module Wiki
  class CompatibilityWriter
    def self.create! tag_name:, body:, created_by_user:, message: nil
      ApplicationRecord.transaction do
        tag_name.lock!
        page = WikiPage.lock.find_by(tag_name_id: tag_name.id)
        if page
          update!(page:, body:, updated_by_user: created_by_user, message:)
          page
        else
          Commit.create_legacy_content!(tag_name:, body:, created_by_user:, message:)
        end
      end
    end

    def self.update! page:, body:, updated_by_user:, message: nil,
                     base_revision_id: nil
      normalised = Commit.normalise_body(body)
      if normalised.blank?
        return Commit.legacy_content!(
            page:, body: normalised, created_user: updated_by_user, message:,
            base_revision_id:)
      end

      if base_revision_id.present?
        current_id = page.wiki_revisions.maximum(:id)
        if current_id && current_id != base_revision_id.to_i
          raise Commit::Conflict,
              "競合が発生してゐます" +
              "（現在の Id.：#{ current_id }，ベース Id.：#{ base_revision_id }）．"
        end
      end

      if Commit.normalise_body(page.body) == normalised && page.wiki_revisions.exists?
        return
      end

      Commit.legacy_content!(
          page:, body: normalised, created_user: updated_by_user, message:,
          base_revision_id:)
    end
  end
end