# Source: src/plugins/path/Path.js

    /**
    * @author       Richard Davey <rich@photonstorm.com>
    * @author       Pete Baron <pete@photonstorm.com>
    * @copyright    2016 Photon Storm Ltd.
    * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
    */

    /**
    * A Phaser.Path contains all the functions need to create and manipulate a single Path object.
    * A Path is a list of PathPoint objects connected by Hermite curves.
    *
    * @class Phaser.Path
    * @constructor
    * @param {Phaser.Game} game - A reference to the Phaser.Game instance.
    * @param {number} [type=Phaser.Path.CoordinateSystems.WORLD] - The coordinate system used by the Path.
    * @param {boolean} [loops=false] - Should this Path loop or not when a PathFollower reaches the end of it?
    */
    Phaser.Path = function (game, type, loops) {

        if (type === undefined) { type = Phaser.Path.CoordinateSystems.WORLD; }
        if (loops === undefined) { loops = false; }

        /**
        * @property {Phaser.Game} game - A reference to the currently running game.
        */
        this.game = game;

        /**
        * @property {number} coordinateSystem - The coordinate system used by the Path.
        */
        this.coordinateSystem = type;

        /**
        * @property {boolean} loops - Should this Path loop or not when a PathFollower reaches the end of it?
        */
        this.loops = loops;

        /**
        * @property {string} cacheKey - The key of the JSON file in the cache used to define this path.
        */
        this.cacheKey = '';

        /**
        * @property {string} key - The key of the object within the JSON data. Used if there are multiple paths per JSON file.
        */
        this.key = '';

        /*
        * @property {Phaser.PathPoint} name - The name of this path.
        */
        this.name = '';

        /*
         * @property {Phaser.PathPoint} type - The Phaser.Path.PathTypes of this path.
         */
        this.type = Phaser.Path.PathTypes.PATH;

        /*
        * @property {Array} branches - A list of branches this path has.
        */
        this.branches = [];

        /**
        * @property {array} _points - A private cache of the Points on this Path.
        * @private
        */
        this._points = [];

        /**
        * @property {Phaser.Point} _offset - Default offset for PathFollowers on this path instance.
        * @private
        */
        this._offset = new Phaser.Point();

        /*
        * @property {Phaser.PathPoint} _p1 - Used for internal calculations.
        * @private
        */
        this._p1 = new Phaser.PathPoint();

        /*
        * @property {Phaser.PathPoint} _p2 - Used for internal calculations.
        * @private
        */
        this._p2 = new Phaser.PathPoint();

        /*
        * @property {Phaser.PathPoint} origin - the origin of this path. Used mostly for BRANCH paths.
        * @private
        */
        this._origin = new Phaser.Point();

    };

    Phaser.Path.prototype.constructor = Phaser.Path;

    Phaser.Path.PathTypes = {};
    Phaser.Path.BranchTypes = {};
    Phaser.Path.CoordinateSystems = {};

    /**
    * @constant
    * @type {number}
    */
    Phaser.Path.PathTypes.PATH = 0;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Path.PathTypes.BRANCH = 1;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Path.BranchTypes.ATTACHED = 0;

    /**
    * @constant
    * @type {number}
    */
    Phaser.Path.BranchTypes.JOINED = 1;

    /**
    * Points are relative to the World origin.
    * @constant
    * @type {number}
    */
    Phaser.Path.CoordinateSystems.WORLD = 1;

    /**
    * Points are relative to the screen origin.
    * @constant
    * @type {number}
    */
    Phaser.Path.CoordinateSystems.SCREEN = 2;

    /**
    * Points are relative to the first point.
    * @constant
    * @type {number}
    */
    Phaser.Path.CoordinateSystems.OFFSET = 3;

    Phaser.Path.prototype = {

        /**
        * Initialize a Path based on the given coordinate system.
        *
        * @method Phaser.Path#create
        * @param {number|string} coordinateSystem - The Phaser.Path.CoordinateSystems type to use.
        * @param {boolean} [loops=false] - Should this Path loop or not when a PathFollower reaches the end of it?
        * @return {Phaser.Path} This Path object.
        */
        create: function (coordinateSystem, loops) {

            if (loops === undefined) { loops = false; }

            switch (coordinateSystem)
            {
                default:
                    this.coordinateSystem = Phaser.Path.CoordinateSystems.WORLD;
                    break;

                case 2:
                case 'SCREEN_COORDINATES':
                    this.coordinateSystem = Phaser.Path.CoordinateSystems.SCREEN;
                    break;

                case 3:
                case 'OFFSET_COORDINATES':
                    this.coordinateSystem = Phaser.Path.CoordinateSystems.OFFSET;
                    break;
            }

            this.loops = loops;

            this._points = [];

            return this;

