refactor(maps): separate source factories and scene coordination

src/maps/defaultSources.js

@@ -0,0 +1,74 @@
+import { MAP_STACKS } from './catalog.js';
+import { photorealUnavailableReason } from './availability.js';
+import { keySetupRequirement } from '../keySetupCore.mjs';
+import {
+  createOsmImagery,
+  createEsriImagery,
+  createIonImagery,
+  ESRI_ATTRIBUTION_HTML,
+} from './imagery.js';
+import { createWorldTerrain, createKeylessTerrain } from './terrain.js';
+
+/** Select sources and setup guidance without putting provider branches in the controller. */
+export function createDefaultMapSources({
+  googleTileset = null,
+  cesiumToken = '',
+  googleApiKey = '',
+} = {}) {
+  const ionToken = String(cesiumToken || '').trim();
+  const hasIon = Boolean(ionToken);
+  const hasGoogle = Boolean(String(googleApiKey || '').trim());
+  const terrain = {
+    id: hasIon ? 'world' : 'keyless',
+    create: hasIon
+      ? (request) => createWorldTerrain(ionToken, request)
+      : createKeylessTerrain,
+  };
+  return {
+    defaultId: googleTileset ? 'photoreal' : 'esri-imagery',
+    unknownId: 'photoreal',
+    recoveryId: googleTileset ? 'photoreal' : null,
+    state: { hasCesiumIonToken: hasIon },
+    sources: MAP_STACKS.map((descriptor) => {
+      const common = {
+        descriptor,
+        available: !descriptor.requiresIon || hasIon,
+        unavailableReason: descriptor.requiresIon
+          ? keySetupRequirement('cesium-ion')
+          : null,
+      };
+      if (descriptor.kind === 'photoreal')
+        return {
+          ...common,
+          available: Boolean(googleTileset),
+          unavailableReason: photorealUnavailableReason(hasIon || hasGoogle),
+          tileset: googleTileset,
+        };
+      const imagery =
+        descriptor.kind === 'ion'
+          ? () => createIonImagery(descriptor.style, ionToken)
+          : descriptor.id === 'osm'
+            ? createOsmImagery
+            : createEsriImagery;
+      return {
+        ...common,
+        imagery,
+        terrain,
+        ...(descriptor.id === 'esri-imagery'
+          ? {
+              credit: ESRI_ATTRIBUTION_HTML,
+              constructionFallback: {
+                id: 'osm',
+                message: 'Esri Satellite is unavailable; using OSM',
+              },
+              tileFailureFallback: {
+                id: 'osm',
+                threshold: 2,
+                message: 'Esri Satellite tile requests failed; using OSM',
+              },
+            }
+          : {}),
+      };
+    }),
+  };
+}