// https://d3js.org/d3-quadtree/ Version 1.0.3. Copyright 2017 Mike Bostock.
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
	typeof define === 'function' && define.amd ? define(['exports'], factory) :
	(factory((global.d3 = global.d3 || {})));
}(this, (function (exports) { 'use strict';

var tree_add = function(d) {
  var x = +this._x.call(null, d),
      y = +this._y.call(null, d);
  return add(this.cover(x, y), x, y, d);
};

function add(tree, x, y, d) {
  if (isNaN(x) || isNaN(y)) return tree; // ignore invalid points

  var parent,
      node = tree._root,
      leaf = {data: d},
      x0 = tree._x0,
      y0 = tree._y0,
      x1 = tree._x1,
      y1 = tree._y1,
      xm,
      ym,
      xp,
      yp,
      right,
      bottom,
      i,
      j;

  // If the tree is empty, initialize the root as a leaf.
  if (!node) return tree._root = leaf, tree;

  // Find the existing leaf for the new point, or add it.
  while (node.length) {
    if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
    if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
    if (parent = node, !(node = node[i = bottom << 1 | right])) return parent[i] = leaf, tree;
  }

  // Is the new point is exactly coincident with the existing point?
  xp = +tree._x.call(null, node.data);
  yp = +tree._y.call(null, node.data);
  if (x === xp && y === yp) return leaf.next = node, parent ? parent[i] = leaf : tree._root = leaf, tree;

  // Otherwise, split the leaf node until the old and new point are separated.
  do {
    parent = parent ? parent[i] = new Array(4) : tree._root = new Array(4);
    if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
    if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
  } while ((i = bottom << 1 | right) === (j = (yp >= ym) << 1 | (xp >= xm)));
  return parent[j] = node, parent[i] = leaf, tree;
}

function addAll(data) {
  var d, i, n = data.length,
      x,
      y,
      xz = new Array(n),
      yz = new Array(n),
      x0 = Infinity,
      y0 = Infinity,
      x1 = -Infinity,
      y1 = -Infinity;

  // Compute the points and their extent.
  for (i = 0; i < n; ++i) {
    if (isNaN(x = +this._x.call(null, d = data[i])) || isNaN(y = +this._y.call(null, d))) continue;
    xz[i] = x;
    yz[i] = y;
    if (x < x0) x0 = x;
    if (x > x1) x1 = x;
    if (y < y0) y0 = y;
    if (y > y1) y1 = y;
  }

  // If there were no (valid) points, inherit the existing extent.
  if (x1 < x0) x0 = this._x0, x1 = this._x1;
  if (y1 < y0) y0 = this._y0, y1 = this._y1;

  // Expand the tree to cover the new points.
  this.cover(x0, y0).cover(x1, y1);

  // Add the new points.
  for (i = 0; i < n; ++i) {
    add(this, xz[i], yz[i], data[i]);
  }

  return this;
}

var tree_cover = function(x, y) {
  if (isNaN(x = +x) || isNaN(y = +y)) return this; // ignore invalid points

  var x0 = this._x0,
      y0 = this._y0,
      x1 = this._x1,
      y1 = this._y1;

  // If the quadtree has no extent, initialize them.
  // Integer extent are necessary so that if we later double the extent,
  // the existing quadrant boundaries don’t change due to floating point error!
  if (isNaN(x0)) {
    x1 = (x0 = Math.floor(x)) + 1;
    y1 = (y0 = Math.floor(y)) + 1;
  }

  // Otherwise, double repeatedly to cover.
  else if (x0 > x || x > x1 || y0 > y || y > y1) {
    var z = x1 - x0,
        node = this._root,
        parent,
        i;

    switch (i = (y < (y0 + y1) / 2) << 1 | (x < (x0 + x1) / 2)) {
      case 0: {
        do parent = new Array(4), parent[i] = node, node = parent;
        while (z *= 2, x1 = x0 + z, y1 = y0 + z, x > x1 || y > y1);
        break;
      }
      case 1: {
        do parent = new Array(4), parent[i] = node, node = parent;
        while (z *= 2, x0 = x1 - z, y1 = y0 + z, x0 > x || y > y1);
        break;
      }
      case 2: {
        do parent = new Array(4), parent[i] = node, node = parent;
        while (z *= 2, x1 = x0 + z, y0 = y1 - z, x > x1 || y0 > y);
        break;
      }
      case 3: {
        do parent = new Array(4), parent[i] = node, node = parent;
        while (z *= 2, x0 = x1 - z, y0 = y1 - z, x0 > x || y0 > y);
        break;
      }
    }

