module GrapeRouteHelpers
  # methods to extend Grape::Endpoint so that calls
  # to unknown methods will look for a route with a matching
  # helper function name
  module NamedRouteMatcher
    def method_missing(method_id, *arguments)
      super unless method_id.to_s.match(/_path$/)
      segments = arguments.first || {}

      route = Grape::API.decorated_routes.detect do |r|
        route_match?(r, method_id, segments)
      end

      if route
        route.send(method_id, *arguments)
      else
        fail ArgumentError, "No matching route found for #{method_id} with parameters #{segments.inspect}"
      end
    end

    def route_match?(route, method_name, segments)
      return false unless route.respond_to?(method_name)
      fail ArgumentError,
           'Helper options must be a hash' unless segments.is_a?(Hash)
      requested_segments = segments.keys.map(&:to_s)
      route.uses_segments_in_path_helper?(requested_segments)
    end
  end
end
