nodeparser.js

var log = require('./log');
var punycode = require('punycode');
var NodeContainer = require('./nodecontainer');
var TextContainer = require('./textcontainer');
var PseudoElementContainer = require('./pseudoelementcontainer');
var FontMetrics = require('./fontmetrics');
var Color = require('./color');
var Promise = require('./promise');
var StackingContext = require('./stackingcontext');
var utils = require('./utils');
var bind = utils.bind;
var getBounds = utils.getBounds;
var parseBackgrounds = utils.parseBackgrounds;
var offsetBounds = utils.offsetBounds;

function NodeParser(element, renderer, support, imageLoader, options) {
    log("Starting NodeParser");
    this.renderer = renderer;
    this.options = options;
    this.range = null;
    this.support = support;
    this.renderQueue = [];
    this.stack = new StackingContext(true, 1, element.ownerDocument, null);
    var parent = new NodeContainer(element, null);
    if (options.background) {
        renderer.rectangle(0, 0, renderer.width, renderer.height, new Color(options.background));
    }
    if (element === element.ownerDocument.documentElement) {
        // http://www.w3.org/TR/css3-background/#special-backgrounds
        var canvasBackground = new NodeContainer(parent.color('backgroundColor').isTransparent() ? element.ownerDocument.body : element.ownerDocument.documentElement, null);
        renderer.rectangle(0, 0, renderer.width, renderer.height, canvasBackground.color('backgroundColor'));
    }
    parent.visibile = parent.isElementVisible();
    this.createPseudoHideStyles(element.ownerDocument);
    this.disableAnimations(element.ownerDocument);
    this.nodes = flatten([parent].concat(this.getChildren(parent)).filter(function(container) {
        return container.visible = container.isElementVisible();
    }).map(this.getPseudoElements, this));
    this.fontMetrics = new FontMetrics();
    log("Fetched nodes, total:", this.nodes.length);
    log("Calculate overflow clips");
    this.calculateOverflowClips();
    log("Start fetching images");
    this.images = imageLoader.fetch(this.nodes.filter(isElement));
    this.ready = this.images.ready.then(bind(function() {
        log("Images loaded, starting parsing");
        log("Creating stacking contexts");
        this.createStackingContexts();
        log("Sorting stacking contexts");
        this.sortStackingContexts(this.stack);
        this.parse(this.stack);
        log("Render queue created with " + this.renderQueue.length + " items");
        return new Promise(bind(function(resolve) {
            if (!options.async) {
                this.renderQueue.forEach(this.paint, this);
                resolve();
            } else if (typeof(options.async) === "function") {
                options.async.call(this, this.renderQueue, resolve);
            } else if (this.renderQueue.length > 0){
                this.renderIndex = 0;
                this.asyncRenderer(this.renderQueue, resolve);
            } else {
                resolve();
            }
        }, this));
    }, this));
}

NodeParser.prototype.calculateOverflowClips = function() {
    this.nodes.forEach(function(container) {
        if (isElement(container)) {
            if (isPseudoElement(container)) {
                container.appendToDOM();
            }
            container.borders = this.parseBorders(container);
            var clip = (container.css('overflow') === "hidden") ? [container.borders.clip] : [];
            var cssClip = container.parseClip();
            if (cssClip && ["absolute", "fixed"].indexOf(container.css('position')) !== -1) {
                clip.push([["rect",
                        container.bounds.left + cssClip.left,
                        container.bounds.top + cssClip.top,
                        cssClip.right - cssClip.left,
                        cssClip.bottom - cssClip.top
                ]]);
            }
            container.clip = hasParentClip(container) ? container.parent.clip.concat(clip) : clip;
            container.backgroundClip = (container.css('overflow') !== "hidden") ? container.clip.concat([container.borders.clip]) : container.clip;
            if (isPseudoElement(container)) {
                container.cleanDOM();
            }
        } else if (isTextNode(container)) {
            container.clip = hasParentClip(container) ? container.parent.clip : [];
        }
        if (!isPseudoElement(container)) {
            container.bounds = null;
        }
    }, this);
};

function hasParentClip(container) {
    return container.parent && container.parent.clip.length;
}

NodeParser.prototype.asyncRenderer = function(queue, resolve, asyncTimer) {
    asyncTimer = asyncTimer || Date.now();
    this.paint(queue[this.renderIndex++]);
    if (queue.length === this.renderIndex) {
        resolve();
    } else if (asyncTimer + 20 > Date.now()) {
        this.asyncRenderer(queue, resolve, asyncTimer);
    } else {
        setTimeout(bind(function() {
            this.asyncRenderer(queue, resolve);
        }, this), 0);
    }
};

