halogenandtoast/timelord

module Timelord
  class NextWeekday
    ONE_WEEK = 7
    TWO_WEEKS = 14

    def initialize(date_index, today)
      @date_index = date_index
      @today = today
    end

    def to_date
      today + amount_to_increase
    end

    private
    attr_reader :today, :date_index

    def amount_to_increase
      diff = date_index - current_index
      diff + number_of_weeks
    end

    def number_of_weeks
      if date_index <= current_index
        TWO_WEEKS
      else
        ONE_WEEK
      end
    end

    def current_index
      today.cwday - 1
    end
  end
end