complex query in arel

arel.rb

  def accounts
    Account.arel_table
  end

  def subscriptions
    Subscription.arel_table
  end

  def charges
    Charge::Base.arel_table
  end

  def users
    User.arel_table
  end

  # Attempt to write query in Arel, it is working, but less readable
  def arel_scope
    Account
      .joins(:owner)
      .join(subscriptions, Arel::Nodes::OuterJoin).on((subscriptions[:account_id].eq(accounts[:id])).or(subscriptions[:id].eq(nil)))
      .join(charges, Arel::Nodes::OuterJoin).on((charges[:subscription_id].eq(subscriptions[:id])).or(charges[:id].eq(nil)).and(Charge::Base.resources.where_values).and(Charge::Base.with_status_new.where_values))
      .group(accounts[:id], users[:balance_limit])
      .having("coalesce(sum(charges.amount),0) <= users.balance_limit")
  end