/**
 * Wetter-Layer: Regenradar via RainViewer (kostenlos, kein API-Key).
 */
const WeatherLayer = {
    _viewer: null,
    _layer: null,
    _interval: null,
    _count: 0,

    start(viewer) {
        if (this._layer) return;
        this._viewer = viewer;
        this._fetchAndShow();
        var self = this;
        this._interval = setInterval(function() { self._fetchAndShow(); }, 300000);
    },

    stop() {
        if (this._interval) { clearInterval(this._interval); this._interval = null; }
        if (this._layer && this._viewer) {
            this._viewer.imageryLayers.remove(this._layer);
            this._layer = null;
        }
        this._count = 0;
    },

    _fetchAndShow() {
        var self = this;
        var statusEl = document.getElementById('status-weather');
        if (statusEl) { statusEl.textContent = 'Lade Radar...'; statusEl.classList.add('active'); }
        fetch('https://api.rainviewer.com/public/weather-maps.json')
        .then(function(r) { return r.json(); })
        .then(function(data) {
            var frames = (data.radar && data.radar.past) || [];
            if (!frames.length) return;
            var latest = frames[frames.length - 1];
            var tileUrl = 'https://tilecache.rainviewer.com' + latest.path + '/256/{z}/{x}/{y}/2/1_1.png';

            if (self._layer && self._viewer) {
                self._viewer.imageryLayers.remove(self._layer);
            }
            self._layer = self._viewer.imageryLayers.addImageryProvider(
                new Cesium.UrlTemplateImageryProvider({
                    url: tileUrl,
                    maximumLevel: 12,
                    credit: 'RainViewer',
                })
            );
            self._layer.alpha = 0.6;
            self._count = 1;
            if (statusEl) statusEl.textContent = 'Regenradar aktiv';
        })
        .catch(function(e) { console.warn('Weather:', e); if (statusEl) statusEl.textContent = 'Fehler'; })
        .finally(function() { setTimeout(function() { if (statusEl) statusEl.classList.remove('active'); }, 5000); });
    },
};