ArturT/Railstom

class OmniauthCallbacksController < Devise::OmniauthCallbacksController
  inject :authentication_service, :user_service, :user_repository, :omniauth_hash

  def new
    session[:email] = params[:email]
    redirect_to user_omniauth_authorize_path(params[:provider])
  end

  def facebook
    handle_omniauth(:facebook)
  end

  private

  def handle_omniauth(provider_name)
    # Find an authentication or if no authentication was found, create a brand new one here
    authentication = authentication_service.find_or_build

    if user_signed_in?
      link_current_user_with_authentication(authentication)
    else
      handle_omniauth_for_guest(provider_name, authentication)
    end
  end

  def handle_omniauth_for_guest(provider_name, authentication)
    if authentication_service.has_user?(authentication)
      # The authentication we found had a user associated with it so let's
      # just log them in here
      sign_in_and_redirect_with_notice(authentication.user, provider_name)
    else
      user = user_repository.find_with_omniauth

      if user.present?
        redirect_to new_user_session_path, notice: t('controllers.omniauth_callbacks.flash.sign_in_before_link_account_html', email: omniauth_email, provider: provider_name)
      else
        handle_omniauth_for_new_user(provider_name, authentication)
      end
    end
  end

  def handle_omniauth_for_new_user(provider_name, authentication)
    # No user associated with the authentication so we need to create a new one
    user = user_service.build_with_omniauth

    if user_has_missing_only_email?(user)
      if session[:email]
        user.email = session[:email]
      else
        render 'ask_for_email' and return
      end
    end

    if user.save
      # And assign it to authentication object
      authentication_service.user_link_with(authentication, user)

      # Finally log in the user
      sign_in_and_redirect_with_notice(user, provider_name)
    else
      session['devise.user.omniauth_data'] = omniauth_hash
      redirect_to new_user_registration_path, notice: t('controllers.omniauth_callbacks.flash.invalid_provider')
    end
  end

  def link_current_user_with_authentication(authentication)
    if authentication_service.user_linked?(authentication)
      # User is signed in so they are trying to link an authentication with their
      # account. But we found the authentication and the user associated with it
      # is the current user. So the authentication is already associated with
      # this user. So let's display an error message.
      redirect_to root_path, notice: t('controllers.omniauth_callbacks.flash.already_linked_account')
    elsif authentication.new_record?
      # The authentication is not associated with the current_user so lets
      # associate the authentication
      authentication_service.user_link_with(authentication)
      redirect_to root_path, notice: t('controllers.omniauth_callbacks.flash.successfully_linked_account')
    else
      redirect_to root_path, notice: t('controllers.omniauth_callbacks.flash.provider_linked_with_other_account_html', provider: authentication.provider)
    end
  end

  def sign_in_and_redirect_with_notice(user, provider_name)
    sign_in_and_redirect user, event: :authentication # this will throw if user is not activated
    set_flash_message(:notice, :success, kind: provider_name.to_s.capitalize)
  end

  def omniauth_email
    omniauth_hash['info'].try(:[], 'email')
  end

  def user_has_missing_only_email?(user)
    !omniauth_hash.empty? && !user.valid? && user.errors.size == 1 && user.email.blank?
  end
end