auth0.ts

import type { H3Event } from 'h3'
import { eventHandler, getQuery, sendRedirect } from 'h3'
import { withQuery } from 'ufo'
import { defu } from 'defu'
import { handleMissingConfiguration, handleAccessTokenErrorResponse, getOAuthRedirectURL, requestAccessToken } from '../utils'
import { useRuntimeConfig } from '#imports'
import type { OAuthConfig } from '#auth-utils'

export interface OAuthAuth0Config {
  /**
   * Auth0 OAuth Client ID
   * @default process.env.NUXT_OAUTH_AUTH0_CLIENT_ID
   */
  clientId?: string
  /**
   * Auth0 OAuth Client Secret
   * @default process.env.NUXT_OAUTH_AUTH0_CLIENT_SECRET
   */
  clientSecret?: string
  /**
   * Auth0 OAuth Issuer
   * @default process.env.NUXT_OAUTH_AUTH0_DOMAIN
   */
  domain?: string
  /**
   * Auth0 OAuth Audience
   * @default process.env.NUXT_OAUTH_AUTH0_AUDIENCE
   */
  audience?: string
  /**
   * Auth0 OAuth Scope
   * @default []
   * @see https://auth0.com/docs/get-started/apis/scopes/openid-connect-scopes
   * @example ['openid']
   */
  scope?: string[]
  /**
   * Require email from user, adds the ['email'] scope if not present
   * @default false
   */
  emailRequired?: boolean
  /**
   * Maximum Authentication Age. If the elapsed time is greater than this value, the OP must attempt to actively re-authenticate the end-user.
   * @default 0
   * @see https://auth0.com/docs/authenticate/login/max-age-reauthentication
   */
  maxAge?: number
  /**
   * Login connection. If no connection is specified, it will redirect to the standard Auth0 login page and show the Login Widget.
   * @default ''
   * @see https://auth0.com/docs/api/authentication#social
   * @example 'github'
   */
  connection?: string
  /**
   * Extra authorization parameters to provide to the authorization URL
   * @see https://auth0.com/docs/api/authentication#social
   * @example { display: 'popup' }
   */
  authorizationParams?: Record<string, string>
  /**
   * Redirect URL to to allow overriding for situations like prod failing to determine public hostname
   * @default process.env.NUXT_OAUTH_AUTH0_REDIRECT_URL or current URL
   */
  redirectURL?: string
}

export function defineOAuthAuth0EventHandler({ config, onSuccess, onError }: OAuthConfig<OAuthAuth0Config>) {
  return eventHandler(async (event: H3Event) => {
    config = defu(config, useRuntimeConfig(event).oauth?.auth0, {
      authorizationParams: {},
    }) as OAuthAuth0Config

    if (!config.clientId || !config.clientSecret || !config.domain) {
      return handleMissingConfiguration(event, 'auth0', ['clientId', 'clientSecret', 'domain'], onError)
    }
    const authorizationURL = `https://${config.domain}/authorize`
    const tokenURL = `https://${config.domain}/oauth/token`

    const query = getQuery<{ code?: string }>(event)
    const redirectURL = config.redirectURL || getOAuthRedirectURL(event)

    if (!query.code) {
      config.scope = config.scope || ['openid', 'offline_access']
      if (config.emailRequired && !config.scope.includes('email')) {
        config.scope.push('email')
      }
      // Redirect to Auth0 Oauth page
      return sendRedirect(
        event,
        withQuery(authorizationURL as string, {
          response_type: 'code',
          client_id: config.clientId,
          redirect_uri: redirectURL,
          scope: config.scope.join(' '),
          audience: config.audience || '',
          max_age: config.maxAge || 0,
          connection: config.connection || '',
          ...config.authorizationParams,
        }),
      )
    }

    const tokens = await requestAccessToken(tokenURL as string, {
      headers: {
        'Content-Type': 'application/json',
      },
      body: {
        grant_type: 'authorization_code',
        client_id: config.clientId,
        client_secret: config.clientSecret,
        redirect_uri: redirectURL,
        code: query.code,
      },
    })

    if (tokens.error) {
      return handleAccessTokenErrorResponse(event, 'auth0', tokens, onError)
    }

    const tokenType = tokens.token_type
    const accessToken = tokens.access_token

    // TODO: improve typing
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const user: any = await $fetch(`https://${config.domain}/userinfo`, {
      headers: {
        Authorization: `${tokenType} ${accessToken}`,
      },
    })

    return onSuccess(event, {
      tokens,
      user,
    })
  })
}