NodeParser.prototype.createPseudoHideStyles = function(document) {
    this.createStyles(document, '.' + PseudoElementContainer.prototype.PSEUDO_HIDE_ELEMENT_CLASS_BEFORE + ':before { content: "" !important; display: none !important; }' +
        '.' + PseudoElementContainer.prototype.PSEUDO_HIDE_ELEMENT_CLASS_AFTER + ':after { content: "" !important; display: none !important; }');
};

NodeParser.prototype.disableAnimations = function(document) {
    this.createStyles(document, '* { -webkit-animation: none !important; -moz-animation: none !important; -o-animation: none !important; animation: none !important; ' +
        '-webkit-transition: none !important; -moz-transition: none !important; -o-transition: none !important; transition: none !important;}');
};

NodeParser.prototype.createStyles = function(document, styles) {
    var hidePseudoElements = document.createElement('style');
    hidePseudoElements.innerHTML = styles;
    document.body.appendChild(hidePseudoElements);
};

NodeParser.prototype.getPseudoElements = function(container) {
    var nodes = [[container]];
    if (container.node.nodeType === Node.ELEMENT_NODE) {
        var before = this.getPseudoElement(container, ":before");
        var after = this.getPseudoElement(container, ":after");

        if (before) {
            nodes.push(before);
        }

        if (after) {
            nodes.push(after);
        }
    }
    return flatten(nodes);
};

function toCamelCase(str) {
    return str.replace(/(\-[a-z])/g, function(match){
        return match.toUpperCase().replace('-','');
    });
}

NodeParser.prototype.getPseudoElement = function(container, type) {
    var style = container.computedStyle(type);
    if(!style || !style.content || style.content === "none" || style.content === "-moz-alt-content" || style.display === "none") {
        return null;
    }

    var content = stripQuotes(style.content);
    var isImage = content.substr(0, 3) === 'url';
    var pseudoNode = document.createElement(isImage ? 'img' : 'html2canvaspseudoelement');
    var pseudoContainer = new PseudoElementContainer(pseudoNode, container, type);

    for (var i = style.length-1; i >= 0; i--) {
        var property = toCamelCase(style.item(i));
        pseudoNode.style[property] = style[property];
    }

    pseudoNode.className = PseudoElementContainer.prototype.PSEUDO_HIDE_ELEMENT_CLASS_BEFORE + " " + PseudoElementContainer.prototype.PSEUDO_HIDE_ELEMENT_CLASS_AFTER;

    if (isImage) {
        pseudoNode.src = parseBackgrounds(content)[0].args[0];
        return [pseudoContainer];
    } else {
        var text = document.createTextNode(content);
        pseudoNode.appendChild(text);
        return [pseudoContainer, new TextContainer(text, pseudoContainer)];
    }
};


NodeParser.prototype.getChildren = function(parentContainer) {
    return flatten([].filter.call(parentContainer.node.childNodes, renderableNode).map(function(node) {
        var container = [node.nodeType === Node.TEXT_NODE ? new TextContainer(node, parentContainer) : new NodeContainer(node, parentContainer)].filter(nonIgnoredElement);
        return node.nodeType === Node.ELEMENT_NODE && container.length && node.tagName !== "TEXTAREA" ? (container[0].isElementVisible() ? container.concat(this.getChildren(container[0])) : []) : container;
    }, this));
};

NodeParser.prototype.newStackingContext = function(container, hasOwnStacking) {
    var stack = new StackingContext(hasOwnStacking, container.getOpacity(), container.node, container.parent);
    container.cloneTo(stack);
    var parentStack = hasOwnStacking ? stack.getParentStack(this) : stack.parent.stack;
    parentStack.contexts.push(stack);
    container.stack = stack;
};

NodeParser.prototype.createStackingContexts = function() {
    this.nodes.forEach(function(container) {
        if (isElement(container) && (this.isRootElement(container) || hasOpacity(container) || isPositionedForStacking(container) || this.isBodyWithTransparentRoot(container) || container.hasTransform())) {
            this.newStackingContext(container, true);
        } else if (isElement(container) && ((isPositioned(container) && zIndex0(container)) || isInlineBlock(container) || isFloating(container))) {
            this.newStackingContext(container, false);
        } else {
            container.assignStack(container.parent.stack);
        }
    }, this);
};

