1_Gemfile

# frozen_string_literal: true
source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

gem 'twilio-ruby'
gem 'dotenv'
gem 'waterfall'

2_main.rb

require 'dotenv/load'
require 'waterfall'
require_relative 'waterfall_custom'
require_relative 'services/send_sms'

puts "Enter Phone Number"
number = gets.chomp!

puts "Enter Message"
message = gets.chomp!

Flow.new
  .chain(twilio_result: :result) do 
    Services::SendSms.new(number, message)
  end
  .chain { puts 'Message sent successfully' }
  .chain {|outflow| puts outflow.twilio_result }
  .on_dam {|errors| puts errors }

2_waterfall_custom.rb

require_relative 'common/errors'

module Waterfall
  def errors
    @errors ||= Services::Common::Errors.new
  end
end

3_send_sms.rb

require_relative 'clients/twilio'

module Services
  class SendSms
    include Waterfall
    
    def initialize(recipient, message)
      @recipient = recipient
      @message = message
    end

    def call
      chain do 
        errors.add :validation, "Missing recipient's number." if @recipient.empty?
        errors.add :validation, "Missing message to recipient." if @message.empty?
        dam(errors) if errors.any?
      end
      chain(result: :client) do 
        Services::Clients::Twilio.new(@recipient, @message)
      end
    end
  end
end

4_twilio.rb

require 'twilio-ruby'
module Services
  module Clients
    class Twilio
      include Waterfall
      
      PHONE_NUMBER = '+18124322807'

      def initialize(recipient, message)
        @recipient = recipient
        @message = message
      end

      def call
        chain(:client) { send_message }
      end

      private

      def send_message
        account_id = ENV['TWILIO_ACCOUNT_ID']
        auth_token = ENV['TWILIO_AUTH_TOKEN']
        client = ::Twilio::REST::Client.new account_id, auth_token
        client.api.account.messages.create(
          from: PHONE_NUMBER,
          to: @recipient,
          body: @message
        )
        client
      rescue ::Twilio::REST::RestError => error
        errors.add :sms, error.message
        dam(errors)
      end
    end
  end
end