sealink/money_extensions

# frozen_string_literal: true

module SplitBetween
  extend ActiveSupport::Concern

  # Override division -- should not do it, but use split_between
  def /(*_params)
    raise "Division of money NOT allowed - use 'split_between' to avoid rounding errors"
  end

  module ClassMethods
    def split_evenly_between(cents, number)
      Money::Allocation.generate(cents, number).map { |num| Money.from_cents(num) }
    end
  end

  def split_evenly_between(number)
    Money.split_evenly_between(cents, number)
  end

  # Split the money between the specified number - and return an array of money
  # Remainder in splits are given to the highest value e.g.
  # $2.00 splits [40, 81, 40] into [49, 102, 49]
  # $1.01 splits [ 1,  1,  1] into [35,  33, 33]
  def split_between(params)
    # if just a number is passed in, then money is split equally
    if params.is_a?(Integer)
      results = split_evenly_between(params)

      # if an array of monies is passed in, then split in proportions
    elsif params.is_a?(Array)

      raise ArgumentError, 'Can only split up over at least one ration' if params.empty? && !zero?

      results = params.map { |p| p.is_a?(::Money) ? p.cents : p }

      total = results.inject(:+)
      if total.zero?
        return Array.new(results.size, ::Money.new(0)) if zero?

        raise ArgumentError, "Total of ratios should not be zero! You sent in: #{params.inspect}"
      end

      results.map! do |ratio|
        ::Money.new((cents * (ratio.to_f / total)).round)
      end

      # Distribute rounding to max absolute to avoid a $0 amount getting the rounding
      remainder = self - results.total_money
      if !remainder.zero?
        biggest_value_index = results.index(results.max_by(&:abs))
        results[biggest_value_index] += remainder
      end
    else
      raise 'Either a Integer or array has to be passed in for splitting money'
    end

    results
  end
end

class Money
  alias lossy_divide /
  include SplitBetween
end