NodeParser.prototype.isBodyWithTransparentRoot = function(container) {
    return container.node.nodeName === "BODY" && container.parent.color('backgroundColor').isTransparent();
};

NodeParser.prototype.isRootElement = function(container) {
    return container.parent === null;
};

NodeParser.prototype.sortStackingContexts = function(stack) {
    stack.contexts.sort(zIndexSort(stack.contexts.slice(0)));
    stack.contexts.forEach(this.sortStackingContexts, this);
};

NodeParser.prototype.parseTextBounds = function(container) {
    return function(text, index, textList) {
        if (container.parent.css("textDecoration").substr(0, 4) !== "none" || text.trim().length !== 0) {
            if (this.support.rangeBounds && !container.parent.hasTransform()) {
                var offset = textList.slice(0, index).join("").length;
                return this.getRangeBounds(container.node, offset, text.length);
            } else if (container.node && typeof(container.node.data) === "string") {
                var replacementNode = container.node.splitText(text.length);
                var bounds = this.getWrapperBounds(container.node, container.parent.hasTransform());
                container.node = replacementNode;
                return bounds;
            }
        } else if(!this.support.rangeBounds || container.parent.hasTransform()){
            container.node = container.node.splitText(text.length);
        }
        return {};
    };
};

NodeParser.prototype.getWrapperBounds = function(node, transform) {
    var wrapper = node.ownerDocument.createElement('html2canvaswrapper');
    var parent = node.parentNode,
        backupText = node.cloneNode(true);

    wrapper.appendChild(node.cloneNode(true));
    parent.replaceChild(wrapper, node);
    var bounds = transform ? offsetBounds(wrapper) : getBounds(wrapper);
    parent.replaceChild(backupText, wrapper);
    return bounds;
};

NodeParser.prototype.getRangeBounds = function(node, offset, length) {
    var range = this.range || (this.range = node.ownerDocument.createRange());
    range.setStart(node, offset);
    range.setEnd(node, offset + length);
    return range.getBoundingClientRect();
};

function ClearTransform() {}

NodeParser.prototype.parse = function(stack) {
    // http://www.w3.org/TR/CSS21/visuren.html#z-index
    var negativeZindex = stack.contexts.filter(negativeZIndex); // 2. the child stacking contexts with negative stack levels (most negative first).
    var descendantElements = stack.children.filter(isElement);
    var descendantNonFloats = descendantElements.filter(not(isFloating));
    var nonInlineNonPositionedDescendants = descendantNonFloats.filter(not(isPositioned)).filter(not(inlineLevel)); // 3 the in-flow, non-inline-level, non-positioned descendants.
    var nonPositionedFloats = descendantElements.filter(not(isPositioned)).filter(isFloating); // 4. the non-positioned floats.
    var inFlow = descendantNonFloats.filter(not(isPositioned)).filter(inlineLevel); // 5. the in-flow, inline-level, non-positioned descendants, including inline tables and inline blocks.
    var stackLevel0 = stack.contexts.concat(descendantNonFloats.filter(isPositioned)).filter(zIndex0); // 6. the child stacking contexts with stack level 0 and the positioned descendants with stack level 0.
    var text = stack.children.filter(isTextNode).filter(hasText);
    var positiveZindex = stack.contexts.filter(positiveZIndex); // 7. the child stacking contexts with positive stack levels (least positive first).
    negativeZindex.concat(nonInlineNonPositionedDescendants).concat(nonPositionedFloats)
        .concat(inFlow).concat(stackLevel0).concat(text).concat(positiveZindex).forEach(function(container) {
            this.renderQueue.push(container);
            if (isStackingContext(container)) {
                this.parse(container);
                this.renderQueue.push(new ClearTransform());
            }
        }, this);
};

NodeParser.prototype.paint = function(container) {
    try {
        if (container instanceof ClearTransform) {
            this.renderer.ctx.restore();
        } else if (isTextNode(container)) {
            if (isPseudoElement(container.parent)) {
                container.parent.appendToDOM();
            }
            this.paintText(container);
            if (isPseudoElement(container.parent)) {
                container.parent.cleanDOM();
            }
        } else {
            this.paintNode(container);
        }
    } catch(e) {
        log(e);
        if (this.options.strict) {
            throw e;
        }
    }
};

