Code changes influnced by https://world.hey.com/jorge/code-i-like-ii-fractal-journeys-b7688f93

contact_export.rb

# app/models/contact_export.rb

class ContactExport < ApplicationRecord
  after_create_commit :process_later

  def process
    LeadSubmission::Exporter.new(self).perform
  end

  private

  def process_later
    ContactExporterWorker.perform_async(self.id)
  end
end

contact_exporter_worker.rb

# app/workers/contact_exporter_worker.rb

class ContactExporterWorker
  include Sidekiq::Worker
  sidekiq_options queue: :export

  def perform(contact_export_id)
    contact_export = ContactExport.find(contact_export_id)
    contact_export.process
  end
end

description.md

• The domain problem is users can export LeadSubmissions to CSVs and Excels.
• LeadSubmission::Exportable concern is added to encapsulate the logic for exportable fields.
  • When rendering the export page, BASE_FIELDS are pre-selected.
  • Call export_sections to get all the exportable fields in the form of sections, which is mapped to the client data structure.
• Move Service::Exporter::ContactExporter to LeadSubmission::Exporter for coheresiveness, which means code for exporting LeadSubmissions is in the same place: app/models/lead_submission/*.

exportable.rb

# app/models/lead_submission/exportable.rb

module LeadSubmission::Exportable
  extend ActiveSupport::Concern

  SECTION_CONTACT = 'contact'
  SECTION_EXTRA = 'extra'
  SECTION_CRM = 'crm'

  CATEGORY_BASE = 'base'
  CATEGORY_STUDENT = 'student'
  CATEGORY_EXTRA = 'extra'

  SECTIONS = {
    SECTION_CONTACT => [
      CATEGORY_BASE,
      CATEGORY_STUDENT,
    ],
    SECTION_EXTRA => [
      CATEGORY_EXTRA,
    ],
    SECTION_CRM => [],
  }

  CATEGORIES = {
    CATEGORY_BASE => [
      { id: 'first_name' },
      { id: 'last_name' },
      { id: 'email' },
      { id: 'phone_number' },
      { id: 'representative_name' },
      { id: 'crm_campaign_name' },
      { id: 'agent_name', condition: ->(school) { school.enable_agent_mode? } },
      { id: 'agency_name', condition: ->(school) { school.enable_agent_mode? } },
      { id: 'created_date' },
    ],
    CATEGORY_STUDENT => [
      { id: 'student_first_name' },
      { id: 'student_last_name' },
      { id: 'student_gender_name' },
      { id: 'student_birthday' },
      { id: 'apply_grade_name' },
      { id: 'apply_academic_year_name' },
    ],
    CATEGORY_EXTRA => [
      { id: 'id' },
      { id: 'openid', condition: ->(school) { school.has_wechat_contact_form_feature? } },
      { id: 'unionid', condition: ->(school) { school.has_wechat_contact_form_feature? } },
    ],
  }

  # BASE_FIELDS are pre-selected automatically.
  BASE_FIELDS = %w(
    first_name
    last_name
    email
  )

  class_methods do
    def export_sections(school)
      SECTIONS.map do |section, categories|
        section_data(section, categories, school)
      end
    end

    private

    def section_name(section)
      I18n.t(section, scope: 'admin.export.contacts.section')
    end

    def category_name(category)
      I18n.t(category, scope: 'admin.export.contacts.category')
    end

    def field_name(field)
      I18n.t(field[:id], scope: 'admin.export.contacts.contact_field')
    end

    def section_data(section, categories, school)
      title = section_name(section)

      form_pages = if section == SECTION_CRM
                     crm_form_pages(school)
                   else
                     form_pages_by_categories(categories, school)
                   end

      { id: section, title: title, form_pages: form_pages }
    end

    def form_pages_by_categories(categories, school)
      categories.map do |category|
        name = category_name(category)
        fields = fields_by_category(category, school)
        { id: category, name: name, fields: fields }
      end
    end

    def fields_by_category(category, school)
      CATEGORIES[category].select do |field|
        field[:condition].blank? || field[:condition].call(school)
      end.map do |field|
        field[:name] = field_name(field)
        field
      end
    end

    def crm_form_pages(school)
      Service::Exporter::CRMContactField.new(school).grouped_fields
    end
  end

  # Following are methods to get field values

  def name
    [first_name, last_name].join(' ')
  end

  def gender_name
    I18n.t(gender, scope: 'gender')
  end

  # ...
end

exporter.rb

# app/models/lead_submission/exporter.rb

class LeadSubmission::Exporter
  attr_reader :contact_export

  delegate :school, :fields, :contact_ids, to: :contact_export

  def initialize(contact_export)
    @contact_export = contact_export
  end

  def perform
    case contact_export.format
    when 'csv'
      export_csv { |file| upload_and_notify(file) }
    when 'xlsx'
      export_xlsx { |file| upload_and_notify(file) }
    else
      raise 'Unknown format!'
    end
  end
  
  private
  # ...
end