module OpenEhr
  module AssumedLibraryTypes
    class Interval
      attr_reader :lower, :lower_included, :lower_unbounded
      attr_reader :upper, :upper_included, :upper_unbounded
      def initialize(lower, upper, 
                     lower_included = nil, upper_included = nil)
        check_lower_upper(lower, upper)
        set_lower_included(lower_included)
        set_upper_included(upper_included)
      end

      def set_lower(lower)
        check_lower_upper(lower, @upper)
      end

      def set_upper(upper)
        check_lower_upper(@lower, upper)
      end

      def set_lower_included(lower_included)
        if (lower == nil) && (lower_included != nil)
          raise ArgumentError, "lower is not set"
        end
        @lower_included = lower_included
      end

      def set_upper_included(upper_included)
        @upper_included = upper_included
        if (upper == nil) && (upper_included != nil)
          raise ArgumentError, "upper is not set"
        end
      end

      def has?(value)
        if ((@lower < value) && (value < @upper) ||
            (@lower_included == true) && (@lower == value) ||
            (@upper_included == true) && (@upper == value))
          true
        else
          false
        end
      end

      private

      def check_lower_upper(lower, upper)
        if (lower == nil) && (upper == nil)
          raise ArgumentError, "Either lower or upper must be assigned"
        end
        if (lower == nil) && (upper != nil)
          @lower_unbounded = true          
        elsif (lower != nil) && (upper == nil)
          @upper_unbounded = true
        elsif lower > upper
          raise ArgumentError, "Upper must be larger than lower."
        end
        @lower = lower
        @upper = upper
      end
    end
  end
end