NodeParser.prototype.paintNode = function(container) {
    if (isStackingContext(container)) {
        this.renderer.setOpacity(container.opacity);
        this.renderer.ctx.save();
        if (container.hasTransform()) {
            this.renderer.setTransform(container.parseTransform());
        }
    }

    if (container.node.nodeName === "INPUT" && container.node.type === "checkbox") {
        this.paintCheckbox(container);
    } else if (container.node.nodeName === "INPUT" && container.node.type === "radio") {
        this.paintRadio(container);
    } else {
        this.paintElement(container);
    }
};

NodeParser.prototype.paintElement = function(container) {
    var bounds = container.parseBounds();
    this.renderer.clip(container.backgroundClip, function() {
        this.renderer.renderBackground(container, bounds, container.borders.borders.map(getWidth));
    }, this);

    this.renderer.clip(container.clip, function() {
        this.renderer.renderBorders(container.borders.borders);
    }, this);

    this.renderer.clip(container.backgroundClip, function() {
        switch (container.node.nodeName) {
        case "svg":
        case "IFRAME":
            var imgContainer = this.images.get(container.node);
            if (imgContainer) {
                this.renderer.renderImage(container, bounds, container.borders, imgContainer);
            } else {
                log("Error loading <" + container.node.nodeName + ">", container.node);
            }
            break;
        case "IMG":
            var imageContainer = this.images.get(container.node.src);
            if (imageContainer) {
                this.renderer.renderImage(container, bounds, container.borders, imageContainer);
            } else {
                log("Error loading <img>", container.node.src);
            }
            break;
        case "CANVAS":
            this.renderer.renderImage(container, bounds, container.borders, {image: container.node});
            break;
        case "SELECT":
        case "INPUT":
        case "TEXTAREA":
            this.paintFormValue(container);
            break;
        }
    }, this);
};

NodeParser.prototype.paintCheckbox = function(container) {
    var b = container.parseBounds();

    var size = Math.min(b.width, b.height);
    var bounds = {width: size - 1, height: size - 1, top: b.top, left: b.left};
    var r = [3, 3];
    var radius = [r, r, r, r];
    var borders = [1,1,1,1].map(function(w) {
        return {color: new Color('#A5A5A5'), width: w};
    });

    var borderPoints = calculateCurvePoints(bounds, radius, borders);

    this.renderer.clip(container.backgroundClip, function() {
        this.renderer.rectangle(bounds.left + 1, bounds.top + 1, bounds.width - 2, bounds.height - 2, new Color("#DEDEDE"));
        this.renderer.renderBorders(calculateBorders(borders, bounds, borderPoints, radius));
        if (container.node.checked) {
            this.renderer.font(new Color('#424242'), 'normal', 'normal', 'bold', (size - 3) + "px", 'arial');
            this.renderer.text("\u2714", bounds.left + size / 6, bounds.top + size - 1);
        }
    }, this);
};

NodeParser.prototype.paintRadio = function(container) {
    var bounds = container.parseBounds();

    var size = Math.min(bounds.width, bounds.height) - 2;

    this.renderer.clip(container.backgroundClip, function() {
        this.renderer.circleStroke(bounds.left + 1, bounds.top + 1, size, new Color('#DEDEDE'), 1, new Color('#A5A5A5'));
        if (container.node.checked) {
            this.renderer.circle(Math.ceil(bounds.left + size / 4) + 1, Math.ceil(bounds.top + size / 4) + 1, Math.floor(size / 2), new Color('#424242'));
        }
    }, this);
};

NodeParser.prototype.paintFormValue = function(container) {
    var value = container.getValue();
    if (value.length > 0) {
        var document = container.node.ownerDocument;
        var wrapper = document.createElement('html2canvaswrapper');
        var properties = ['lineHeight', 'textAlign', 'fontFamily', 'fontWeight', 'fontSize', 'color',
            'paddingLeft', 'paddingTop', 'paddingRight', 'paddingBottom',
            'width', 'height', 'borderLeftStyle', 'borderTopStyle', 'borderLeftWidth', 'borderTopWidth',
            'boxSizing', 'whiteSpace', 'wordWrap'];

        properties.forEach(function(property) {
            try {
                wrapper.style[property] = container.css(property);
            } catch(e) {
                // Older IE has issues with "border"
                log("html2canvas: Parse: Exception caught in renderFormValue: " + e.message);
            }
        });
        var bounds = container.parseBounds();
        wrapper.style.position = "fixed";
        wrapper.style.left = bounds.left + "px";
        wrapper.style.top = bounds.top + "px";
        wrapper.textContent = value;
        document.body.appendChild(wrapper);
        this.paintText(new TextContainer(wrapper.firstChild, container));
        document.body.removeChild(wrapper);
    }
};

