// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

part of base;

/**
 * A utility class for representing two-dimensional sizes.
 */
class Size {
  num width;
  num height;

  Size(num this.width, num this.height) {}

  bool operator ==(covariant Size other) {
    return other != null && width == other.width && height == other.height;
  }

  int get hashCode => throw new UnimplementedError();

  /**
   * Returns the area of the size (width * height).
   */
  num area() {
    return width * height;
  }

  /**
   * Returns the ratio of the size's width to its height.
   */
  num aspectRatio() {
    return width / height;
  }

  /**
   * Clamps the width and height parameters upward to integer values.
   * Returns this size with ceil'd components.
   */
  Size ceil() {
    width = width.ceil();
    height = height.ceil();
    return this;
  }

  /**
   * Returns a new copy of the Size.
   */
  Size clone() {
    return new Size(width, height);
  }

  /**
   * Returns true if this Size is the same size or smaller than the
   * [target] size in both dimensions.
   */
  bool fitsInside(Size target) {
    return width <= target.width && height <= target.height;
  }

  /**
   * Clamps the width and height parameters downward to integer values.
   * Returns this size with floored components.
   */
  Size floor() {
    width = width.floor();
    height = height.floor();
    return this;
  }

  /**
   * Returns the longer of the two dimensions in the size.
   */
  num getLongest() {
    return max(width, height);
  }

  /**
   * Returns the shorter of the two dimensions in the size.
   */
  num getShortest() {
    return min(width, height);
  }

  /**
   * Returns true if the size has zero area, false if both dimensions
   *     are non-zero numbers.
   */
  bool get isEmpty {
    return area() == 0;
  }

  /**
   * Returns the perimeter of the size (width + height) * 2.
   */
  num perimeter() {
    return (width + height) * 2;
  }

  /**
   * Rounds the width and height parameters to integer values.
   * Returns this size with rounded components.
   */
  Size round() {
    width = width.round();
    height = height.round();
    return this;
  }

  /**
   * Scales the size uniformly by a factor.
   * [s] The scale factor.
   * Returns this Size object after scaling.
   */
  Size scale(num s) {
    width *= s;
    height *= s;
    return this;
  }

  /**
   * Uniformly scales the size to fit inside the dimensions of a given size. The
   * original aspect ratio will be preserved.
   *
   * This function assumes that both Sizes contain strictly positive dimensions.
   * Returns this Size object, after optional scaling.
   */
  Size scaleToFit(Size target) {
    num s = aspectRatio() > target.aspectRatio()
        ? target.width / width
        : target.height / height;
    return scale(s);
  }

  /**
   * Returns a nice string representing size.
   * Returns in the form (50 x 73).
   */
  String toString() {
    return "(${width} x ${height})";
  }
}