version.rb

module Project
  class Version
    ##
    # The location of the version number file
    # VERSION_FILE  = File.join(Rails.root, 'config/build.version')
    VERSION_FILE  = File.join(File.dirname(__FILE__), 'build.version')
    @@releases = %w[major minor point].freeze
    
    
    ##
    # Generate build version file
    #
    def self.generate_build_file
      File.open(VERSION_FILE, 'w') { |f| f.write '0.0.1' }
      print "Created your build file (build.version) located at #{VERSION_FILE.to_s}"
    end
    
    
    ##
    # Current Version
    #
    # Pulls the current build version 
    #
    def self.current
      print File.read(VERSION_FILE).chomp
    end

    
    ##
    # Verion it
    #
    # @param  [String, Symbol]
    #
    def self.version_it(direction, release)
      version     = File.read(VERSION_FILE).chomp
      int_ver     = version.split('.').join().to_i
      new_version = case release
      when :major then update_build_version(int_ver, direction, 100)
      when :minor then update_build_version(int_ver, direction, 10)
      when :point then update_build_version(int_ver, direction, 1)
      else
        raise ArgumentError, "You can only increase the version number by major, minor, or point."
      end

      File.open(VERSION_FILE, 'w') { |f| f.write new_version }
      print "Previous Version: #{version} - New Version: #{new_version}" and return
    end
    
    
    ##
    # Method Missing
    #
    # @param  [String, Symbol]
    #
    # Project::Version.up(:point)
    # Project::Version.down(:point)
    # Project::Version.up(:minor)
    # Project::Version.down(:major)
    # 
    #
    def self.method_missing(direction, release)
      if @@releases.include?(release.to_s.downcase)
        version_it(direction, release)
      else
        super
      end
    end
    
    private
      
      ##
      # Update build version
      #
      # @param  [Integer, Symbol, Symbol]
      # @return [String]
      #
      def self.update_build_version(version, direction, points)
        new_version = case direction
        when :up    then ("%03d" % (version + points)).split(//).join('.')
        when :down  then ("%03d" % (version - points unless version == 0)).split(//).join('.')
        else
          "%03d" % version
        end
        return new_version
      end

  end
end


# Project::Version.generate_build_file
# Project::Version.current
# Project::Version.up(:point)