module Ensurance
  class Date
    FORMATS = %w|%m/%d/%Y %Y/%m/%d|.freeze
    def self.ensure(thing)
      case thing.class.name
      when "NilClass"
        nil
      when "Integer","Float"
        Time.ensure(thing).to_date
      when "Date"
        thing
      when "String"
        if thing.to_i.to_s == thing
          ::Time.at(thing.to_i).to_date
        elsif thing.to_f.to_s == thing
          ::Time.at(thing.to_f).to_date
        elsif thing.index("/")
          # Assume US Date format
          result = nil
          FORMATS.each do |f|
            begin
              result = Date.strptime(thing, f)
              break
            rescue ArgumentError
            end
          end
          raise ArgumentError.new("Bad Date: #{thing}".yellow) unless result
          result
        else
          ::Date.parse(thing)
        end
      else
        if thing.respond_to?(:to_date)
          thing.to_date
        else
          raise ArgumentError.new("Unknown Type for Date to ensure: #{thing.class.name}")
        end
      end
    end
  end
end