refactor: separate aircraft and vessel server providers

server/providers/aircraft/adsb-lol.js

@@ -0,0 +1,50 @@
+/**
+ * Vite plugin: adsb.lol military aircraft proxy with 12 s response cache.
+ *
+ * Proxies GET /api/adsblol/mil to https://api.adsb.lol/v2/mil. On upstream
+ * failure, serves a stale cached response if one exists.
+ *
+ * @returns {import('vite').Plugin}
+ */
+export function adsbLolProxy() {
+  /** @type {string|null} Cached upstream JSON body. */
+  let _cache = null;
+  /** @type {number} Epoch-ms when the cache was populated. */
+  let _cacheAt = 0;
+  /** Response cache TTL (ms). */
+  const CACHE_MS = 12000;
+  return {
+    name: 'adsblol-proxy',
+    configureServer(server) {
+      server.middlewares.use('/api/adsblol/mil', async (req, res) => {
+        try {
+          const now = Date.now();
+          if (_cache && now - _cacheAt < CACHE_MS) {
+            res.writeHead(200, { 'Content-Type': 'application/json', 'Cache-Control': 'no-store', 'X-ADS-B-Cache': 'HIT' });
+            res.end(_cache);
+            return;
+          }
+          const upstream = await fetch('https://api.adsb.lol/v2/mil', {
+            headers: { 'User-Agent': 'gods-eye-view-adsblol-proxy/1.0' },
+          });
+          const body = await upstream.text();
+          if (upstream.ok) {
+            _cache = body;
+            _cacheAt = now;
+          }
+          res.writeHead(upstream.status, { 'Content-Type': 'application/json', 'Cache-Control': 'no-store', 'X-ADS-B-Cache': 'MISS' });
+          res.end(body);
+        } catch (e) {
+          console.error('[adsb.lol Proxy]', e.message);
+          if (_cache) {
+            res.writeHead(200, { 'Content-Type': 'application/json', 'X-ADS-B-Cache': 'STALE' });
+            res.end(_cache);
+            return;
+          }
+          res.writeHead(502, { 'Content-Type': 'application/json' });
+          res.end(JSON.stringify({ error: 'ADS-B proxy error' }));
+        }
+      });
+    },
+  };
+}

server/providers/aircraft/enrichment.js

@@ -0,0 +1,123 @@
+import path from 'node:path';
+import { promises as fsp } from 'node:fs';
+/**
+ * adsbdb.com enrichment proxy: callsign → route (airline + origin/destination
+ * airports) and hex → aircraft type/registration. Free community API — cached
+ * aggressively: ONE upstream request per new key ever (404s negative-cached),
+ * persisted to disk so restarts don't re-hammer it. Adapted from skylight
+ * (MIT) server/src/enrich/routes.ts.
+ */
+export function adsbdbProxy() {
+  const TTL_MS = 24 * 3600_000;
+  const CACHE_PATH = path.join(process.cwd(), '.gev-cache', 'adsbdb.json');
+  let cache = { routes: {}, aircraft: {} };
+  let dirty = false;
+  let loaded = false;
+  const inflight = new Map();
+
+  async function loadOnce() {
+    if (loaded) return;
+    loaded = true;
+    try {
+      const parsed = JSON.parse(await fsp.readFile(CACHE_PATH, 'utf8'));
+      cache = { routes: parsed.routes ?? {}, aircraft: parsed.aircraft ?? {} };
+    } catch { /* first run */ }
+    setInterval(async () => {
+      if (!dirty) return;
+      dirty = false;
+      try {
+        await fsp.mkdir(path.dirname(CACHE_PATH), { recursive: true });
+        await fsp.writeFile(CACHE_PATH, JSON.stringify(cache), 'utf8');
+      } catch { dirty = true; } // retry next tick
+    }, 15_000).unref?.();
+  }
+
+  const fresh = (e) => e && Date.now() - e.at < TTL_MS;
+
+  function parseRoute(json) {
+    const fr = json?.response?.flightroute;
+    if (!fr?.origin || !fr?.destination) return null;
+    const airport = (a) => ({
+      code: a.iata_code || a.icao_code || '',
+      name: a.municipality || a.name || '',
+      lat: Number.isFinite(a.latitude) ? a.latitude : null,
+      lon: Number.isFinite(a.longitude) ? a.longitude : null,
+    });
+    return { airline: fr.airline?.name || null, origin: airport(fr.origin), destination: airport(fr.destination) };
+  }
+
+  function parseAircraft(json) {
+    const a = json?.response?.aircraft;
+    if (!a) return null;
+    return {
+      typeCode: a.icao_type || null, // ICAO designator, e.g. "B738" — feeds classifyAircraft
+      typeName: a.manufacturer && a.type ? `${a.manufacturer} ${a.type}` : (a.type || null),
+      registration: a.registration || null,
+    };
+  }
+
+  function lookup(kind, key) {
+    const store = kind === 'route' ? cache.routes : cache.aircraft;
+    if (fresh(store[key])) return Promise.resolve(store[key].data);
+    const ik = `${kind}:${key}`;
+    if (!inflight.has(ik)) {
+      inflight.set(ik, (async () => {
+        try {
+          const url = kind === 'route'
+            ? `https://api.adsbdb.com/v0/callsign/${encodeURIComponent(key)}`
