make kestrel a tak server, so that it can send and receive pois as cots data

server/utils/cotStore.js

@@ -0,0 +1,71 @@
+/**
+ * In-memory CoT entity store: upsert by id, prune on read by TTL.
+ * Single source of truth; getActiveEntities returns new objects (no mutation of returned refs).
+ */
+
+import { acquire } from './asyncLock.js'
+import { COT_ENTITY_TTL_MS } from './constants.js'
+
+const entities = new Map()
+
+/**
+ * Upsert entity by id. Input is not mutated; stored value is a new object.
+ * @param {{ id: string, lat: number, lng: number, label?: string, eventType?: string, type?: string }} parsed
+ */
+export async function updateFromCot(parsed) {
+  if (!parsed || typeof parsed.id !== 'string') return
+  const lat = Number(parsed.lat)
+  const lng = Number(parsed.lng)
+  if (!Number.isFinite(lat) || !Number.isFinite(lng)) return
+
+  await acquire(`cot-${parsed.id}`, async () => {
+    const now = Date.now()
+    const existing = entities.get(parsed.id)
+    const label = typeof parsed.label === 'string' ? parsed.label : (existing?.label ?? parsed.id)
+    const type = typeof parsed.eventType === 'string' ? parsed.eventType : (typeof parsed.type === 'string' ? parsed.type : (existing?.type ?? ''))
+
+    entities.set(parsed.id, {
+      id: parsed.id,
+      lat,
+      lng,
+      label,
+      type,
+      updatedAt: now,
+    })
+  })
+}
+
+/**
+ * Active entities (updated within ttlMs). Prunes expired. Returns new array of new objects.
+ * @param {number} [ttlMs]
+ * @returns {Promise<Array<{ id: string, lat: number, lng: number, label: string, type: string, updatedAt: number }>>} Snapshot of active entities.
+ */
+export async function getActiveEntities(ttlMs = COT_ENTITY_TTL_MS) {
+  return acquire('cot-prune', async () => {
+    const now = Date.now()
+    const active = []
+    const expired = []
+    for (const entity of entities.values()) {
+      if (now - entity.updatedAt <= ttlMs) {
+        active.push({
+          id: entity.id,
+          lat: entity.lat,
+          lng: entity.lng,
+          label: entity.label ?? entity.id,
+          type: entity.type ?? '',
+          updatedAt: entity.updatedAt,
+        })
+      }
+      else {
+        expired.push(entity.id)
+      }
+    }
+    for (const id of expired) entities.delete(id)
+    return active
+  })
+}
+
+/** Clear store (tests only). */
+export function clearCotStore() {
+  entities.clear()
+}