devotdev

# app/services/fetch_product_details.rb
class FetchProductDetails
  def initialize(api: Integration::CachingProductApiProxy.new)
    @api = api
  end

  def call(sku)
    @api.find_product(sku)
  end
end

devotdev

# app/services/integration/caching_product_api_proxy.rb
module Integration
  class CachingProductApiProxy
    def initialize(real_api: SlowProductApi.new, cache: Rails.cache)
      @real_api = real_api
      @cache = cache
    end

    def find_product(sku)
      @cache.fetch("product_api/#{sku}", expires_in: 5.minutes) do

devotdev

# app/services/integration/slow_product_api.rb
module Integration
  class SlowProductApi
    def find_product(sku)
      # Simulate external HTTP request
      sleep(2)
      { sku: sku, name: "Product #{sku}", price_cents: 1000 }
    end
  end
end

devotdev

* Main Menu
  * Products
    - Laptops (/products/laptops)
    - Monitors (/products/monitors)
  * Account
    - Profile (/account/profile)
    - Settings (/account/settings)
  - Help (/help)

devotdev

root = MenuGroup.new("Main Menu")

products = MenuGroup.new("Products")
products.add(MenuItem.new("Laptops", "/products/laptops"))
products.add(MenuItem.new("Monitors", "/products/monitors"))

account = MenuGroup.new("Account")
account.add(MenuItem.new("Profile", "/account/profile"))
account.add(MenuItem.new("Settings", "/account/settings"))

devotdev

# app/models/menu_group.rb
class MenuGroup < MenuComponent
  attr_reader :name

  def initialize(name)
    @name = name
    @children = []
  end

  def add(component)

devotdev

# app/models/menu_item.rb
class MenuItem < MenuComponent
  attr_reader :name, :path

  def initialize(name, path)
    @name = name
    @path = path
  end

  def render(indent: 0)

devotdev

# app/models/menu_component.rb
class MenuComponent
  def render(indent: 0)
    raise NotImplementedError, "#{self.class} must implement #render"
  end
end

devotdev

# app/controllers/payments_controller.rb
class PaymentsController < ApplicationController
  def create
    order = current_user.orders.find(params[:order_id])
    transaction = PaymentFacade.new.process(order, params[:payment_method_token])

    if transaction.success?
      redirect_to order_path(order), notice: "Payment successful"
    else
      redirect_to order_path(order), alert: "Payment failed"

devotdev

# app/facades/payment_facade.rb
class PaymentFacade
  def initialize(
    charge_gateway: Payment::ChargeGateway.new,
    create_transaction_record: Payment::CreateTransactionRecord.new,
    send_receipt: Payment::SendReceipt.new
  )
    @charge_gateway = charge_gateway
    @create_transaction_record = create_transaction_record
    @send_receipt = send_receipt