+            : `https://api.adsbdb.com/v0/aircraft/${encodeURIComponent(key)}`;
+          const res = await fetch(url, { signal: AbortSignal.timeout(8000) });
+          if (res.ok) {
+            const data = kind === 'route' ? parseRoute(await res.json()) : parseAircraft(await res.json());
+            store[key] = { at: Date.now(), data }; // data may be null — negative cache
+            dirty = true;
+            return data;
+          }
+          if (res.status === 404) {
+            store[key] = { at: Date.now(), data: null }; // known-missing — cache the miss
+            dirty = true;
+          }
+          // other statuses: leave uncached so we retry later
+          return fresh(store[key]) ? store[key].data : null;
+        } catch {
+          return fresh(store[key]) ? store[key].data : null; // network error → stale if any
+        } finally {
+          inflight.delete(ik);
+        }
+      })());
+    }
+    return inflight.get(ik);
+  }
+
+  return {
+    name: 'adsbdb-proxy',
+    configureServer(server) {
+      server.middlewares.use('/api/adsbdb', async (req, res) => {
+        await loadOnce();
+        const send = (status, obj) => {
+          res.writeHead(status, { 'Content-Type': 'application/json' });
+          res.end(JSON.stringify(obj));
+        };
+        try {
+          const [, kind, rawKey] = String(req.url || '').split('?')[0].split('/');
+          if (kind === 'route') {
+            const cs = String(rawKey || '').toUpperCase();
+            if (!/^[A-Z0-9]{2,8}$/.test(cs)) return send(400, { error: 'invalid callsign' });
+            const data = await lookup('route', cs);
+            return send(200, data ? { found: true, ...data } : { found: false });
+          }
+          if (kind === 'type') {
+            const hex = String(rawKey || '').toLowerCase();
+            if (!/^[0-9a-f]{6}$/.test(hex)) return send(400, { error: 'invalid hex' });
+            const data = await lookup('aircraft', hex);
+            return send(200, data ? { found: true, ...data } : { found: false });
+          }
+          return send(404, { error: 'unknown endpoint' });
+        } catch (err) {
+          console.error('[adsbdb-proxy] request failed');
+          return send(500, { error: 'adsbdb proxy error' });
+        }
+      });
+    },
+  };
+}

server/providers/aircraft/opensky.js

@@ -0,0 +1,596 @@
+import { normalizeAdsbLolPointResponse } from '../../../src/data/adsbLolFallback.js';
+import { coalesceProxyRequest, readResponseJsonCapped } from '../common/http.js';
+import { requiredFiniteQueryNumber } from '../common/query.js';
+// ---------------------------------------------------------------------------
+// OpenSky OAuth2 token + response cache state
+// ---------------------------------------------------------------------------
+/** @type {string|null} Current OAuth2 bearer token. */
+let _openskyToken = null;
+/** @type {number} Epoch-ms when the current token expires. */
+let _openskyTokenExpiry = 0;
+/** @type {Promise<string|null>|null} In-flight token refresh promise (coalesces concurrent callers). */
+let _openskyTokenPromise = null;
+/** @type {string|null} Cached upstream response body (JSON text). */
+let _openskyCacheBody = null;
+/** @type {number} HTTP status of the cached response. */
+let _openskyCacheStatus = 0;
+/** @type {number} Epoch-ms when the response was cached. */
+let _openskyCacheTime = 0;
+/** @type {{requestedMode:string,usedMode:string,reason:string}|null} Auth metadata for the cached response. */
+let _openskyCacheMeta = null;
+/** @type {number|null} Source snapshot epoch from the cached OpenSky body. */
+let _openskyCacheSourceEpochMs = null;
+/** TTL for the OpenSky response cache (ms). */
+const OPENSKY_CACHE_MS = 9000;
+// --- OpenSky credit governor (field-test fix 2026-07-06) -------------------
+// The global /states/all this proxy fetches costs 4 CREDITS per call against
+// OpenSky's ~4000/day authenticated budget — a day with the app open burned
+// the whole quota in ~8h and the layer then hard-died until the daily reset
+// ("rate limited for 48h" owner report; auth itself was fine). Three levers:
+//  1. Adaptive TTL: OpenSky returns X-Rate-Limit-Remaining on success; as the
+//     budget thins, the proxy stretches its cache TTL so a full day of
+//     continuous use never exhausts it.
+//  2. 429 cooldown: honor X-Rate-Limit-Retry-After-Seconds — no upstream
+//     attempts until it passes (bounded 30 s … 30 min).
+//  3. Serve-stale: while rate-limited/cooling, serve the last-good body (200 +
+//     X-OpenSky-Stale) so the layer keeps rendering instead of dying.
