(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
typeof define === 'function' && define.amd ? define(factory) :
(global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.Supercluster = factory());
})(this, (function () { 'use strict';

function sortKD(ids, coords, nodeSize, left, right, depth) {
    if (right - left <= nodeSize) { return; }

    var m = (left + right) >> 1;

    select(ids, coords, m, left, right, depth % 2);

    sortKD(ids, coords, nodeSize, left, m - 1, depth + 1);
    sortKD(ids, coords, nodeSize, m + 1, right, depth + 1);
}

function select(ids, coords, k, left, right, inc) {

    while (right > left) {
        if (right - left > 600) {
            var n = right - left + 1;
            var m = k - left + 1;
            var z = Math.log(n);
            var s = 0.5 * Math.exp(2 * z / 3);
            var sd = 0.5 * Math.sqrt(z * s * (n - s) / n) * (m - n / 2 < 0 ? -1 : 1);
            var newLeft = Math.max(left, Math.floor(k - m * s / n + sd));
            var newRight = Math.min(right, Math.floor(k + (n - m) * s / n + sd));
            select(ids, coords, k, newLeft, newRight, inc);
        }

        var t = coords[2 * k + inc];
        var i = left;
        var j = right;

        swapItem(ids, coords, left, k);
        if (coords[2 * right + inc] > t) { swapItem(ids, coords, left, right); }

        while (i < j) {
            swapItem(ids, coords, i, j);
            i++;
            j--;
            while (coords[2 * i + inc] < t) { i++; }
            while (coords[2 * j + inc] > t) { j--; }
        }

        if (coords[2 * left + inc] === t) { swapItem(ids, coords, left, j); }
        else {
            j++;
            swapItem(ids, coords, j, right);
        }

        if (j <= k) { left = j + 1; }
        if (k <= j) { right = j - 1; }
    }
}

function swapItem(ids, coords, i, j) {
    swap(ids, i, j);
    swap(coords, 2 * i, 2 * j);
    swap(coords, 2 * i + 1, 2 * j + 1);
}

function swap(arr, i, j) {
    var tmp = arr[i];
    arr[i] = arr[j];
    arr[j] = tmp;
}

function range(ids, coords, minX, minY, maxX, maxY, nodeSize) {
    var stack = [0, ids.length - 1, 0];
    var result = [];
    var x, y;

    while (stack.length) {
        var axis = stack.pop();
        var right = stack.pop();
        var left = stack.pop();

        if (right - left <= nodeSize) {
            for (var i = left; i <= right; i++) {
                x = coords[2 * i];
                y = coords[2 * i + 1];
                if (x >= minX && x <= maxX && y >= minY && y <= maxY) { result.push(ids[i]); }
            }
            continue;
        }

        var m = Math.floor((left + right) / 2);

        x = coords[2 * m];
        y = coords[2 * m + 1];

        if (x >= minX && x <= maxX && y >= minY && y <= maxY) { result.push(ids[m]); }

        var nextAxis = (axis + 1) % 2;

        if (axis === 0 ? minX <= x : minY <= y) {
            stack.push(left);
            stack.push(m - 1);
            stack.push(nextAxis);
        }
        if (axis === 0 ? maxX >= x : maxY >= y) {
            stack.push(m + 1);
            stack.push(right);
            stack.push(nextAxis);
        }
    }

    return result;
}

function within(ids, coords, qx, qy, r, nodeSize) {
    var stack = [0, ids.length - 1, 0];
    var result = [];
    var r2 = r * r;

    while (stack.length) {
        var axis = stack.pop();
        var right = stack.pop();
        var left = stack.pop();

        if (right - left <= nodeSize) {
            for (var i = left; i <= right; i++) {
                if (sqDist(coords[2 * i], coords[2 * i + 1], qx, qy) <= r2) { result.push(ids[i]); }
            }
            continue;
        }

        var m = Math.floor((left + right) / 2);

        var x = coords[2 * m];
        var y = coords[2 * m + 1];

        if (sqDist(x, y, qx, qy) <= r2) { result.push(ids[m]); }

        var nextAxis = (axis + 1) % 2;

