feat: default web API calls to same origin

apps/web/src/lib/api-base.ts

@@ -0,0 +1,22 @@
+const LOCALHOST_API_ORIGIN = 'http://localhost:3001';
+
+function trimTrailingSlashes(value: string): string {
+  return value.replace(/\/+$/, '');
+}
+
+export function getApiBaseUrl(
+  configuredApiBaseUrl?: string,
+  windowOrigin?: string,
+): string {
+  const configured = configuredApiBaseUrl?.trim();
+  if (configured) {
+    return trimTrailingSlashes(configured);
+  }
+
+  const origin = windowOrigin?.trim();
+  if (origin) {
+    return trimTrailingSlashes(origin);
+  }
+
+  return LOCALHOST_API_ORIGIN;
+}

apps/web/src/lib/api.ts

@@ -10,9 +10,13 @@ import type {
   UsageSummary,
   UserProfile,
 } from '@codexdash/shared-types';
+import { getApiBaseUrl } from './api-base';
 import { clearToken, getToken } from './storage';
 
-const API_BASE_URL = import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:3001';
+const API_BASE_URL = getApiBaseUrl(
+  import.meta.env.VITE_API_BASE_URL,
+  typeof window === 'undefined' ? undefined : window.location.origin,
+);
 
 async function request<T>(path: string, init?: RequestInit): Promise<T> {
   const token = getToken();