+/** @type {number} Current adaptive TTL (ms) — starts at the base cache TTL. */
+let _openskyTtlMs = OPENSKY_CACHE_MS;
+/** @type {number} Epoch-ms before which no upstream fetch is attempted. */
+let _openskyCooldownUntil = 0;
+/**
+ * Picks the cache TTL from the remaining daily credit budget.
+ * Client polls every 30 s, so tiers ≤30 s cost the same 480 credits/h; the
+ * later tiers stretch the day: >2400 → ~3 h of full freshness, then 30 s
+ * (~2.5 h), 90 s (~5 h), 300 s (~8 h) ≈ 18+ h of continuous use per day.
+ * @param {number} remaining - X-Rate-Limit-Remaining header value.
+ * @returns {number} TTL in ms.
+ */
+function openskyAdaptiveTtlMs(remaining) {
+  if (!Number.isFinite(remaining)) return OPENSKY_CACHE_MS;
+  if (remaining > 2400) return OPENSKY_CACHE_MS;
+  if (remaining > 1200) return 30_000;
+  if (remaining > 400) return 90_000;
+  return 300_000;
+}
+/** @type {boolean} Guards duplicate auth-failure warnings in logs. */
+let _openskyAuthWarned = false;
+/** @type {boolean} Guards duplicate invalid-auth-mode warnings. */
+let _openskyAuthModeWarned = false;
+/** Default auth mode when OPENSKY_AUTH_MODE env is unset. */
+const OPENSKY_AUTH_MODE_DEFAULT = 'oauth';
+/** Set of valid OPENSKY_AUTH_MODE values. */
+const OPENSKY_AUTH_MODE_SET = new Set(['basic', 'oauth', 'auto', 'anon']);
+/** Regional civilian fallback cache, keyed by a coarse 0.25° view anchor. */
+const _adsbLolPointCache = new Map();
+/** Per-anchor single-flight map for concurrent regional fallback requests. */
+const _adsbLolPointInFlight = new Map();
+const ADSBLOL_POINT_CACHE_MS = 12000;
+const ADSBLOL_POINT_CACHE_MAX = 80;
+const ADSBLOL_POINT_RADIUS_NM = 250;
+const ADSBLOL_POINT_MAX_RESPONSE_BYTES = 8 * 1024 * 1024;
+// A 200 response can still contain an old OpenSky snapshot. Past this point
+// the viewport-scoped adsb.lol source is more honest and keeps local motion
+// current instead of coasting a stale worldwide frame indefinitely.
+const OPENSKY_SOURCE_STALE_MS = 120_000;
+
+/**
+ * Obtain a valid OpenSky OAuth2 bearer token, refreshing if needed.
+ *
+ * Uses the client_credentials grant against the OpenSky Keycloak realm.
+ * Concurrent callers share a single in-flight refresh promise so only
+ * one token request is issued at a time.
+ *
+ * @returns {Promise<string|null>} Bearer token string, or null if unavailable.
+ */
+export async function getOpenSkyToken() {
+  const now = Date.now();
+  // Return cached token if still valid (with 60 s safety margin)
+  if (_openskyToken && now < _openskyTokenExpiry - 60000) return _openskyToken;
+
+  // Coalesce concurrent refresh requests — if a refresh is already in-flight,
+  // return the same promise instead of issuing a duplicate token request
+  if (_openskyTokenPromise) return _openskyTokenPromise;
+
+  const clientId = process.env.OPENSKY_CLIENT_ID;
+  const clientSecret = process.env.OPENSKY_CLIENT_SECRET;
+  if (!clientId || !clientSecret) return null;
+
+  // Wrap the async token fetch in a shared promise stored in _openskyTokenPromise
+  _openskyTokenPromise = (async () => {
+    try {
+      const res = await fetch(
+        'https://auth.opensky-network.org/auth/realms/opensky-network/protocol/openid-connect/token',
+        {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
+          body: `grant_type=client_credentials&client_id=${encodeURIComponent(clientId)}&client_secret=${encodeURIComponent(clientSecret)}`,
+        }
+      );
+
+      let data = null;
+      try {
+        data = await res.json();
+      } catch {
+        data = null;
+      }
+
+      const accessToken = data?.access_token;
+      const expiresIn = Number(data?.expires_in);
+      if (!res.ok || !accessToken) {
+        if (!_openskyAuthWarned) {
+          const detail = data?.error_description || data?.error || `HTTP ${res.status}`;
+          console.warn('[OpenSky] OAuth client_credentials failed:', detail);
+          _openskyAuthWarned = true;
+        }
+        _openskyToken = null;
+        _openskyTokenExpiry = 0;
+        return null;
+      }
+
+      _openskyToken = accessToken;
+      // Default to 1800 s (30 min) if expires_in is missing or non-finite
+      _openskyTokenExpiry = Date.now() + (Number.isFinite(expiresIn) ? expiresIn : 1800) * 1000;
+      console.log('[OpenSky] OAuth token refreshed, expires in', Number.isFinite(expiresIn) ? expiresIn : 1800, 's');
+      _openskyAuthWarned = false;
+      return _openskyToken;
+    } catch (err) {
+      if (!_openskyAuthWarned) {
+        console.warn('[OpenSky] OAuth token request failed:', err?.message || String(err));
+        _openskyAuthWarned = true;
+      }
+      _openskyToken = null;
+      _openskyTokenExpiry = 0;
+      return null;
+    } finally {
+      // Clear the shared promise so the next caller can start a fresh refresh
+      _openskyTokenPromise = null;
+    }
+  })();
+
+  return _openskyTokenPromise;
+}
+
+/**
+ * Validate and normalize the OPENSKY_AUTH_MODE env value.
