// Copyright (c) 2013 Adobe Systems Incorporated. All rights reserved.
// 
// 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.
Snap.plugin(function (Snap, Element, Paper, glob, Fragment) {
    var proto = Paper.prototype,
        is = Snap.is;
    /*\
     * Paper.rect
     [ method ]
     *
     * Draws a rectangle
     **
     - x (number) x coordinate of the top left corner
     - y (number) y coordinate of the top left corner
     - width (number) width
     - height (number) height
     - rx (number) #optional horizontal radius for rounded corners, default is 0
     - ry (number) #optional vertical radius for rounded corners, default is rx or 0
     = (object) the `rect` element
     **
     > Usage
     | // regular rectangle
     | var c = paper.rect(10, 10, 50, 50);
     | // rectangle with rounded corners
     | var c = paper.rect(40, 40, 50, 50, 10);
    \*/
    proto.rect = function (x, y, w, h, rx, ry) {
        var attr;
        if (ry == null) {
            ry = rx;
        }
        if (is(x, "object") && x == "[object Object]") {
            attr = x;
        } else if (x != null) {
            attr = {
                x: x,
                y: y,
                width: w,
                height: h
            };
            if (rx != null) {
                attr.rx = rx;
                attr.ry = ry;
            }
        }
        return this.el("rect", attr);
    };
    /*\
     * Paper.circle
     [ method ]
     **
     * Draws a circle
     **
     - x (number) x coordinate of the centre
     - y (number) y coordinate of the centre
     - r (number) radius
     = (object) the `circle` element
     **
     > Usage
     | var c = paper.circle(50, 50, 40);
    \*/
    proto.circle = function (cx, cy, r) {
        var attr;
        if (is(cx, "object") && cx == "[object Object]") {
            attr = cx;
        } else if (cx != null) {
            attr = {
                cx: cx,
                cy: cy,
                r: r
            };
        }
        return this.el("circle", attr);
    };

    var preload = (function () {
        function onerror() {
            this.parentNode.removeChild(this);
        }
        return function (src, f) {
            var img = glob.doc.createElement("img"),
                body = glob.doc.body;
            img.style.cssText = "position:absolute;left:-9999em;top:-9999em";
            img.onload = function () {
                f.call(img);
                img.onload = img.onerror = null;
                body.removeChild(img);
            };
            img.onerror = onerror;
            body.appendChild(img);
            img.src = src;
        };
    }());

    /*\
     * Paper.image
     [ method ]
     **
     * Places an image on the surface
     **
     - src (string) URI of the source image
     - x (number) x offset position
     - y (number) y offset position
     - width (number) width of the image
     - height (number) height of the image
     = (object) the `image` element
     * or
     = (object) Snap element object with type `image`
     **
     > Usage
     | var c = paper.image("apple.png", 10, 10, 80, 80);
    \*/
    proto.image = function (src, x, y, width, height) {
        var el = this.el("image");
        if (is(src, "object") && "src" in src) {
            el.attr(src);
        } else if (src != null) {
            var set = {
                "xlink:href": src,
                preserveAspectRatio: "none"
            };
            if (x != null && y != null) {
                set.x = x;
                set.y = y;
            }
            if (width != null && height != null) {
                set.width = width;
                set.height = height;
            } else {
                preload(src, function () {
                    Snap._.$(el.node, {
                        width: this.offsetWidth,
                        height: this.offsetHeight
                    });
                });
            }
            Snap._.$(el.node, set);
        }
        return el;
    };
    /*\
     * Paper.ellipse
     [ method ]
     **
     * Draws an ellipse
     **
     - x (number) x coordinate of the centre
     - y (number) y coordinate of the centre
     - rx (number) horizontal radius
     - ry (number) vertical radius
     = (object) the `ellipse` element
     **
     > Usage
     | var c = paper.ellipse(50, 50, 40, 20);
    \*/
    proto.ellipse = function (cx, cy, rx, ry) {
        var attr;
        if (is(cx, "object") && cx == "[object Object]") {
            attr = cx;
        } else if (cx != null) {
            attr ={
                cx: cx,
                cy: cy,
                rx: rx,
                ry: ry
            };
        }
        return this.el("ellipse", attr);
    };
    // SIERRA Paper.path(): Unclear from the link what a Catmull-Rom curveto is, and why it would make life any easier.
