/**
 * Flugverkehr-Layer: Grüne Punkte mit Höhenprofil auf dem 3D-Globus.
 */
const FlightsLayer = {
    _viewer: null,
    _dataSource: null,
    _interval: null,
    _count: 0,

    start(viewer) {
        if (this._dataSource) return;
        this._viewer = viewer;
        this._dataSource = new Cesium.CustomDataSource('flights');
        viewer.dataSources.add(this._dataSource);
        this._fetch();
        var self = this;
        this._interval = setInterval(function() { self._fetch(); }, 30000);
    },

    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/flights')
        .then(function(r) { return r.json(); })
        .then(function(data) {
            if (!self._dataSource) return;
            self._dataSource.entities.removeAll();
            var ac = data.ac || [];
            self._count = ac.length;
            ac.forEach(function(a) {
                if (!a.lat || !a.lon) return;
                var alt = (a.alt_baro || a.alt_geom || 10000) * 0.3048; // ft -> m
                if (alt < 100) alt = 10000; // ground = default
                var cs = (a.flight || a.callsign || a.hex || '???').trim();
                var spd = a.gs || 0;
                self._dataSource.entities.add({
                    position: Cesium.Cartesian3.fromDegrees(a.lon, a.lat, alt),
                    point: {
                        pixelSize: 4,
                        color: Cesium.Color.fromCssColorString('#00ff88'),
                        outlineColor: Cesium.Color.fromCssColorString('#004422'),
                        outlineWidth: 1,
                        heightReference: Cesium.HeightReference.NONE,
                        disableDepthTestDistance: Number.POSITIVE_INFINITY,
                    },
                    label: {
                        text: cs,
                        font: '10px monospace',
                        fillColor: Cesium.Color.fromCssColorString('#00ff88').withAlpha(0.8),
                        outlineColor: Cesium.Color.BLACK,
                        outlineWidth: 2,
                        style: Cesium.LabelStyle.FILL_AND_OUTLINE,
                        pixelOffset: new Cesium.Cartesian2(8, -4),
                        scale: 0.8,
                        showBackground: false,
                        disableDepthTestDistance: Number.POSITIVE_INFINITY,
                        distanceDisplayCondition: new Cesium.DistanceDisplayCondition(0, 2000000),
                    },
                    description: '<div style="font-family:monospace;font-size:12px;color:#00ff88">' +
                        '<strong>' + cs + '</strong><br>' +
                        'ALT: ' + (a.alt_baro || '?') + ' ft<br>' +
                        'SPD: ' + Math.round(spd) + ' kts<br>' +
                        'HDG: ' + Math.round(a.track || 0) + '°' +
                        (a.t ? '<br>TYP: ' + a.t : '') +
                        '</div>',
                });
            });
        })
        .catch(function(e) { console.warn('Flights fetch error:', e); });
    },
};