+ *
+ * @param {string} value - Raw env value (e.g. 'basic', 'oauth', 'auto', 'anon').
+ * @returns {string} One of the valid mode strings, or the default ('oauth').
+ */
+function normalizeOpenSkyAuthMode(value) {
+  const raw = String(value || '').trim().toLowerCase();
+  if (!raw) return OPENSKY_AUTH_MODE_DEFAULT;
+  if (OPENSKY_AUTH_MODE_SET.has(raw)) return raw;
+  if (!_openskyAuthModeWarned) {
+    console.warn(
+      `[OpenSky] Invalid OPENSKY_AUTH_MODE="${raw}", defaulting to "${OPENSKY_AUTH_MODE_DEFAULT}"`
+    );
+    _openskyAuthModeWarned = true;
+  }
+  return OPENSKY_AUTH_MODE_DEFAULT;
+}
+
+/**
+ * Build standard response headers for OpenSky proxy responses.
+ *
+ * Includes diagnostic X-OpenSky-* headers so the client can inspect
+ * cache hit/miss status and which auth mode was actually used.
+ *
+ * @param {object} opts
+ * @param {string} opts.cacheStatus - 'HIT', 'MISS', or 'STALE'.
+ * @param {string} opts.requestedMode - The auth mode the config requested.
+ * @param {string} opts.usedMode - The auth mode actually used for the upstream call.
+ * @param {string} opts.reason - Human-readable reason string for diagnostics.
+ * @returns {Record<string,string>} Header object.
+ */
+function buildOpenSkyHeaders({ cacheStatus, requestedMode, usedMode, reason, staleSeconds, retryAfterSeconds }) {
+  const headers = {
+    'Content-Type': 'application/json',
+    'Cache-Control': 'no-store',
+    'X-OpenSky-Cache': cacheStatus,
+    'X-OpenSky-Auth': usedMode,
+    'X-OpenSky-Auth-Mode-Requested': requestedMode,
+    'X-OpenSky-Auth-Mode-Used': usedMode,
+    'X-OpenSky-Auth-Reason': reason,
+  };
+  // Credit-governor extras (field-test fix 2026-07-06): the client can show a
+  // STALE cue / countdown without parsing the body.
+  if (Number.isFinite(staleSeconds)) headers['X-OpenSky-Stale-Seconds'] = String(Math.round(staleSeconds));
+  if (Number.isFinite(retryAfterSeconds)) headers['X-OpenSky-Retry-After-Seconds'] = String(Math.round(retryAfterSeconds));
+  return headers;
+}
+
+export function adsbLolFallbackAnchor(req) {
+  const incoming = new URL(req?.url || '', 'http://localhost');
+  const latitude = requiredFiniteQueryNumber(incoming.searchParams, 'lat');
+  const longitude = requiredFiniteQueryNumber(incoming.searchParams, 'lon');
+  if (!Number.isFinite(latitude) || latitude < -90 || latitude > 90) return null;
+  if (!Number.isFinite(longitude) || longitude < -180 || longitude > 180) return null;
+  return { latitude, longitude };
+}
+
+async function fetchAdsbLolPointFallback(req) {
+  const anchor = adsbLolFallbackAnchor(req);
+  if (!anchor) return null;
+  const roundedLat = Math.round(anchor.latitude * 4) / 4;
+  const roundedLon = Math.round(anchor.longitude * 4) / 4;
+  const cacheKey = `${roundedLat.toFixed(2)},${roundedLon.toFixed(2)}`;
+  const cached = _adsbLolPointCache.get(cacheKey);
+  const now = Date.now();
+  if (cached && now - cached.cachedAt < ADSBLOL_POINT_CACHE_MS) {
+    return { ...cached, cacheStatus: 'HIT' };
+  }
+
+  const request = coalesceProxyRequest(_adsbLolPointInFlight, cacheKey, async () => {
+    const controller = new AbortController();
+    const timeoutId = setTimeout(() => controller.abort(), 10000);
+    try {
+      const upstream = await fetch(
+        `https://api.adsb.lol/v2/lat/${roundedLat}/lon/${roundedLon}/dist/${ADSBLOL_POINT_RADIUS_NM}`,
+        {
+          headers: {
+            Accept: 'application/json',
+            'User-Agent': 'gods-eye-view-adsblol-regional-fallback/1.0',
+          },
+          signal: controller.signal,
+        },
+      );
+      if (!upstream.ok) throw new Error(`upstream HTTP ${upstream.status}`);
+      const payload = await readResponseJsonCapped(upstream, ADSBLOL_POINT_MAX_RESPONSE_BYTES);
+      const normalized = normalizeAdsbLolPointResponse(payload);
+      const record = {
+        body: JSON.stringify(normalized),
+        cachedAt: Date.now(),
+        count: normalized.states.length,
+      };
+      _adsbLolPointCache.delete(cacheKey);
+      _adsbLolPointCache.set(cacheKey, record);
+      while (_adsbLolPointCache.size > ADSBLOL_POINT_CACHE_MAX) {
+        _adsbLolPointCache.delete(_adsbLolPointCache.keys().next().value);
+      }
+      return record;
