/**
 * Schiffsverkehr-Layer: GPU-beschleunigte Punkt-Primitive.
 */
const ShipsLayer = {
    _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(); }, 60000);

        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;
        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 s = this._data[i];
            var d = Math.abs(s.lat - clickLat) + Math.abs(s.lon - clickLon);
            if (d < bestDist) { bestDist = d; best = s; }
        }
        if (best && bestDist < 1) {
            var name = best.name || ('MMSI ' + (best.mmsi || '?'));
            var html = '<strong style="color:#4499ff">' + name + '</strong><br>' +
                'MMSI: ' + (best.mmsi || '?') + '<br>' +
                'SOG: ' + (best.sog || 0).toFixed(1) + ' kn<br>' +
                'COG: ' + Math.round(best.cog || 0) + '&deg;';
            this._viewer.selectedEntity = new Cesium.Entity({
                name: name,
                description: '<div style="font-family:monospace;font-size:13px;color:#4499ff;padding:8px">' + html + '</div>',
            });
        }
    },

    _fetch() {
        var self = this;
        var loadEl = document.getElementById('loading-ships');
        var statusEl = document.getElementById('status-ships');
        if (loadEl) loadEl.classList.add('active');
        if (statusEl) { statusEl.textContent = 'Lade Daten...'; statusEl.classList.add('active'); }
        fetch('/api/ships')
        .then(function(r) { return r.json(); })
        .then(function(data) {
            if (!self._points) return;
            self._points.removeAll();
            var ships = data.ships || [];
            self._data = ships;
            self._count = ships.length;
            var blue = Cesium.Color.fromCssColorString('#4499ff');
            var gray = Cesium.Color.fromCssColorString('#445577');
            for (var i = 0; i < ships.length; i++) {
                var s = ships[i];
                if (!s.lat || !s.lon) continue;
                self._points.add({
                    position: Cesium.Cartesian3.fromDegrees(s.lon, s.lat, 0),
                    pixelSize: 2.5,
                    color: (s.sog || 0) > 0.5 ? blue : gray,
                });
            }
            if (statusEl) statusEl.textContent = ships.length.toLocaleString('de-DE') + ' Schiffe';
        })
        .catch(function(e) { console.warn('Ships error:', e); if (statusEl) statusEl.textContent = 'Fehler'; })
        .finally(function() { if (loadEl) loadEl.classList.remove('active'); setTimeout(function() { if (statusEl) statusEl.classList.remove('active'); }, 5000); });
    },
};