terriajs/lib/ViewModels/GnafSearchProviderViewModel.js

Geospatial data visualization platform.

'use strict';

/*global require*/
var inherit = require('../Core/inherit');
var SearchProviderViewModel = require('./SearchProviderViewModel');
var SearchResultViewModel = require('./SearchResultViewModel');
var zoomRectangleFromPoint = require('../Map/zoomRectangleFromPoint');
var GnafApi = require('../Models/GnafApi');

var defaultValue = require('terriajs-cesium/Source/Core/defaultValue');
var defined = require('terriajs-cesium/Source/Core/defined');

var NAME = 'Addresses';

/**
 * Search provider that uses the Data61 Elastic Search GNAF service to look up addresses.
 *
 * @param options.terria Terria instance
 * @param [options.gnafApi] The GnafApi object to query - if none is provided one will be created using terria.corsProxy
 *      and the default settings.
 * @param [options.flightDurationSeconds] The number of seconds for the flight animation when zooming to new results.
 * @constructor
 */
var GnafSearchProviderViewModel = function(options) {
    SearchProviderViewModel.call(this);

    options = defaultValue(options, defaultValue.EMPTY_OBJECT);
    this.terria = options.terria;

    var url = defaultValue(options.url, this.terria.configParameters.gnafSearchUrl);

    this.name = NAME;
    this.gnafApi = defaultValue(options.gnafApi, new GnafApi(this.terria.corsProxy, url));
    this._geocodeInProgress = undefined;
    this.flightDurationSeconds = defaultValue(options.flightDurationSeconds, 1.5);
};

inherit(SearchProviderViewModel, GnafSearchProviderViewModel);

GnafSearchProviderViewModel.prototype.search = function(searchText) {
    this.isSearching = true;
    this.searchResults.removeAll();

    if (!defined(searchText) || /^\s*$/.test(searchText)) {
        return;
    }

    this.searchMessage = undefined;
    this.terria.analytics.logEvent('search', 'gnaf', searchText);

    // If there is already a search in progress, cancel it.
    if (defined(this._geocodeInProgress)) {
        this._geocodeInProgress.cancel = true;
        this._geocodeInProgress = undefined;
    }

    var thisGeocode = this.gnafApi.geoCode(searchText)
        .then(function(hits) {
            if (thisGeocode.cancel) {
                return;
            }

            this.isSearching = false;

            if (hits.length === 0) {
                this.searchMessage = 'Sorry, no locations match your search query.';
                return;
            }

            this.searchResults = hits.map(function(hit) {
                return new SearchResultViewModel({
                    name: hit.name,
                    isImportant: hit.locational,
                    clickAction: createZoomToFunction(this.terria, hit.location, this.flightDurationSeconds),
                    location: hit.location
                });
            }.bind(this));
        }.bind(this)).otherwise(function() {
            if (thisGeocode.cancel) {
                return;
            }

            this.isSearching = false;
            this.searchMessage = 'An error occurred while searching.  Please check your internet connection or try again later.';
        }.bind(this));

    this._geocodeInProgress = thisGeocode;
};

function createZoomToFunction(terria, location, duration) {
    var rectangle = zoomRectangleFromPoint(location.latitude, location.longitude, 0.01);

    return function() {
        terria.currentViewer.zoomTo(rectangle, duration);
    };
}

module.exports = GnafSearchProviderViewModel;