Strilanc/Quirk

/**
 * Copyright 2017 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * A two dimensional point with real coordinates.
 */
class Point {
    /**
     * @param {!number} x The new point's x coordinate.
     * @param {!number} y The new point's y coordinate.
     */
    constructor(x, y) {
        /**
         * The point's x coordinate.
         * @type {!number}
         */
        this.x = x;
        /**
         * The point's y coordinate.
         * @member Point#y
         * @type {!number}
         */
        this.y = y;
    }

    /**
     * Determines if the given value is a point with the same coordinates as the receiving point.
     * @param {!Point|*} obj The point, or other value, to compare against.
     * @returns {!boolean}
     */
    isEqualTo(obj) {
        if (!(obj instanceof Point)) {
            return false;
        }
        /** @type {!Point} */
        let other = obj;
        return other.x === this.x && other.y === this.y;
    }

    /**
     * @returns {!string}
     */
    toString() {
        return `(x: ${this.x}, y: ${this.y})`;
    }

    /**
     * Returns the result of adding the receiving point's coordinates to the given offset values.
     * @param {!number} dx The x offset.
     * @param {!number} dy The y offset.
     * @returns {!Point}
     */
    offsetBy(dx, dy) {
        return new Point(this.x + dx, this.y + dy);
    }

    /**
     * Returns the result of pairing and adding the receiving point's, and the given point's, coordinates.
     * @param {!Point} p
     * @returns {!Point}
     */
    plus(p) {
        return new Point(this.x + p.x, this.y + p.y);
    }

    /**
     * Returns the result of subtracting the given point's coordinates from the receiving point.
     * @param {!Point} p
     * @returns {!Point}
     */
    minus(p) {
        return new Point(this.x - p.x, this.y - p.y);
    }

    /**
     * Returns the result of scaling the receiving point's coordinates by the given factor.
     * @param {!number} c The scaling factor.
     * @returns {!Point}
     */
    times(c) {
        return new Point(this.x * c, this.y * c);
    }

    /**
     * Returns the Euclidean distance between the receiving point and the given point.
     * @param {!Point} other
     * @returns {!number}
     */
    distanceTo(other) {
        let dx = this.x - other.x;
        let dy = this.y - other.y;
        return Math.sqrt(dx*dx + dy*dy);
    }
}

export {Point}