wing-ops/backend/src/vessels/vesselService.ts

import type { VesselPosition, BoundingBox } from './vesselTypes.js';

const VESSEL_TTL_MS = 10 * 60 * 1000; // 10분

const cachedVessels = new Map<string, VesselPosition>();
let lastUpdated: Date | null = null;

// lastUpdate가 TTL을 초과한 선박을 캐시에서 제거.
// lastUpdate 파싱이 불가능한 경우 보수적으로 유지한다.
function evictStale(): void {
  const now = Date.now();
  for (const [mmsi, vessel] of cachedVessels) {
    const ts = Date.parse(vessel.lastUpdate);
    if (Number.isNaN(ts)) continue;
    if (now - ts > VESSEL_TTL_MS) {
      cachedVessels.delete(mmsi);
    }
  }
}

export function updateVesselCache(vessels: VesselPosition[]): void {
  for (const vessel of vessels) {
    if (!vessel.mmsi) continue;
    cachedVessels.set(vessel.mmsi, vessel);
  }
  evictStale();
  lastUpdated = new Date();
}

export function getVesselsInBounds(bounds: BoundingBox): VesselPosition[] {
  const result: VesselPosition[] = [];
  for (const v of cachedVessels.values()) {
    if (
      v.lon >= bounds.minLon &&
      v.lon <= bounds.maxLon &&
      v.lat >= bounds.minLat &&
      v.lat <= bounds.maxLat
    ) {
      result.push(v);
    }
  }
  return result;
}

export function getCacheStatus(): {
  count: number;
  bangjeCount: number;
  lastUpdated: Date | null;
} {
  let bangjeCount = 0;
  for (const v of cachedVessels.values()) {
    if (v.shipNm && v.shipNm.toUpperCase().includes('BANGJE')) bangjeCount++;
  }
  return { count: cachedVessels.size, bangjeCount, lastUpdated };
}