check product is valid and in stock before payment

app/exceptions/cart/zero_price_error.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+# Raised when order amount = 0
+class Cart::ZeroPriceError < StandardError
+end

app/models/order.rb

@@ -5,10 +5,10 @@ class Order < ApplicationRecord
   belongs_to :statistic_profile
   has_many :order_items, dependent: :destroy
 
-  ALL_STATES = %w[cart].freeze
+  ALL_STATES = %w[cart in_progress ready canceled return].freeze
   enum state: ALL_STATES.zip(ALL_STATES).to_h
 
-  PAYMENT_STATES = %w[paid failed].freeze
+  PAYMENT_STATES = %w[paid failed refunded].freeze
   enum payment_state: PAYMENT_STATES.zip(PAYMENT_STATES).to_h
 
   validates :token, :state, presence: true

app/services/checkout/payment_service.rb

@@ -6,6 +6,10 @@ class Checkout::PaymentService
   require 'stripe/helper'
 
   def payment(order, operator, payment_id = '')
+    raise Cart::OutStockError unless Orders::OrderService.new.in_stock?(order, 'external')
+
+    raise Cart::InactiveProductError unless Orders::OrderService.new.all_products_is_active?
+
     if operator.member?
       if Stripe::Helper.enabled?
         Payments::StripeService.new.payment(order, payment_id)

app/services/orders/in_stock_service.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# Provides methods for Check if the product is in stock
+class Cart::SetQuantityService
+  def call(order)
+    
+    return order if quantity.to_i.zero?
+
+    raise Cart::OutStockError if quantity.to_i > orderable.stock['external']
+
+    item = order.order_items.find_by(orderable: orderable)
+
+    raise ActiveRecord::RecordNotFound if item.nil?
+
+    different_quantity = quantity.to_i - item.quantity
+    order.amount += (orderable.amount * different_quantity)
+    ActiveRecord::Base.transaction do
+      item.update(quantity: quantity.to_i)
+      order.save
+    end
+    order.reload
+  end
+end

app/services/orders/order_service.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+# Provides methods for Order
+class Orders::OrderService
+  def in_stock?(order, stock_type = 'external')
+    order.order_items.each do |item|
+      return false if item.orderable.stock[stock_type] < item.quantity
+    end
+    true
+  end
+
+  def all_products_is_active?(order)
+    order.order_items.each do |item|
+      return false unless item.orderable.is_active
+    end
+    true
+  end
+end

app/services/payments/payment_concern.rb

@@ -18,7 +18,7 @@ module Payments::PaymentConcern
   def payment_success(order)
     ActiveRecord::Base.transaction do
       WalletService.debit_user_wallet(order, order.statistic_profile.user)
-      order.update(payment_state: 'paid')
+      order.update(state: 'in_progress', payment_state: 'paid')
       order.order_items.each do |item|
         ProductService.update_stock(item.orderable, 'external', 'sold', -item.quantity)
       end

app/services/payments/payzen_service.rb

@@ -11,6 +11,8 @@ class Payments::PayzenService
   def payment(order)
     amount = debit_amount(order)
 
+    raise Cart::ZeroPriceError if amount.zero?
+
     id = PayZen::Helper.generate_ref(order, order.statistic_profile.user.id)
 
     client = PayZen::Charge.new

app/services/payments/stripe_service.rb

@@ -7,6 +7,9 @@ class Payments::StripeService
 
   def payment(order, payment_id)
     amount = debit_amount(order)
+
+    raise Cart::ZeroPriceError if amount.zero?
+
     # Create the PaymentIntent
     intent = Stripe::PaymentIntent.create(
       {