wouterbulten/slacjs

import { polarToCartesian, meanHeading, limitTheta } from '../util/motion';
import { randn } from '../util/math';
import LinkedList from '../util/linked-list';

class User {
    /**
     * Create a new user
     * @param  {float} options.x     Starting x location of the user
     * @param  {float} options.y     Starting y location of the user
     * @param  {float} options.theta Direction of the user in radials relative to the x-axis
     * @param  {object} userConfig
     * @param  {LinkedList} trace      Optional trace to extend
     * @return {User}
     */
    constructor({x, y, theta}, userConfig, trace = undefined) {
        this.x = x;
        this.y = y;
        this.theta = theta;
        this.userConfig = userConfig;

        this.previousOdometry = {x, y, theta};

        if (trace === undefined) {
            this.trace = new LinkedList().add({x, y, theta});
        }
        else {
            //We use a LinkedList here to make use of the reference to the
            //trace instead of copying the whole list
            this.trace = new LinkedList(trace);
        }
    }

    /**
     * Move a user to a new position
     * @param  {float} r
     * @param  {float} theta
     * @return {User}
     */
    move({r, theta}) {

        const {dx, dy} = polarToCartesian(r, theta);

        this.x += dx;
        this.y += dy;
        this.theta = theta;

        this.trace.add({x: this.x, y: this.y, theta: this.theta});

        return this;
    }

    /**
     * Move the user to a specific position using a sampling function
     * @param  {Number} x
     * @param  {Number} y
     * @param  {Number} theta
     * @return {User}
     */
    samplePose({r, theta}) {

        const sdHeading = this.userConfig.sdHeading;

        const sampledHeading = limitTheta(randn(theta, sdHeading));

        //Comput the deviation of the noise of the step size
        //@todo Base the deviation of the steps on the pedometer
        const sdStep = this.userConfig.sdStep;

        const sampledR = randn(r, sdStep);

        //Use odometry to find a new position
        const {dx, dy} = polarToCartesian(sampledR, sampledHeading);

        this.x += dx;
        this.y += dy;
        this.theta = sampledHeading;

        this.trace.add({x: this.x, y: this.y, theta: this.theta});

        return this;
    }

    /**
     * Safely copy a user object
     * @param  {User} user User to copy
     * @return {User}
     */
    static copyUser(user) {
        return new User({
            x: user.x,
            y: user.y,
            theta: user.theta
        }, user.userConfig, user.trace);
    }
}

export default User;