class Mailings::RecipientBuilder
  def initialize(mailing)
    @mailing = mailing
  end

  def call
    split_index = 0
    ordered_scope.each do |org|
      contact = org.primary_contact || org.contacts.min_by(&:id)
      email = contact&.email.presence || org.email.presence
      attrs = {
        organization: org,
        contact: contact,
        email: email&.downcase
      }
      if email.blank?
        attrs[:status] = "skipped"
        attrs[:skip_reason] = "manca email"
      elsif !email.match?(URI::MailTo::EMAIL_REGEXP)
        attrs[:status] = "skipped"
        attrs[:skip_reason] = "email non valida"
      else
        attrs[:status] = "pending"
      end
      assign_variant!(attrs, org, split_index)
      split_index += 1 if attrs[:status] == "pending"
      @mailing.mailing_recipients.create!(attrs)
    end
    @mailing.mailing_recipients.ordered
  end

  private

  def ordered_scope
    scope.reorder(Arel.sql("organizations.list_position ASC NULLS LAST"), "organizations.name ASC")
  end

  def scope
    orgs = Organization.for_project(@mailing.project).includes(:contacts, :opportunities)
    org_ids =
      case @mailing.audience
      when "to_send"
        Opportunity.where(project_id: @mailing.project_id, send_status: "to_send").select(:organization_id)
      when "test_a"
        Opportunity.where(project_id: @mailing.project_id, ab_variant: "A").select(:organization_id)
      when "test_b"
        Opportunity.where(project_id: @mailing.project_id, ab_variant: "B").select(:organization_id)
      else
        orgs.select(:id)
      end
    orgs.where(id: org_ids)
  end

  def assign_variant!(attrs, org, split_index)
    return unless @mailing.ab_test?

    opportunity = org.campaign_opportunity(@mailing.project)
    recorded = opportunity&.ab_variant.to_s.upcase
    variant =
      if @mailing.ab_from_record? && recorded.in?(%w[A B])
        recorded
      else
        split_index.even? ? "A" : "B"
      end
    attrs[:ab_variant] = variant
  end
end