const _ = require('lodash');
const Debug = require('../../helper/debug');
const debugLog = new Debug('controller:predicates:has_results_at_layers');
const stackTraceLine = require('../../helper/stackTraceLine');

module.exports = {
  // returns a function that returns true if any result.layer is in any of the
  // supplied layers using array intersection
  // example usage: determining if the response contains only admin results
  any(layers) {
    return (request, response) => {
      const has_results_at_any_layer = !_.isEmpty(
        _.intersection(
          // convert layers to an array if it isn't already one
          _.castArray(layers),
          // pull all the layer properties into an array
          _.map(response.data, _.property('layer'))
      ));

      debugLog.push(request, () => ({
        reply: {[layers]: has_results_at_any_layer},
        stack_trace: stackTraceLine()
      }));
      return has_results_at_any_layer;

    };
  },
  // returns a function that returns true IFF the layers in all the results are
  // in the supplied layers
  // example usage: determining if all results are either neighbourhoods or localities
  all(layers) {
    return (request, response) => {
      const has_results_at_all_layers = _.isEmpty(
        _.difference(
          // get all layers of all the results into an array
          _.map(response.data, _.property('layer')),
          // convert layers to an array if it isn't already one
          _.castArray(layers)
        )
      );

      debugLog.push(request, () => ({
        reply: {[layers]: has_results_at_all_layers},
        stack_trace: stackTraceLine()
      }));
      return has_results_at_all_layers;

    };
  }

};