const TREES_MIN_ZOOM = 17;

var map = L.map('map').setView([51.05, 13.75], TREES_MIN_ZOOM, {
    maxZoom: 20,
});

var tiles = L.tileLayer('https://stamen-tiles.a.ssl.fastly.net/terrain/{z}/{x}/{y}.jpg', {
    attribution: '&copy; <a href="https://osm.org/copyright">OpenStreetMap</a> contributors',
    maxZoom: 17,
}).addTo(map);

var HeatmapLayer = L.TileLayer.extend({
    getTileUrl: function (coords) {
        var cs = this._tileCoordsToNwSe(coords);
        var x1 = Math.min(cs[0].lng, cs[1].lng);
        var y1 = Math.min(cs[0].lat, cs[1].lat);
        var x2 = Math.max(cs[0].lng, cs[1].lng);
        var y2 = Math.max(cs[0].lat, cs[1].lat);
        return ["", "heatmap", x1, y1, x2, y2].join("/");
    },
});
L.tileLayer('/heatmap/{z}/{x}/{y}/tile.png', {
    maxZoom: TREES_MIN_ZOOM - 1,
    opacity: 0.8,
}).addTo(map);

var treeIcon = L.icon({
    iconUrl: "tree.png",
    iconSize: [12, 12],
    iconAnchor: [6, 6],
    popupAnchor: [0, -6],
});

function treePopup(coords, entry) {
    var popup = L.popup()
        .setLatLng(coords);
    popup.on('add', function() {
        var info = {};
        function update(newInfo) {
            Object.keys(newInfo).forEach(function(k) {
                info[k] = newInfo[k];
            });

            popup.setContent(function() {
                var div = document.createElement("div");
                var h2 = document.createElement("h2");
                h2.textContent = entry.german;
                if (entry.age)
                    h2.textContent += " (" + entry.age + ")";
                div.appendChild(h2);
                var p = document.createElement("p");
                p.textContent = entry.botanic;
                div.appendChild(p);

                if (info.area) {
                    p = document.createElement("p");
                    p.textContent = JSON.stringify(info.area);
                    div.appendChild(p);
                }
                if (info.tree) {
                    p = document.createElement("p");
                    p.style.maxHeight = "10em";
                    p.style.overflow = "scroll";
                    p.textContent = JSON.stringify(info.tree);
                    div.appendChild(p);
                }

                return div;
            });
        }
        update({});

        fetch(["", "area", coords[1], coords[0]].join("/"))
            .then(res => res.json())
            .then(data => {
                update({ area: data });
            });
        fetch(["", "tree", entry.id].join("/"))
            .then(res => res.json())
            .then(data => {
                console.log("tree data", data);
                update({ tree: data });
            });
    });
    return popup;
}

var trees;
var trees_pending = false;
var visible_trees;

function updateTrees() {
    if (map.getZoom() < TREES_MIN_ZOOM) {
        if (trees) {
            trees.remove();
            trees = null;
        }
        return;
    }
    var bounds = map.getBounds();
    if (!trees) {
        trees = L.layerGroup().addTo(map);
        visible_trees = {};
    } else {
        trees.eachLayer(function(marker) {
            var ll = marker.getLatLng();
            if (ll.lng < bounds.getWest() || ll.lng > bounds.getEast() ||
                ll.lat < bounds.getSouth() || ll.lat > bounds.getNorth()) {

                delete visible_trees[marker.options.id];
                trees.removeLayer(marker);
            }
        });
    }

    if (trees_pending) return;
    trees_pending = true;

    fetch(["", "trees", bounds.getWest(), bounds.getSouth(), bounds.getEast(), bounds.getNorth()].join("/"))
        .then(res => res.json())
        .then(data => {
            if (map.getZoom() < TREES_MIN_ZOOM) {
                return;
            }
            data.forEach(function(entry) {
                var coords = [entry.coords[1], entry.coords[0]];
                if (entry.planted) {
                    entry.age = Math.round((Date.now() - Date.parse(entry.planted)) / (365.25 * 24 * 60 * 60 * 1000));
                }

                if (!visible_trees[entry.id]) {
                    visible_trees[entry.id] = true;

                    var marker = L.marker(coords, {
                        id: entry.id,
                        title: entry.german,
                        icon: treeIcon,
                    }).bindPopup(treePopup(coords, entry));
                    trees.addLayer(marker);
                }
            });
            trees_pending = false;
        })
        .catch (error => {
            console.error('Error:' + error)
            trees_pending = false;
        });
}
map.on('moveend', updateTrees);
map.on('zoomend', updateTrees);
updateTrees();