hj_twee.rb

class LocalCampaign
  attr_accessor :id, :job_id, :status, :external_reference, :ad_description, :discrepancies
  def self.remote_mappings
    {
      external_reference: :external_reference,
      ad_description: :ad_description
    }
  end
  
  def eql?(remote_campaign)
    remote_mappings.each |local_key,remote_key|
      @discrepancies << { ..fill in.. } unless self.send(local_key) == remote_campaign.send(remote_key)
    end
    @discrepancies.present?
  end
end

class RemoteCampaign

  URL = ""
  
  attr_accessor :id, :external_reference, :ad_description

  def self.fetch
    puts "Fetching details from external service ..."

    response = HTTParty.get(URL)
    if response.ok?
        return JSON.parse(response.body)['ads']
    else
        raise 'External service not accessible.'
    end
  end
  

  def self.call
    # This is supposed to build objs
    fetch.each {|ad| self.class.new(ad) }
  end
end

class Sync
  def call
    remotes = RemoteCampaign.call
    discrepancies = []
    LocalCampaign.all.each do |campaign_local|
      campaign_remote = remotes.find_by(id: campaign_local.id )
      unless campaign_local.eql?(campaign_remote)
        discrepancies << {discrepancies: campaign_local.discrepancies, id: campaign_local.id}
      end
    end
    discrepancies
  end
end