module Crudable
  extend ActiveSupport::Concern
  included do
    before_action :set_resource, only: [:audits, :show, :update, :destroy]

    def index
      # @todo: hmmm....
      if params[:portal_id].present?
        render json: _resource_class.send(:all_for_portal, params[:portal_id])
      else
        render json: _resource_class.all.try(:with_all)
      end
    end

    def page
      return index unless _resource_class.respond_to? :page
      return _page_result unless params[:search].present?
      return _page_result unless _resource_class.respond_to? :search
      return _search_result
    end

    def show
      render partial: _resource_name and return if _partial_exist?
      render json: _resource_class.find(params[:id])
    end

    def create
      res = _resource_class.new _get_strong_params
      if res.save
        render json: res, status: :created
      else
        render json: res.errors, status: :unprocessable_entity
      end
    end

    def update
      res = instance_variable_get %(@#{_resource_name})
      if res.update _get_strong_params
        render json: res, status: :ok
      else
        render json: res.errors, status: :unprocessable_entity
      end
    end

    def destroy
      instance_variable_get(%(@#{_resource_name})).destroy
      head 204
    end

    private

    @@resource_class ||= nil
    @@resource_name  ||= nil

    def set_resource
      instance_variable_set %(@#{_resource_name}), _resource_class.find(params[:id])
    end

    def _partial_exist?
      lookup_context.template_exists? _resource_name, _resource_class.name.pluralize.underscore, true
    end

    def _resource_class
      @@resource_class || self.class.name.gsub('Controller', '').singularize.constantize
    end

    def _resource_name
      @@resource_name || self.class.name.gsub('Controller', '').singularize.demodulize.downcase
    end

    def _get_strong_params
      strong_params = %(#{_resource_name}_params).to_sym
      raise NoMethodError, %(Method #{strong_params} does not exist) unless self.private_methods.include? strong_params
      send strong_params
    end

    def _search_result
      page_num = params[:page] || 1
      list = _resource_class

      # @todo: very bad decision
      params[:search] = %(title.title:(#{params[:search].gsub('/', '_')}))
      list = list.search(params[:search]) if list.respond_to? :search
      list = list.page(page_num)

      list = list.per(params[:per].to_i) if params[:per].present?
      render body: JSON.generate({
        total: list.total_count,
        list: params[:portal_id].present? ? list.records.try(:all_for_portal, params[:portal_id]) : list.records.try(:with_all)
      }), content_type: 'application/json; charset=utf-8'
    end

    def _page_result
      page_num = params[:page] || 1
      list = _resource_class.all

      if params[:portal_id].present?
        list = _resource_class.all.try(:all_for_portal, params[:portal_id])
      elsif list.respond_to? :with_all
        list = list.with_all
      else
        list = _resource_class.all
      end

      if params[:json_filter].present? && list.respond_to?(:params_json_filter)
        list = list.params_json_filter params[:json_filter]
      end

      list = list.page(page_num)
      list = list.per(params[:per].to_i) if params[:per].present?
      # we should use JSON.generate to call .to_json for every component; "render json" does not work
      render body: JSON.generate({
        total: list.total_count,
        list: list
      }), content_type: 'application/json; charset=utf-8'
    end
  end
end