    if (this._root && this._root.length) this._root = node;
  }

  // If the quadtree covers the point already, just return.
  else return this;

  this._x0 = x0;
  this._y0 = y0;
  this._x1 = x1;
  this._y1 = y1;
  return this;
};

var tree_data = function() {
  var data = [];
  this.visit(function(node) {
    if (!node.length) do data.push(node.data); while (node = node.next)
  });
  return data;
};

var tree_extent = function(_) {
  return arguments.length
      ? this.cover(+_[0][0], +_[0][1]).cover(+_[1][0], +_[1][1])
      : isNaN(this._x0) ? undefined : [[this._x0, this._y0], [this._x1, this._y1]];
};

var Quad = function(node, x0, y0, x1, y1) {
  this.node = node;
  this.x0 = x0;
  this.y0 = y0;
  this.x1 = x1;
  this.y1 = y1;
};

var tree_find = function(x, y, radius) {
  var data,
      x0 = this._x0,
      y0 = this._y0,
      x1,
      y1,
      x2,
      y2,
      x3 = this._x1,
      y3 = this._y1,
      quads = [],
      node = this._root,
      q,
      i;

  if (node) quads.push(new Quad(node, x0, y0, x3, y3));
  if (radius == null) radius = Infinity;
  else {
    x0 = x - radius, y0 = y - radius;
    x3 = x + radius, y3 = y + radius;
    radius *= radius;
  }

  while (q = quads.pop()) {

    // Stop searching if this quadrant can’t contain a closer node.
    if (!(node = q.node)
        || (x1 = q.x0) > x3
        || (y1 = q.y0) > y3
        || (x2 = q.x1) < x0
        || (y2 = q.y1) < y0) continue;

    // Bisect the current quadrant.
    if (node.length) {
      var xm = (x1 + x2) / 2,
          ym = (y1 + y2) / 2;

      quads.push(
        new Quad(node[3], xm, ym, x2, y2),
        new Quad(node[2], x1, ym, xm, y2),
        new Quad(node[1], xm, y1, x2, ym),
        new Quad(node[0], x1, y1, xm, ym)
      );

      // Visit the closest quadrant first.
      if (i = (y >= ym) << 1 | (x >= xm)) {
        q = quads[quads.length - 1];
        quads[quads.length - 1] = quads[quads.length - 1 - i];
        quads[quads.length - 1 - i] = q;
      }
    }

    // Visit this point. (Visiting coincident points isn’t necessary!)
    else {
      var dx = x - +this._x.call(null, node.data),
          dy = y - +this._y.call(null, node.data),
          d2 = dx * dx + dy * dy;
      if (d2 < radius) {
        var d = Math.sqrt(radius = d2);
        x0 = x - d, y0 = y - d;
        x3 = x + d, y3 = y + d;
        data = node.data;
      }
    }
  }

  return data;
};

var tree_remove = function(d) {
  if (isNaN(x = +this._x.call(null, d)) || isNaN(y = +this._y.call(null, d))) return this; // ignore invalid points

  var parent,
      node = this._root,
      retainer,
      previous,
      next,
      x0 = this._x0,
      y0 = this._y0,
      x1 = this._x1,
      y1 = this._y1,
      x,
      y,
      xm,
      ym,
      right,
      bottom,
      i,
      j;

  // If the tree is empty, initialize the root as a leaf.
  if (!node) return this;

  // Find the leaf node for the point.
  // While descending, also retain the deepest parent with a non-removed sibling.
  if (node.length) while (true) {
    if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
    if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
    if (!(parent = node, node = node[i = bottom << 1 | right])) return this;
    if (!node.length) break;
    if (parent[(i + 1) & 3] || parent[(i + 2) & 3] || parent[(i + 3) & 3]) retainer = parent, j = i;
  }

  // Find the point to remove.
  while (node.data !== d) if (!(previous = node, node = node.next)) return this;
  if (next = node.next) delete node.next;

  // If there are multiple coincident points, remove just the point.
  if (previous) return (next ? previous.next = next : delete previous.next), this;

  // If this is the root point, remove it.
  if (!parent) return this._root = next, this;

  // Remove this leaf.
  next ? parent[i] = next : delete parent[i];

