osem-fcy/app/models/payment.rb

class Payment < ActiveRecord::Base
  has_many :ticket_purchases
  belongs_to :user
  belongs_to :conference

  attr_accessor :stripe_customer_email
  attr_accessor :stripe_customer_token

  validates :status, presence: true
  validates :amount, presence: true, numericality: { greater_than: 0 }
  validates :user_id, presence: true
  validates :conference_id, presence: true

  enum status: {
    unpaid: 0,
    success: 1,
    failure: 2
  }

  def amount_to_pay
    Ticket.total_price(conference, user, paid: false).cents
  end

  def purchase
    customer = Stripe::Customer.create email: stripe_customer_email,
                                       source: stripe_customer_token,
                                       description: user.name

    gateway_response = Stripe::Charge.create customer: customer.id,
                                             receipt_email: stripe_customer_email,
                                             description: 'ticket purchases',
                                             amount: amount_to_pay,
                                             currency: conference.tickets.first.price_currency

    self.last4 = gateway_response[:source][:last4]
    self.authorization_code = gateway_response[:id]
    self.status = 'success'
    true

  rescue => error
    errors.add(:base, error.message)
    self.status = 'failure'
    false
  end
end