// Rectangle operations.

// **Rectangle** is a utility class to help with rectangle operations. A
// rectangle is implemented as a 4-element array. Element 0 is *x*, element
// 1 is *y*, element 2 is *width* and element 3 is *height*.

import * as Vector from '../vector';

// Check if a rectangle intersects with another rectangle.
//
//     avocado> Rectangle.intersects [0, 0, 16, 16], [8, 8, 24, 24]
//     true
//
//     avocado> Rectangle.intersects [0, 0, 16, 16], [16, 16, 32, 32]
//     false
export function intersects (l, r) {
  if (l[0] >= r[0] + r[2]) {
    return false;
  }
  if (r[0] >= l[0] + l[2]) {
    return false;
  }
  if (l[1] >= r[1] + r[3]) {
    return false;
  }
  if (r[1] >= l[1] + l[3]) {
    return false;
  }
  return true;
}

// Check if a rectangle is touching a vector.
//
//     avocado> Rectangle.isTouching [0, 0, 16, 16], [0, 0]
//     true
//
//     avocado> Rectangle.intersects [0, 0, 16, 16], [16, 16]
//     false
export function isTouching (r, v) {
  if (v[0] < r[0]) {
    return false;
  }
  if (v[1] < r[1]) {
    return false;
  }
  if (v[0] >= r[0] + r[2]) {
    return false;
  }
  if (v[1] >= r[1] + r[3]) {
    return false;
  }
  return true
}

// Compose a rectangle from a position vector and a size vector.
//
//     avocado> Rectangle.compose [0, 0], [16, 16]
//     [0, 0, 16, 16]
export function compose (l, r) {
  return [l[0], l[1], r[0], r[1]];
}

// Make a deep copy of the rectangle.
//
//     avocado> rectangle = [0, 0, 16, 16]
//     avocado> rectangle is Rectangle.copy rectangle
//     false
export function copy (r) {
  return [r[0], r[1], r[2], r[3]];
}

// Convert a rectangle to an object. If you *useShortKeys*, The width and
// height keys will be named w and h, respectively.
//
//     avocado> Rectangle.toObject [3, 4, 5, 6]
//     {x: 3, y: 4, width: 5, height: 6}
//
//     avocado> Rectangle.toObject [3, 4, 5, 6], true
//     {x: 3, y: 4, w: 5, h: 6}
export function toObject (r, useShortKeys = false) {
  const whKeys = useShortKeys ? ['w', 'h'] : ['width', 'height'];
  const O = {x: r[0], y: r[1]};
  O[whKeys[0]] = r[2];
  O[whKeys[1]] = r[3];
  return O;
}

export function fromObject(O) {
  return [O.x, O.y, O.width, O.height];
}

// Returns the position of a rectangle.
//
//     avocado> Rectangle.position [8, 8, 16, 16]
//     [8, 8]
export function position(r) {
  return [r[0], r[1]];
}

// Returns the size of a rectangle.
//
//     avocado> Rectangle.size [8, 8, 16, 16]
//     [16, 16]
export function size(r) {
  return [r[2], r[3]];
}

// Compute the intersection rectangle of two rectangles.
//
//     avocado> Rectangle.intersection [0, 0, 16, 16], [8, 8, 24, 24]
//     [8, 8, 8, 8]
export function intersection(l, r) {
  if (!intersects(l, r)) {
    return [0, 0, 0, 0];
  }
  const x = Math.max(l[0], r[0]);
  const y = Math.max(l[1], r[1]);
  const lx2 = l[0] + l[2];
  const rx2 = r[0] + r[2];
  const ly2 = l[1] + l[3];
  const ry2 = r[1] + r[3];
  const w = (lx2 <= rx2 ? lx2 : rx2) - x;
  const h = (ly2 <= ry2 ? ly2 : ry2) - y;
  return [x, y, w, h];
}

// Returns a rectangle translated along the [*x*, *y*] axis of a vector.
//
//     avocado> Rectangle.translated [0, 0, 16, 16], [8, 8]
//     [8, 8, 16, 16]
export function translated(r, v) {
  return compose(Vector.add(v, position(r)), size(r));
}

// Checks if a rectangle is null. A null rectangle is defined by having any
// 0-length axis.
//
//     avocado> Rectangle.isNull [0, 0, 1, 1]
//     false
//
//     avocado> Rectangle.isNull [0, 0, 1, 0]
//     true
export function isNull(r) {
  if (!r) {
    return true;
  }
  if (4 !== r.length) {
    return true;
  }
  return Vector.isNull(size(r));
}

// Check whether a rectangle equals another rectangle.
//
//     avocado> Rectangle.equals [0, 0, 0, 0], [0, 0, 0, 1]
//     false
//
//     avocado> Rectangle.equals [0, 0, 0, 0], [0, 0, 0, 0]
//     true
export function equals(l, r) {
  return l[0] === r[0] && l[1] === r[1] && l[2] === r[2] && l[3] === r[3];
}

// Returns a rectangle that is the united area of two rectangles.
//
//     avocado> Rectangle.united [0, 0, 4, 4], [4, 4, 8, 8]
//     [0, 0, 12, 12]
export function united(l, r) {
  if (isNull(l)) {
    return r;
  }
  if (isNull(r)) {
    return l;
  }
  const x = Math.min(l[0], r[0]);
  const y = Math.min(l[1], r[1]);
  const x2 = Math.max(l[0] + l[2], r[0] + r[2]);
  const y2 = Math.max(l[1] + l[3], r[1] + r[3]);
  return [x, y, x2 - x, y2 - y];
}

// Round the position and size of a rectangle.
//
//     avocado> Rectangle.round [3.14, 4.70, 5.32, 1.8]
//     [3, 5, 5, 2]
export function round(r) {
  return [
    Math.round(r[0]),
    Math.round(r[1]),
    Math.round(r[2]),
    Math.round(r[3]),
  ];
}

// Floor the position and size of a rectangle.
//
//     avocado> Rectangle.floor [3.14, 4.70, 5.32, 1.8]
//     [3, 4, 5, 1]
export function floor(r) {
  return [
    Math.floor(r[0]),
    Math.floor(r[1]),
    Math.floor(r[2]),
    Math.floor(r[3]),
  ];
}

export function toPoints(r) {
  // Break into 4 points.
  const width = r[2] - .0001;
  const height = r[3] - .0001;
  const upperLeft = position(r);
  const upperRight = Vector.add(upperLeft, [width, 0]);
  const lowerLeft = Vector.add(upperLeft, [0, height]);
  const lowerRight = Vector.add(upperLeft, [width, height]);
  return [
    upperLeft,
    upperRight,
    lowerLeft,
    lowerRight,
  ];
}