使用Firebase实现苹果登录，可以通过以下步骤进行配置：

1. 在 Firebase 控制台中，启用 Apple 登录

2. 添加苹果开发者账号的授权密钥

3. 配置 Info.plist 文件，并包含下面的代码示例：

CFBundleURLTypes CFBundleTypeRole Editor CFBundleURLSchemes com.example.apple

com.apple.developer.applesignin Default

4. 在 AppDelegate.swift 文件中，添加以下代码示例：

import Firebase import AuthenticationServices

@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate { func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { FirebaseApp.configure() return true }

@available(iOS 13.0, *)
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
  Messaging.messaging().apnsToken = deviceToken
}

@available(iOS 13.0, *)
func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
  print("Unable to register for remote notifications: \(error.localizedDescription)")
}

@available(iOS 13.0, *)
func application(_ application: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any]) -> Bool {
  if let appleIDCredential = ASAuthorizationAppleIDCredential(url: url) {
    let credential = OAuthProvider.credential(withProviderID: "apple.com", idToken: appleIDCredential.identityToken?.base64EncodedString(), rawNonce: "")
    Auth.auth().signIn(with: credential) { (authResult, error) in
      if let error = error {
        print("Unable to sign in with Apple: \(error.localizedDescription)")
      } else {
        print("Successfully signed in with Apple")
      }
    }
    return true
  }
  return false
}

}

其中，ASAuthorizationAppleIDCredential 是 iOS 13 新增的 API，用于处理苹果登录的凭证。使用 OAuthProvider 的 credential 方法创建 Firebase 的凭证，然后使用 Auth 的 signIn 方法进行登录。