Update exhibit

server/sync-server.js

@@ -2,7 +2,7 @@ import 'dotenv/config';
 import express from 'express';
 import { createServer } from 'http';
 import { WebSocketServer } from 'ws';
-import { readFileSync } from 'fs';
+import { readFileSync, writeFileSync, copyFileSync, existsSync, mkdirSync } from 'fs';
 import { fileURLToPath } from 'url';
 import { dirname, join } from 'path';
 
@@ -19,6 +19,20 @@ function loadScene() {
 }
 let scene = loadScene();
 
+// ---- Ghost roster (for the admin picker) ---------------------------------
+// Full enriched roster lives in data/ghosts.json. We serve a trimmed view with
+// just what the scene editor needs to pick a ghost and auto-fill its colour.
+let roster = [];
+try {
+  const rraw = readFileSync(join(ROOT, 'data', 'ghosts.json'), 'utf-8');
+  roster = JSON.parse(rraw).map((g) => ({
+    id: g.id, name: g.name, color: g.color, rarity: g.rarity,
+    rarityTier: g.rarityTier, isBoss: !!g.isBoss, ability: g.abilityId,
+  }));
+} catch (_) {
+  roster = []; // roster optional; editor falls back to free-text id
+}
+
 // ---- Motion solvers ------------------------------------------------------
 // Every solver takes (spawn, tSeconds) and returns { x,y,z, yawDeg }.
 // Positions are in world millimetres, matching scene.json.
@@ -95,22 +109,60 @@ function round(n) {
 
 // ---- HTTP + static -------------------------------------------------------
 const app = express();
+app.use(express.json({ limit: '4mb' })); // for the admin save endpoint
 app.use(express.static(join(ROOT, 'public')));
 
-// Scene metadata (anchors + spawn definitions) for clients to align/render.
+// Full scene for the admin editor (everything) and clients (anchors+spawns).
 app.get('/api/scene', (_req, res) => {
-  res.json({
-    world: scene.world,
-    anchors: scene.anchors,
-    spawns: scene.spawns.map((s) => ({
-      id: s.id,
-      ghostId: s.ghostId,
-      label: s.label,
-      motion: s.motion,
-    })),
-  });
+  res.json(scene);
 });
 
+// Ghost roster for the admin picker (trimmed).
+app.get('/api/ghosts', (_req, res) => {
+  res.json(roster);
+});
+
+// Admin save: validate, back up the old file, write, hot-reload.
+app.post('/api/scene', (req, res) => {
+  const incoming = req.body;
+  const err = validateScene(incoming);
+  if (err) return res.status(400).json({ ok: false, error: err });
+  try {
+    const dataDir = join(ROOT, 'data');
+    const target = join(dataDir, 'scene.json');
+    // timestamped backup so a bad save is always recoverable
+    const backupDir = join(dataDir, 'backups');
+    if (!existsSync(backupDir)) mkdirSync(backupDir, { recursive: true });
+    if (existsSync(target)) {
+      const stamp = new Date().toISOString().replace(/[:.]/g, '-');
+      copyFileSync(target, join(backupDir, `scene-${stamp}.json`));
+    }
+    writeFileSync(target, JSON.stringify(incoming, null, 2), 'utf-8');
+    scene = incoming;            // hot-reload: live ghosts update immediately
+    broadcastHello();            // push new anchors/world to connected viewers
+    res.json({ ok: true, spawns: scene.spawns.length, anchors: scene.anchors.length, blockers: (scene.blockers || []).length });
+  } catch (e) {
+    res.status(500).json({ ok: false, error: String(e.message || e) });
+  }
+});
+
+// Minimal schema guard so a malformed save can't crash the motion loop.
+function validateScene(s) {
+  if (!s || typeof s !== 'object') return 'scene must be an object';
+  if (!s.world || !s.world.buildSize) return 'missing world.buildSize';
+  if (!Array.isArray(s.anchors)) return 'anchors must be an array';
+  if (!Array.isArray(s.spawns)) return 'spawns must be an array';
+  if (s.blockers && !Array.isArray(s.blockers)) return 'blockers must be an array';
+  for (const sp of s.spawns) {
+    if (!sp.id || !sp.motion) return `spawn missing id/motion: ${JSON.stringify(sp).slice(0, 80)}`;
+    if (sp.motion === 'patrol' && (!Array.isArray(sp.path) || sp.path.length < 2)) {
+      return `patrol spawn "${sp.id}" needs a path of >=2 points`;
+    }
+    if (sp.motion === 'hover' && !sp.position) return `hover spawn "${sp.id}" needs a position`;
+  }
+  return null;
+}
+
 app.get('/api/health', (_req, res) => {
   res.json({ ok: true, viewers: wss ? wss.clients.size : 0, tickHz: TICK_HZ });
 });
@@ -120,9 +172,25 @@ const httpServer = createServer(app);
 // ---- WebSocket broadcast -------------------------------------------------
 const wss = new WebSocketServer({ server: httpServer, path: '/sync' });
 
+function helloPayload() {
+  return JSON.stringify({
+    type: 'hello',
+    world: scene.world,
+    anchors: scene.anchors,
+    blockers: scene.blockers || [],
+  });
+}
+
+function broadcastHello() {
+  const payload = helloPayload();
+  for (const client of wss.clients) {
+    if (client.readyState === 1) client.send(payload);
+  }
+}
+
 wss.on('connection', (socket) => {
   // Send scene + immediate snapshot on connect so a new phone is instantly aligned.
-  socket.send(JSON.stringify({ type: 'hello', world: scene.world, anchors: scene.anchors }));
+  socket.send(helloPayload());
   socket.send(JSON.stringify(buildSnapshot()));
 });