/**
 * Flugverkehr-Layer: GPU-beschleunigte Punkt-Primitive.
 */
const FlightsLayer = {
    _viewer: null,
    _points: null,
    _interval: null,
    _count: 0,
    _data: [],

    start(viewer) {
        if (this._points) return;
        this._viewer = viewer;
        this._points = viewer.scene.primitives.add(new Cesium.PointPrimitiveCollection());
        this._fetch();
        var self = this;
        this._interval = setInterval(function() { self._fetch(); }, 30000);

        // Klick-Handler fuer Flugzeug-Details
        this._handler = new Cesium.ScreenSpaceEventHandler(viewer.scene.canvas);
        this._handler.setInputAction(function(click) {
            self._onClick(click.position);
        }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
    },

    stop() {
        if (this._interval) { clearInterval(this._interval); this._interval = null; }
        if (this._points && this._viewer) {
            this._viewer.scene.primitives.remove(this._points);
            this._points = null;
        }
        if (this._handler) { this._handler.destroy(); this._handler = null; }
        this._count = 0;
        this._data = [];
    },

    _onClick(position) {
        if (!this._viewer || !this._data.length) return;
        var picked = this._viewer.scene.pick(position);
        if (!picked || !picked.primitive || picked.primitive.constructor.name !== 'PointPrimitive') return;
        // Finde naechsten Flug zur Klickposition
        var cartesian = this._viewer.scene.pickPosition(position);
        if (!cartesian) return;
        var carto = Cesium.Cartographic.fromCartesian(cartesian);
        var clickLat = Cesium.Math.toDegrees(carto.latitude);
        var clickLon = Cesium.Math.toDegrees(carto.longitude);
        var best = null, bestDist = 999;
        for (var i = 0; i < this._data.length; i++) {
            var a = this._data[i];
            var d = Math.abs(a.lat - clickLat) + Math.abs(a.lon - clickLon);
            if (d < bestDist) { bestDist = d; best = a; }
        }
        if (best && bestDist < 2) {
            var cs = (best.flight || best.hex || '?').trim();
            var html = '<strong style="color:#00ff88">' + cs + '</strong><br>' +
                'ALT: ' + (best.alt_baro || '?') + ' ft<br>' +
                'SPD: ' + (best.gs || '?') + ' kts<br>' +
                'HDG: ' + Math.round(best.track || 0) + '&deg;' +
                (best.origin ? '<br>FROM: ' + best.origin : '');
            this._viewer.selectedEntity = new Cesium.Entity({
                name: cs,
                description: '<div style="font-family:monospace;font-size:13px;color:#00ff88;padding:8px">' + html + '</div>',
            });
        }
    },

    _fetch() {
        var self = this;
        var loadEl = document.getElementById('loading-flights');
        var statusEl = document.getElementById('status-flights');
        if (loadEl) loadEl.classList.add('active');
        if (statusEl) { statusEl.textContent = 'Lade Daten...'; statusEl.classList.add('active'); }
        fetch('/api/flights')
        .then(function(r) { return r.json(); })
        .then(function(data) {
            if (!self._points) return;
            self._points.removeAll();
            var ac = data.ac || [];
            self._data = ac;
            self._count = ac.length;
            var green = Cesium.Color.fromCssColorString('#00ff88');
            for (var i = 0; i < ac.length; i++) {
                var a = ac[i];
                if (!a.lat || !a.lon) continue;
                var altM = (a.alt_baro || 10000) * 0.3048;
                self._points.add({
                    position: Cesium.Cartesian3.fromDegrees(a.lon, a.lat, altM),
                    pixelSize: 3.0,
                    color: green,
                });
            }
            if (statusEl) statusEl.textContent = ac.length.toLocaleString('de-DE') + ' Flugzeuge';
        })
        .catch(function(e) { console.warn('Flights error:', e); if (statusEl) statusEl.textContent = 'Fehler'; })
        .finally(function() { if (loadEl) loadEl.classList.remove('active'); setTimeout(function() { if (statusEl) statusEl.classList.remove('active'); }, 5000); });
    },
};