(function() {
    /**
     * Path constructor.
     * @author Jason Follas
     * @constructor
     * @augments Kinetic.Shape
     * @param {Object} config
     * @param {String} config.data SVG data string
     * {{ShapeParams}}
     * {{NodeParams}}
     */
    Kinetic.Path = function(config) {
        this._initPath(config);
    };

    Kinetic.Path.prototype = {
        _initPath: function(config) {
            this.dataArray = [];
            var that = this;

            // call super constructor
            Kinetic.Shape.call(this, config);
            this.shapeType = 'Path';
            this._setDrawFuncs();

            this.dataArray = Kinetic.Path.parsePathData(this.getData());
            this.on('dataChange', function() {
                that.dataArray = Kinetic.Path.parsePathData(this.getData());
            });
        },
        drawFunc: function(canvas) {
            var ca = this.dataArray, context = canvas.getContext();
            // context position
            context.beginPath();
            for(var n = 0; n < ca.length; n++) {
                var c = ca[n].command;
                var p = ca[n].points;
                switch (c) {
                    case 'L':
                        context.lineTo(p[0], p[1]);
                        break;
                    case 'M':
                        context.moveTo(p[0], p[1]);
                        break;
                    case 'C':
                        context.bezierCurveTo(p[0], p[1], p[2], p[3], p[4], p[5]);
                        break;
                    case 'Q':
                        context.quadraticCurveTo(p[0], p[1], p[2], p[3]);
                        break;
                    case 'A':
                        var cx = p[0], cy = p[1], rx = p[2], ry = p[3], theta = p[4], dTheta = p[5], psi = p[6], fs = p[7];

                        var r = (rx > ry) ? rx : ry;
                        var scaleX = (rx > ry) ? 1 : rx / ry;
                        var scaleY = (rx > ry) ? ry / rx : 1;

                        context.translate(cx, cy);
                        context.rotate(psi);
                        context.scale(scaleX, scaleY);
                        context.arc(0, 0, r, theta, theta + dTheta, 1 - fs);
                        context.scale(1 / scaleX, 1 / scaleY);
                        context.rotate(-psi);
                        context.translate(-cx, -cy);

                        break;
                    case 'z':
                        context.closePath();
                        break;
                }
            }
            canvas.fillStroke(this);
        }
    };
    Kinetic.Util.extend(Kinetic.Path, Kinetic.Shape);

    Kinetic.Path.getLineLength = function(x1, y1, x2, y2) {
        return Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
    };
    Kinetic.Path.getPointOnLine = function(dist, P1x, P1y, P2x, P2y, fromX, fromY) {
        if(fromX === undefined) {
            fromX = P1x;
        }
        if(fromY === undefined) {
            fromY = P1y;
        }

        var m = (P2y - P1y) / ((P2x - P1x) + 0.00000001);
        var run = Math.sqrt(dist * dist / (1 + m * m));
        if(P2x < P1x)
            run *= -1;
        var rise = m * run;
        var pt;

        if((fromY - P1y) / ((fromX - P1x) + 0.00000001) === m) {
            pt = {
                x: fromX + run,
                y: fromY + rise
            };
        }
        else {
            var ix, iy;

            var len = this.getLineLength(P1x, P1y, P2x, P2y);
            if(len < 0.00000001) {
                return undefined;
            }
            var u = (((fromX - P1x) * (P2x - P1x)) + ((fromY - P1y) * (P2y - P1y)));
            u = u / (len * len);
            ix = P1x + u * (P2x - P1x);
            iy = P1y + u * (P2y - P1y);

            var pRise = this.getLineLength(fromX, fromY, ix, iy);
            var pRun = Math.sqrt(dist * dist - pRise * pRise);
            run = Math.sqrt(pRun * pRun / (1 + m * m));
            if(P2x < P1x)
                run *= -1;
            rise = m * run;
            pt = {
                x: ix + run,
                y: iy + rise
            };
        }

        return pt;
    };