NodeParser.prototype.paintText = function(container) {
    container.applyTextTransform();
    var characters = punycode.ucs2.decode(container.node.data);
    var textList = (!this.options.letterRendering || noLetterSpacing(container)) && !hasUnicode(container.node.data) ? getWords(characters) : characters.map(function(character) {
        return punycode.ucs2.encode([character]);
    });

    var weight = container.parent.fontWeight();
    var size = container.parent.css('fontSize');
    var family = container.parent.css('fontFamily');
    var shadows = container.parent.parseTextShadows();

    this.renderer.font(container.parent.color('color'), container.parent.css('fontStyle'), container.parent.css('fontVariant'), weight, size, family);
    if (shadows.length) {
        // TODO: support multiple text shadows
        this.renderer.fontShadow(shadows[0].color, shadows[0].offsetX, shadows[0].offsetY, shadows[0].blur);
    } else {
        this.renderer.clearShadow();
    }

    this.renderer.clip(container.parent.clip, function() {
        textList.map(this.parseTextBounds(container), this).forEach(function(bounds, index) {
            if (bounds) {
                this.renderer.text(textList[index], bounds.left, bounds.bottom);
                this.renderTextDecoration(container.parent, bounds, this.fontMetrics.getMetrics(family, size));
            }
        }, this);
    }, this);
};

NodeParser.prototype.renderTextDecoration = function(container, bounds, metrics) {
    switch(container.css("textDecoration").split(" ")[0]) {
    case "underline":
        // Draws a line at the baseline of the font
        // TODO As some browsers display the line as more than 1px if the font-size is big, need to take that into account both in position and size
        this.renderer.rectangle(bounds.left, Math.round(bounds.top + metrics.baseline + metrics.lineWidth), bounds.width, 1, container.color("color"));
        break;
    case "overline":
        this.renderer.rectangle(bounds.left, Math.round(bounds.top), bounds.width, 1, container.color("color"));
        break;
    case "line-through":
        // TODO try and find exact position for line-through
        this.renderer.rectangle(bounds.left, Math.ceil(bounds.top + metrics.middle + metrics.lineWidth), bounds.width, 1, container.color("color"));
        break;
    }
};

var borderColorTransforms = {
    inset: [
        ["darken", 0.60],
        ["darken", 0.10],
        ["darken", 0.10],
        ["darken", 0.60]
    ]
};

NodeParser.prototype.parseBorders = function(container) {
    var nodeBounds = container.parseBounds();
    var radius = getBorderRadiusData(container);
    var borders = ["Top", "Right", "Bottom", "Left"].map(function(side, index) {
        var style = container.css('border' + side + 'Style');
        var color = container.color('border' + side + 'Color');
        if (style === "inset" && color.isBlack()) {
            color = new Color([255, 255, 255, color.a]); // this is wrong, but
        }
        var colorTransform = borderColorTransforms[style] ? borderColorTransforms[style][index] : null;
        return {
            width: container.cssInt('border' + side + 'Width'),
            color: colorTransform ? color[colorTransform[0]](colorTransform[1]) : color,
            args: null
        };
    });
    var borderPoints = calculateCurvePoints(nodeBounds, radius, borders);

    return {
        clip: this.parseBackgroundClip(container, borderPoints, borders, radius, nodeBounds),
        borders: calculateBorders(borders, nodeBounds, borderPoints, radius)
    };
};

function calculateBorders(borders, nodeBounds, borderPoints, radius) {
    return borders.map(function(border, borderSide) {
        if (border.width > 0) {
            var bx = nodeBounds.left;
            var by = nodeBounds.top;
            var bw = nodeBounds.width;
            var bh = nodeBounds.height - (borders[2].width);

            switch(borderSide) {
            case 0:
                // top border
                bh = borders[0].width;
                border.args = drawSide({
                        c1: [bx, by],
                        c2: [bx + bw, by],
                        c3: [bx + bw - borders[1].width, by + bh],
                        c4: [bx + borders[3].width, by + bh]
                    }, radius[0], radius[1],
                    borderPoints.topLeftOuter, borderPoints.topLeftInner, borderPoints.topRightOuter, borderPoints.topRightInner);
                break;
            case 1:
                // right border
                bx = nodeBounds.left + nodeBounds.width - (borders[1].width);
                bw = borders[1].width;

