tab/app/controllers/concerns/statistics.rb

class Statistics < Rails::Application

  def shameful_users
    User.where('balance > :amount', amount: config.shameful_balance)
        .order(balance: :desc)
  end

  def total_debt
    User.where.not(id: User.zeus).where('balance > 0').sum(:balance)
  end

  def shamehash
    none_shaming = shameful_users.sum(:balance)
    shameful_users.inject({'None-shameful users' => none_shaming}) do |h, u|
      h.merge({u.name => u.balance})
    end
  end

  def by_issuer
    Transaction.group(:issuer_id).count.inject(Hash.new) do |hash, (id, count)|
      hash.merge({User.find(id).name => count})
    end
  end

  def amount_distribution
    Transaction.group("round(amount / 10)").count.inject(Hash.new) do |hash, (group, count)|
      hash.merge({10 * group.to_i => count})
    end
  end

  private

  def zeus_balance
    User.zeus.balance
  end

end