update.rb

module Slack
  module UseCases
    module Users
      class Update
        include Import[user_repository: "repositories.user_repository"]

        def initialize(
          slack_api: ::Slack::Services::SlackApi,
          create_command: ::Slack::Commands::Create,
          archive_command: ::Slack::Commands::Archive
        )
          @slack_api = slack_api
          @create_command = create_command
          @archive_command = archive_command
        end

        def call
          @db_users = user_repository.scope_active.to_a
          @slack_users = slack_api.new.fetch_users
          manage_users
        rescue slack_api::SlackCustomError
          nil
        end

        private

        attr_reader :slack_users, :db_users, :slack_api, :create_command, :archive_command

        def manage_users
          db_users_emails = db_users.map(&:email)
          slack_users_emails = slack_users.map { |user| user[:email] }

          intersection = db_users_emails & slack_users_emails
          new_users_emails = slack_users_emails - intersection
          old_users_emails = db_users_emails - intersection

          add_users(new_users_emails)
          delete_users(old_users_emails)
        end

        def add_users(users_emails)
          users_emails.each do |email|
            params = slack_users.find { |user| user[:email] == email }
            create_command.new.call(params)
          end
        end

        def delete_users(users_emails)
          users_emails.each { |email| archive_command.new.call(email) }
        end
      end
    end
  end
end