    Kinetic.Path.getPointOnCubicBezier = function(pct, P1x, P1y, P2x, P2y, P3x, P3y, P4x, P4y) {
        function CB1(t) {
            return t * t * t;
        }
        function CB2(t) {
            return 3 * t * t * (1 - t);
        }
        function CB3(t) {
            return 3 * t * (1 - t) * (1 - t);
        }
        function CB4(t) {
            return (1 - t) * (1 - t) * (1 - t);
        }
        var x = P4x * CB1(pct) + P3x * CB2(pct) + P2x * CB3(pct) + P1x * CB4(pct);
        var y = P4y * CB1(pct) + P3y * CB2(pct) + P2y * CB3(pct) + P1y * CB4(pct);

        return {
            x: x,
            y: y
        };
    };
    Kinetic.Path.getPointOnQuadraticBezier = function(pct, P1x, P1y, P2x, P2y, P3x, P3y) {
        function QB1(t) {
            return t * t;
        }
        function QB2(t) {
            return 2 * t * (1 - t);
        }
        function QB3(t) {
            return (1 - t) * (1 - t);
        }
        var x = P3x * QB1(pct) + P2x * QB2(pct) + P1x * QB3(pct);
        var y = P3y * QB1(pct) + P2y * QB2(pct) + P1y * QB3(pct);

        return {
            x: x,
            y: y
        };
    };
    Kinetic.Path.getPointOnEllipticalArc = function(cx, cy, rx, ry, theta, psi) {
        var cosPsi = Math.cos(psi), sinPsi = Math.sin(psi);
        var pt = {
            x: rx * Math.cos(theta),
            y: ry * Math.sin(theta)
        };
        return {
            x: cx + (pt.x * cosPsi - pt.y * sinPsi),
            y: cy + (pt.x * sinPsi + pt.y * cosPsi)
        };
    };
    /**
     * get parsed data array from the data
     *  string.  V, v, H, h, and l data are converted to
     *  L data for the purpose of high performance Path
     *  rendering
     */
    Kinetic.Path.parsePathData = function(data) {
        // Path Data Segment must begin with a moveTo
        //m (x y)+  Relative moveTo (subsequent points are treated as lineTo)
        //M (x y)+  Absolute moveTo (subsequent points are treated as lineTo)
        //l (x y)+  Relative lineTo
        //L (x y)+  Absolute LineTo
        //h (x)+    Relative horizontal lineTo
        //H (x)+    Absolute horizontal lineTo
        //v (y)+    Relative vertical lineTo
        //V (y)+    Absolute vertical lineTo
        //z (closepath)
        //Z (closepath)
        //c (x1 y1 x2 y2 x y)+ Relative Bezier curve
        //C (x1 y1 x2 y2 x y)+ Absolute Bezier curve
        //q (x1 y1 x y)+       Relative Quadratic Bezier
        //Q (x1 y1 x y)+       Absolute Quadratic Bezier
        //t (x y)+    Shorthand/Smooth Relative Quadratic Bezier
        //T (x y)+    Shorthand/Smooth Absolute Quadratic Bezier
        //s (x2 y2 x y)+       Shorthand/Smooth Relative Bezier curve
        //S (x2 y2 x y)+       Shorthand/Smooth Absolute Bezier curve
        //a (rx ry x-axis-rotation large-arc-flag sweep-flag x y)+     Relative Elliptical Arc
        //A (rx ry x-axis-rotation large-arc-flag sweep-flag x y)+  Absolute Elliptical Arc

        // return early if data is not defined
        if(!data) {
            return [];
        }

        // command string
        var cs = data;

        // command chars
        var cc = ['m', 'M', 'l', 'L', 'v', 'V', 'h', 'H', 'z', 'Z', 'c', 'C', 'q', 'Q', 't', 'T', 's', 'S', 'a', 'A'];
        // convert white spaces to commas
        cs = cs.replace(new RegExp(' ', 'g'), ',');
        // create pipes so that we can split the data
        for(var n = 0; n < cc.length; n++) {
            cs = cs.replace(new RegExp(cc[n], 'g'), '|' + cc[n]);
        }
        // create array
        var arr = cs.split('|');
        var ca = [];
        // init context point
        var cpx = 0;
        var cpy = 0;
        for(var n = 1; n < arr.length; n++) {
            var str = arr[n];
            var c = str.charAt(0);
            str = str.slice(1);
            // remove ,- for consistency
            str = str.replace(new RegExp(',-', 'g'), '-');
            // add commas so that it's easy to split
            str = str.replace(new RegExp('-', 'g'), ',-');
            str = str.replace(new RegExp('e,-', 'g'), 'e-');
            var p = str.split(',');
            if(p.length > 0 && p[0] === '') {
                p.shift();
            }
            // convert strings to floats
            for(var i = 0; i < p.length; i++) {
                p[i] = parseFloat(p[i]);
            }
            while(p.length > 0) {
                if(isNaN(p[0]))// case for a trailing comma before next command
                    break;