        if (axis === 0 ? qx - r <= x : qy - r <= y) {
            stack.push(left);
            stack.push(m - 1);
            stack.push(nextAxis);
        }
        if (axis === 0 ? qx + r >= x : qy + r >= y) {
            stack.push(m + 1);
            stack.push(right);
            stack.push(nextAxis);
        }
    }

    return result;
}

function sqDist(ax, ay, bx, by) {
    var dx = ax - bx;
    var dy = ay - by;
    return dx * dx + dy * dy;
}

var defaultGetX = function (p) { return p[0]; };
var defaultGetY = function (p) { return p[1]; };

var KDBush = function KDBush(points, getX, getY, nodeSize, ArrayType) {
    if ( getX === void 0 ) getX = defaultGetX;
    if ( getY === void 0 ) getY = defaultGetY;
    if ( nodeSize === void 0 ) nodeSize = 64;
    if ( ArrayType === void 0 ) ArrayType = Float64Array;

    this.nodeSize = nodeSize;
    this.points = points;

    var IndexArrayType = points.length < 65536 ? Uint16Array : Uint32Array;

    var ids = this.ids = new IndexArrayType(points.length);
    var coords = this.coords = new ArrayType(points.length * 2);

    for (var i = 0; i < points.length; i++) {
        ids[i] = i;
        coords[2 * i] = getX(points[i]);
        coords[2 * i + 1] = getY(points[i]);
    }

    sortKD(ids, coords, nodeSize, 0, ids.length - 1, 0);
};

KDBush.prototype.range = function range$1 (minX, minY, maxX, maxY) {
    return range(this.ids, this.coords, minX, minY, maxX, maxY, this.nodeSize);
};

KDBush.prototype.within = function within$1 (x, y, r) {
    return within(this.ids, this.coords, x, y, r, this.nodeSize);
};

var defaultOptions = {
    minZoom: 0,   // min zoom to generate clusters on
    maxZoom: 16,  // max zoom level to cluster the points on
    minPoints: 2, // minimum points to form a cluster
    radius: 40,   // cluster radius in pixels
    extent: 512,  // tile extent (radius is calculated relative to it)
    nodeSize: 64, // size of the KD-tree leaf node, affects performance
    log: false,   // whether to log timing info

    // whether to generate numeric ids for input features (in vector tiles)
    generateId: false,

    // a reduce function for calculating custom cluster properties
    reduce: null, // (accumulated, props) => { accumulated.sum += props.sum; }

    // properties to use for individual points when running the reducer
    map: function (props) { return props; } // props => ({sum: props.my_value})
};

var fround = Math.fround || (function (tmp) { return (function (x) { tmp[0] = +x; return tmp[0]; }); })(new Float32Array(1));

var Supercluster = function Supercluster(options) {
    this.options = extend(Object.create(defaultOptions), options);
    this.trees = new Array(this.options.maxZoom + 1);
};

Supercluster.prototype.load = function load (points) {
    var ref = this.options;
        var log = ref.log;
        var minZoom = ref.minZoom;
        var maxZoom = ref.maxZoom;
        var nodeSize = ref.nodeSize;

    if (log) { console.time('total time'); }

    var timerId = "prepare " + (points.length) + " points";
    if (log) { console.time(timerId); }

    this.points = points;

    // generate a cluster object for each point and index input points into a KD-tree
    var clusters = [];
    for (var i = 0; i < points.length; i++) {
        if (!points[i].geometry) { continue; }
        clusters.push(createPointCluster(points[i], i));
    }
    this.trees[maxZoom + 1] = new KDBush(clusters, getX, getY, nodeSize, Float32Array);

    if (log) { console.timeEnd(timerId); }

    // cluster points on max zoom, then cluster the results on previous zoom, etc.;
    // results in a cluster hierarchy across zoom levels
    for (var z = maxZoom; z >= minZoom; z--) {
        var now = +Date.now();

