refactor(app): share application components and request services

src/app/scene.js

@@ -0,0 +1,113 @@
+import * as Cesium from 'cesium';
+import { createApplicationViewer } from '../app/viewer.js';
+import { registerDataCredits } from '../data/dataCredits.js';
+import { configureCreditKeyboardAccess } from '../creditKeyboard.js';
+import { MapStackController } from '../mapStackController.js';
+import { loadPhotorealisticTileset } from '../mapStartup.js';
+import { initLogoGaze } from '../logoGaze.js';
+import {
+  uninstallRenderGovernor,
+  governorRequestRender,
+} from '../renderGovernor.js';
+import { describeError } from './errors.js';
+
+/** Construct the application globe using the caller's local configuration. */
+export async function createApplicationScene({
+  googleApiKey,
+  cesiumToken,
+  credits,
+  MapController = MapStackController,
+  mapOptions = {},
+  loaderStatus,
+  signal,
+  defer,
+}) {
+  defer(initLogoGaze());
+  const previousKey = window.__GOOGLE_MAPS_API_KEY__;
+  if (googleApiKey) {
+    window.__GOOGLE_MAPS_API_KEY__ = googleApiKey;
+    defer(() => {
+      if (window.__GOOGLE_MAPS_API_KEY__ !== googleApiKey) return;
+      if (previousKey === undefined) delete window.__GOOGLE_MAPS_API_KEY__;
+      else window.__GOOGLE_MAPS_API_KEY__ = previousKey;
+    });
+  }
+  loaderStatus.textContent = 'Configuring viewer...';
+  // Provider attribution stays visible, including clean-view and recording.
+  const creditContainer = document.createElement('div');
+  creditContainer.id = 'cesium-credits';
+  document.body.appendChild(creditContainer);
+  defer(() => creditContainer.remove());
+  const viewer = createApplicationViewer({
+    container: 'cesiumContainer',
+    creditContainer,
+  });
+  defer(() => {
+    uninstallRenderGovernor(viewer);
+    if (!viewer.isDestroyed()) viewer.destroy();
+  });
+  registerDataCredits(viewer, credits);
+  configureCreditKeyboardAccess(document);
+  loaderStatus.textContent =
+    googleApiKey || cesiumToken
+      ? 'Loading Google 3D Tiles...'
+      : 'Loading the keyless globe...';
+  const photoreal = await loadPhotorealisticTileset(Cesium, {
+    googleApiKey,
+    cesiumToken,
+  });
+  const tileset = photoreal.tileset;
+  // A provider can finish after cancellation; retain ownership of its result.
+  defer(() => {
+    if (tileset && !tileset.isDestroyed()) {
+      if (!viewer.scene.primitives.remove(tileset)) tileset.destroy();
+    }
+  });
+  signal.throwIfAborted();
+  if (tileset) {
+    viewer.scene.primitives.add(tileset);
+    // NOTE: Cesium World Terrain intentionally disabled — conflicts with Google 3D Tiles at high zoom.
+    // Google Photorealistic 3D Tiles provide their own terrain/elevation.
+    viewer.scene.globe.show = false;
+    console.info(`[Init] Google 3D Tiles loaded via ${photoreal.route}.`);
+  } else {
+    if (photoreal.errors.length) {
+      const tileError = photoreal.errors.at(-1);
+      console.warn(
+        '[Init] Google 3D Tiles unavailable, using the keyless globe:',
+        tileError,
+      );
+      const tileErrorDetail = describeError(tileError);
+      loaderStatus.textContent = `Google 3D Tiles unavailable (${tileErrorDetail}). Loading the keyless globe...`;
+    }
+    viewer.scene.globe.show = true;
+  }
+
+  loaderStatus.textContent = 'Initializing systems...';
+
+  const mapStackController = new MapController(viewer, {
+    requestRender: governorRequestRender,
+    ...mapOptions,
+    googleTileset: tileset,
+    cesiumToken,
+    initialStack: tileset ? 'photoreal' : 'esri-imagery',
+    // Task 5 (height-datum fix): rebroadcast stack changes as a window
+    // CustomEvent so data layers (CCTV per-regime ground resolution) can
+    // react without coupling MapStackController to layer modules. Fires on
+    // 'switching'/'ready'/'error'; listeners derive the surface regime from
+    // live scene state, so intermediate emissions are harmless.
+    onChange: (state) => {
+      window.dispatchEvent(
+        new CustomEvent('gev:map-stack-changed', { detail: state }),
+      );
+    },
+    onError: (message) => console.warn('[MapStack]', message),
+  });
+  defer(() => mapStackController.destroy());
+  await mapStackController.setStack(tileset ? 'photoreal' : 'esri-imagery', {
+    silent: true,
+  });
+
+  signal.throwIfAborted();
+  return { viewer, tileset, mapStackController };
+}