import { readFileSync } from 'node:fs'
import { fileURLToPath } from 'node:url'
import { defineConfig, loadEnv } from 'vite'
import react from '@vitejs/plugin-react'

// Clerk publishable keys are public. Default to the engine's own key so Express
// and learning-lab share one Clerk instance (same users, organizations, credits).
function engineClerkKey(): string {
  try {
    const env = readFileSync(fileURLToPath(new URL('../learning-lab/backend/.env', import.meta.url)), 'utf8')
    return env.match(/^VITE_CLERK_PUBLISHABLE_KEY=["']?([^"'\s]+)/m)?.[1] ?? ''
  } catch {
    return ''
  }
}

export default defineConfig(({ mode }) => {
  const env = loadEnv(mode, process.cwd(), '')
  const engineUrl = env.ENGINE_URL || 'http://localhost:8000'
  const clerkKey = env.VITE_CLERK_PUBLISHABLE_KEY || engineClerkKey()
  // Learning Studio (learning-lab/frontend), where a result opens in Compose for full editing.
  const studioUrl = env.VITE_STUDIO_URL || 'http://localhost:5173'

  return {
    plugins: [react()],
    define: {
      'import.meta.env.VITE_CLERK_PUBLISHABLE_KEY': JSON.stringify(clerkKey),
      'import.meta.env.VITE_STUDIO_URL': JSON.stringify(studioUrl),
    },
    // Same-origin /api keeps the engine free of CORS setup, as in production behind one domain.
    server: { port: 5174, proxy: { '/api': { target: engineUrl, changeOrigin: true } } },
    preview: { port: 5174, proxy: { '/api': { target: engineUrl, changeOrigin: true } } },
  }
})