terriajs/lib/ViewModels/NominatimSearchProviderViewModel.js

Geospatial data visualization platform.

'use strict';

/*global require*/
var inherit = require('../Core/inherit');
var SearchProviderViewModel = require('./SearchProviderViewModel');
var SearchResultViewModel = require('./SearchResultViewModel');

var CesiumMath = require('terriajs-cesium/Source/Core/Math');
var Cartesian2 = require('terriajs-cesium/Source/Core/Cartesian2');
var defaultValue = require('terriajs-cesium/Source/Core/defaultValue');
var defined = require('terriajs-cesium/Source/Core/defined');
var Ellipsoid = require('terriajs-cesium/Source/Core/Ellipsoid');
var loadJson = require('../Core/loadJson');
var Rectangle = require('terriajs-cesium/Source/Core/Rectangle');
var when = require('terriajs-cesium/Source/ThirdParty/when');

var NominatimSearchProviderViewModel = function(options) {
    SearchProviderViewModel.call(this);

    options = defaultValue(options, defaultValue.EMPTY_OBJECT);

    this.terria = options.terria;
    this.countryCodes = defined(options.countryCodes) ? "&countrycodes=" + options.countryCodes : "";

    this._geocodeInProgress = undefined;

    this.name = 'Nominatim';
    this.url = defaultValue(options.url, '//nominatim.openstreetmap.org/');
    if (this.url.length > 0 && this.url[this.url.length - 1] !== '/') {
        this.url += '/';
    }
    this.flightDurationSeconds = defaultValue(options.flightDurationSeconds, 1.5);
    this.limitBounded = 2;
    this.limitOthers = 2;
};

inherit(SearchProviderViewModel, NominatimSearchProviderViewModel);

NominatimSearchProviderViewModel.prototype.search = function(searchText) {
    if (!defined(searchText) || /^\s*$/.test(searchText)) {
        this.isSearching = false;
        this.searchResults.removeAll();
        return;
    }

    this.isSearching = true;
    this.searchResults.removeAll();
    this.searchMessage = undefined;

    this.terria.analytics.logEvent('search', 'nominatim', searchText);

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

    var bboxStr = '';

    if (defined(this.terria.cesium)) {
        var viewer =  this.terria.cesium.viewer;
        var posUL = viewer.camera.pickEllipsoid(new Cartesian2(0, 0), Ellipsoid.WGS84);
        var posLR = viewer.camera.pickEllipsoid(new Cartesian2(viewer.canvas.width, viewer.canvas.height), Ellipsoid.WGS84);
        if(defined(posUL) && defined(posLR)) {
            posUL = Ellipsoid.WGS84.cartesianToCartographic(posUL);
            posLR = Ellipsoid.WGS84.cartesianToCartographic(posLR);
            bboxStr = "&viewbox=" + CesiumMath.toDegrees(posUL.longitude) + "," +
            CesiumMath.toDegrees(posUL.latitude) + "," +
            CesiumMath.toDegrees(posLR.longitude) + "," +
            CesiumMath.toDegrees(posLR.latitude);
        } else {
            bboxStr = "";
        }
    } else if (defined( this.terria.leaflet)) {
        var bbox =  this.terria.leaflet.map.getBounds();
        bboxStr = "&viewbox=" + bbox.getWest() + "," +
        bbox.getNorth() + "," + bbox.getEast() + "," + bbox.getSouth();
    }
    var promiseBounded = loadJson(this.url + 'search?q=' + searchText + bboxStr +
                  '&bounded=1&format=json' + this.countryCodes + '&limit='
                  + this.limitBounded);
    var promiseOthers = loadJson(this.url + 'search?q=' + searchText +
                 '&format=json' + this.countryCodes + '&limit=' + this.limitOthers);

    var that = this;
    var geocodeInProgress = this._geocodeInProgress = {
        cancel: false
    };

    return when.all([ promiseBounded, promiseOthers ]).then(function(result) {
        if (geocodeInProgress.cancel) {
            return;
        }
        that.isSearching = false;

        if(result.length === 0) {
            return;
        }

        var locations = [];

            // Locations in the bounded query go on top, locations elsewhere go undernearth
        var findDbl = function(elts, id) {
            return elts.filter(function(elt) {
                return elt.id === id;
            })[0];
        };

        for(var i = 0; i < result.length; ++i) {
            for(var j = 0; j < result[i].length; ++j) {
            var resource = result[i][j];

            var name = resource.display_name;
            if (!defined(name)) {
                        continue;
            }

            if(!findDbl(locations, resource.place_id)) {
                locations.push(new SearchResultViewModel({
                id: resource.place_id,
                name: name,
                isImportant: true,
                clickAction: createZoomToFunction(that, resource)
                }));
            }
                }
        }

        that.searchResults.push.apply(that.searchResults, locations);

        if (that.searchResults.length === 0) {
            that.searchMessage = 'Sorry, no locations match your search query.';
        }
    }).otherwise(function() {
        if (geocodeInProgress.cancel) {
            return;
        }

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

function createZoomToFunction(viewModel, resource) {
    var bbox = resource.boundingbox;
    var south = bbox[0];
    var west = bbox[2];
    var north = bbox[1];
    var east = bbox[3];

    var rectangle = Rectangle.fromDegrees(west, south, east, north);

    return function() {
        var terria = viewModel.terria;
        terria.currentViewer.zoomTo(rectangle, viewModel.flightDurationSeconds);
    };
}

module.exports = NominatimSearchProviderViewModel;