cprussin/formatted-date

require 'date'

module FormattedDate

    # This module contains instance extensions for the `Date` class.
    module DateInstanceMethods

        # Returns the word _Today_, _Tomorrow_, or _Yesterday_ as appropriate
        # relative to the passed date.
        #
        # @param date [Date] the date to compare this object with
        # @return [String] _Today_, _Tomorrow_, _Yesterday_, or `nil`
        def alternative(date = Date.today)
            if self === date
                'Today'
            elsif self === date + 1
                'Tomorrow'
            elsif self === date - 1
                'Yesterday'
            end
        end

        # If the method called was one of the keys in the `Date.formats` hash, then
        # this will return the date formatted appropriately.  If a `Date` is
        # passed, then it will be used as the reference date whenever calling
        # `Date.alternative`.
        #
        # @param method [Symbol] the name of the called method
        # @param args [Array] the arguments passed
        # @return [String] the formatted date, if the called method was a format
        # @raise [NoMethodError] if the called method was not a format
        def method_missing(method, *args)
            if self.class.formats.has_key?(method)
                format = self.class.formats[method]
                if format.is_a?(Hash)
                    alt = format.has_key?(:alternatives) ? format[:alternatives] : true
                    format = format[:format]
                else
                    alt = true
                end
                if alt
                    args.empty? ? alternative : alternative(args.first)
                end || strftime(format)
            else
                super
            end
        end
    end

    # This module contains class extensions for the `Date` class.
    module DateClassMethods

        # This hash lists recognized formats on the `Date` class.  The keys are the
        # symbol names of the formats.  The values can be in one of two formats:
        #
        # - **A string**: this string is passed to `strftime` when using this
        #   format
        # - **A hash**: this hash has two keys:
        #   - **format**: this string is passed to strftime when using this format.
        #     The same as if the format was specified only with a string.
        #   - **alternatives**: `false` if you don't want the format to be replaced
        #     by the words _Today_, _Tomorrow_, or _Yesterday_, as appropriate.
        attr_accessor :formats
    end

    Date.include(DateInstanceMethods)
    Date.extend(DateClassMethods)
end