feat: unify settings (#3128)

packages/lib/utils/settings-switcher.ts

@@ -0,0 +1,57 @@
+export type ComputeSwitcherContinuityPathArgs = {
+  currentPath: string;
+
+  /**
+   * Every settings path navigable in the destination scope — pass the destination's
+   * `SettingsNavGroup.items` paths from `getSettingsNavGroups`.
+   *
+   * Sourcing these from the nav builder (rather than a hardcoded list) means the switcher
+   * can only ever land on a page that is actually reachable there: permission and
+   * claim/billing gating are already applied when the group is built.
+   */
+  destinationPaths: string[];
+
+  /** Where to land when the current section has no equivalent in the destination. */
+  fallbackPath: string;
+};
+
+/**
+ * Extract the "section" portion of a settings URL. Returns null if not a scoped
+ * settings URL (account settings and non-settings pages have no equivalent to carry over).
+ *
+ * Examples:
+ *   /o/acme/settings/members      → 'members'
+ *   /o/acme/settings              → 'general'  (bare index redirects to General)
+ *   /t/eng/settings/webhooks/42   → 'webhooks'
+ *   /o/acme/documents             → null
+ *   /settings/profile             → null
+ */
+const parseSettingsSection = (path: string): string | null => {
+  const match = /^\/[ot]\/[^/]+\/settings(?:\/([^/?#]+))?(?:[/?#]|$)/.exec(path);
+
+  if (!match) {
+    return null;
+  }
+
+  return match[1] ?? 'general';
+};
+
+/**
+ * Compute the destination URL when the user switches organisation or team via the
+ * unified settings sidebar's switcher.
+ *
+ * Rule: stay on the same section if the destination has one; else use the fallback.
+ */
+export const computeSwitcherContinuityPath = ({
+  currentPath,
+  destinationPaths,
+  fallbackPath,
+}: ComputeSwitcherContinuityPathArgs): string => {
+  const currentSection = parseSettingsSection(currentPath);
+
+  if (!currentSection) {
+    return fallbackPath;
+  }
+
+  return destinationPaths.find((path) => parseSettingsSection(path) === currentSection) ?? fallbackPath;
+};