  // If the parent now contains exactly one leaf, collapse superfluous parents.
  if ((node = parent[0] || parent[1] || parent[2] || parent[3])
      && node === (parent[3] || parent[2] || parent[1] || parent[0])
      && !node.length) {
    if (retainer) retainer[j] = node;
    else this._root = node;
  }

  return this;
};

function removeAll(data) {
  for (var i = 0, n = data.length; i < n; ++i) this.remove(data[i]);
  return this;
}

var tree_root = function() {
  return this._root;
};

var tree_size = function() {
  var size = 0;
  this.visit(function(node) {
    if (!node.length) do ++size; while (node = node.next)
  });
  return size;
};

var tree_visit = function(callback) {
  var quads = [], q, node = this._root, child, x0, y0, x1, y1;
  if (node) quads.push(new Quad(node, this._x0, this._y0, this._x1, this._y1));
  while (q = quads.pop()) {
    if (!callback(node = q.node, x0 = q.x0, y0 = q.y0, x1 = q.x1, y1 = q.y1) && node.length) {
      var xm = (x0 + x1) / 2, ym = (y0 + y1) / 2;
      if (child = node[3]) quads.push(new Quad(child, xm, ym, x1, y1));
      if (child = node[2]) quads.push(new Quad(child, x0, ym, xm, y1));
      if (child = node[1]) quads.push(new Quad(child, xm, y0, x1, ym));
      if (child = node[0]) quads.push(new Quad(child, x0, y0, xm, ym));
    }
  }
  return this;
};

var tree_visitAfter = function(callback) {
  var quads = [], next = [], q;
  if (this._root) quads.push(new Quad(this._root, this._x0, this._y0, this._x1, this._y1));
  while (q = quads.pop()) {
    var node = q.node;
    if (node.length) {
      var child, x0 = q.x0, y0 = q.y0, x1 = q.x1, y1 = q.y1, xm = (x0 + x1) / 2, ym = (y0 + y1) / 2;
      if (child = node[0]) quads.push(new Quad(child, x0, y0, xm, ym));
      if (child = node[1]) quads.push(new Quad(child, xm, y0, x1, ym));
      if (child = node[2]) quads.push(new Quad(child, x0, ym, xm, y1));
      if (child = node[3]) quads.push(new Quad(child, xm, ym, x1, y1));
    }
    next.push(q);
  }
  while (q = next.pop()) {
    callback(q.node, q.x0, q.y0, q.x1, q.y1);
  }
  return this;
};

function defaultX(d) {
  return d[0];
}

var tree_x = function(_) {
  return arguments.length ? (this._x = _, this) : this._x;
};

function defaultY(d) {
  return d[1];
}

var tree_y = function(_) {
  return arguments.length ? (this._y = _, this) : this._y;
};

function quadtree(nodes, x, y) {
  var tree = new Quadtree(x == null ? defaultX : x, y == null ? defaultY : y, NaN, NaN, NaN, NaN);
  return nodes == null ? tree : tree.addAll(nodes);
}

function Quadtree(x, y, x0, y0, x1, y1) {
  this._x = x;
  this._y = y;
  this._x0 = x0;
  this._y0 = y0;
  this._x1 = x1;
  this._y1 = y1;
  this._root = undefined;
}

function leaf_copy(leaf) {
  var copy = {data: leaf.data}, next = copy;
  while (leaf = leaf.next) next = next.next = {data: leaf.data};
  return copy;
}

var treeProto = quadtree.prototype = Quadtree.prototype;

treeProto.copy = function() {
  var copy = new Quadtree(this._x, this._y, this._x0, this._y0, this._x1, this._y1),
      node = this._root,
      nodes,
      child;

  if (!node) return copy;

  if (!node.length) return copy._root = leaf_copy(node), copy;

  nodes = [{source: node, target: copy._root = new Array(4)}];
  while (node = nodes.pop()) {
    for (var i = 0; i < 4; ++i) {
      if (child = node.source[i]) {
        if (child.length) nodes.push({source: child, target: node.target[i] = new Array(4)});
        else node.target[i] = leaf_copy(child);
      }
    }
  }

  return copy;
};

treeProto.add = tree_add;
treeProto.addAll = addAll;
treeProto.cover = tree_cover;
treeProto.data = tree_data;
treeProto.extent = tree_extent;
treeProto.find = tree_find;
treeProto.remove = tree_remove;
treeProto.removeAll = removeAll;
treeProto.root = tree_root;
treeProto.size = tree_size;
treeProto.visit = tree_visit;
treeProto.visitAfter = tree_visitAfter;
treeProto.x = tree_x;
treeProto.y = tree_y;

exports.quadtree = quadtree;

Object.defineProperty(exports, '__esModule', { value: true });

})));