/**
 * Imagery Switcher: Verschiedene Satellitenbilder + historische Aufnahmen.
 */
const ImagerySwitch = {
    _viewer: null,
    _currentLayer: null,
    _currentId: 'default',

    _sources: {
        'default': { name: 'Cesium Ion (Standard)', url: null },
        'esri': {
            name: 'Esri World Imagery',
            url: 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}',
        },
        's2-2024': {
            name: 'Sentinel-2 (2024)',
            url: 'https://tiles.maps.eox.at/wmts/1.0.0/s2cloudless-2024_3857/default/GoogleMapsCompatible/{z}/{x}/{y}.jpg',
        },
        's2-2023': {
            name: 'Sentinel-2 (2023)',
            url: 'https://tiles.maps.eox.at/wmts/1.0.0/s2cloudless-2023_3857/default/GoogleMapsCompatible/{z}/{x}/{y}.jpg',
        },
        's2-2022': {
            name: 'Sentinel-2 (2022)',
            url: 'https://tiles.maps.eox.at/wmts/1.0.0/s2cloudless-2022_3857/default/GoogleMapsCompatible/{z}/{x}/{y}.jpg',
        },
        's2-2020': {
            name: 'Sentinel-2 (2020)',
            url: 'https://tiles.maps.eox.at/wmts/1.0.0/s2cloudless-2020_3857/default/GoogleMapsCompatible/{z}/{x}/{y}.jpg',
        },
        's2-2018': {
            name: 'Sentinel-2 (2018)',
            url: 'https://tiles.maps.eox.at/wmts/1.0.0/s2cloudless-2018_3857/default/GoogleMapsCompatible/{z}/{x}/{y}.jpg',
        },
        'topo': {
            name: 'OpenTopoMap',
            url: 'https://tile.opentopomap.org/{z}/{x}/{y}.png',
        },
        'osm': {
            name: 'OpenStreetMap',
            url: 'https://a.tile.openstreetmap.org/{z}/{x}/{y}.png',
        },
    },

    init(viewer) {
        this._viewer = viewer;
    },

    switchTo(id) {
        if (!this._viewer || this._currentId === id) return;
        var src = this._sources[id];
        if (!src) return;

        // Alle eigenen Imagery-Layer entfernen (nicht den Cesium-Default und nicht Labels)
        if (this._currentLayer) {
            this._viewer.imageryLayers.remove(this._currentLayer);
            this._currentLayer = null;
        }

        if (id === 'default') {
            // Cesium Ion Default wiederherstellen — nichts tun, der ist immer da
            this._currentId = id;
        } else {
            // Neuen Layer als untersten hinzufuegen (ueber dem Default)
            this._currentLayer = this._viewer.imageryLayers.addImageryProvider(
                new Cesium.UrlTemplateImageryProvider({
                    url: src.url,
                    maximumLevel: 18,
                    credit: src.name,
                })
            );
            // Unter Labels aber ueber Default
            this._viewer.imageryLayers.lower(this._currentLayer);
            this._currentId = id;
        }

        // Dropdown aktualisieren
        var sel = document.getElementById('imagery-select');
        if (sel) sel.value = id;

        // Status
        var label = document.getElementById('imagery-label');
        if (label) label.textContent = src.name;
    },
};