SpreeCreditCardBuilder.rb

# this class builds a Spree::CreditCard for saved payment
# from our existing user profile structure
class SpreeCreditCardBuilder
  def self.create!(user)
    new(user).create_without_validation!
  end

  def initialize(user)
    @params = {}
    # spree cc icons depend on downcased cc type
    @params[:cc_type] = user.cc_brand.downcase
    @params[:last_digits] = user.cc_last4
    @params[:gateway_customer_profile_id] = user.stripe_customer_id
    @params[:user_id] = user.id

    raise "Invalid payment details on profile for user #{user.email}" if @params.values.find(&:blank?)
  end

  def build
    Spree::CreditCard.new(
      @params.merge(
        payment_method_id: stripe_payment_method.id,
        gateway_payment_profile_id: stripe_default_source(@params[:gateway_customer_profile_id])
      )
    )
  end

  def create_without_validation!
    raise 'Stripe payment method not created' if stripe_payment_method.blank?
    build.save!(validate: false)
  end

  def stripe_payment_method
    Spree::PaymentMethod.find_by(type: 'Spree::Gateway::StripeGateway')
  end

  def stripe_default_source(stripe_customer)
    Stripe::Customer.retrieve(stripe_customer).default_source
  end
end