Env typing and config

// app/lib/env.ts
import { z } from "zod"

const serverSchema = z.object({
  NODE_ENV: z.enum(["development", "test", "production"]),
  DATABASE_URL: z.string().url(),
  API_SECRET: z.string().min(1)
})

const clientSchema = z.object({
  NEXT_PUBLIC_API_BASE: z.string().url()
})

function parseEnv<T extends z.ZodTypeAny>(schema: T, source: Record<string, unknown>) {
  const r = schema.safeParse(source)
  if (!r.success) {
    console.error(r.error.format())
    throw new Error("Invalid environment variables")
  }
  return r.data as z.infer<T>
}

export const serverEnv = parseEnv(serverSchema, process.env)
export const clientEnv = parseEnv(clientSchema, process.env)

// app/api/users/route.ts
import { NextResponse } from "next/server"
import { serverEnv } from "@/app/lib/env"

export async function GET() {
  // Safe to read secrets on the server
  const db = serverEnv.DATABASE_URL
  return NextResponse.json({ ok: true, dbConfigured: Boolean(db) })
}

"use client"
import { clientEnv } from "@/app/lib/env"

export default function ApiBaseNotice() {
  return <small>API base: {clientEnv.NEXT_PUBLIC_API_BASE}</small>
}

// env.d.ts (optional hints; runtime validation still required)
/// <reference types="node" />

declare namespace NodeJS {
  interface ProcessEnv {
    NODE_ENV: "development" | "test" | "production"
    DATABASE_URL?: string
    API_SECRET?: string
    NEXT_PUBLIC_API_BASE?: string
  }
}