+    } finally {
+      clearTimeout(timeoutId);
+    }
+  });
+  try {
+    const record = await request.promise;
+    return { ...record, cacheStatus: request.shared ? 'INFLIGHT' : 'MISS' };
+  } catch (error) {
+    if (!request.shared && error?.name !== 'AbortError') {
+      console.warn('[adsb.lol Flights Fallback]', error?.message || error);
+    }
+    return cached ? { ...cached, cacheStatus: 'STALE' } : null;
+  }
+}
+
+async function serveAdsbLolPointFallback(req, res, requestedMode, reason) {
+  const fallback = await fetchAdsbLolPointFallback(req);
+  if (!fallback) return false;
+  res.writeHead(200, {
+    ...buildOpenSkyHeaders({
+      cacheStatus: fallback.cacheStatus,
+      requestedMode,
+      usedMode: 'adsblol-regional',
+      reason,
+    }),
+    'X-Flight-Source': 'adsb.lol',
+    'X-Flight-Coverage': `${ADSBLOL_POINT_RADIUS_NM}nm regional fallback`,
+    'X-Flight-Count': String(fallback.count),
+  });
+  res.end(fallback.body);
+  return true;
+}
+
+function openSkySourceEpochMs(body) {
+  try {
+    const seconds = Number(JSON.parse(body)?.time);
+    return Number.isFinite(seconds) && seconds > 0 ? seconds * 1000 : null;
+  } catch {
+    return null;
+  }
+}
+
+function openSkySourceIsStale(sourceEpochMs, now = Date.now()) {
+  return Number.isFinite(sourceEpochMs)
+    && now - sourceEpochMs > OPENSKY_SOURCE_STALE_MS;
+}
+
+/**
+ * Vite plugin: OpenSky Network proxy with multi-mode auth and response caching.
+ *
+ * Supports four auth modes controlled by OPENSKY_AUTH_MODE env:
+ *   - 'oauth'  (default) — client_credentials bearer token
+ *   - 'basic'  — HTTP Basic with OPENSKY_USERNAME / OPENSKY_PASSWORD
+ *   - 'auto'   — try OAuth first, fall back to Basic, then anon
+ *   - 'anon'   — no credentials
+ *
+ * Successful responses are cached for OPENSKY_CACHE_MS (~9 s). On
+ * upstream failure the proxy serves a stale cached response if available, or
+ * a bounded 250 nm adsb.lol point snapshot around the current view anchor.
+ *
+ * @returns {import('vite').Plugin}
+ */
+export function openSkyProxy() {
+  return {
+    name: 'opensky-proxy',
+    configureServer(server) {
+      server.middlewares.use('/api/opensky', async (req, res) => {
+        try {
+          const requestedMode = normalizeOpenSkyAuthMode(process.env.OPENSKY_AUTH_MODE);
+          const now = Date.now();
+          const inCooldown = now < _openskyCooldownUntil;
+          // Fresh-enough cache (adaptive TTL) OR any cache during a 429
+          // cooldown: serve it without touching upstream. Stale-during-cooldown
+          // is deliberate (credit governor): last-good planes beat a dead layer.
+          if (_openskyCacheBody && (now - _openskyCacheTime < _openskyTtlMs || inCooldown)) {
+            if (
+              openSkySourceIsStale(_openskyCacheSourceEpochMs, now)
+              && await serveAdsbLolPointFallback(
+                req,
+                res,
+                requestedMode,
+                'opensky_snapshot_stale_regional_fallback',
+              )
+            ) {
+              return;
+            }
+            const cachedMeta = _openskyCacheMeta || {
+              requestedMode,
+              usedMode: 'unknown',
+              reason: 'cached',
+            };
+            const isStale = now - _openskyCacheTime >= _openskyTtlMs;
+            res.writeHead(
+              _openskyCacheStatus || 200,
+              buildOpenSkyHeaders({
+                cacheStatus: isStale ? 'STALE' : 'HIT',
+                requestedMode: cachedMeta.requestedMode || requestedMode,
+                usedMode: cachedMeta.usedMode || 'unknown',
+                reason: isStale ? 'rate_limited_serving_stale' : (cachedMeta.reason || 'cached'),
+                staleSeconds: isStale ? (now - _openskyCacheTime) / 1000 : undefined,
+                retryAfterSeconds: inCooldown ? (_openskyCooldownUntil - now) / 1000 : undefined,
+              })
+            );
+            res.end(_openskyCacheBody);
+            return;
+          }
+          // Cooling down with nothing cached (cold start into a rate limit):
+          // synthesize the 429 locally — hammering upstream mid-cooldown can't
+          // succeed and just burns goodwill.