    /*\
     * Paper.path
     [ method ]
     **
     * Creates a `<path>` element using the given string as the path's definition
     - pathString (string) #optional path string in SVG format
     * Path string consists of one-letter commands, followed by comma seprarated arguments in numerical form. Example:
     | "M10,20L30,40"
     * This example features two commands: `M`, with arguments `(10, 20)` and `L` with arguments `(30, 40)`. Uppercase letter commands express coordinates in absolute terms, while lowercase commands express them in relative terms from the most recently declared coordinates.
     *
     # <p>Here is short list of commands available, for more details see <a href="http://www.w3.org/TR/SVG/paths.html#PathData" title="Details of a path's data attribute's format are described in the SVG specification.">SVG path string format</a> or <a href="https://developer.mozilla.org/en/SVG/Tutorial/Paths">article about path strings at MDN</a>.</p>
     # <table><thead><tr><th>Command</th><th>Name</th><th>Parameters</th></tr></thead><tbody>
     # <tr><td>M</td><td>moveto</td><td>(x y)+</td></tr>
     # <tr><td>Z</td><td>closepath</td><td>(none)</td></tr>
     # <tr><td>L</td><td>lineto</td><td>(x y)+</td></tr>
     # <tr><td>H</td><td>horizontal lineto</td><td>x+</td></tr>
     # <tr><td>V</td><td>vertical lineto</td><td>y+</td></tr>
     # <tr><td>C</td><td>curveto</td><td>(x1 y1 x2 y2 x y)+</td></tr>
     # <tr><td>S</td><td>smooth curveto</td><td>(x2 y2 x y)+</td></tr>
     # <tr><td>Q</td><td>quadratic Bézier curveto</td><td>(x1 y1 x y)+</td></tr>
     # <tr><td>T</td><td>smooth quadratic Bézier curveto</td><td>(x y)+</td></tr>
     # <tr><td>A</td><td>elliptical arc</td><td>(rx ry x-axis-rotation large-arc-flag sweep-flag x y)+</td></tr>
     # <tr><td>R</td><td><a href="http://en.wikipedia.org/wiki/Catmull–Rom_spline#Catmull.E2.80.93Rom_spline">Catmull-Rom curveto</a>*</td><td>x1 y1 (x y)+</td></tr></tbody></table>
     * * _Catmull-Rom curveto_ is a not standard SVG command and added to make life easier.
     * Note: there is a special case when a path consists of only three commands: `M10,10R…z`. In this case the path connects back to its starting point.
     > Usage
     | var c = paper.path("M10 10L90 90");
     | // draw a diagonal line:
     | // move to 10,10, line to 90,90
    \*/
    proto.path = function (d) {
        var attr;
        if (is(d, "object") && !is(d, "array")) {
            attr = d;
        } else if (d) {
            attr = {d: d};
        }
        return this.el("path", attr);
    };
    /*\
     * Paper.g
     [ method ]
     **
     * Creates a group element
     **
     - varargs (…) #optional elements to nest within the group
     = (object) the `g` element
     **
     > Usage
     | var c1 = paper.circle(),
     |     c2 = paper.rect(),
     |     g = paper.g(c2, c1); // note that the order of elements is different
     * or
     | var c1 = paper.circle(),
     |     c2 = paper.rect(),
     |     g = paper.g();
     | g.add(c2, c1);
    \*/
    /*\
     * Paper.group
     [ method ]
     **
     * See @Paper.g
    \*/
    proto.group = proto.g = function (first) {
        var attr,
            el = this.el("g");
        if (arguments.length == 1 && first && !first.type) {
            el.attr(first);
        } else if (arguments.length) {
            el.add(Array.prototype.slice.call(arguments, 0));
        }
        return el;
    };
    /*\
     * Paper.svg
     [ method ]
     **
     * Creates a nested SVG element.
