import Coord from "./Coord";

/** A rectangle on a grid whose origin is in the top left. */
export default class Rect {
  private readonly _topLeft: Coord;
  private readonly _width: number;
  private readonly _height: number;

  constructor(
    topLeftX: number,
    topLeftY: number,
    width: number,
    height: number,
  ) {
    this._topLeft = new Coord(topLeftX, topLeftY);
    this._width = width;
    this._height = height;
  }

  /** Width of this rectangle. */
  get width(): number {
    return this._width;
  }

  /** Height of this rectangle. */
  get height(): number {
    return this._height;
  }

  /** Coord of the top-left point of this rectangle. */
  get topLeft(): Coord {
    return this._topLeft;
  }

  /** Coord of the bottom-right point of this rectangle. */
  get bottomRight(): Coord {
    return new Coord(
      this._topLeft.x + this._width,
      this._topLeft.y + this._height,
    );
  }

  /** Determine if this rectangle contains the point at `coord`. */
  containsCoord(coord: Coord): boolean {
    return (
      this.topLeft.x <= coord.x &&
      coord.x <= this.bottomRight.x &&
      this.topLeft.y <= coord.y &&
      coord.y <= this.bottomRight.y
    );
  }

  verticallyContainsCoord(coord: Coord): boolean {
    return this.topLeft.y <= coord.y && coord.y <= this.bottomRight.y;
  }

  horizontallyContainsCoord(coord: Coord): boolean {
    return this.topLeft.x <= coord.x && coord.x <= this.bottomRight.x;
  }

  extend(other: Rect): Rect {
    const topLeftX = Math.min(
      this.topLeft.x,
      this.bottomRight.x,
      other.topLeft.x,
      other.bottomRight.x,
    );

    const topLeftY = Math.min(
      this.topLeft.y,
      this.bottomRight.y,
      other.topLeft.y,
      other.bottomRight.y,
    );

    const bottomRightX = Math.max(
      this.topLeft.x,
      this.bottomRight.x,
      other.topLeft.x,
      other.bottomRight.x,
    );

    const bottomRightY = Math.max(
      this.topLeft.y,
      this.bottomRight.y,
      other.topLeft.y,
      other.bottomRight.y,
    );

    return new Rect(
      topLeftX,
      topLeftY,
      bottomRightX - topLeftX,
      bottomRightY - topLeftY,
    );
  }
}