diff-area.js

(function ($, L, zoneController, map) {
    'use strict';
    
    $.getScript('https://npmcdn.com/@turf/turf/turf.min.js');

    var Control = L.Control.extend({
        options: {
            position: 'topleft'
        },

        onAdd: function (map) {
            var $container = $('<div></div>'),
                $findButton = $('<button>Trouver les zones vides</button>'),
                $nextButton = $('<button>Afficher la prochaine zone vide</button>');
            
            $findButton.click(function (event) {
                event.stopPropagation();
                event.preventDefault();
                
                mbShowLoadingOverlay();
                $findButton.hide();
                
                findEmptyAreas(function () {
                    $nextButton.click();
                    mbHideLoadingOverlay();
                    
                    if (emptyAreas.length > 0) {
                        $nextButton.show();
                    }
                });
            });
            
            $nextButton.click(function (event) {
                event.stopPropagation();
                event.preventDefault();
                
                displayNextEmptyArea();
                
                if (emptyAreas.length === 0) {
                    $findButton.show();
                    $nextButton.hide();
                }
            });
            
            $nextButton.hide();
            
            $container.append($findButton);
            $container.append($nextButton);
            
            return $container.get(0);
        }
    });
    
    function latLngBoundsToTurfPolygon(bounds) {
        return turf.polygon([[
            [bounds.getNorth(), bounds.getWest()],
            [bounds.getNorth(), bounds.getEast()],
            [bounds.getSouth(), bounds.getEast()],
            [bounds.getSouth(), bounds.getWest()],
            [bounds.getNorth(), bounds.getWest()]
        ]]);
    }
    
    function addTurfPolygonToMap(polygon) {
        map.addLayer(L.multiPolygon(polygon.geometry.coordinates));
    }
    
    function computeIntersection(id, coordinates, data) {
        try {
            var area, intersection,
                view = latLngBoundsToTurfPolygon(map.getBounds());
            
            if (!coordinates[0][0][0]) {
                coordinates = [coordinates];
            }
          
            area = turf.polygon(coordinates);
            intersection = turf.intersect(view, area);
            
            if (intersection !== undefined) {
                if (filledArea === null) {
                    filledArea = intersection;
                } else {
                    filledArea = turf.merge({ type: 'FeatureCollection', features: [filledArea, intersection] });
                }
            }
        } catch (exception) {
            console.error(exception);
        }
    }
    
    function findEmptyAreas(callback) {
        filledArea = null;
        emptyAreas = [];
        
        zoneController.zoneVilleLayer.load.hook = computeIntersection;
        zoneController.requestMapUpdate();
        
        $(zoneController).one('villeLoaded', function () {
            var coordinates = filledArea.geometry.coordinates,
                length = coordinates.length;
            
            delete zoneController.zoneVilleLayer.load.hook;
            
            if (length > 1) {
                for (var i = 1; i < length; ++i) {
                    emptyAreas.push(coordinates[i]);
                }
            }
            
            if (typeof callback === 'function') {
                callback();
            }
        });
    }
    
    function displayNextEmptyArea() {
        if (emptyAreas.length) {
            currentCoordinates = emptyAreas.shift();
            
            if (currentPolygon) {
                map.removeLayer(currentPolygon);
            }
            
            currentPolygon = L.polygon(currentCoordinates);
            
            map.addLayer(currentPolygon);
            console.log('JSON: ' + JSON.stringify(currentCoordinates));
        }
    }
    
    var filledArea = null,
        emptyAreas = null,
        currentCoordinates = null,
        currentPolygon = null;

    map.addControl(new Control());
    
}(jQuery, L, mbZoneController, cdf_map_zones));