Allow "open" date range in AmountsExtension balance method via defaults

[davidkuhta]

Hi @mbulat
Currently the balance method in AmountsExtension supports two cases:

1. All - No date hash provided; return sum of all amounts
2. Closed Range - Hash provided with from_date and to_date; return sum of all amounts between these dates.

I believe that a reasonable argument could be made for provision of two additional cases, based on the frequency with which to_date = Date.today is used and eliminating the need to find the earliest entry date to set a from_date:

1. Open Range (after) - Hash provided with from_date; return sum of all amounts after this date (up to today).
2. Open Range (before) - Hash provided with to_date; return sum of all amounts before this date (down to the earliest entry).

Current balance method:

   def balance(hash={})
      if hash[:from_date] && hash[:to_date]
        from_date = hash[:from_date].kind_of?(Date) ? hash[:from_date] : Date.parse(hash[:from_date])
        to_date = hash[:to_date].kind_of?(Date) ? hash[:to_date] : Date.parse(hash[:to_date])
        includes(:entry).where('plutus_entries.date' => from_date..to_date).sum(:amount)
      else
        sum(:amount)
      end
    end

Revised method:

   def balance(hash={})
      if hash[:from_date] && hash[:to_date]
        from_date = hash[:from_date].kind_of?(Date) ? hash[:from_date] : Date.parse(hash[:from_date])
        to_date = hash[:to_date].kind_of?(Date) ? hash[:to_date] : Date.parse(hash[:to_date])
        includes(:entry).where('plutus_entries.date' => from_date..to_date).sum(:amount)
      elsif hash[:from_date]
        # if only :from_date provided default assumes all amounts requested after that date
        from_date = hash[:from_date].kind_of?(Date) ? hash[:from_date] : Date.parse(hash[:from_date])
        includes(:entry).where('plutus_entries.date >= ?, from_date).sum(:amount)
      elsif hash[:to_date]
        # if only :to_date provided default assumes all amounts requested before that date
        to_date = hash[:to_date].kind_of?(Date) ? hash[:to_date] : Date.parse(hash[:to_date])
        includes(:entry).where('plutus_entries.date <= ?, to_date).sum(:amount)
      else
        sum(:amount)
      end
    end

Some class methods might make this neater

   def balance(hash={})
      if hash[:from_date] && hash[:to_date]
        from_date = hash[:from_date].kind_of?(Date) ? hash[:from_date] : Date.parse(hash[:from_date])
        to_date = hash[:to_date].kind_of?(Date) ? hash[:to_date] : Date.parse(hash[:to_date])
        between(from_date, to_date)
      elsif hash[:from_date]
        # if only :from_date provided default assumes all amounts requested after that date
        from_date = hash[:from_date].kind_of?(Date) ? hash[:from_date] : Date.parse(hash[:from_date])
        after(from_date)
      elsif hash[:to_date]
        # if only :to_date provided default assumes all amounts requested before that date
        to_date = hash[:to_date].kind_of?(Date) ? hash[:to_date] : Date.parse(hash[:to_date])
        before(to_date)
      else
        sum(:amount)
      end
    end

  def self.between(from_date, to_date)
    includes(:entry).where('plutus_entries.date' => from_date..to_date).sum(:amount)
  end
  def self.after(from_date, to_date)
    includes(:entry).where('plutus_entries.date >= ?, from_date).sum(:amount)
  end
  def self.before(to_date)
    includes(:entry).where('plutus_entries.date <= ?, to_date).sum(:amount)
  end

I don't see any impact to existing installations either as the existing if hash[:from_date] && hash[:to_date] and else catch-all remain unchanged.

Let me know if you'd like a PR.

[mbulat]

Yes, I like this implementation. PR is welcome! Thanks