module ActionDispatch
  module Journey
    ###
    # The Routing table.  Contains all routes for a system.  Routes can be
    # added to the table by calling Routes#add_route
    class Routes
      include Enumerable

      attr_reader :routes, :named_routes

      def initialize
        @routes             = []
        @named_routes       = {}
        @ast                = nil
        @partitioned_routes = nil
        @simulator          = nil
      end

      def length
        @routes.length
      end
      alias :size :length

      def last
        @routes.last
      end

      def each(&block)
        routes.each(&block)
      end

      def clear
        routes.clear
      end

      def partitioned_routes
        @partitioned_routes ||= routes.partition { |r|
          r.path.anchored && r.ast.grep(Nodes::Symbol).all? { |n| n.default_regexp?  }
        }
      end

      def ast
        return @ast if @ast
        return if partitioned_routes.first.empty?

        asts = partitioned_routes.first.map { |r| r.ast }
        @ast = Nodes::Or.new(asts)
      end

      def simulator
        return @simulator if @simulator

        gtg = GTG::Builder.new(ast).transition_table
        @simulator = GTG::Simulator.new gtg
      end

      ###
      # Add a route to the routing table.
      def add_route app, path, conditions, defaults, name = nil
        route = Route.new(name, app, path, conditions, defaults)

        route.precedence = routes.length
        routes << route
        named_routes[name] = route if name && !named_routes[name]
        clear_cache!
        route
      end

      private
      def clear_cache!
        @ast                = nil
        @partitioned_routes = nil
        @simulator          = nil
      end
    end
  end
end