/**
 * Schiffsverkehr-Layer: Blaue Punkte auf Meereshöhe.
 */
const ShipsLayer = {
    _viewer: null,
    _dataSource: null,
    _interval: null,
    _count: 0,

    start(viewer) {
        if (this._dataSource) return;
        this._viewer = viewer;
        this._dataSource = new Cesium.CustomDataSource('ships');
        viewer.dataSources.add(this._dataSource);
        this._fetch();
        var self = this;
        this._interval = setInterval(function() { self._fetch(); }, 60000);
    },

    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;
        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._dataSource) return;
            self._dataSource.entities.removeAll();
            var ships = data.ships || [];
            self._count = ships.length;
            ships.forEach(function(s) {
                if (!s.lat || !s.lon) return;
                var sog = s.sog || 0;
                var color = sog > 0.5
                    ? Cesium.Color.fromCssColorString('#4499ff')
                    : Cesium.Color.fromCssColorString('#556688');
                var name = s.name || ('MMSI ' + (s.mmsi || '?'));
                self._dataSource.entities.add({
                    position: Cesium.Cartesian3.fromDegrees(s.lon, s.lat, 0),
                    point: {
                        pixelSize: 3,
                        color: color,
                        outlineColor: Cesium.Color.fromCssColorString('#112244'),
                        outlineWidth: 0.5,
                        heightReference: Cesium.HeightReference.NONE,
                    },
                    label: {
                        text: name,
                        font: '9px monospace',
                        fillColor: Cesium.Color.fromCssColorString('#4499ff').withAlpha(0.7),
                        outlineColor: Cesium.Color.BLACK,
                        outlineWidth: 2,
                        style: Cesium.LabelStyle.FILL_AND_OUTLINE,
                        pixelOffset: new Cesium.Cartesian2(6, -3),
                        scale: 0.7,
                        distanceDisplayCondition: new Cesium.DistanceDisplayCondition(0, 500000),
                    },
                    description: '<div style="font-family:monospace;font-size:12px;color:#4499ff">' +
                        '<strong>' + name + '</strong><br>' +
                        'MMSI: ' + (s.mmsi || '?') + '<br>' +
                        'SOG: ' + sog.toFixed(1) + ' kn<br>' +
                        'COG: ' + Math.round(s.cog || 0) + '°<br>' +
                        'HDG: ' + (s.heading || '?') + '°' +
                        '</div>',
                });
            });
        })
        .catch(function(e) { console.warn('Ships fetch error:', e); if (statusEl) { statusEl.textContent = 'Fehler beim Laden'; } })
        .finally(function() { if (loadEl) loadEl.classList.remove('active'); setTimeout(function() { if (statusEl) statusEl.classList.remove('active'); }, 3000); });
    },
};