     - x (number) @optional X of the element
     - y (number) @optional Y of the element
     - width (number) @optional width of the element
     - height (number) @optional height of the element
     - vbx (number) @optional viewbox X
     - vby (number) @optional viewbox Y
     - vbw (number) @optional viewbox width
     - vbh (number) @optional viewbox height
     **
     = (object) the `svg` element
     **
    \*/
    proto.svg = function (x, y, width, height, vbx, vby, vbw, vbh) {
        var attrs = {};
        if (is(x, "object") && y == null) {
            attrs = x;
        } else {
            if (x != null) {
                attrs.x = x;
            }
            if (y != null) {
                attrs.y = y;
            }
            if (width != null) {
                attrs.width = width;
            }
            if (height != null) {
                attrs.height = height;
            }
            if (vbx != null && vby != null && vbw != null && vbh != null) {
                attrs.viewBox = [vbx, vby, vbw, vbh];
            }
        }
        return this.el("svg", attrs);
    };
    /*\
     * Paper.mask
     [ method ]
     **
     * Equivalent in behaviour to @Paper.g, except it’s a mask.
     **
     = (object) the `mask` element
     **
    \*/
    proto.mask = function (first) {
        var attr,
            el = this.el("mask");
        if (arguments.length == 1 && first && !first.type) {
            el.attr(first);
        } else if (arguments.length) {
            el.add(Array.prototype.slice.call(arguments, 0));
        }
        return el;
    };
    /*\
     * Paper.ptrn
     [ method ]
     **
     * Equivalent in behaviour to @Paper.g, except it’s a pattern.
     - x (number) @optional X of the element
     - y (number) @optional Y of the element
     - width (number) @optional width of the element
     - height (number) @optional height of the element
     - vbx (number) @optional viewbox X
     - vby (number) @optional viewbox Y
     - vbw (number) @optional viewbox width
     - vbh (number) @optional viewbox height
     **
     = (object) the `pattern` element
     **
    \*/
    proto.ptrn = function (x, y, width, height, vx, vy, vw, vh) {
        if (is(x, "object")) {
            var attr = x;
        } else {
            attr = {patternUnits: "userSpaceOnUse"};
            if (x) {
                attr.x = x;
            }
            if (y) {
                attr.y = y;
            }
            if (width != null) {
                attr.width = width;
            }
            if (height != null) {
                attr.height = height;
            }
            if (vx != null && vy != null && vw != null && vh != null) {
                attr.viewBox = [vx, vy, vw, vh];
            } else {
                attr.viewBox = [x || 0, y || 0, width || 0, height || 0];
            }
        }
        return this.el("pattern", attr);
    };
    /*\
     * Paper.use
     [ method ]
     **
     * Creates a <use> element.
     - id (string) @optional id of element to link
     * or
     - id (Element) @optional element to link
     **
     = (object) the `use` element
     **
    \*/
    proto.use = function (id) {
        if (id != null) {
            if (id instanceof Element) {
                if (!id.attr("id")) {
                    id.attr({id: Snap._.id(id)});
                }
                id = id.attr("id");
            }
            if (String(id).charAt() == "#") {
                id = id.substring(1);
            }
            return this.el("use", {"xlink:href": "#" + id});
        } else {
            return Element.prototype.use.call(this);
        }
    };
    /*\
     * Paper.symbol
     [ method ]
     **
     * Creates a <symbol> element.
     - vbx (number) @optional viewbox X
     - vby (number) @optional viewbox Y
     - vbw (number) @optional viewbox width
     - vbh (number) @optional viewbox height
     = (object) the `symbol` element
     **
    \*/
    proto.symbol = function (vx, vy, vw, vh) {
        var attr = {};
        if (vx != null && vy != null && vw != null && vh != null) {
            attr.viewBox = [vx, vy, vw, vh];
        }

        return this.el("symbol", attr);
    };
    /*\
     * Paper.text
     [ method ]
     **
     * Draws a text string
     **
     - x (number) x coordinate position
     - y (number) y coordinate position
     - text (string|array) The text string to draw or array of strings to nest within separate `<tspan>` elements
     = (object) the `text` element
     **
     > Usage
     | var t1 = paper.text(50, 50, "Snap");
     | var t2 = paper.text(50, 50, ["S","n","a","p"]);
     | // Text path usage
     | t1.attr({textpath: "M10,10L100,100"});
     | // or
     | var pth = paper.path("M10,10L100,100");
     | t1.attr({textpath: pth});
    \*/
    proto.text = function (x, y, text) {
