refactor: isolate Map Source controls and selection lifecycle

src/ui/mapSourceControls.js

@@ -0,0 +1,75 @@
+import { renderMapStackChips, syncMapStackChips } from '../mapStackChips.js';
+
+/**
+ * Own Map Source presentation and selection without constructing map providers.
+ * The supplied controller remains authoritative for availability and active state.
+ */
+export function createMapSourceControls({
+  container, statusElement, controller, subscribe,
+  claimSelection = () => {}, onStateChanged = () => {}, onError = () => {},
+}) {
+  let destroyed = false;
+  let generation = 0;
+  const removers = [];
+  const bind = (element, type, listener) => {
+    element.addEventListener(type, listener);
+    removers.push(() => element.removeEventListener(type, listener));
+  };
+  function render(state) {
+    if (destroyed || !state) return;
+    syncMapStackChips(container, state.activeId);
+    if (statusElement) {
+      const stack = state.activeStack;
+      statusElement.textContent = state.status === 'switching' ? '...' : (stack?.shortLabel || stack?.label || 'MAP');
+      statusElement.classList.toggle('warn', !!state.lastError);
+    }
+  }
+  async function select(stackId, { syncShare = true } = {}) {
+    if (destroyed) return null;
+    const current = ++generation;
+    if (syncShare) claimSelection();
+    const before = controller.getActiveId();
+    render(controller.getState('switching'));
+    let state;
+    try {
+      state = await controller.setStack(stackId);
+    } catch (error) {
+      if (!destroyed && current === generation) {
+        render(controller.getState());
+        onError(error?.message || String(error));
+      }
+      throw error;
+    }
+    if (destroyed || current !== generation) return state;
+    render(controller.getState());
+    if (state?.activeId === before && stackId !== before && state?.lastError) onError(state.lastError);
+    if (syncShare) onStateChanged();
+    return state;
+  }
+  function refresh() {
+    if (destroyed) return;
+    for (const remove of removers.splice(0)) remove();
+    renderMapStackChips(container, controller.getStacks(), {
+      activeId: controller.getActiveId(),
+      onSelect: (id) => { void select(id).catch(() => {}); },
+      bind,
+    });
+    render(controller.getState());
+  }
+  const unsubscribe = subscribe(() => {
+    if (destroyed) return;
+    render(controller.getState());
+    onStateChanged();
+  });
+  refresh();
+  return {
+    render, select, refresh,
+    destroy() {
+      if (destroyed) return;
+      destroyed = true;
+      generation++;
+      unsubscribe?.();
+      for (const remove of removers.splice(0)) remove();
+    },
+  };
+}