                var cmd = null;
                var points = [];
                var startX = cpx, startY = cpy;

                // convert l, H, h, V, and v to L
                switch (c) {

                    // Note: Keep the lineTo's above the moveTo's in this switch
                    case 'l':
                        cpx += p.shift();
                        cpy += p.shift();
                        cmd = 'L';
                        points.push(cpx, cpy);
                        break;
                    case 'L':
                        cpx = p.shift();
                        cpy = p.shift();
                        points.push(cpx, cpy);
                        break;

                    // Note: lineTo handlers need to be above this point
                    case 'm':
                        cpx += p.shift();
                        cpy += p.shift();
                        cmd = 'M';
                        points.push(cpx, cpy);
                        c = 'l';
                        // subsequent points are treated as relative lineTo
                        break;
                    case 'M':
                        cpx = p.shift();
                        cpy = p.shift();
                        cmd = 'M';
                        points.push(cpx, cpy);
                        c = 'L';
                        // subsequent points are treated as absolute lineTo
                        break;

                    case 'h':
                        cpx += p.shift();
                        cmd = 'L';
                        points.push(cpx, cpy);
                        break;
                    case 'H':
                        cpx = p.shift();
                        cmd = 'L';
                        points.push(cpx, cpy);
                        break;
                    case 'v':
                        cpy += p.shift();
                        cmd = 'L';
                        points.push(cpx, cpy);
                        break;
                    case 'V':
                        cpy = p.shift();
                        cmd = 'L';
                        points.push(cpx, cpy);
                        break;
                    case 'C':
                        points.push(p.shift(), p.shift(), p.shift(), p.shift());
                        cpx = p.shift();
                        cpy = p.shift();
                        points.push(cpx, cpy);
                        break;
                    case 'c':
                        points.push(cpx + p.shift(), cpy + p.shift(), cpx + p.shift(), cpy + p.shift());
                        cpx += p.shift();
                        cpy += p.shift();
                        cmd = 'C';
                        points.push(cpx, cpy);
                        break;
                    case 'S':
                        var ctlPtx = cpx, ctlPty = cpy;
                        var prevCmd = ca[ca.length - 1];
                        if(prevCmd.command === 'C') {
                            ctlPtx = cpx + (cpx - prevCmd.points[2]);
                            ctlPty = cpy + (cpy - prevCmd.points[3]);
                        }
                        points.push(ctlPtx, ctlPty, p.shift(), p.shift());
                        cpx = p.shift();
                        cpy = p.shift();
                        cmd = 'C';
                        points.push(cpx, cpy);
                        break;
                    case 's':
                        var ctlPtx = cpx, ctlPty = cpy;
                        var prevCmd = ca[ca.length - 1];
                        if(prevCmd.command === 'C') {
                            ctlPtx = cpx + (cpx - prevCmd.points[2]);
                            ctlPty = cpy + (cpy - prevCmd.points[3]);
                        }
                        points.push(ctlPtx, ctlPty, cpx + p.shift(), cpy + p.shift());
                        cpx += p.shift();
                        cpy += p.shift();
                        cmd = 'C';
                        points.push(cpx, cpy);
                        break;
                    case 'Q':
                        points.push(p.shift(), p.shift());
                        cpx = p.shift();
                        cpy = p.shift();
                        points.push(cpx, cpy);
                        break;
                    case 'q':
                        points.push(cpx + p.shift(), cpy + p.shift());
                        cpx += p.shift();
                        cpy += p.shift();
                        cmd = 'Q';
                        points.push(cpx, cpy);
                        break;
                    case 'T':
                        var ctlPtx = cpx, ctlPty = cpy;
                        var prevCmd = ca[ca.length - 1];
                        if(prevCmd.command === 'Q') {
                            ctlPtx = cpx + (cpx - prevCmd.points[0]);
                            ctlPty = cpy + (cpy - prevCmd.points[1]);
                        }
                        cpx = p.shift();
                        cpy = p.shift();
                        cmd = 'Q';
                        points.push(ctlPtx, ctlPty, cpx, cpy);
                        break;
                    case 't':
                        var ctlPtx = cpx, ctlPty = cpy;
                        var prevCmd = ca[ca.length - 1];
                        if(prevCmd.command === 'Q') {
                            ctlPtx = cpx + (cpx - prevCmd.points[0]);
                            ctlPty = cpy + (cpy - prevCmd.points[1]);
                        }
                        cpx += p.shift();
                        cpy += p.shift();
                        cmd = 'Q';
                        points.push(ctlPtx, ctlPty, cpx, cpy);
                        break;
                    case 'A':
                        var rx = p.shift(), ry = p.shift(), psi = p.shift(), fa = p.shift(), fs = p.shift();
                        var x1 = cpx, y1 = cpy; cpx = p.shift(), cpy = p.shift();
                        cmd = 'A';
                        points = this.convertEndpointToCenterParameterization(x1, y1, cpx, cpy, fa, fs, rx, ry, psi);
                        break;
                    case 'a':
                        var rx = p.shift(), ry = p.shift(), psi = p.shift(), fa = p.shift(), fs = p.shift();
                        var x1 = cpx, y1 = cpy; cpx += p.shift(), cpy += p.shift();
                        cmd = 'A';
                        points = this.convertEndpointToCenterParameterization(x1, y1, cpx, cpy, fa, fs, rx, ry, psi);
                        break;
                }

