Apple Authentication Concern for Mixing into a User model

apple_authenticatable.rb

##
#
# Intended to be included in your User model
# class User < ApplicationRecord
#  include AppleAuthenticatable
#  
#  <everything else>
#
# end
# 

module AppleAuthenticatable
  extend ActiveSupport::Concern

  included do
    # Class method to find existing user or create a new one from Apple Sign In data
    def self.find_or_create_from_apple(id_token, user_params)
      # Try to find existing user by Apple's unique identifier
      user = User.find_by(
        oauth_uid: id_token.sub,
        oauth_provider: "apple"
      )

      # Return existing user if found
      return user if user.present?

      # Otherwise create a new user
      user = User.new

      # Store Apple's unique identifier (sub) as the oauth_uid
      user.oauth_uid = id_token.sub
      user.oauth_provider = "apple"

      # Generate a secure random password (user won't need this for OAuth login)
      # Optional, but if you have a password field that's validated, you might need 
      # to set it here when creating a user.
      # user.password = SecureRandom.hex(16)
      # user.password_confirmation = user.password

      # Set email if provided by Apple (may be nil for private email relay)
      user.email = user_params["email"] if user_params["email"].present?
      # Combine first and last name if provided
      user.name = [ user_params["name"]["firstName"], user_params["name"]["lastName"] ].compact.join(" ") if user_params["name"].present?

      # Save the new user
      user.save!

      user
    end
  end
end