        },

        /**
        * Clone this Path object. It clones the origin and points data.
        *
        * @method Phaser.Path#clone
        * @return {Phaser.Path} The cloned Path.
        */
        clone: function () {

            var clone = new Phaser.Path(this.coordinateSystem, this.loops);

            this.origin.clone(clone.origin);

            this.points.forEach(function(p) {
                clone._points.push(p.clone());
            });

            return clone;

        },

        /**
        * Creates a new PathPoint object, relative to the path origin, and adds it to this path.
        *
        * @method Phaser.Path#addPathPoint
        * @param {number} [x=0] - The x position of the PathPoint.
        * @param {number} [y=0] - The y position of the PathPoint.
        * @param {number} [vx=0] - The vx tangent vector value of the PathPoint.
        * @param {number} [vy=0] - The vy tangent vector value of the PathPoint.
        * @param {number} [speed=1] - The speed value of the PathPoint.
        * @param {number} [data={}] - The data object
        * @param {number} [index=null] - The index of the new path point. If not given, will add point to end of point list.
        * @return {Phaser.PathPoint} The PathPoint object that was created.
        */
        addPathPoint: function (x, y, vx, vy, speed, data, index) {

            if (x === undefined) { x = 0; }
            if (y === undefined) { y = 0; }
            if (vx === undefined) { vx = 0; }
            if (vy === undefined) { vy = 0; }

            var pp = new Phaser.PathPoint(x - this.origin.x, y - this.origin.y, vx, vy, speed, data);

            if (index !== null && index !== undefined)
            {
                this._points.splice(index, 0, pp);
            }
            else
            {
                this._points.push(pp);
            }

            return pp;

        },

        /**
        * Remove a PathPoint from this paths point list.
        *
        * @method Phaser.Path#removePathPoint
        * @param {number} [index] - The index of the PathPoint to remove.
        * @return {Phaser.PathPoint} The removed PathPoint object.
        */
        removePathPoint: function (index) {

            var p = this.getPathPointReference(index);

            if (p)
            {
                this._points.splice(index, 1);
            }

            return p;

        },

        /**
        * Set a PathPoint objects position and tangent vector.
        *
        * @method Phaser.Path#setPathPoint
        * @param {number} index - The index of the PathPoint in this paths point list.
        * @param {number} x - The x coordinate of the PathPoint.
        * @param {number} y - The y coordinate of the PathPoint.
        * @param {number} [vx] - The x coordinate of the tangent vector to create the curve from.
        * @param {number} [vy] - The y coordinate of the tangent vector to create the curve from.
        * @return {Phaser.PathPoint} A reference to the PathPoint object that was updated.
        */
        setPathPoint: function (index, x, y, vx, vy) {

            var p = this.getPathPointReference(index);

            if (p)
            {
                p.setTo(x, y, vx, vy);
            }

            return p;

        },

        /**
        * Translate all points in a path by the given point.
        *
        * @method Phaser.Path#translatePoints
        * @param {Phaser.Point|object} point - A Phaser.Point, or a Point-like Object with public `x` and `y` properties, that will be used to modify all points in this paths point list.
        * @return {Phaser.Path} This Path object.
        */
        translatePoints: function (point) {

            this._points.forEach(function(pnt) {
                pnt.x += point.x;
                pnt.y += point.y;
            });

            return this;

        },

        /**
        * Set the Path level offset which will affect all of this paths PathFollowers.
        *
        * @method Phaser.Path#setOffset
        * @param {number} x - The x offset.
        * @param {number} y - The y offset.
        * @return {Phaser.Path} This Path object.
        */
        setOffset: function (x, y) {

            this._offset.x = x;
            this._offset.y = y;

            return this;