                border.args = drawSide({
                        c1: [bx + bw, by],
                        c2: [bx + bw, by + bh + borders[2].width],
                        c3: [bx, by + bh],
                        c4: [bx, by + borders[0].width]
                    }, radius[1], radius[2],
                    borderPoints.topRightOuter, borderPoints.topRightInner, borderPoints.bottomRightOuter, borderPoints.bottomRightInner);
                break;
            case 2:
                // bottom border
                by = (by + nodeBounds.height) - (borders[2].width);
                bh = borders[2].width;
                border.args = drawSide({
                        c1: [bx + bw, by + bh],
                        c2: [bx, by + bh],
                        c3: [bx + borders[3].width, by],
                        c4: [bx + bw - borders[3].width, by]
                    }, radius[2], radius[3],
                    borderPoints.bottomRightOuter, borderPoints.bottomRightInner, borderPoints.bottomLeftOuter, borderPoints.bottomLeftInner);
                break;
            case 3:
                // left border
                bw = borders[3].width;
                border.args = drawSide({
                        c1: [bx, by + bh + borders[2].width],
                        c2: [bx, by],
                        c3: [bx + bw, by + borders[0].width],
                        c4: [bx + bw, by + bh]
                    }, radius[3], radius[0],
                    borderPoints.bottomLeftOuter, borderPoints.bottomLeftInner, borderPoints.topLeftOuter, borderPoints.topLeftInner);
                break;
            }
        }
        return border;
    });
}

NodeParser.prototype.parseBackgroundClip = function(container, borderPoints, borders, radius, bounds) {
    var backgroundClip = container.css('backgroundClip'),
        borderArgs = [];

    switch(backgroundClip) {
    case "content-box":
    case "padding-box":
        parseCorner(borderArgs, radius[0], radius[1], borderPoints.topLeftInner, borderPoints.topRightInner, bounds.left + borders[3].width, bounds.top + borders[0].width);
        parseCorner(borderArgs, radius[1], radius[2], borderPoints.topRightInner, borderPoints.bottomRightInner, bounds.left + bounds.width - borders[1].width, bounds.top + borders[0].width);
        parseCorner(borderArgs, radius[2], radius[3], borderPoints.bottomRightInner, borderPoints.bottomLeftInner, bounds.left + bounds.width - borders[1].width, bounds.top + bounds.height - borders[2].width);
        parseCorner(borderArgs, radius[3], radius[0], borderPoints.bottomLeftInner, borderPoints.topLeftInner, bounds.left + borders[3].width, bounds.top + bounds.height - borders[2].width);
        break;

    default:
        parseCorner(borderArgs, radius[0], radius[1], borderPoints.topLeftOuter, borderPoints.topRightOuter, bounds.left, bounds.top);
        parseCorner(borderArgs, radius[1], radius[2], borderPoints.topRightOuter, borderPoints.bottomRightOuter, bounds.left + bounds.width, bounds.top);
        parseCorner(borderArgs, radius[2], radius[3], borderPoints.bottomRightOuter, borderPoints.bottomLeftOuter, bounds.left + bounds.width, bounds.top + bounds.height);
        parseCorner(borderArgs, radius[3], radius[0], borderPoints.bottomLeftOuter, borderPoints.topLeftOuter, bounds.left, bounds.top + bounds.height);
        break;
    }

    return borderArgs;
};

function getCurvePoints(x, y, r1, r2) {
    var kappa = 4 * ((Math.sqrt(2) - 1) / 3);
    var ox = (r1) * kappa, // control point offset horizontal
        oy = (r2) * kappa, // control point offset vertical
        xm = x + r1, // x-middle
        ym = y + r2; // y-middle
    return {
        topLeft: bezierCurve({x: x, y: ym}, {x: x, y: ym - oy}, {x: xm - ox, y: y}, {x: xm, y: y}),
        topRight: bezierCurve({x: x, y: y}, {x: x + ox,y: y}, {x: xm, y: ym - oy}, {x: xm, y: ym}),
        bottomRight: bezierCurve({x: xm, y: y}, {x: xm, y: y + oy}, {x: x + ox, y: ym}, {x: x, y: ym}),
        bottomLeft: bezierCurve({x: xm, y: ym}, {x: xm - ox, y: ym}, {x: x, y: y + oy}, {x: x, y:y})
    };
}

