# Mixin to Cucumber World (for step defs) and page classes that need it
module World
  module MathHelper
    ## Currency helpers

    # Convert to a bigdecimal in US number format, stripping any non-digit chars,
    # while still preserving negative amount
    def currency_amount_from(string)
      string.gsub(/[^\d-]/, "").to_d / 100
    end

    # Format a big decimal to 2 decimal places
    def formatted_to_2d_precision(decimal)
      format("%.2f", decimal)
    end

    ## Period helpers
    def quarter_start_for_period(num)
      # Probably not edge case safe for numbers 0-1 but doesn't matter
      return num if num % 3 == 1
      return num - 1 if num % 3 == 2
      return num - 2 if (num % 3).zero?
    end

    def quarter_end_for_period(num)
      return num if (num % 3).zero?
      return num + 2 if num % 3 == 1
      return num + 1 if num % 3 == 2
    end

    def period_to_quarter_string(num)
      quarter = (((num - 1) / 3) % 4) + 1
      year = ((num - 1) / 12) + 1999
      "Q#{quarter} #{year}"
    end

    def period_to_month_string(num)
      require "date"
      month_int = num % 12
      month_int = 12 if month_int.zero? # to account for December
      month = Date::MONTHNAMES[month_int][0..2] # 1 -> "Jan", 12 -> "Dec"
      year = ((num - 1) / 12) + 1999
      "#{month} #{year}"
    end
  end
end