        },

        /**
        * Get a point on the the current Path curve.
        *
        * @method Phaser.Path#getPointOnThisCurve
        * @param {Phaser.Hermite} curve - A Phaser.Hermite curve object.
        * @param {number} [t=0 .. 1.0] - The distance on the curve to get the point from. Where 0 is the start of the curve, and 1 is the end.
        * @return {Phaser.Point} A point containing the x and y values at the specified distance (t) value in the curve.
        */
        getPointOnThisCurve: function (curve, t) {

            if (!curve)
            {
                return null;
            }

            var pnt = curve.getPoint(t);

            pnt.x += this._offset.x;
            pnt.y += this._offset.y;

            return pnt;

        },

        /**
        * Gets the points on the curve representing the end points of the line segments that make up the curve.
        *
        * @method Phaser.Path#getControlPointsOnThisCurve
        * @param {Phaser.Hermite} curve - A Phaser.Hermite curve.
        * @return {array} An array of points representing the end points of 10 line segments that make up the curve.
        */
        getControlPointsOnThisCurve: function (curve) {

            var pnts = Phaser.ArrayUtils.numberArrayStep(0, 1.1, 0.1).map(function(num) {
                return this.getPointOnThisCurve(curve, num);
            }, this);

            return pnts;

        },

        /**
        * Get a PathPoint from this path. Automatically handles path looping.
        *
        * The values from the PathPoint are copied into the given PathPoint object, which must
        * be a reference to a pre-existing PathPoint, as it's not returned by this method.
        *
        * @method Phaser.Path#getPathPoint
        * @param {number} index - The index of the point in this path to get.
        * @param {Phaser.PathPoint} point - A PathPoint object into which the found point object is cloned.
        * @return {boolean} false if the index is past the end of the path and it doesn't loop, otherwise true.
        */
        getPathPoint: function (index, point) {

            var i = this.loops ? index % this._points.length : index;

            //  If index is in the points list range
            if (this._points.length > i)
            {
                point.copy(this._points[i]);

                switch (this.coordinateSystem)
                {
                    case Phaser.Path.CoordinateSystems.SCREEN:

                        point.x -= this.game.camera.x;
                        point.y -= this.game.camera.y;
                        break;

                    case Phaser.Path.CoordinateSystems.OFFSET:

                        point.x += this.origin.x;
                        point.y += this.origin.y;
                        break;
                }

                return true;
            }
            else
            {
                //  The path doesn't loop and the index is out of range, so fail
                return false;
            }

        },

        /**
        * Get a reference to a PathPoint from this Path, handle path looping.
        *
        * NOTE: because this is a PathPoint reference, it does not take into account the coordinateSystem selected, it will be WORLD, or OFFSET unmodified
        *
        * @method Phaser.Path#getPathPointReference
        * @param {number} index - The index of the point in this path to get.
        * @return {Phaser.PathPoint} A reference to the PathPoint object in this Path, or null if index is out of range.
        */
        getPathPointReference: function (index) {

            var i = this.loops ? index % this._points.length : index;

            //  If index is in the points list range
            if (this._points.length > i)
            {
                return this._points[i];
            }

            //  The path doesn't loop and the index is out of range, fail
            return null;

        },

        /**
        * Get the curve from the given point index to the next.
        *
        * If the curve has been created previously, use that definition again, otherwise calculate it now.
        *
        * @method Phaser.Path#getCurve
        * @param {number} [index=0] - The index of the point in this path to get the curve from.
        * @return {Phaser.Hermite} A new Hermite object representing the curve starting at the 'index' path point.
        */
        getCurve: function (index) {

            if (index === undefined) { index = 0; }

            //  Beginning of the curve
            if (!this.getPathPoint(index, this._p1))
            {
                return null;
            }

            //  Has this curve been calculated already?
            if (this._p1.curve)
            {
                return this._p1.curve;
            }

            //  End of the curve
            if (!this.getPathPoint(index + 1, this._p2))
            {
                if (!this._p1.branchPath)
                {
                    return null;
                }

                //  We joined another Path
                var newPath = this._p1.branchPath;
                var joinIndex = this._p1.branchPointIndex;

                if (!newPath.getPathPoint(joinIndex + 1, this._p2))
                {
                    return null;
                }
            }

            //  Create and return the new Hermite object
            this._p1.curve = new Phaser.Hermite(this._p1.x, this._p1.y, this._p2.x, this._p2.y, this._p1.vx, this._p1.vy, this._p2.vx, this._p2.vy);

            this.curvePointIndex = index;

            return this._p1.curve;

