Ruby on Rails: لایه سرویس شما یک دروغ است

class UserService
  def self.create(params)
    user = User.new(params)
    if user.save
      UserMailer.welcome_email(user).deliver_later
      user
    else
      false
    end
  end
end

# In your controller
def create
  @user = UserService.create(user_params)
  if @user
    redirect_to @user, notice: 'User was successfully created.'
  else
    render :new
  end
end

class CommentService
  def self.create_for_post(post, user, content)
    Comment.create(
      post: post,
      user: user,
      content: content
    )
  end
end

module Orders
  class ProcessingWorkflow
    include Dry::Transaction

    step :start_processing
    step :process_payment
    step :allocate_inventory
    step :create_shipping_label
    step :send_confirmation
    step :complete_processing

    private

    def start_processing(input)
      order = input[:order]
      order.update!(status: 'processing')
      Success(input)
    rescue => e
      Failure([:processing_failed, e.message])
    end

    def process_payment(input)
      order = input[:order]
      payment = Payments::Gateway.new.charge(
        amount: order.total,
        token: order.payment_token
      )
      Success(input.merge(payment: payment))
    rescue => e
      Failure([:payment_failed, e.message])
    end

    def allocate_inventory(input)
        # ...
    end

    def create_shipping_label(input)
        # ...
    end

    def send_confirmation(input)
      OrderMailer.confirmation(input[:order]).deliver_later
      Success(input)
    rescue => e
      Failure([:notification_failed, e.message])
    end

    def complete_processing(input)
      order = input[:order]
      order.update!(status: 'processed')
      Success(input)
    rescue => e
      Failure([:completion_failed, e.message])
    end
  end
end

module Subscriptions
  class StripeWorkflow
    include Dry::Transaction

    step :validate_subscription
    step :create_stripe_customer
    step :create_stripe_subscription
    step :update_user_records

    private

    def validate_subscription(input)
      contract = Subscriptions::ValidationContract.new
      result = contract.call(input)
      result.success? ? Success(input) : Failure([:validation_failed, result.errors])
    end

    def create_stripe_customer(input)
        # ... stripe code
    end

    def create_stripe_subscription(input)
        # ... stripe code
    end

    def update_user_records(input)
      user = input[:user]
      user.update!(
        stripe_customer_id: input[:customer].id,
        stripe_subscription_id: input[:subscription].id,
        subscription_status: input[:subscription].status
      )
      Success(input)
    rescue => e
      Failure([:record_update_failed, e.message])
    end
  end
end

module Loans
  class ApplicationProcess
    include Dry::Transaction

    step :validate_application
    step :check_credit_score
    step :evaluate_debt_ratio
    step :calculate_risk_score
    step :determine_approval
    step :process_result

    private

    def validate_application(input)
      contract = Loans::ApplicationContract.new
      result = contract.call(input)
      result.success? ? Success(input) : Failure([:validation_failed, result.errors])
    end

    def check_credit_score(input)
      application = input[:application]
      if application.credit_score < 600
        Failure([:credit_score_too_low, "Credit score below minimum requirement"])
      else
        Success(input)
      end
    end

    def evaluate_debt_ratio(input)
      calculator = Loans::DebtRatioCalculator.new(input[:application])
      ratio = calculator.compute

      if ratio > 0.43
        Failure([:debt_ratio_too_high, "Debt-to-income ratio exceeds maximum"])
      else
        Success(input.merge(debt_ratio: ratio))
      end
    end

    def calculate_risk_score(input)
        # ...
    end

    def determine_approval(input)
        # ...
    end

    def process_result(input)
      application = input[:application]

      if input[:approved]
        rate_calculator = Loans::InterestRateCalculator.new(
          application: application,
          risk_score: input[:risk_score]
        )

        application.update!(
          status: 'approved',
          interest_rate: rate_calculator.compute,
          approval_date: Time.current
        )
        LoanMailer.approval_notice(application).deliver_later
      else
        application.update!(status: 'rejected')
        LoanMailer.rejection_notice(application).deliver_later
      end

      Success(input)
    rescue => e
      Failure([:processing_failed, e.message])
    end
  end
end