        // create a new set of clusters for the zoom and index them with a KD-tree
        clusters = this._cluster(clusters, z);
        this.trees[z] = new KDBush(clusters, getX, getY, nodeSize, Float32Array);

        if (log) { console.log('z%d: %d clusters in %dms', z, clusters.length, +Date.now() - now); }
    }

    if (log) { console.timeEnd('total time'); }

    return this;
};

Supercluster.prototype.getClusters = function getClusters (bbox, zoom) {
    var minLng = ((bbox[0] + 180) % 360 + 360) % 360 - 180;
    var minLat = Math.max(-90, Math.min(90, bbox[1]));
    var maxLng = bbox[2] === 180 ? 180 : ((bbox[2] + 180) % 360 + 360) % 360 - 180;
    var maxLat = Math.max(-90, Math.min(90, bbox[3]));

    if (bbox[2] - bbox[0] >= 360) {
        minLng = -180;
        maxLng = 180;
    } else if (minLng > maxLng) {
        var easternHem = this.getClusters([minLng, minLat, 180, maxLat], zoom);
        var westernHem = this.getClusters([-180, minLat, maxLng, maxLat], zoom);
        return easternHem.concat(westernHem);
    }

    var tree = this.trees[this._limitZoom(zoom)];
    var ids = tree.range(lngX(minLng), latY(maxLat), lngX(maxLng), latY(minLat));
    var clusters = [];
    for (var i = 0, list = ids; i < list.length; i += 1) {
        var id = list[i];

            var c = tree.points[id];
        clusters.push(c.numPoints ? getClusterJSON(c) : this.points[c.index]);
    }
    return clusters;
};

Supercluster.prototype.getChildren = function getChildren (clusterId) {
    var originId = this._getOriginId(clusterId);
    var originZoom = this._getOriginZoom(clusterId);
    var errorMsg = 'No cluster with the specified id.';

    var index = this.trees[originZoom];
    if (!index) { throw new Error(errorMsg); }

    var origin = index.points[originId];
    if (!origin) { throw new Error(errorMsg); }

    var r = this.options.radius / (this.options.extent * Math.pow(2, originZoom - 1));
    var ids = index.within(origin.x, origin.y, r);
    var children = [];
    for (var i = 0, list = ids; i < list.length; i += 1) {
        var id = list[i];

            var c = index.points[id];
        if (c.parentId === clusterId) {
            children.push(c.numPoints ? getClusterJSON(c) : this.points[c.index]);
        }
    }

    if (children.length === 0) { throw new Error(errorMsg); }

    return children;
};

Supercluster.prototype.getLeaves = function getLeaves (clusterId, limit, offset) {
    limit = limit || 10;
    offset = offset || 0;

    var leaves = [];
    this._appendLeaves(leaves, clusterId, limit, offset, 0);

    return leaves;
};

Supercluster.prototype.getTile = function getTile (z, x, y) {
    var tree = this.trees[this._limitZoom(z)];
    var z2 = Math.pow(2, z);
    var ref = this.options;
        var extent = ref.extent;
        var radius = ref.radius;
    var p = radius / extent;
    var top = (y - p) / z2;
    var bottom = (y + 1 + p) / z2;

    var tile = {
        features: []
    };

    this._addTileFeatures(
        tree.range((x - p) / z2, top, (x + 1 + p) / z2, bottom),
        tree.points, x, y, z2, tile);

    if (x === 0) {
        this._addTileFeatures(
            tree.range(1 - p / z2, top, 1, bottom),
            tree.points, z2, y, z2, tile);
    }
    if (x === z2 - 1) {
        this._addTileFeatures(
            tree.range(0, top, p / z2, bottom),
            tree.points, -1, y, z2, tile);
    }

    return tile.features.length ? tile : null;
};

Supercluster.prototype.getClusterExpansionZoom = function getClusterExpansionZoom (clusterId) {
    var expansionZoom = this._getOriginZoom(clusterId) - 1;
    while (expansionZoom <= this.options.maxZoom) {
        var children = this.getChildren(clusterId);
        expansionZoom++;
        if (children.length !== 1) { break; }
        clusterId = children[0].properties.cluster_id;
    }
    return expansionZoom;
};