+          if (inCooldown) {
+            if (await serveAdsbLolPointFallback(req, res, requestedMode, 'opensky_cooldown_regional_fallback')) return;
+            res.writeHead(429, buildOpenSkyHeaders({
+              cacheStatus: 'COOLDOWN',
+              requestedMode,
+              usedMode: 'none',
+              reason: 'rate_limited',
+              retryAfterSeconds: (_openskyCooldownUntil - now) / 1000,
+            }));
+            res.end(JSON.stringify({ error: 'OpenSky rate limited; proxy cooling down.' }));
+            return;
+          }
+
+          const basicUser = process.env.OPENSKY_USERNAME || '';
+          const basicPass = process.env.OPENSKY_PASSWORD || '';
+          const hasBasicCreds = Boolean(basicUser && basicPass);
+          const headers = { 'Accept': 'application/json' };
+          let usedMode = 'anon';
+          let reason = 'forced_anonymous';
+
+          if (requestedMode === 'basic') {
+            if (hasBasicCreds) {
+              headers.Authorization = `Basic ${Buffer.from(`${basicUser}:${basicPass}`).toString('base64')}`;
+              usedMode = 'basic';
+              reason = 'basic_credentials';
+            } else {
+              reason = 'missing_basic_creds';
+            }
+          } else if (requestedMode === 'oauth') {
+            const token = await getOpenSkyToken();
+            if (token) {
+              headers.Authorization = `Bearer ${token}`;
+              usedMode = 'oauth';
+              reason = 'oauth_token';
+            } else {
+              reason = 'oauth_invalid_or_missing';
+            }
+          } else if (requestedMode === 'auto') {
+            const token = await getOpenSkyToken();
+            if (token) {
+              headers.Authorization = `Bearer ${token}`;
+              usedMode = 'oauth';
+              reason = 'oauth_token';
+            } else if (hasBasicCreds) {
+              headers.Authorization = `Basic ${Buffer.from(`${basicUser}:${basicPass}`).toString('base64')}`;
+              usedMode = 'basic';
+              reason = 'oauth_unavailable_fallback_basic';
+            } else {
+              reason = 'missing_oauth_and_basic_creds';
+            }
+          }
+
+          let upstream = await fetch('https://opensky-network.org/api/states/all?extended=1', { headers });
+          // Auto-mode fallback: if OAuth was rejected, retry with Basic credentials
+          if (
+            (upstream.status === 401 || upstream.status === 403) &&
+            requestedMode === 'auto' &&
+            usedMode === 'oauth' &&
+            hasBasicCreds
+          ) {
+            const retryHeaders = {
+              Accept: 'application/json',
+              Authorization: `Basic ${Buffer.from(`${basicUser}:${basicPass}`).toString('base64')}`,
+            };
+            upstream = await fetch('https://opensky-network.org/api/states/all?extended=1', { headers: retryHeaders });
+            usedMode = 'basic';
+            reason = 'oauth_rejected_fallback_basic';
+          }
+
+          let body = await upstream.text();
+          const sourceEpochMs = upstream.ok ? openSkySourceEpochMs(body) : null;
+          if (
+            upstream.ok
+            && openSkySourceIsStale(sourceEpochMs, now)
+            && await serveAdsbLolPointFallback(
+              req,
+              res,
+              requestedMode,
+              'opensky_snapshot_stale_regional_fallback',
+            )
+          ) {
+            // Keep the last global snapshot available as a fail-soft cache,
+            // but do not label or render it as a fresh live result.
+            _openskyCacheBody = body;
+            _openskyCacheStatus = upstream.status;
+            _openskyCacheTime = now;
+            _openskyCacheSourceEpochMs = sourceEpochMs;
+            _openskyCacheMeta = { requestedMode, usedMode, reason };
+            return;
+          }
+          if (upstream.status === 429) {
+            reason = 'rate_limited';
+            // Credit governor: honor OpenSky's retry-after (bounded 30 s … 30 min;
+            // 2 min when the header is absent) — no upstream attempts until then.
+            const retryAfterSec = Number(upstream.headers.get('x-rate-limit-retry-after-seconds'));
+            const cooldownMs = Math.min(
+              Math.max(Number.isFinite(retryAfterSec) ? retryAfterSec * 1000 : 120_000, 30_000),
+              30 * 60_000
+            );
+            _openskyCooldownUntil = now + cooldownMs;
+            // Serve the last-good body instead of the 429 when we have one —
+            // the layer keeps rendering (STALE-cued) instead of dying.
