require 'scrivito/blob'

module Scrivito
  #
  # Configures the Scrivito SDK.
  # The configuration keys +tenant+ and +api_key+ _must_ be provided.
  #
  # @example
  #   Scrivito.configure do |config|
  #     config.tenant  = 'my-tenant-name'
  #     config.api_key = 'secret'
  #   end
  #
  # @api public
  #
  def self.configure
    yield ::Scrivito::Configuration
  end

  #
  # @api public
  #
  class Configuration
    #
    # Default path of a CA certification file in PEM format.
    #
    # @api public
    #
    DEFAULT_CA_FILE = File.expand_path('../../../config/ca-bundle.crt', __FILE__)

    class << self
      # Determine if current visitor is permitted to edit content.
      attr_accessor :editing_auth_callback

      attr_accessor :find_user_proc

      # Configure a callback to be invoked when the Scrivito SDK determines,
      # if current visitor is permitted to edit content.
      # Default is <code>false</code>.
      #
      # Example Usage:
      #     Scrivito::Configuration.editing_auth do |env|
      #       request = Rack::Request.new(env)
      #       # return truey if current visitor is permitted to edit content, falsy otherwise
      #     end
      # @api public
      def editing_auth(&block)
        if block.respond_to?(:arity) && block.arity == 1
          self.editing_auth_callback = block
        else
          raise ArgumentError, 'editing_auth should have only one attribute!'
        end
      end

      # Configures how to find users for the in-place GUI.
      # @api public
      # @param [Proc] find_user_proc proc for finding a user by the user id
      # @yieldparam [String] user_id id of the user
      # @yieldreturn [Scrivito::User] if the user with the given user id was found
      # @yieldreturn [NilClass] if the user with the given user id was not found
      # @raise [Scrivito::ScrivitoError] if the proc returns neither a {Scrivito::User}, nor +nil+
      # @note This configuration key is optional. If it is not configured the in-place GUI would
      #   behave normally, but would not be able to find any users.
      # @example Return a "dummy" {Scrivito::User}
      #   Scrivito.configure do |config|
      #     config.find_user do |user_id|
      #       Scrivito::User.new(user_id)
      #     end
      #   end
      # @example Find the user with a custom user model and convert it to a {Scrivito::User}
      #   Scrivito.configure do |config|
      #     config.find_user do |user_id|
      #       my_user = MyUserModel.find(user_id)
      #       if my_user
      #         my_user.to_scrivito_user
      #       end
      #     end
      #   end
      def find_user(&find_user_proc)
        self.find_user_proc = find_user_proc
      end

      # TODO: Legacy compatiblity. Remove when DisplayHelper gets removed.
      def editor_interface_enabled?
        false
      end

      # The +Scrivito+ makes heavy use of filesystem caching.
      # Use this method to configure the directory that should be used to store cached data.
      # By default, +RAILS_ROOT/tmp/scrivito_cache+ will be used.
      # @param path [String] Path to directory that should be used to store cached data.
      # @example Configure +Scrivito+ to store its cache under +/tmp/my_cache+.
      #     Scrivito::Configuration.cache_path = '/tmp/my_cache'
      # @api public
      def cache_path=(path)
        CmsCacheStorage.backend_cache = ActiveSupport::Cache::FileStore.new(path)
      end

      #
      # Sets the tenant name.
      # This configuration key _must_ be provided.
      #
      # @api public
      #
      def tenant=(tenant_name)
        @endpoint_uri = nil
        @tenant = tenant_name
      end

      #
      # Sets the API key.
      # This configuration key _must_ be provided.
      #
      # @api public
      #
      attr_writer :api_key

      #
      # Sets the API endpoint URL.
      # This configuration key is optional.
      # Default is +'api.scrivito.com'+.
      # If no schema is provided HTTPS is assumed.
      #
      # @api public
      #
      attr_writer :endpoint

      #
      # Gets the path of a CA certification file in PEM format.
      #
      # @return [String]
      # @api public
      #
      attr_reader :ca_file

      # Sets path of a CA certification file in PEM format.
      # The file can contain several CA certificates.
      # Certifications will be used for endpoint peer verification of various scrivito services
      # e.g. Content Read Service.
      # @api public
      def ca_file=(path)
        File.read(path) if path # Try to read the given file and fail if it doesn't exist or is not readable.
        @ca_file = path
      end

      def to_prepare
        unless Rails.configuration.cache_classes
          NamedLink.reset_cache
          BasicObj.reset_type_computer!
          BasicWidget.reset_type_computer!
          ::ApplicationController.__send__(:helper, :cms)
        end
      end

      def configure_cms_database
      end

      def tenant
        assert_key_present(:tenant)
        @tenant
      end

      def api_key
        assert_key_present(:api_key)
        @api_key
      end

      def endpoint
        assert_key_present(:endpoint)
        @endpoint
      end

      def endpoint_uri
        @endpoint_uri ||= calculate_endpoint_uri
      end

      def set_defaults!
        self.ca_file = DEFAULT_CA_FILE
        self.editing_auth { |env| false }
        self.endpoint = 'api.scrivito.com'
        self.check_batch_size = 100
      end

      attr_accessor :choose_homepage_callback, :check_batch_size

      # Configure a callback to be invoked when the Scrivito SDK delivers the homepage.
      # The given callback will receive the rack env
      # and must return an {BasicObj Obj} to be used as the homepage.
      # If no callback is configured, {BasicObj.homepage Obj.homepage} will be used as the default.
      # @api public
      def choose_homepage(&block)
        self.choose_homepage_callback = block
      end

      def cms_routes(*args)
        raise <<-EOS.gsub(/\s+/, ' ')
        Calling Scrivito::Configuration.cms_routes is not needed anymore.
        Please remove it from config/routes.rb
        EOS
      end

      def use_x_sendfile=(value)
        raise 'Configuration.use_x_sendfile is now available as Rails configuration:'\
              ' config.action_dispatch.x_sendfile_header = "X-Sendfile"'
      end

      def obj_formats
        @obj_formats ||= {
          '_default' => proc do |obj, user|
            {
              id: obj.id,
              obj_class_name: obj.obj_class_name,
              description_for_editor: obj.description_for_editor,
              modification: obj.modification,
              has_conflict: obj.has_conflict?,
              last_changed: obj.last_changed.utc.iso8601,
              is_binary: obj.binary?,
              restriction_messages: user.restriction_messages_for(obj)
            }
          end
        }
      end

      def register_obj_format(name, &block)
        if name.start_with? '_'
          raise InvalidFormatNameError.new('Format names starting with underscore are not allowed.')
        else
          obj_formats[name] = block
        end
      end

      private

      def assert_key_present(key)
        if instance_variable_get("@#{key}").nil?
          raise "Missing required configuration key '#{key}'."
        end
      end

      def calculate_endpoint_uri
        url = endpoint
        url = "https://#{url}" unless url.match(/^http/)
        url = "#{url}/tenants/#{tenant}"
        URI.parse(url)
      end
    end

    self.set_defaults!
  end

  class InvalidFormatNameError < StandardError
  end
end