import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'

/**
 * Dev-only stub for /api/* requests.
 *
 * The files in /api are Vercel serverless functions — they run only on Vercel,
 * not in the local Vite dev server. When the frontend polls an endpoint like
 * /api/hail-status during local dev, Vite would otherwise resolve that URL to
 * the on-disk api/*.js file and push it through its module-transform pipeline,
 * which crashes on server-only imports such as `@vercel/kv`.
 *
 * This middleware intercepts /api/* before Vite transforms anything and returns
 * a 503. Every frontend hook that hits these endpoints already degrades
 * gracefully on a failed fetch (falls back to mock data / inactive storm state),
 * so the app behaves correctly in local dev — just without the live API.
 */
const devApiStub = {
  name: 'dev-api-stub',
  apply: 'serve',
  configureServer(server) {
    server.middlewares.use((req, res, next) => {
      if (req.url && req.url.startsWith('/api/')) {
        res.statusCode = 503
        res.setHeader('Content-Type', 'application/json')
        res.end(JSON.stringify({
          error: 'API routes run only on Vercel and are unavailable in local dev.',
        }))
        return
      }
      next()
    })
  },
}

export default defineConfig({
  plugins: [react(), devApiStub],
  server: {
    // Don't watch or serve /api — those are Vercel serverless functions, not frontend code
    watch: { ignored: ['**/api/**'] },
    fs: { deny: ['api'] },
  },
  optimizeDeps: {
    // Don't pre-bundle serverless function files
    exclude: ['api'],
  },
})