/**
 * Nachtlicht-Layer: NASA VIIRS Black Marble Nighttime Lights.
 */
const NightlightsLayer = {
    _viewer: null,
    _layer: null,

    start: function(viewer) {
        if (this._layer) return;
        this._viewer = viewer;
        this._layer = viewer.imageryLayers.addImageryProvider(
            new Cesium.WebMapTileServiceImageryProvider({
                url: 'https://gibs.earthdata.nasa.gov/wmts/epsg4326/best/VIIRS_Black_Marble/default/2024-01-01/500m/{TileMatrix}/{TileRow}/{TileCol}.png',
                layer: 'VIIRS_Black_Marble',
                style: 'default',
                tileMatrixSetID: '500m',
                tileMatrixLabels: [
                    '0', '1', '2', '3', '4', '5', '6', '7', '8',
                ],
                format: 'image/png',
                tilingScheme: new Cesium.GeographicTilingScheme(),
                tileWidth: 512,
                tileHeight: 512,
                credit: 'NASA VIIRS Black Marble',
            })
        );
        this._layer.alpha = 0.85;
    },

    stop: function() {
        if (this._layer && this._viewer) {
            this._viewer.imageryLayers.remove(this._layer);
            this._layer = null;
        }
    },
};