export default function Bounds(b) {
  this.clear();
  if (b) this.union(b);
}

var prototype = Bounds.prototype;

prototype.clone = function() {
  return new Bounds(this);
};

prototype.clear = function() {
  this.x1 = +Number.MAX_VALUE;
  this.y1 = +Number.MAX_VALUE;
  this.x2 = -Number.MAX_VALUE;
  this.y2 = -Number.MAX_VALUE;
  return this;
};

prototype.empty = function() {
  return (
    this.x1 === +Number.MAX_VALUE &&
    this.y1 === +Number.MAX_VALUE &&
    this.x2 === -Number.MAX_VALUE &&
    this.y2 === -Number.MAX_VALUE
  );
};

prototype.equals = function(b) {
  return (
    this.x1 === b.x1 &&
    this.y1 === b.y1 &&
    this.x2 === b.x2 &&
    this.y2 === b.y2
  );
};

prototype.set = function(x1, y1, x2, y2) {
  if (x2 < x1) {
    this.x2 = x1;
    this.x1 = x2;
  } else {
    this.x1 = x1;
    this.x2 = x2;
  }
  if (y2 < y1) {
    this.y2 = y1;
    this.y1 = y2;
  } else {
    this.y1 = y1;
    this.y2 = y2;
  }
  return this;
};

prototype.add = function(x, y) {
  if (x < this.x1) this.x1 = x;
  if (y < this.y1) this.y1 = y;
  if (x > this.x2) this.x2 = x;
  if (y > this.y2) this.y2 = y;
  return this;
};

prototype.expand = function(d) {
  this.x1 -= d;
  this.y1 -= d;
  this.x2 += d;
  this.y2 += d;
  return this;
};

prototype.round = function() {
  this.x1 = Math.floor(this.x1);
  this.y1 = Math.floor(this.y1);
  this.x2 = Math.ceil(this.x2);
  this.y2 = Math.ceil(this.y2);
  return this;
};

prototype.scale = function(s) {
  this.x1 *= s;
  this.y1 *= s;
  this.x2 *= s;
  this.y2 *= s;
  return this;
};

prototype.translate = function(dx, dy) {
  this.x1 += dx;
  this.x2 += dx;
  this.y1 += dy;
  this.y2 += dy;
  return this;
};

prototype.rotate = function(angle, x, y) {
  const p = this.rotatedPoints(angle, x, y);
  return this.clear()
    .add(p[0], p[1])
    .add(p[2], p[3])
    .add(p[4], p[5])
    .add(p[6], p[7]);
};

prototype.rotatedPoints = function(angle, x, y) {
  var {x1, y1, x2, y2} = this,
      cos = Math.cos(angle),
      sin = Math.sin(angle),
      cx = x - x*cos + y*sin,
      cy = y - x*sin - y*cos;

  return [
    cos*x1 - sin*y1 + cx, sin*x1 + cos*y1 + cy,
    cos*x1 - sin*y2 + cx, sin*x1 + cos*y2 + cy,
    cos*x2 - sin*y1 + cx, sin*x2 + cos*y1 + cy,
    cos*x2 - sin*y2 + cx, sin*x2 + cos*y2 + cy
  ];
};

prototype.union = function(b) {
  if (b.x1 < this.x1) this.x1 = b.x1;
  if (b.y1 < this.y1) this.y1 = b.y1;
  if (b.x2 > this.x2) this.x2 = b.x2;
  if (b.y2 > this.y2) this.y2 = b.y2;
  return this;
};

prototype.intersect = function(b) {
  if (b.x1 > this.x1) this.x1 = b.x1;
  if (b.y1 > this.y1) this.y1 = b.y1;
  if (b.x2 < this.x2) this.x2 = b.x2;
  if (b.y2 < this.y2) this.y2 = b.y2;
  return this;
};

prototype.encloses = function(b) {
  return b && (
    this.x1 <= b.x1 &&
    this.x2 >= b.x2 &&
    this.y1 <= b.y1 &&
    this.y2 >= b.y2
  );
};

prototype.alignsWith = function(b) {
  return b && (
    this.x1 == b.x1 ||
    this.x2 == b.x2 ||
    this.y1 == b.y1 ||
    this.y2 == b.y2
  );
};

prototype.intersects = function(b) {
  return b && !(
    this.x2 < b.x1 ||
    this.x1 > b.x2 ||
    this.y2 < b.y1 ||
    this.y1 > b.y2
  );
};

prototype.contains = function(x, y) {
  return !(
    x < this.x1 ||
    x > this.x2 ||
    y < this.y1 ||
    y > this.y2
  );
};

prototype.width = function() {
  return this.x2 - this.x1;
};

prototype.height = function() {
  return this.y2 - this.y1;
};