function calculateCurvePoints(bounds, borderRadius, borders) {
    var x = bounds.left,
        y = bounds.top,
        width = bounds.width,
        height = bounds.height,

        tlh = borderRadius[0][0],
        tlv = borderRadius[0][1],
        trh = borderRadius[1][0],
        trv = borderRadius[1][1],
        brh = borderRadius[2][0],
        brv = borderRadius[2][1],
        blh = borderRadius[3][0],
        blv = borderRadius[3][1];

    var topWidth = width - trh,
        rightHeight = height - brv,
        bottomWidth = width - brh,
        leftHeight = height - blv;

    return {
        topLeftOuter: getCurvePoints(x, y, tlh, tlv).topLeft.subdivide(0.5),
        topLeftInner: getCurvePoints(x + borders[3].width, y + borders[0].width, Math.max(0, tlh - borders[3].width), Math.max(0, tlv - borders[0].width)).topLeft.subdivide(0.5),
        topRightOuter: getCurvePoints(x + topWidth, y, trh, trv).topRight.subdivide(0.5),
        topRightInner: getCurvePoints(x + Math.min(topWidth, width + borders[3].width), y + borders[0].width, (topWidth > width + borders[3].width) ? 0 :trh - borders[3].width, trv - borders[0].width).topRight.subdivide(0.5),
        bottomRightOuter: getCurvePoints(x + bottomWidth, y + rightHeight, brh, brv).bottomRight.subdivide(0.5),
        bottomRightInner: getCurvePoints(x + Math.min(bottomWidth, width - borders[3].width), y + Math.min(rightHeight, height + borders[0].width), Math.max(0, brh - borders[1].width),  brv - borders[2].width).bottomRight.subdivide(0.5),
        bottomLeftOuter: getCurvePoints(x, y + leftHeight, blh, blv).bottomLeft.subdivide(0.5),
        bottomLeftInner: getCurvePoints(x + borders[3].width, y + leftHeight, Math.max(0, blh - borders[3].width), blv - borders[2].width).bottomLeft.subdivide(0.5)
    };
}

function bezierCurve(start, startControl, endControl, end) {
    var lerp = function (a, b, t) {
        return {
            x: a.x + (b.x - a.x) * t,
            y: a.y + (b.y - a.y) * t
        };
    };

    return {
        start: start,
        startControl: startControl,
        endControl: endControl,
        end: end,
        subdivide: function(t) {
            var ab = lerp(start, startControl, t),
                bc = lerp(startControl, endControl, t),
                cd = lerp(endControl, end, t),
                abbc = lerp(ab, bc, t),
                bccd = lerp(bc, cd, t),
                dest = lerp(abbc, bccd, t);
            return [bezierCurve(start, ab, abbc, dest), bezierCurve(dest, bccd, cd, end)];
        },
        curveTo: function(borderArgs) {
            borderArgs.push(["bezierCurve", startControl.x, startControl.y, endControl.x, endControl.y, end.x, end.y]);
        },
        curveToReversed: function(borderArgs) {
            borderArgs.push(["bezierCurve", endControl.x, endControl.y, startControl.x, startControl.y, start.x, start.y]);
        }
    };
}

function drawSide(borderData, radius1, radius2, outer1, inner1, outer2, inner2) {
    var borderArgs = [];

    if (radius1[0] > 0 || radius1[1] > 0) {
        borderArgs.push(["line", outer1[1].start.x, outer1[1].start.y]);
        outer1[1].curveTo(borderArgs);
    } else {
        borderArgs.push([ "line", borderData.c1[0], borderData.c1[1]]);
    }

    if (radius2[0] > 0 || radius2[1] > 0) {
        borderArgs.push(["line", outer2[0].start.x, outer2[0].start.y]);
        outer2[0].curveTo(borderArgs);
        borderArgs.push(["line", inner2[0].end.x, inner2[0].end.y]);
        inner2[0].curveToReversed(borderArgs);
    } else {
        borderArgs.push(["line", borderData.c2[0], borderData.c2[1]]);
        borderArgs.push(["line", borderData.c3[0], borderData.c3[1]]);
    }

    if (radius1[0] > 0 || radius1[1] > 0) {
        borderArgs.push(["line", inner1[1].end.x, inner1[1].end.y]);
        inner1[1].curveToReversed(borderArgs);
    } else {
        borderArgs.push(["line", borderData.c4[0], borderData.c4[1]]);
    }