        var attr = {};
        if (is(x, "object")) {
            attr = x;
        } else if (x != null) {
            attr = {
                x: x,
                y: y,
                text: text || ""
            };
        }
        return this.el("text", attr);
    };
    /*\
     * Paper.line
     [ method ]
     **
     * Draws a line
     **
     - x1 (number) x coordinate position of the start
     - y1 (number) y coordinate position of the start
     - x2 (number) x coordinate position of the end
     - y2 (number) y coordinate position of the end
     = (object) the `line` element
     **
     > Usage
     | var t1 = paper.line(50, 50, 100, 100);
    \*/
    proto.line = function (x1, y1, x2, y2) {
        var attr = {};
        if (is(x1, "object")) {
            attr = x1;
        } else if (x1 != null) {
            attr = {
                x1: x1,
                x2: x2,
                y1: y1,
                y2: y2
            };
        }
        return this.el("line", attr);
    };
    /*\
     * Paper.polyline
     [ method ]
     **
     * Draws a polyline
     **
     - points (array) array of points
     * or
     - varargs (…) points
     = (object) the `polyline` element
     **
     > Usage
     | var p1 = paper.polyline([10, 10, 100, 100]);
     | var p2 = paper.polyline(10, 10, 100, 100);
    \*/
    proto.polyline = function (points) {
        if (arguments.length > 1) {
            points = Array.prototype.slice.call(arguments, 0);
        }
        var attr = {};
        if (is(points, "object") && !is(points, "array")) {
            attr = points;
        } else if (points != null) {
            attr = {points: points};
        }
        return this.el("polyline", attr);
    };
    /*\
     * Paper.polygon
     [ method ]
     **
     * Draws a polygon. See @Paper.polyline
    \*/
    proto.polygon = function (points) {
        if (arguments.length > 1) {
            points = Array.prototype.slice.call(arguments, 0);
        }
        var attr = {};
        if (is(points, "object") && !is(points, "array")) {
            attr = points;
        } else if (points != null) {
            attr = {points: points};
        }
        return this.el("polygon", attr);
    };
    // gradients
    (function () {
        var $ = Snap._.$;
        // gradients' helpers
        function Gstops() {
            return this.selectAll("stop");
        }
        function GaddStop(color, offset) {
            var stop = $("stop"),
                attr = {
                    offset: +offset + "%"
                };
            color = Snap.color(color);
            attr["stop-color"] = color.hex;
            if (color.opacity < 1) {
                attr["stop-opacity"] = color.opacity;
            }
            $(stop, attr);
            this.node.appendChild(stop);
            return this;
        }
        function GgetBBox() {
            if (this.type == "linearGradient") {
                var x1 = $(this.node, "x1") || 0,
                    x2 = $(this.node, "x2") || 1,
                    y1 = $(this.node, "y1") || 0,
                    y2 = $(this.node, "y2") || 0;
                return Snap._.box(x1, y1, math.abs(x2 - x1), math.abs(y2 - y1));
            } else {
                var cx = this.node.cx || .5,
                    cy = this.node.cy || .5,
                    r = this.node.r || 0;
                return Snap._.box(cx - r, cy - r, r * 2, r * 2);
            }
        }
        function gradient(defs, str) {
            var grad = eve("snap.util.grad.parse", null, str).firstDefined(),
                el;
            if (!grad) {
                return null;
            }
            grad.params.unshift(defs);
            if (grad.type.toLowerCase() == "l") {
                el = gradientLinear.apply(0, grad.params);
            } else {
                el = gradientRadial.apply(0, grad.params);
            }
            if (grad.type != grad.type.toLowerCase()) {
                $(el.node, {
                    gradientUnits: "userSpaceOnUse"
                });
            }
            var stops = grad.stops,
                len = stops.length,
                start = 0,
                j = 0;
            function seed(i, end) {
                var step = (end - start) / (i - j);
                for (var k = j; k < i; k++) {
                    stops[k].offset = +(+start + step * (k - j)).toFixed(2);
                }
                j = i;
                start = end;
            }
            len--;
            for (var i = 0; i < len; i++) if ("offset" in stops[i]) {
                seed(i, stops[i].offset);
            }
            stops[len].offset = stops[len].offset || 100;
            seed(len, stops[len].offset);
            for (i = 0; i <= len; i++) {
                var stop = stops[i];
                el.addStop(stop.color, stop.offset);