Supercluster.prototype._appendLeaves = function _appendLeaves (result, clusterId, limit, offset, skipped) {
    var children = this.getChildren(clusterId);

    for (var i = 0, list = children; i < list.length; i += 1) {
        var child = list[i];

            var props = child.properties;

        if (props && props.cluster) {
            if (skipped + props.point_count <= offset) {
                // skip the whole cluster
                skipped += props.point_count;
            } else {
                // enter the cluster
                skipped = this._appendLeaves(result, props.cluster_id, limit, offset, skipped);
                // exit the cluster
            }
        } else if (skipped < offset) {
            // skip a single point
            skipped++;
        } else {
            // add a single point
            result.push(child);
        }
        if (result.length === limit) { break; }
    }

    return skipped;
};

Supercluster.prototype._addTileFeatures = function _addTileFeatures (ids, points, x, y, z2, tile) {
    for (var i$1 = 0, list = ids; i$1 < list.length; i$1 += 1) {
        var i = list[i$1];

            var c = points[i];
        var isCluster = c.numPoints;

        var tags = (void 0), px = (void 0), py = (void 0);
        if (isCluster) {
            tags = getClusterProperties(c);
            px = c.x;
            py = c.y;
        } else {
            var p = this.points[c.index];
            tags = p.properties;
            px = lngX(p.geometry.coordinates[0]);
            py = latY(p.geometry.coordinates[1]);
        }

        var f = {
            type: 1,
            geometry: [[
                Math.round(this.options.extent * (px * z2 - x)),
                Math.round(this.options.extent * (py * z2 - y))
            ]],
            tags: tags
        };

        // assign id
        var id = (void 0);
        if (isCluster) {
            id = c.id;
        } else if (this.options.generateId) {
            // optionally generate id
            id = c.index;
        } else if (this.points[c.index].id) {
            // keep id if already assigned
            id = this.points[c.index].id;
        }

        if (id !== undefined) { f.id = id; }

        tile.features.push(f);
    }
};

Supercluster.prototype._limitZoom = function _limitZoom (z) {
    return Math.max(this.options.minZoom, Math.min(Math.floor(+z), this.options.maxZoom + 1));
};

Supercluster.prototype._cluster = function _cluster (points, zoom) {
    var clusters = [];
    var ref = this.options;
        var radius = ref.radius;
        var extent = ref.extent;
        var reduce = ref.reduce;
        var minPoints = ref.minPoints;
    var r = radius / (extent * Math.pow(2, zoom));

    // loop through each point
    for (var i = 0; i < points.length; i++) {
        var p = points[i];
        // if we've already visited the point at this zoom level, skip it
        if (p.zoom <= zoom) { continue; }
        p.zoom = zoom;

        // find all nearby points
        var tree = this.trees[zoom + 1];
        var neighborIds = tree.within(p.x, p.y, r);

        var numPointsOrigin = p.numPoints || 1;
        var numPoints = numPointsOrigin;

        // count the number of points in a potential cluster
        for (var i$1 = 0, list = neighborIds; i$1 < list.length; i$1 += 1) {
            var neighborId = list[i$1];

                var b = tree.points[neighborId];
            // filter out neighbors that are already processed
            if (b.zoom > zoom) { numPoints += b.numPoints || 1; }
        }

        // if there were neighbors to merge, and there are enough points to form a cluster
        if (numPoints > numPointsOrigin && numPoints >= minPoints) {
            var wx = p.x * numPointsOrigin;
            var wy = p.y * numPointsOrigin;

            var clusterProperties = reduce && numPointsOrigin > 1 ? this._map(p, true) : null;

