module DynamicController
  module HelperMethods

    def resource_class
      @resource_class ||= (resource_namespace.to_s.split('::') << controller_name.classify).join('::').constantize
    end

    def resource_namespace
      self.class.to_s.deconstantize.constantize
    end

    def collection=(value)
      instance_variable_set("@#{controller_name}", value)
    end

    def collection
      instance_variable_get("@#{controller_name}")
    end

    def model=(value)
      instance_variable_set("@#{controller_name.singularize}", value)
    end

    def model
      instance_variable_get("@#{controller_name.singularize}")
    end

    def load_parent_models
      parent = nil
      self.class.parent_resources.each do |resource|
        if parent
          parent = parent.send(resource.children_name).find(params[resource.param_name])
        else
          parent = resource.find params[resource.param_name]
        end
        instance_variable_set resource.instance_variable_name, parent
      end
    end

    def parent_models
      return nil if self.class.parent_resources.empty?
      self.class.parent_resources.map do |resource|
        instance_variable_get resource.instance_variable_name
      end
    end

    def parent_model
      (parent_models || []).last
    end

    def handle_error(error)
      respond_to do |format|
        format.html { raise error }
        format.json { render json: error.message, status: :internal_server_error }
      end
    end

    def model_extended_attributes
      resource_class.column_names | resource_class.reflections.map { |k, v| v.klass.column_names.map { |c| "#{k}_#{c}" } }.flatten
    end

    def search_query
      return @search_query if @search_query

      query_key = "query_#{params[:controller]}_#{params[:action]}"

      @search_query = if params.has_key?(:q)
                        session[query_key] = params[:q]
                      else
                        session[query_key]
                      end
    end

    def ransack_query
      search_query.is_a?(String) ? NQL.to_ransack(search_query) : search_query
    end

    def search_query_valid?
      begin
        search_node_valid? ransack_query, model_extended_attributes
      rescue NQL::InvalidExpressionError => ex
        Rails.logger.debug "Invalid search query: #{params[:q]} | Error: #{ex.message}"
        false
      end
    end

    def search_node_valid?(node, valid_attributes)
      return true unless node
      node.deep_symbolize_keys.each do |k, v|
        if k == :a
          return false unless valid_attributes.include?(v['0'.to_sym][:name])
        else
          if v.is_a?(Hash)
            return false unless search_node_valid?(v, valid_attributes)
          elsif v.is_a?(Array)
            v.select { |e| e.is_a?(Hash) }.each { |e| return false unless search_node_valid?(e, valid_attributes) }
          end
        end
      end
      true
    end

  end
end