# frozen_string_literal: true

class Range
  # Compare two ranges and see if they overlap each other
  #  (1..5).overlaps?(4..6) # => true
  #  (1..5).overlaps?(7..9) # => false
  def overlaps?(other)
    raise TypeError unless other.is_a? Range

    self_begin = self.begin
    other_end = other.end
    other_excl = other.exclude_end?

    return false if _empty_range?(self_begin, other_end, other_excl)

    other_begin = other.begin
    self_end = self.end
    self_excl = self.exclude_end?

    return false if _empty_range?(other_begin, self_end, self_excl)
    return true if self_begin == other_begin

    return false if _empty_range?(self_begin, self_end, self_excl)
    return false if _empty_range?(other_begin, other_end, other_excl)

    true
  end

  private
    def _empty_range?(b, e, excl)
      return false if b.nil? || e.nil?

      comp = b <=> e
      comp.nil? || comp > 0 || (comp == 0 && excl)
    end
end
