google.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 OAuthGoogleConfig {
  /**
   * Google OAuth Client ID
   * @default process.env.NUXT_OAUTH_GOOGLE_CLIENT_ID
   */
  clientId?: string

  /**
   * Google OAuth Client Secret
   * @default process.env.NUXT_OAUTH_GOOGLE_CLIENT_SECRET
   */
  clientSecret?: string

  /**
   * Google OAuth Scope
   * @default []
   * @see https://developers.google.com/identity/protocols/oauth2/scopes#google-sign-in
   * @example ['email', 'openid', 'profile']
   */
  scope?: string[]

  /**
   * Google OAuth Authorization URL
   * @default 'https://accounts.google.com/o/oauth2/v2/auth'
   */
  authorizationURL?: string

  /**
   * Google OAuth Token URL
   * @default 'https://oauth2.googleapis.com/token'
   */
  tokenURL?: string

  /**
   * Google OAuth User URL
   * @default 'https://www.googleapis.com/oauth2/v3/userinfo'
   */
  userURL?: string

  /**
   * Extra authorization parameters to provide to the authorization URL
   * @see https://developers.google.com/identity/protocols/oauth2/web-server#httprest_3
   * @example { access_type: 'offline' }
   */
  authorizationParams?: Record<string, string>

  /**
   * Redirect URL to to allow overriding for situations like prod failing to determine public hostname
   * @default process.env.NUXT_OAUTH_GOOGLE_REDIRECT_URL or current URL
   */
  redirectURL?: string
}

export function defineOAuthGoogleEventHandler({
  config,
  onSuccess,
  onError,
}: OAuthConfig<OAuthGoogleConfig>) {
  return eventHandler(async (event: H3Event) => {
    config = defu(config, useRuntimeConfig(event).oauth?.google, {
      authorizationURL: 'https://accounts.google.com/o/oauth2/v2/auth',
      tokenURL: 'https://oauth2.googleapis.com/token',
      userURL: 'https://www.googleapis.com/oauth2/v3/userinfo',
      authorizationParams: {},
    }) as OAuthGoogleConfig

    const query = getQuery<{ code?: string, state?: string }>(event)

    if (!config.clientId || !config.clientSecret) {
      return handleMissingConfiguration(event, 'google', ['clientId', 'clientSecret'], onError)
    }

    const redirectURL = config.redirectURL || getOAuthRedirectURL(event)
    if (!query.code) {
      config.scope = config.scope || ['email', 'profile']
      // Redirect to Google Oauth page
      return sendRedirect(
        event,
        withQuery(config.authorizationURL as string, {
          response_type: 'code',
          client_id: config.clientId,
          redirect_uri: redirectURL,
          scope: config.scope.join(' '),
          state: query.state || '',
          ...config.authorizationParams,
        }),
      )
    }

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

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

    const accessToken = tokens.access_token
    // TODO: improve typing
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const user: any = await $fetch(
      config.userURL as string,
      {
        headers: {
          Authorization: `Bearer ${accessToken}`,
        },
      },
    )

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