        },

        /**
        * Find the first matching PathPoint in this path.
        * It works by taking the given PathPoint object, and then iterating through all points
        * in this Path until it finds one with the same values, then returns the index to it.
        *
        * @method Phaser.Path#pointIndex
        * @param {Phaser.PathPoint} pathPoint - The PathPoint object that will have its values compared to all the points in this Path.
        * @return {number} The index of the PathPoint in this Path if an equal match is found, or -1 if no match is found.
        */
        pointIndex: function (pathPoint) {

            var l = this._points.length;

            for (var i = 0; i < l; i++)
            {
                if (this.coordinateSystem === Phaser.Path.CoordinateSystems.OFFSET && i !== 0)
                {
                    if (pathPoint.equals(this._points[i], this._points[0].x, this._points[0].y))
                    {
                        return i;
                    }
                }
                else
                {
                    if (pathPoint.equals(this._points[i]))
                    {
                        return i;
                    }
                }
            }

            return -1;

        },

        /**
        * Is the given PathPoint index the end of this path?
        *
        * @method Phaser.Path#atEnd
        * @param {number} index - The index of the PathPoint to test.
        * @return {boolean} true if index is the last point in this path.
        */
        atEnd: function (index) {

            //  If the path loops, the end of the path is the end of the last curve
            if (this.loops)
            {
                return (index === this._points.length);
            }

            //  If the path doesn't loop, the end of the path is the last point on it
            return (index === this._points.length - 1);

        },

        /**
        * The total number of PathPoints in this Path.
        *
        * @method Phaser.Path#numPoints
        * return {number} The total number of PathPoints in this Path.
        */
        numPoints: function () {

            return this._points.length;

        },

        /*
        *  DATA PROCESSING
        */

        /**
        * Process the data associated with a point on this Path.
        * Used by Phaser.PathFollower objects as they pass each control point.
        *
        * @method Phaser.Path#processData
        * @param {Phaser.PathFollower} follower - The PathFollower that is processing the data.
        * @param {number} pathPointIndex - The index of the path point to process.
        * @param {boolean} reversing - Whether or not the follower is traversing the path in reverse.
        * @return {Phaser.PathPoint} The PathPoint that has been processed.
        */
        processData: function (follower, pathPointIndex, reversing) {

            if (this.getPathPoint(pathPointIndex, this._p1))
            {
                //  If there is a branch that can be taken from this point,
                //  trigger an event to decide whether to take it or stay on the current path.
                //  Branches are forwards facing so they are ignored when the follower is reversing.
                if (this._p1.branchPath && !reversing)
                {
                    follower.dispatchEvent({
                        type: Phaser.PathFollower.EVENT_BRANCH_CHOICE,
                        target: follower,
                        data: this._p1.clone()
                    });
                }

                //  If there is information in the data member of this point
                if (this._p1.data && this._p1.data.type)
                {
                    switch (this._p1.data.type)
                    {
                        case Phaser.PathPoint.DATA_PAUSE:

                            follower.pause(this._p1.data.value);
                            break;

                        case Phaser.PathPoint.DATA_COUNTER:

                            // first time past, set the count
                            if (follower.branchCount === 0)
                            {
                                follower.branchCount = this._p1.data.value;
                            }
                            else
                            {
                                //  After that decrease the count
                                follower.branchCount--;

                                if (follower.branchCount <= 0)
                                {
                                    follower.branchCount = 0;

                                    //  Trigger event when counter expires
                                    follower.dispatchEvent({
                                        type: Phaser.PathFollower.EVENT_COUNT_FINISH,
                                        target: follower,
                                        data: this._p1.clone()
                                    });
                                }
                            }
                            break;
                    }
                }

                //  Trigger event when passing any point on the path
                follower.dispatchEvent({
                    type: Phaser.PathFollower.EVENT_REACHED_POINT,
                    target: follower,
                    data: this._p1.clone()
                });
            }

            return this._p1;