                ca.push({
                    command: cmd || c,
                    points: points,
                    start: {
                        x: startX,
                        y: startY
                    },
                    pathLength: this.calcLength(startX, startY, cmd || c, points)
                });
            }

            if(c === 'z' || c === 'Z') {
                ca.push({
                    command: 'z',
                    points: [],
                    start: undefined,
                    pathLength: 0
                });
            }
        }

        return ca;
    };
    Kinetic.Path.calcLength = function(x, y, cmd, points) {
        var len, p1, p2;
        var path = Kinetic.Path;

        switch (cmd) {
            case 'L':
                return path.getLineLength(x, y, points[0], points[1]);
            case 'C':
                // Approximates by breaking curve into 100 line segments
                len = 0.0;
                p1 = path.getPointOnCubicBezier(0, x, y, points[0], points[1], points[2], points[3], points[4], points[5]);
                for( t = 0.01; t <= 1; t += 0.01) {
                    p2 = path.getPointOnCubicBezier(t, x, y, points[0], points[1], points[2], points[3], points[4], points[5]);
                    len += path.getLineLength(p1.x, p1.y, p2.x, p2.y);
                    p1 = p2;
                }
                return len;
            case 'Q':
                // Approximates by breaking curve into 100 line segments
                len = 0.0;
                p1 = path.getPointOnQuadraticBezier(0, x, y, points[0], points[1], points[2], points[3]);
                for( t = 0.01; t <= 1; t += 0.01) {
                    p2 = path.getPointOnQuadraticBezier(t, x, y, points[0], points[1], points[2], points[3]);
                    len += path.getLineLength(p1.x, p1.y, p2.x, p2.y);
                    p1 = p2;
                }
                return len;
            case 'A':
                // Approximates by breaking curve into line segments
                len = 0.0;
                var start = points[4];
                // 4 = theta
                var dTheta = points[5];
                // 5 = dTheta
                var end = points[4] + dTheta;
                var inc = Math.PI / 180.0;
                // 1 degree resolution
                if(Math.abs(start - end) < inc) {
                    inc = Math.abs(start - end);
                }
                // Note: for purpose of calculating arc length, not going to worry about rotating X-axis by angle psi
                p1 = path.getPointOnEllipticalArc(points[0], points[1], points[2], points[3], start, 0);
                if(dTheta < 0) {// clockwise
                    for( t = start - inc; t > end; t -= inc) {
                        p2 = path.getPointOnEllipticalArc(points[0], points[1], points[2], points[3], t, 0);
                        len += path.getLineLength(p1.x, p1.y, p2.x, p2.y);
                        p1 = p2;
                    }
                }
                else {// counter-clockwise
                    for( t = start + inc; t < end; t += inc) {
                        p2 = path.getPointOnEllipticalArc(points[0], points[1], points[2], points[3], t, 0);
                        len += path.getLineLength(p1.x, p1.y, p2.x, p2.y);
                        p1 = p2;
                    }
                }
                p2 = path.getPointOnEllipticalArc(points[0], points[1], points[2], points[3], end, 0);
                len += path.getLineLength(p1.x, p1.y, p2.x, p2.y);

