env.mjs

import { z } from 'zod'

/**
 * Specify server-side environment variables schema here.
 */
const server = z.object({
  NODE_ENV: z.enum(['development', 'test', 'production']),
  DATABASE_URL: z.string().min(1),
  RESEND_API_KEY: z.string().min(1),
  VERCEL_ENV: z
    .enum(['development', 'preview', 'production'])
    .default('development'),
  UPSTASH_REDIS_REST_URL: z.string().min(1),
  UPSTASH_REDIS_REST_TOKEN: z.string().min(1),
  LINK_PREVIEW_API_BASE_URL: z.string().optional(),
  SITE_NOTIFICATION_EMAIL_TO: z.string().optional(),
})

const client = z.object({
  NEXT_PUBLIC_SANITY_PROJECT_ID: z.string().min(1),
  NEXT_PUBLIC_SANITY_DATASET: z.string().min(1),
  NEXT_PUBLIC_SANITY_USE_CDN: z.boolean(),
  NEXT_PUBLIC_SITE_URL: z.string().min(1),
  NEXT_PUBLIC_SITE_EMAIL_FROM: z.string().min(1),
  NEXT_PUBLIC_SITE_LINK_PREVIEW_ENABLED: z.boolean().optional().default(false),
})

/**
 * You can't destruct `process.env` as a regular object in the Next.js edge runtimes (e.g.
 * middlewares) or client-side so we need to destruct manually.
 *
 * @type {Record<keyof z.infer<typeof server> | keyof z.infer<typeof client>, string | undefined>}
 */
const processEnv = {
  NODE_ENV: process.env.NODE_ENV,
  DATABASE_URL: process.env.DATABASE_URL,
  RESEND_API_KEY: process.env.RESEND_API_KEY,
  VERCEL_ENV: process.env.VERCEL_ENV,
  UPSTASH_REDIS_REST_URL: process.env.UPSTASH_REDIS_REST_URL,
  UPSTASH_REDIS_REST_TOKEN: process.env.UPSTASH_REDIS_REST_TOKEN,
  NEXT_PUBLIC_SANITY_PROJECT_ID: process.env.NEXT_PUBLIC_SANITY_PROJECT_ID,
  NEXT_PUBLIC_SANITY_DATASET: process.env.NEXT_PUBLIC_SANITY_DATASET,
  NEXT_PUBLIC_SANITY_USE_CDN: process.env.NEXT_PUBLIC_SANITY_USE_CDN == 'true',
  NEXT_PUBLIC_SITE_URL: process.env.NEXT_PUBLIC_SITE_URL,
  NEXT_PUBLIC_SITE_EMAIL_FROM: process.env.NEXT_PUBLIC_SITE_EMAIL_FROM,
  LINK_PREVIEW_API_BASE_URL: process.env.LINK_PREVIEW_API_BASE_URL,
  SITE_NOTIFICATION_EMAIL_TO: process.env.SITE_NOTIFICATION_EMAIL_TO,
  NEXT_PUBLIC_SITE_LINK_PREVIEW_ENABLED:
    process.env.NEXT_PUBLIC_SITE_LINK_PREVIEW_ENABLED == 'true',
}

// Don't touch the part below
// --------------------------

const merged = server.merge(client)

/** @typedef {z.input<typeof merged>} MergedInput */
/** @typedef {z.infer<typeof merged>} MergedOutput */
/** @typedef {z.SafeParseReturnType<MergedInput, MergedOutput>} MergedSafeParseReturn */

let env = /** @type {MergedOutput} */ (process.env)

if (!!process.env.SKIP_ENV_VALIDATION == false) {
  const isServer = typeof window === 'undefined'

  const parsed = /** @type {MergedSafeParseReturn} */ (
    isServer
      ? merged.safeParse(processEnv) // on server we can validate all env vars
      : client.safeParse(processEnv) // on client we can only validate the ones that are exposed
  )

  if (parsed.success === false) {
    console.error(
      '❌ Invalid environment variables:',
      parsed.error.flatten().fieldErrors
    )
    throw new Error('Invalid environment variables')
  }

  env = new Proxy(parsed.data, {
    get(target, prop) {
      if (typeof prop !== 'string') return undefined
      // Throw a descriptive error if a server-side env var is accessed on the client
      // Otherwise it would just be returning `undefined` and be annoying to debug
      if (!isServer && !prop.startsWith('NEXT_PUBLIC_'))
        throw new Error(
          process.env.NODE_ENV === 'production'
            ? '❌ Attempted to access a server-side environment variable on the client'
            : `❌ Attempted to access server-side environment variable '${prop}' on the client`
        )
      return target[/** @type {keyof typeof target} */ (prop)]
    },
  })
}

export { env }