# classes/point.js

    /**
     * Created by Alex Bol on 2/18/2017.
     */

    import Flatten from '../flatten';

    /**
     *
     * Class representing a point
     * @type {Point}
     */
    export class Point {
        /**
         * Point may be constructed by two numbers, or by array of two numbers
         * @param {number} x - x-coordinate (float number)
         * @param {number} y - y-coordinate (float number)
         */
        constructor(...args) {
            /**
             * x-coordinate (float number)
             * @type {number}
             */
            this.x = 0;
            /**
             * y-coordinate (float number)
             * @type {number}
             */
            this.y = 0;

            if (args.length === 0) {
                return;
            }

            if (args.length === 1 && args[0] instanceof Array && args[0].length === 2) {
                let arr = args[0];
                if (typeof (arr[0]) == "number" && typeof (arr[1]) == "number") {
                    this.x = arr[0];
                    this.y = arr[1];
                    return;
                }
            }

            if (args.length === 1 && args[0] instanceof Object && args[0].name === "point") {
                let {x, y} = args[0];
                this.x = x;
                this.y = y;
                return;
            }

            if (args.length === 2) {
                if (typeof (args[0]) == "number" && typeof (args[1]) == "number") {
                    this.x = args[0];
                    this.y = args[1];
                    return;
                }
            }

            throw Flatten.Errors.ILLEGAL_PARAMETERS;

        }

        /**
         * Returns bounding box of a point
         * @returns {Box}
         */
        get box() {
            return new Flatten.Box(this.x, this.y, this.x, this.y);
        }

        /**
         * Return new cloned instance of point
         * @returns {Point}
         */
        clone() {
            return new Flatten.Point(this.x, this.y);
        }

        get vertices() {
            return [this.clone()];
        }

        /**
         * Returns true if points are equal up to [Flatten.Utils.DP_TOL]{@link DP_TOL} tolerance
         * @param {Point} pt Query point
         * @returns {boolean}
         */
        equalTo(pt) {
            return Flatten.Utils.EQ(this.x, pt.x) && Flatten.Utils.EQ(this.y, pt.y);
        }

        /**
         * Defines predicate "less than" between points. Returns true if the point is less than query points, false otherwise <br/>
         * By definition point1 < point2 if {point1.y < point2.y || point1.y == point2.y && point1.x < point2.x <br/>
         * Numeric values compared with [Flatten.Utils.DP_TOL]{@link DP_TOL} tolerance
         * @param {Point} pt Query point
         * @returns {boolean}
         */
        lessThan(pt) {
            if (Flatten.Utils.LT(this.y, pt.y))
                return true;
            if (Flatten.Utils.EQ(this.y, pt.y) && Flatten.Utils.LT(this.x, pt.x))
                return true;
            return false;
        }

        /**
         * Returns new point rotated by given angle around given center point.
         * If center point is omitted, rotates around zero point (0,0).
         * Positive value of angle defines rotation in counter clockwise direction,
         * negative angle defines rotation in clockwise clockwise direction
         * @param {number} angle - angle in radians
         * @param {Point} [center=(0,0)] center
         * @returns {Point}
         */
        rotate(angle, center = {x: 0, y: 0}) {
            var x_rot = center.x + (this.x - center.x) * Math.cos(angle) - (this.y - center.y) * Math.sin(angle);
            var y_rot = center.y + (this.x - center.x) * Math.sin(angle) + (this.y - center.y) * Math.cos(angle);

            return new Flatten.Point(x_rot, y_rot);
        }

        /**
         * Returns new point translated by given vector.
         * Translation vector may by also defined by a pair of numbers.
         * @param {Vector} vector - Translation vector defined as Flatten.Vector or
         * @param {number|number} - Translation vector defined as pair of numbers
         * @returns {Point}
         */
        translate(...args) {
            if (args.length == 1 &&
                (args[0] instanceof Flatten.Vector || !isNaN(args[0].x) && !isNaN(args[0].y))) {
                return new Flatten.Point(this.x + args[0].x, this.y + args[0].y);
            }

            if (args.length == 2 && typeof (args[0]) == "number" && typeof (args[1]) == "number") {
                return new Flatten.Point(this.x + args[0], this.y + args[1]);
            }

            throw Flatten.Errors.ILLEGAL_PARAMETERS;
        }

        /**
         * Return new point transformed by affine transformation matrix m
         * @param {Matrix} m - affine transformation matrix (a,b,c,d,tx,ty)
         * @returns {Point}
         */
        transform(m) {
            // let [x,y] = m.transform([this.x,this.y]);
            return new Flatten.Point(m.transform([this.x, this.y]))
        }

