controller.rb

def submit
    @order = Order.find(params[:id])
    begin
      customer = Stripe::Customer.create(
        email: params[:order][:email],
        :card  => params[:order][:stripe_token]
      )
      charge = Stripe::Charge.create(
        :customer    => customer.id,
        :amount      => params[:order_total_price],
        description: params[:order][:email],
        :currency    => 'usd'
      )
    rescue Stripe::CardError => e
      render json: { status: 'failure', message: e.message, template: nil }
    else
      finalize_order
    end
  end

  def finalize_order
    update_quantities

    if @order.update_attributes(params[:order])
      @order.billing_name = charge.card.name
      @order.stripe_token = charge.id
      @order.state_tax = params[:order_sales_tax]

      transaction = { order_id: charge.id,
                      total: (@order.subtotal/100),
                      tax: (@order.state_tax/100),
                      shipping: (@order.shipping/100),
                      city: @order.city,
                      state: @order.state,
                      country: @order.country
      }

      items = []
      @order.line_items.each do |line_item|
        item = { order_id: charge.id,
                 sku_id: line_item.sku.id,
                 sku_name: line_item.sku.long_title,
                 product_type: line_item.sku.product.product_type.title,
                 price: (line_item.sku.product_real_price/100), quantity: line_item.quantity
        }
        items << item
      end

      @order.save

      template = render_to_string(template: '/carts/_receipt', layout: false, locals: { order: @order })
      render json: { status: 'success', template: template, items: items, transaction: transaction }
      OrderNotifier.received(@order).deliver
    else
      template = render_to_string(template: '/carts/_receipt', layout: false, locals: { order: @order })
      render json: { status: 'failure', alert: 'Something went wrong' }
    end
  end
  
  
  def update_quantities
    @cart.destroy
    session[:cart_id] = nil
    @order.line_items.each do |line_item|
      @sku = line_item.sku
      @sku.quantity = @sku.quantity - line_item.quantity
      if @sku.quantity < 0
        @sku.quantity = 0
      end
      @sku.save
    end
  end