require "equalizer"

module StudyEngine
  class StudyID
    def self.load slug
      return unless slug
      new slug
    end

    def self.dump study_id
      study_id.to_s
    end

    include Equalizer.new(:study, :site, :id)

    attr_accessor :study, :site, :id

    def initialize slug=nil
      @study, @site, @id = slug.split("-") if slug
    end

    def study= value
      @study = value.try(:upcase)
    end

    def site= value
      @site = value.try(:upcase)
    end

    def to_s
      [study, site, id].join("-")
    end

    def <=> other
      to_s <=> other.to_s
    end

    def present?
      [@study, @site, @id].all?(&:present?)
    end

    def valid?
      to_s =~ %r{\A[A-Z]{3}-[A-Z]{3}-[0-9]{4}\Z}
    end
  end
end