Class: Interests::Calculator

Inherits:
Object
  • Object
show all
Defined in:
lib/interests/calculator.rb

Class Method Summary collapse

Class Method Details

.config_rates(scope = :default) ⇒ Object 



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# File 'lib/interests/calculator.rb', line 9

def config_rates(scope = :default)
  Interests::Config.send(scope).map{ |cfg| OpenStruct.new(date: Date.parse(cfg[:date]), rate: cfg[:rate]) }
end

.interests(amount = 0.0, from_date = BEGINNING_OF_COMPUTER_ERA, to_date = Date.today) ⇒ Object 



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# File 'lib/interests/calculator.rb', line 33

def interests(amount = 0.0, from_date = BEGINNING_OF_COMPUTER_ERA, to_date = Date.today)
  rates(to_date).select{ |rate| rate.to_date >= from_date && rate.from_date <= to_date }.map do |rate|
    date_beg = [from_date + 1.day, rate.from_date].max
    date_end = [to_date, rate.to_date].min
    OpenStruct.new(
      date_beg: date_beg,
      date_end: date_end,
      days: (date_beg..date_end).count,
      day_rate: rate.day_rate,
      interests: amount * (date_beg..date_end).count * rate.day_rate
    )
  end
end

.rates(till = Date.today) ⇒ Object 



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# File 'lib/interests/calculator.rb', line 13

def rates(till = Date.today)
  @rates = []
  return @rates if config_rates.none? || !starts_in_computers_era?

  prev_rate = nil
  config_rates.sort!{ |x, y| x.date <=> y.date }
  ([blank_rate] + config_rates + [blank_rate(till + 1.day, config_rates.last.rate)]).each_with_index do |rate, i|
    if i > 0
      from_date = prev_rate.date
      to_date = rate.date - 1.day
      days = (to_date - from_date).to_i
      day_rate = prev_rate.rate.to_f / 365
      @rates << OpenStruct.new(from_date: from_date, to_date: to_date, days: days, rate: prev_rate.rate, day_rate: day_rate)
    end
    prev_rate = rate
  end

  @rates
end

.total_interests(amount = 0.0, from_date = BEGINNING_OF_COMPUTER_ERA, to_date = Date.today) ⇒ Object 



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# File 'lib/interests/calculator.rb', line 47

def total_interests(amount = 0.0, from_date = BEGINNING_OF_COMPUTER_ERA, to_date = Date.today)
  interests(amount, from_date, to_date).map(&:interests).inject(0, :+)
end