        },

        /**
        * If your Path has 3 points or more, this will walk through it and auto-smooth them out.
        * Note: It ignores branches.
        *
        * @method Phaser.Path#smooth
        * @return {Phaser.Path} This Path object.
        */
        smooth: function () {

            if (this._points.length === 0)
            {
                return this;
            }

            var i;
            var thisPoint;
            var p1;
            var p2;
            var dx;
            var dy;

            for (i = 1; i < this._points.length - 1; i++)
            {
                thisPoint = this.getPathPointReference(i);

                p1 = this.getPathPointReference(i - 1);
                p2 = this.getPathPointReference(i + 1);

                dx = p2.x - p1.x;
                dy = p2.y - p1.y;

                thisPoint.setTangent(dx, dy);
            }

            if (this.loops)
            {
                i = this._points.length - 1;

                thisPoint = this.getPathPointReference(i);

                p1 = this.getPathPointReference(i - 1);
                p2 = this.getPathPointReference(0);

                dx = p2.x - p1.x;
                dy = p2.y - p1.y;

                thisPoint.setTangent(dx, dy);

                i = 0;

                thisPoint = this.getPathPointReference(i);

                p1 = this.getPathPointReference(this._points.length - 1);
                p2 = this.getPathPointReference(1);

                dx = p2.x - p1.x;
                dy = p2.y - p1.y;

                thisPoint.setTangent(dx, dy);
            }

            return this;

        },

        /**
        * Draw the path on given canvas context. Used for debugging.
        *
        * @method Phaser.Path#debug
        * @param {CanvasContext2D} ctx - The canvas context to draw the path on.
        * @param {boolean} [active=false] - Whether or not to highlight the active segments of this Path or not.
        * @return {Phaser.Path} This Path object.
        */
        debug: function (ctx, active) {

            var lineColor = '#333333';

            if (active)
            {
                lineColor = '#ffff00';
            }

            if (this._points.length === 0)
            {
                return this;
            }

            this._p1.setTo(0, 0);

            //  Draw the lines

            var lastPoint = this._points.length;

            if (!this.loops)
            {
                lastPoint--;
            }

            var p = new Phaser.PathPoint();

            for (var i = 0; i < lastPoint; i++)
            {
                var curve = this.getCurve(i);

                this.getPathPoint(i, p);

                ctx.lineWidth = 2;
                ctx.strokeStyle = 'rgb(100, 0, 250)';

                ctx.save();

                //  Control Points
                var controlPoints = this.getControlPointsOnThisCurve(curve);

                //  Draw lines
                ctx.beginPath();

                controlPoints.forEach(function(pnt, index) {

                    if (!!pnt)
                    {
                        if (index === 0)
                        {
                            ctx.moveTo(pnt.x, pnt.y);
                        }
                        else
                        {
                            ctx.lineTo(pnt.x, pnt.y);
                        }
                    }

                });

                ctx.stroke();
                ctx.closePath();

                if (p.active)
                {
                    ctx.fillStyle = '#ffffff';
                    ctx.strokeStyle = '#333333';
                    ctx.lineWidth = 1;

                    //  Copy control points to the point object
                    this.getPathPointReference(i).controlPoints = controlPoints;

                    controlPoints.forEach(function(pnt) {

                        ctx.beginPath();

                        ctx.arc(pnt.x, pnt.y, 3, 0, Math.PI * 2);
                        ctx.fill();
                        ctx.stroke();

                        ctx.closePath();

                    });
                }

                ctx.restore();
            }

            return this;

        },

        /**
        * Serializes this Path into a JSON object and returns it.
        *
        * @methods Phaser.Path#toJSON
        * @return {Object} A JSON object representing this Path.
        */
        toJSON: function () {

            return {
                name: this.name,
                id: this.id,
                type: this.type,
                coordinateSystem: this.coordinateSystem,
                loops: this.loops,
                speed: 1,
                pointList: this._points.map(function(p) {
                    return p.toJSON();
                }),
            };

        }

    };

    /**
    * @property {Array} - The list of PathPoints that make up this path.
    * @readonly
    */
    Object.defineProperty(Phaser.Path.prototype, 'points', {

        get: function () {

            return this._points;

        }

    });

    /**
    * @property {number} - The number of points in this path.
    * @readonly
    */
    Object.defineProperty(Phaser.Path.prototype, 'length', {

        get: function () {

            return this._points.length;

        }

    });

    /**
    * @property {Phaser.Point} - The origin of the path.
    */
    Object.defineProperty(Phaser.Path.prototype, 'origin', {

        get: function() {

            return this._origin;

        },

        set: function (val) {

            this._origin.setTo(val.x, val.y);

        }

    });