module Scrivito

# @api public
module RoutingExtensions

  # @api public
  #
  #+scrivito_route+ defines routes for Scrivito pages. The default routes are:
  #
  #   scrivito_route '(/)(*slug-):id', using: 'slug_id', via: :all
  #   scrivito_route '/', using: 'homepage', via: :all
  #   scrivito_route '/*permalink', using: 'permalink', format: false, via: :all
  #
  # The first parameter of +scrivito_route+ should look familiar - it is just a regular
  # Rails route pattern. You can make full use of the Rails route patterns when specifying
  # Scrivito routes.
  #
  # In addition to directing incoming traffic to the code that handles it, Scrivito
  # routes have another distinct functionality: They determine which URL or path is generated
  # for a given CMS object. The +using:+ option needs to be provided to tell Scrivito which
  # route should be used for which type of CMS objects.  For example, <code>using:
  # "permalink"</code> instructs Scrivito to use the route for CMS objects to which a
  # +_permalink+ has been assigned. The Scrivito routes expect the route pattern to contain
  # route parameters for dynamically inserting the values for individual CMS objects. If,
  # for example, the permalink of an object is +about+ and the route pattern is
  # +my_page/*permalink+, Scrivito generates the url +http://www.example.com/my_page/about+.
  # Valid +:using+ values and their required route parameters are:
  #
  # [+slug_id+] Route pattern for a normal CMS object. Expected route parameters are +slug+
  #             and +id+.
  # [+homepage+] Route pattern for a homepage CMS object. No route parameters needed.
  # [+permalink+] Route pattern for CMS objects that have a +_permalink+ assigned to them. The
  #               required route parameter is +permalink+.
  #
  # @example Route that starts with the object ID
  #   scrivito_route '(/):id(/*slug)', using: 'slug_id', via: [:get, :post]
  #
  # @example Scoped permalink with disabled format
  #   scrivito_route '/pl/*permalink', using: 'permalink', format: false
  #
  # @param path [String] a Rails route pattern
  # @param using [String] The name of the route. Valid values are +slug_id+, +homepage+, and
  #   +permalink+.
  # @param format [Boolean] Use +format+ +true+ or +false+ to enforce or disable the format.
  # @param via [Symbol] Use to specify for which HTTP verbs the route should match. +:get+ is
  #   the default. Use +:all+ to allow every verb.
  #
  # @note To use +scrivito_route+ {Scrivito::Configuration.inject_preset_routes} needs to be
  #   disabled.
  def scrivito_route(path, using:, format: nil, via: :get)
    assert_scrivito_route_enabled
    # @set is a ActionDispatch::Routing::RouteSet
    # see: http://git.io/v4UYF and http://git.io/v4UOI
    route_set = @set

    route_name = using.to_sym

    route = Route.register(route_set, route_name)

    options = {
      to: 'scrivito/cms_dispatch#index',
      via: via,
      format: format,
      as: route.helper_name,
    }

    options[:constraints] = {id: /[a-z0-9]{16}/} if route_name == :slug_id

    begin
      match(path, options)
    rescue ArgumentError => error
      if error.message.include?(route.helper_name)
        raise ScrivitoError,
            %(You have already defined a Scrivito route with the name "#{route_name}".)
      else
        raise error
      end
    end
  end

  private

  def assert_scrivito_route_enabled
    unless Scrivito::Configuration.scrivito_route_enabled?
      raise ScrivitoError, 'The preset routes are still enabled. Please disable them by ' \
        'setting the configuration "inject_preset_routes" to false before using scrivito_route'
    end
  end

end

end