phone_verification_service.rb

class Account::PhoneVerificationService
  attr_reader :account, :errors

  MAX_FAILED_ATTEMPTS = 3

  def initialize(account)
    @account = account
  end

  def verify(code)
    reset_errors!

    validate_blank_phone_verification_code!
    validate_verification_status!
    validate_verification_expiration!

    return if has_errors?

    validate_code!(code)
  end

  private

  def validate_verification_expiration!
    return if account.phone_verification_sent_at.nil? ||
        account.phone_verification_sent_at > Account::PHONE_VERIFICATION_TTL.ago

    error! I18n.t('account.phone_verification.errors.expired')
  end

  def validate_verification_status!
    return unless account.phone_verified?

    error! I18n.t('account.phone_verification.errors.already_verified')
  end

  def validate_blank_phone_verification_code!
    return if account.phone_verification_code.present?

    error! I18n.t('account.phone_verification.errors.no_verification_code')
  end

  def validate_code!(code)
    stored_verification_code = account.phone_verification_code

    if code == stored_verification_code
      account.update_column(:phone_verified_at, Time.zone.now)
      account.update_column(:phone_verification_code, nil)
    else
      failed_attempt!

      if failed_attempts_limit_exceeded?
        resend_message
        error! I18n.t('account.phone_verification.errors.failed_attempts_count_exceeded')
      else
        error! I18n.t('account.phone_verification.errors.invalid_code')
      end
    end
  end

  def failed_attempt!
    account.increment!(:phone_verification_attempts)
  end

  def failed_attempts_limit_exceeded?
    account.phone_verification_attempts >= MAX_FAILED_ATTEMPTS
  end

  def error!(message)
    @errors = message
    false
  end

  def has_errors?
    @errors.present?
  end

  def reset_errors!
    @errors = nil
  end

  def resend_message
    account.update_column(:phone_verification_attempts, 0)

    service = Account::PhoneVerificationDeliveryService.new(account)
    service.force_code_generation!
    service.send_verification
  end
end