+            if (_openskyCacheBody && _openskyCacheStatus === 200) {
+              res.writeHead(200, buildOpenSkyHeaders({
+                cacheStatus: 'STALE',
+                requestedMode,
+                usedMode,
+                reason: 'rate_limited_serving_stale',
+                staleSeconds: (now - _openskyCacheTime) / 1000,
+                retryAfterSeconds: cooldownMs / 1000,
+              }));
+              res.end(_openskyCacheBody);
+              return;
+            }
+          }
+
+          if (!upstream.ok && !_openskyCacheBody) {
+            const servedFallback = await serveAdsbLolPointFallback(
+              req,
+              res,
+              requestedMode,
+              `opensky_http_${upstream.status}_regional_fallback`,
+            );
+            if (servedFallback) return;
+          }
+
+          if (upstream.status === 401 || upstream.status === 403) {
+            if (requestedMode === 'basic' && !hasBasicCreds) {
+              body = JSON.stringify({
+                error: 'OpenSky auth missing. Basic mode requires OPENSKY_USERNAME and OPENSKY_PASSWORD.',
+              });
+              reason = 'missing_basic_creds';
+            } else if (requestedMode === 'oauth' && usedMode !== 'oauth') {
+              body = JSON.stringify({
+                error: 'OpenSky auth invalid. OAuth mode requires valid OPENSKY_CLIENT_ID and OPENSKY_CLIENT_SECRET.',
+              });
+              reason = 'oauth_invalid_or_missing';
+            } else if (usedMode === 'basic') {
+              body = JSON.stringify({
+                error: 'OpenSky auth invalid. Username/password were rejected.',
+              });
+              reason = 'basic_invalid_credentials';
+            } else if (usedMode === 'oauth') {
+              body = JSON.stringify({
+                error: 'OpenSky auth invalid. OAuth client credentials were rejected.',
+              });
+              reason = 'oauth_invalid_credentials';
+            } else if (requestedMode === 'auto' && !hasBasicCreds) {
+              body = JSON.stringify({
+                error: 'OpenSky auth missing. Provide basic credentials or valid OAuth client credentials.',
+              });
+              reason = 'missing_oauth_and_basic_creds';
+            } else {
+              body = JSON.stringify({
+                error: 'OpenSky auth required.',
+              });
+              reason = 'auth_required';
+            }
+          }
+
+          // Refine the reason string to reflect the actual outcome
+          if (upstream.ok && reason === 'forced_anonymous') {
+            reason = 'anonymous_ok';
+          } else if (upstream.ok && usedMode === 'basic' && reason === 'basic_credentials') {
+            reason = 'basic_ok';
+          } else if (upstream.ok && usedMode === 'oauth' && reason === 'oauth_token') {
+            reason = 'oauth_ok';
+          }
+
+          // Only cache successful responses — error responses (401/403/429/5xx)
+          // should not be served from cache on subsequent requests
+          if (upstream.ok) {
+            _openskyCacheBody = body;
+            _openskyCacheStatus = upstream.status;
+            _openskyCacheTime = now;
+            _openskyCacheSourceEpochMs = sourceEpochMs;
+            _openskyCacheMeta = {
+              requestedMode,
+              usedMode,
+              reason,
+            };
+            // Credit governor: adapt the cache TTL to the remaining daily
+            // budget so a continuously-open app stretches its polls instead of
+            // exhausting the quota mid-day. Success also clears any cooldown.
+            const remaining = Number(upstream.headers.get('x-rate-limit-remaining'));
+            _openskyTtlMs = openskyAdaptiveTtlMs(remaining);
+            _openskyCooldownUntil = 0;
+          }
+
+          res.writeHead(
+            upstream.status,
+            buildOpenSkyHeaders({
+              cacheStatus: 'MISS',
+              requestedMode,
+              usedMode,
+              reason,
+            })
+          );
+          res.end(body);
+        } catch (e) {
+          console.error('[OpenSky Proxy]', e.message);
+          if (_openskyCacheBody) {
+            const cachedMeta = _openskyCacheMeta || {
+              requestedMode: normalizeOpenSkyAuthMode(process.env.OPENSKY_AUTH_MODE),
+              usedMode: 'unknown',
+              reason: 'cached_stale',
+            };
+            res.writeHead(
+              _openskyCacheStatus || 200,
+              buildOpenSkyHeaders({
+                cacheStatus: 'STALE',
+                requestedMode: cachedMeta.requestedMode || OPENSKY_AUTH_MODE_DEFAULT,
+                usedMode: cachedMeta.usedMode || 'unknown',
+                reason: cachedMeta.reason || 'cached_stale',
+              })
+            );
+            res.end(_openskyCacheBody);
+            return;
+          }
+          const requestedMode = normalizeOpenSkyAuthMode(process.env.OPENSKY_AUTH_MODE);
+          if (await serveAdsbLolPointFallback(req, res, requestedMode, 'opensky_proxy_error_regional_fallback')) return;
+          res.writeHead(
+            502,
+            buildOpenSkyHeaders({
+              cacheStatus: 'MISS',
+              requestedMode,
+              usedMode: 'error',
+              reason: 'proxy_error',
+            })
+          );
+          res.end(JSON.stringify({ error: 'OpenSky proxy error' }));
+        }
+      });
+    },
+  };
+}

server/providers/aircraft/tracks.js

@@ -0,0 +1,114 @@
+import { getOpenSkyToken } from './opensky.js';
+import { readCappedResponseText } from '../common/http.js';
+/**
+ * Vite plugin: aircraft track-history backfill proxies (PRD WS-F F1/F2).