                return len;
        }

        return 0;
    };
    Kinetic.Path.convertEndpointToCenterParameterization = function(x1, y1, x2, y2, fa, fs, rx, ry, psiDeg) {
        // Derived from: http://www.w3.org/TR/SVG/implnote.html#ArcImplementationNotes
        var psi = psiDeg * (Math.PI / 180.0);
        var xp = Math.cos(psi) * (x1 - x2) / 2.0 + Math.sin(psi) * (y1 - y2) / 2.0;
        var yp = -1 * Math.sin(psi) * (x1 - x2) / 2.0 + Math.cos(psi) * (y1 - y2) / 2.0;

        var lambda = (xp * xp) / (rx * rx) + (yp * yp) / (ry * ry);

        if(lambda > 1) {
            rx *= Math.sqrt(lambda);
            ry *= Math.sqrt(lambda);
        }

        var f = Math.sqrt((((rx * rx) * (ry * ry)) - ((rx * rx) * (yp * yp)) - ((ry * ry) * (xp * xp))) / ((rx * rx) * (yp * yp) + (ry * ry) * (xp * xp)));

        if(fa == fs) {
            f *= -1;
        }
        if(isNaN(f)) {
            f = 0;
        }

        var cxp = f * rx * yp / ry;
        var cyp = f * -ry * xp / rx;

        var cx = (x1 + x2) / 2.0 + Math.cos(psi) * cxp - Math.sin(psi) * cyp;
        var cy = (y1 + y2) / 2.0 + Math.sin(psi) * cxp + Math.cos(psi) * cyp;

        var vMag = function(v) {
            return Math.sqrt(v[0] * v[0] + v[1] * v[1]);
        };
        var vRatio = function(u, v) {
            return (u[0] * v[0] + u[1] * v[1]) / (vMag(u) * vMag(v));
        };
        var vAngle = function(u, v) {
            return (u[0] * v[1] < u[1] * v[0] ? -1 : 1) * Math.acos(vRatio(u, v));
        };
        var theta = vAngle([1, 0], [(xp - cxp) / rx, (yp - cyp) / ry]);
        var u = [(xp - cxp) / rx, (yp - cyp) / ry];
        var v = [(-1 * xp - cxp) / rx, (-1 * yp - cyp) / ry];
        var dTheta = vAngle(u, v);

        if(vRatio(u, v) <= -1) {
            dTheta = Math.PI;
        }
        if(vRatio(u, v) >= 1) {
            dTheta = 0;
        }
        if(fs === 0 && dTheta > 0) {
            dTheta = dTheta - 2 * Math.PI;
        }
        if(fs == 1 && dTheta < 0) {
            dTheta = dTheta + 2 * Math.PI;
        }
        return [cx, cy, rx, ry, theta, dTheta, psi, fs];
    };
    // add getters setters
    Kinetic.Node.addGetterSetter(Kinetic.Path, 'data');

    /**
     * set SVG path data string.  This method
     *  also automatically parses the data string
     *  into a data array.  Currently supported SVG data:
     *  M, m, L, l, H, h, V, v, Q, q, T, t, C, c, S, s, A, a, Z, z
     * @name setData
     * @methodOf Kinetic.Path.prototype
     * @param {String} SVG path command string
     */

    /**
     * get SVG path data string
     * @name getData
     * @methodOf Kinetic.Path.prototype
     */
})();