            // encode both zoom and point index on which the cluster originated -- offset by total length of features
            var id = (i << 5) + (zoom + 1) + this.points.length;

            for (var i$2 = 0, list$1 = neighborIds; i$2 < list$1.length; i$2 += 1) {
                var neighborId$1 = list$1[i$2];

                    var b$1 = tree.points[neighborId$1];

                if (b$1.zoom <= zoom) { continue; }
                b$1.zoom = zoom; // save the zoom (so it doesn't get processed twice)

                var numPoints2 = b$1.numPoints || 1;
                wx += b$1.x * numPoints2; // accumulate coordinates for calculating weighted center
                wy += b$1.y * numPoints2;

                b$1.parentId = id;

                if (reduce) {
                    if (!clusterProperties) { clusterProperties = this._map(p, true); }
                    reduce(clusterProperties, this._map(b$1));
                }
            }

            p.parentId = id;
            clusters.push(createCluster(wx / numPoints, wy / numPoints, id, numPoints, clusterProperties));

        } else { // left points as unclustered
            clusters.push(p);

            if (numPoints > 1) {
                for (var i$3 = 0, list$2 = neighborIds; i$3 < list$2.length; i$3 += 1) {
                    var neighborId$2 = list$2[i$3];

                        var b$2 = tree.points[neighborId$2];
                    if (b$2.zoom <= zoom) { continue; }
                    b$2.zoom = zoom;
                    clusters.push(b$2);
                }
            }
        }
    }

    return clusters;
};

// get index of the point from which the cluster originated
Supercluster.prototype._getOriginId = function _getOriginId (clusterId) {
    return (clusterId - this.points.length) >> 5;
};

// get zoom of the point from which the cluster originated
Supercluster.prototype._getOriginZoom = function _getOriginZoom (clusterId) {
    return (clusterId - this.points.length) % 32;
};

Supercluster.prototype._map = function _map (point, clone) {
    if (point.numPoints) {
        return clone ? extend({}, point.properties) : point.properties;
    }
    var original = this.points[point.index].properties;
    var result = this.options.map(original);
    return clone && result === original ? extend({}, result) : result;
};

function createCluster(x, y, id, numPoints, properties) {
    return {
        x: fround(x), // weighted cluster center; round for consistency with Float32Array index
        y: fround(y),
        zoom: Infinity, // the last zoom the cluster was processed at
        id: id, // encodes index of the first child of the cluster and its zoom level
        parentId: -1, // parent cluster id
        numPoints: numPoints,
        properties: properties
    };
}

function createPointCluster(p, id) {
    var ref = p.geometry.coordinates;
    var x = ref[0];
    var y = ref[1];
    return {
        x: fround(lngX(x)), // projected point coordinates
        y: fround(latY(y)),
        zoom: Infinity, // the last zoom the point was processed at
        index: id, // index of the source feature in the original input array,
        parentId: -1 // parent cluster id
    };
}

function getClusterJSON(cluster) {
    return {
        type: 'Feature',
        id: cluster.id,
        properties: getClusterProperties(cluster),
        geometry: {
            type: 'Point',
            coordinates: [xLng(cluster.x), yLat(cluster.y)]
        }
    };
}

function getClusterProperties(cluster) {
    var count = cluster.numPoints;
    var abbrev =
        count >= 10000 ? ((Math.round(count / 1000)) + "k") :
        count >= 1000 ? ((Math.round(count / 100) / 10) + "k") : count;
    return extend(extend({}, cluster.properties), {
        cluster: true,
        cluster_id: cluster.id,
        point_count: count,
        point_count_abbreviated: abbrev
    });
}

// longitude/latitude to spherical mercator in [0..1] range
function lngX(lng) {
    return lng / 360 + 0.5;
}
function latY(lat) {
    var sin = Math.sin(lat * Math.PI / 180);
    var y = (0.5 - 0.25 * Math.log((1 + sin) / (1 - sin)) / Math.PI);
    return y < 0 ? 0 : y > 1 ? 1 : y;
}

// spherical mercator to longitude/latitude
function xLng(x) {
    return (x - 0.5) * 360;
}
function yLat(y) {
    var y2 = (180 - y * 360) * Math.PI / 180;
    return 360 * Math.atan(Math.exp(y2)) / Math.PI - 90;
}

function extend(dest, src) {
    for (var id in src) { dest[id] = src[id]; }
    return dest;
}

function getX(p) {
    return p.x;
}
function getY(p) {
    return p.y;
}

return Supercluster;

}));