    return borderArgs;
}

function parseCorner(borderArgs, radius1, radius2, corner1, corner2, x, y) {
    if (radius1[0] > 0 || radius1[1] > 0) {
        borderArgs.push(["line", corner1[0].start.x, corner1[0].start.y]);
        corner1[0].curveTo(borderArgs);
        corner1[1].curveTo(borderArgs);
    } else {
        borderArgs.push(["line", x, y]);
    }

    if (radius2[0] > 0 || radius2[1] > 0) {
        borderArgs.push(["line", corner2[0].start.x, corner2[0].start.y]);
    }
}

function negativeZIndex(container) {
    return container.cssInt("zIndex") < 0;
}

function positiveZIndex(container) {
    return container.cssInt("zIndex") > 0;
}

function zIndex0(container) {
    return container.cssInt("zIndex") === 0;
}

function inlineLevel(container) {
    return ["inline", "inline-block", "inline-table"].indexOf(container.css("display")) !== -1;
}

function isStackingContext(container) {
    return (container instanceof StackingContext);
}

function hasText(container) {
    return container.node.data.trim().length > 0;
}

function noLetterSpacing(container) {
    return (/^(normal|none|0px)$/.test(container.parent.css("letterSpacing")));
}

function getBorderRadiusData(container) {
    return ["TopLeft", "TopRight", "BottomRight", "BottomLeft"].map(function(side) {
        var value = container.css('border' + side + 'Radius');
        var arr = value.split(" ");
        if (arr.length <= 1) {
            arr[1] = arr[0];
        }
        return arr.map(asInt);
    });
}

function renderableNode(node) {
    return (node.nodeType === Node.TEXT_NODE || node.nodeType === Node.ELEMENT_NODE);
}

function isPositionedForStacking(container) {
    var position = container.css("position");
    var zIndex = (["absolute", "relative", "fixed"].indexOf(position) !== -1) ? container.css("zIndex") : "auto";
    return zIndex !== "auto";
}

function isPositioned(container) {
    return container.css("position") !== "static";
}

function isFloating(container) {
    return container.css("float") !== "none";
}

function isInlineBlock(container) {
    return ["inline-block", "inline-table"].indexOf(container.css("display")) !== -1;
}

function not(callback) {
    var context = this;
    return function() {
        return !callback.apply(context, arguments);
    };
}

function isElement(container) {
    return container.node.nodeType === Node.ELEMENT_NODE;
}

function isPseudoElement(container) {
    return container.isPseudoElement === true;
}

function isTextNode(container) {
    return container.node.nodeType === Node.TEXT_NODE;
}

function zIndexSort(contexts) {
    return function(a, b) {
        return (a.cssInt("zIndex") + (contexts.indexOf(a) / contexts.length)) - (b.cssInt("zIndex") + (contexts.indexOf(b) / contexts.length));
    };
}

function hasOpacity(container) {
    return container.getOpacity() < 1;
}

function asInt(value) {
    return parseInt(value, 10);
}

function getWidth(border) {
    return border.width;
}

function nonIgnoredElement(nodeContainer) {
    return (nodeContainer.node.nodeType !== Node.ELEMENT_NODE || ["SCRIPT", "HEAD", "TITLE", "OBJECT", "BR", "OPTION"].indexOf(nodeContainer.node.nodeName) === -1);
}

function flatten(arrays) {
    return [].concat.apply([], arrays);
}

function stripQuotes(content) {
    var first = content.substr(0, 1);
    return (first === content.substr(content.length - 1) && first.match(/'|"/)) ? content.substr(1, content.length - 2) : content;
}

function getWords(characters) {
    var words = [], i = 0, onWordBoundary = false, word;
    while(characters.length) {
        if (isWordBoundary(characters[i]) === onWordBoundary) {
            word = characters.splice(0, i);
            if (word.length) {
                words.push(punycode.ucs2.encode(word));
            }
            onWordBoundary =! onWordBoundary;
            i = 0;
        } else {
            i++;
        }

        if (i >= characters.length) {
            word = characters.splice(0, i);
            if (word.length) {
                words.push(punycode.ucs2.encode(word));
            }
        }
    }
    return words;
}

function isWordBoundary(characterCode) {
    return [
        32, // <space>
        13, // \r
        10, // \n
        9, // \t
        45 // -
    ].indexOf(characterCode) !== -1;
}

function hasUnicode(string) {
    return (/[^\u0000-\u00ff]/).test(string);
}

module.exports = NodeParser;