            }
            return el;
        }
        function gradientLinear(defs, x1, y1, x2, y2) {
            var el = Snap._.make("linearGradient", defs);
            el.stops = Gstops;
            el.addStop = GaddStop;
            el.getBBox = GgetBBox;
            if (x1 != null) {
                $(el.node, {
                    x1: x1,
                    y1: y1,
                    x2: x2,
                    y2: y2
                });
            }
            return el;
        }
        function gradientRadial(defs, cx, cy, r, fx, fy) {
            var el = Snap._.make("radialGradient", defs);
            el.stops = Gstops;
            el.addStop = GaddStop;
            el.getBBox = GgetBBox;
            if (cx != null) {
                $(el.node, {
                    cx: cx,
                    cy: cy,
                    r: r
                });
            }
            if (fx != null && fy != null) {
                $(el.node, {
                    fx: fx,
                    fy: fy
                });
            }
            return el;
        }
        /*\
         * Paper.gradient
         [ method ]
         **
         * Creates a gradient element
         **
         - gradient (string) gradient descriptor
         > Gradient Descriptor
         * The gradient descriptor is an expression formatted as
         * follows: `<type>(<coords>)<colors>`.  The `<type>` can be
         * either linear or radial.  The uppercase `L` or `R` letters
         * indicate absolute coordinates offset from the SVG surface.
         * Lowercase `l` or `r` letters indicate coordinates
         * calculated relative to the element to which the gradient is
         * applied.  Coordinates specify a linear gradient vector as
         * `x1`, `y1`, `x2`, `y2`, or a radial gradient as `cx`, `cy`,
         * `r` and optional `fx`, `fy` specifying a focal point away
         * from the center of the circle. Specify `<colors>` as a list
         * of dash-separated CSS color values.  Each color may be
         * followed by a custom offset value, separated with a colon
         * character.
         > Examples
         * Linear gradient, relative from top-left corner to bottom-right
         * corner, from black through red to white:
         | var g = paper.gradient("l(0, 0, 1, 1)#000-#f00-#fff");
         * Linear gradient, absolute from (0, 0) to (100, 100), from black
         * through red at 25% to white:
         | var g = paper.gradient("L(0, 0, 100, 100)#000-#f00:25-#fff");
         * Radial gradient, relative from the center of the element with radius
         * half the width, from black to white:
         | var g = paper.gradient("r(0.5, 0.5, 0.5)#000-#fff");
         * To apply the gradient:
         | paper.circle(50, 50, 40).attr({
         |     fill: g
         | });
         = (object) the `gradient` element
        \*/
        proto.gradient = function (str) {
            return gradient(this.defs, str);
        };
        proto.gradientLinear = function (x1, y1, x2, y2) {
            return gradientLinear(this.defs, x1, y1, x2, y2);
        };
        proto.gradientRadial = function (cx, cy, r, fx, fy) {
            return gradientRadial(this.defs, cx, cy, r, fx, fy);
        };
        /*\
         * Paper.toString
         [ method ]
         **
         * Returns SVG code for the @Paper
         = (string) SVG code for the @Paper
        \*/
        proto.toString = function () {
            var doc = this.node.ownerDocument,
                f = doc.createDocumentFragment(),
                d = doc.createElement("div"),
                svg = this.node.cloneNode(true),
                res;
            f.appendChild(d);
            d.appendChild(svg);
            Snap._.$(svg, {xmlns: "http://www.w3.org/2000/svg"});
            res = d.innerHTML;
            f.removeChild(f.firstChild);
            return res;
        };
        /*\
         * Paper.toDataURL
         [ method ]
         **
         * Returns SVG code for the @Paper as Data URI string.
         = (string) Data URI string
        \*/
        proto.toDataURL = function () {
            if (window && window.btoa) {
                return "data:image/svg+xml;base64," + btoa(unescape(encodeURIComponent(this)));
            }
        };
        /*\
         * Paper.clear
         [ method ]
         **
         * Removes all child nodes of the paper, except <defs>.
        \*/
        proto.clear = function () {
            var node = this.node.firstChild,
                next;
            while (node) {
                next = node.nextSibling;
                if (node.tagName != "defs") {
                    node.parentNode.removeChild(node);
                } else {
                    proto.clear.call({node: node});
                }
                node = next;
            }
        };
    }());
});
