/**
 * Erdbeben-Layer: Farbige Kreise auf der Erdoberfläche.
 */
const QuakesLayer = {
    _viewer: null,
    _dataSource: null,
    _interval: null,
    _count: 0,

    start(viewer) {
        if (this._dataSource) return;
        this._viewer = viewer;
        this._dataSource = new Cesium.CustomDataSource('quakes');
        viewer.dataSources.add(this._dataSource);
        this._fetch();
        var self = this;
        this._interval = setInterval(function() { self._fetch(); }, 300000);
    },

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

    _fetch() {
        var self = this;
        fetch('/api/quakes')
        .then(function(r) { return r.json(); })
        .then(function(data) {
            if (!self._dataSource) return;
            self._dataSource.entities.removeAll();
            var features = data.features || [];
            self._count = features.length;
            var now = Date.now();
            features.forEach(function(f) {
                var c = f.geometry.coordinates;
                var p = f.properties;
                var mag = p.mag || 1;
                var ageH = (now - p.time) / 3600000;
                var color = ageH < 1
                    ? Cesium.Color.RED.withAlpha(0.8)
                    : ageH < 6 ? Cesium.Color.ORANGE.withAlpha(0.7)
                    : ageH < 12 ? Cesium.Color.YELLOW.withAlpha(0.6)
                    : Cesium.Color.YELLOW.withAlpha(0.4);
                var radius = Math.max(mag * 15000, 20000); // Meter
                self._dataSource.entities.add({
                    position: Cesium.Cartesian3.fromDegrees(c[0], c[1]),
                    ellipse: {
                        semiMinorAxis: radius,
                        semiMajorAxis: radius,
                        material: color,
                        outline: true,
                        outlineColor: color.withAlpha(1.0),
                        outlineWidth: 1,
                        heightReference: Cesium.HeightReference.NONE,
                    },
                    description: '<div style="font-family:monospace;font-size:12px;color:#ff6644">' +
                        '<strong>M' + mag.toFixed(1) + '</strong> ' + (p.place || '') + '<br>' +
                        'Tiefe: ' + (c[2] || '?') + ' km<br>' +
                        'Zeit: ' + new Date(p.time).toLocaleString('de-DE') +
                        '</div>',
                });
            });
        })
        .catch(function(e) { console.warn('Quakes fetch error:', e); });
    },
};