        /**
         * Returns projection point on given line
         * @param {Line} line Line this point be projected on
         * @returns {Point}
         */
        projectionOn(line) {
            if (this.equalTo(line.pt))                   // this point equal to line anchor point
                return this.clone();

            let vec = new Flatten.Vector(this, line.pt);
            if (Flatten.Utils.EQ_0(vec.cross(line.norm)))    // vector to point from anchor point collinear to normal vector
                return line.pt.clone();

            let dist = vec.dot(line.norm);             // signed distance
            let proj_vec = line.norm.multiply(dist);
            return this.translate(proj_vec);
        }

        /**
         * Returns true if point belongs to the "left" semi-plane, which means, point belongs to the same semi plane where line normal vector points to
         * Return false if point belongs to the "right" semi-plane or to the line itself
         * @param {Line} line Query line
         * @returns {boolean}
         */
        leftTo(line) {
            let vec = new Flatten.Vector(line.pt, this);
            let onLeftSemiPlane = Flatten.Utils.GT(vec.dot(line.norm), 0);
            return onLeftSemiPlane;
        }

        /**
         * Calculate distance and shortest segment from point to shape and return as array [distance, shortest segment]
         * @param {Shape} shape Shape of the one of supported types Point, Line, Circle, Segment, Arc, Polygon or Planar Set
         * @returns {number} distance from point to shape
         * @returns {Segment} shortest segment between point and shape (started at point, ended at shape)
         */
        distanceTo(shape) {
            if (shape instanceof Point) {
                let dx = shape.x - this.x;
                let dy = shape.y - this.y;
                return [Math.sqrt(dx * dx + dy * dy), new Flatten.Segment(this, shape)];
            }

            if (shape instanceof Flatten.Line) {
                return Flatten.Distance.point2line(this, shape);
            }

            if (shape instanceof Flatten.Circle) {
                return Flatten.Distance.point2circle(this, shape);
            }

            if (shape instanceof Flatten.Segment) {
                return Flatten.Distance.point2segment(this, shape);
            }

            if (shape instanceof Flatten.Arc) {
                // let [dist, ...rest] = Distance.point2arc(this, shape);
                // return dist;
                return Flatten.Distance.point2arc(this, shape);
            }

            if (shape instanceof Flatten.Polygon) {
                // let [dist, ...rest] = Distance.point2polygon(this, shape);
                // return dist;
                return Flatten.Distance.point2polygon(this, shape);
            }

            if (shape instanceof Flatten.PlanarSet) {
                return Flatten.Distance.shape2planarSet(this, shape);
            }
        }

        /**
         * Returns true if point is on a shape, false otherwise
         * @param {Shape} shape Shape of the one of supported types Point, Line, Circle, Segment, Arc, Polygon
         * @returns {boolean}
         */
        on(shape) {
            if (shape instanceof Flatten.Point) {
                return this.equalTo(shape);
            }

            if (shape instanceof Flatten.Line) {
                return shape.contains(this);
            }

            if (shape instanceof Flatten.Circle) {
                return shape.contains(this);
            }

            if (shape instanceof Flatten.Segment) {
                return shape.contains(this);
            }

            if (shape instanceof Flatten.Arc) {
                return shape.contains(this);
            }

            if (shape instanceof Flatten.Polygon) {
                return shape.contains(this);
            }
        }

        /**
         * This method returns an object that defines how data will be
         * serialized when called JSON.stringify() method
         * @returns {Object}
         */
        toJSON() {
            return Object.assign({}, this, {name: "point"});
        }

        /**
         * Return string to draw point in svg as circle with radius "r" <br/>
         * Accept any valid attributes of svg elements as svg object
         * Defaults attribues are: <br/>
         * {
         *    r:"3",
         *    stroke:"black",
         *    strokeWidth:"1",
         *    fill:"red"
         * }
         * @param {Object} attrs - Any valid attributes of svg circle element, like "r", "stroke", "strokeWidth", "fill"
         * @returns {String}
         */
        svg(attrs = {}) {
            let {r, stroke, strokeWidth, fill, id, className} = attrs;
            // let rest_str = Object.keys(rest).reduce( (acc, key) => acc += ` ${key}="${rest[key]}"`, "");
            let id_str = (id && id.length > 0) ? `id="${id}"` : "";
            let class_str = (className && className.length > 0) ? `class="${className}"` : "";
            return `\n<circle cx="${this.x}" cy="${this.y}" r="${r || 3}" stroke="${stroke || "black"}" stroke-width="${strokeWidth || 1}" fill="${fill || "red"}" ${id_str} ${class_str} />`;
        }

    };

    Flatten.Point = Point;
    /**
     * Function to create point equivalent to "new" constructor
     * @param args
     */
    export const point = (...args) => new Flatten.Point(...args);
    Flatten.point = point;

    // export {Point};