/region detail stays on the snapshot review panel, not the at-a-glance feed.
+
+/** The best advisory plate observed for a session, for display. */
+export interface PlateView {
+  readonly plate: string;
+  readonly confidence: number | null;
+  readonly direction: "entry" | "exit" | null;
+}
+
+interface ReadDetail {
+  identity?: string;
+  plate?: string;
+  confidence?: number;
+  direction?: string;
+}
+
+/** Best plate for one identity, or null. Prefers an entry read, then the newest read. */
+export function plateForIdentity(db: Db, identity: string): PlateView | null {
+  const rows = db
+    .select({ detail: deviceEvents.detail })
+    .from(deviceEvents)
+    .where(and(eq(deviceEvents.category, "camera"), eq(deviceEvents.kind, "read")))
+    .orderBy(desc(deviceEvents.occurredAt))
+    .all();
+  return pickBest(rows.map((r) => (r.detail ?? {}) as ReadDetail), identity);
+}
+
+/** Resolve plates for MANY identities in one device_events scan (used by the active-
+ *  sessions list and the feed page, which each carry tens–hundreds of rows). */
+export function platesForIdentities(db: Db, identities: Iterable<string>): Map<string, PlateView> {
+  const want = new Set(identities);
+  const out = new Map<string, PlateView>();
+  if (want.size === 0) return out;
+  // Newest first so the first acceptable read per (identity,direction) is the freshest.
+  const rows = db
+    .select({ detail: deviceEvents.detail })
+    .from(deviceEvents)
+    .where(and(eq(deviceEvents.category, "camera"), eq(deviceEvents.kind, "read")))
+    .orderBy(desc(deviceEvents.occurredAt))
+    .all();
+  const byId = new Map<string, ReadDetail[]>();
+  for (const r of rows) {
+    const d = (r.detail ?? {}) as ReadDetail;
+    if (!d.identity || !d.plate || !want.has(d.identity)) continue;
+    let list = byId.get(d.identity);
+    if (!list) byId.set(d.identity, (list = []));
+    list.push(d);
+  }
+  for (const [id, reads] of byId) {
+    const best = pickBest(reads, id);
+    if (best) out.set(id, best);
+  }
+  return out;
+}
+
+/** Pick the best read for `identity` from a NEWEST-FIRST list: an entry read beats an
+ *  exit read; otherwise the first (newest) acceptable read wins. */
+function pickBest(reads: ReadDetail[], identity: string): PlateView | null {
+  let fallback: ReadDetail | null = null;
+  for (const d of reads) {
+    if (d.identity !== identity || !d.plate) continue;
+    if (d.direction === "entry") return toView(d);
+    if (!fallback) fallback = d;
+  }
+  return fallback ? toView(fallback) : null;
+}
+
+function toView(d: ReadDetail): PlateView {
+  return {
+    plate: d.plate!.trim().toUpperCase(),
+    confidence: typeof d.confidence === "number" ? d.confidence : null,
+    direction: d.direction === "entry" || d.direction === "exit" ? d.direction : null,
+  };
+}