+ *
+ * /api/opensky-track?icao24=<hex6> — OpenSky GET /tracks/all (experimental;
+ *   own credit bucket, 4 credits per call on the free tier). OAuth via the
+ *   shared coalesced token. 60s per-icao cache; 404/429 forwarded so the
+ *   client can fall back to its accumulated trail silently.
+ * /api/adsblol/trace?hex=<hex> — adsb.lol tar1090 readsb trace
+ *   (undocumented but live; no browser CORS, hence this proxy). Up to ~24h
+ *   of real history per aircraft. Treat as best-effort; data is ODbL —
+ *   credit "adsb.lol (ODbL)" in the UI.
+ */
+export function trackBackfillProxies() {
+  const TRACK_CACHE_MS = 60000;
+  const TRACK_CACHE_MAX = 200;
+  const RESPONSE_CAP_BYTES = 5 * 1024 * 1024;
+  /** @type {Map<string, {at:number,status:number,body:string}>} */
+  const cache = new Map();
+
+  function cachePut(key, entry) {
+    cache.set(key, entry);
+    if (cache.size > TRACK_CACHE_MAX) {
+      const oldest = [...cache.entries()].sort((a, b) => a[1].at - b[1].at)[0];
+      if (oldest) cache.delete(oldest[0]);
+    }
+  }
+
+  async function proxyJson(res, key, upstreamUrl, headers = {}) {
+    const cached = cache.get(key);
+    if (cached && Date.now() - cached.at < TRACK_CACHE_MS) {
+      res.statusCode = cached.status;
+      res.setHeader('Content-Type', 'application/json; charset=utf-8');
+      res.setHeader('Cache-Control', 'no-store');
+      res.end(cached.body);
+      return;
+    }
+    const upstream = await fetch(upstreamUrl, { headers, signal: AbortSignal.timeout(12000) });
+    const { tooLarge, text } = await readCappedResponseText(upstream, RESPONSE_CAP_BYTES);
+    let body;
+    if (tooLarge) {
+      body = JSON.stringify({ error: 'Upstream track response too large' });
+    } else if (!upstream.ok) {
+      // Sanitize upstream error surface; status code is signal enough
+      body = JSON.stringify({ error: `Track source HTTP ${upstream.status}` });
+    } else {
+      body = text;
+    }
+    cachePut(key, { at: Date.now(), status: upstream.status, body });
+    res.statusCode = upstream.status;
+    res.setHeader('Content-Type', 'application/json; charset=utf-8');
+    res.setHeader('Cache-Control', 'no-store');
+    res.end(body);
+  }
+
+  function install(middlewares) {
+    middlewares.use('/api/opensky-track', async (req, res) => {
+      try {
+        const incoming = new URL(req.url || '', 'http://localhost');
+        const icao24 = String(incoming.searchParams.get('icao24') || '').trim().toLowerCase();
+        if (!/^[0-9a-f]{6}$/.test(icao24)) {
+          res.statusCode = 400;
+          res.setHeader('Content-Type', 'application/json');
+          res.end(JSON.stringify({ error: 'icao24 must be a 6-char hex string' }));
+          return;
+        }
+        const token = await getOpenSkyToken();
+        await proxyJson(
+          res,
+          `osky:${icao24}`,
+          `https://opensky-network.org/api/tracks/all?icao24=${icao24}&time=0`,
+          token ? { Authorization: `Bearer ${token}` } : {}
+        );
+      } catch (error) {
+        res.statusCode = 502;
+        res.setHeader('Content-Type', 'application/json');
+        res.end(JSON.stringify({ error: 'OpenSky track fetch failed' }));
+      }
+    });
+
+    middlewares.use('/api/adsblol/trace', async (req, res) => {
+      try {
+        const incoming = new URL(req.url || '', 'http://localhost');
+        const hex = String(incoming.searchParams.get('hex') || '').trim().toLowerCase();
+        if (!/^[0-9a-f~]{6,7}$/.test(hex)) {
+          res.statusCode = 400;
+          res.setHeader('Content-Type', 'application/json');
+          res.end(JSON.stringify({ error: 'hex must be a 6-7 char hex string' }));
+          return;
+        }
+        await proxyJson(
+          res,
+          `lol:${hex}`,
+          `https://adsb.lol/data/traces/${hex.slice(-2)}/trace_full_${hex}.json`
+        );
+      } catch (error) {
+        res.statusCode = 502;
+        res.setHeader('Content-Type', 'application/json');
+        res.end(JSON.stringify({ error: 'adsb.lol trace fetch failed' }));
+      }
+    });
+  }
+
+  return {
+    name: 'track-backfill-proxies',
+    configureServer(server) {
+      install(server.middlewares);
+    },
+    configurePreviewServer(server) {
+      install(server.middlewares);
+    },
+  };
+}