function NodeContainer(node, parent) {
    this.node = node;
    this.parent = parent;
    this.stack = null;
    this.bounds = null;
    this.borders = null;
    this.clip = [];
    this.backgroundClip = [];
    this.offsetBounds = null;
    this.visible = null;
    this.computedStyles = null;
    this.styles = {};
    this.backgroundImages = null;
    this.transformData = null;
    this.transformMatrix = null;
    this.isPseudoElement = false;
    this.opacity = null;
}

NodeContainer.prototype.cloneTo = function(stack) {
    stack.visible = this.visible;
    stack.borders = this.borders;
    stack.bounds = this.bounds;
    stack.clip = this.clip;
    stack.backgroundClip = this.backgroundClip;
    stack.computedStyles = this.computedStyles;
    stack.styles = this.styles;
    stack.backgroundImages = this.backgroundImages;
    stack.opacity = this.opacity;
};

NodeContainer.prototype.getOpacity = function() {
    return this.opacity === null ? (this.opacity = this.cssFloat('opacity')) : this.opacity;
};

NodeContainer.prototype.assignStack = function(stack) {
    this.stack = stack;
    stack.children.push(this);
};

NodeContainer.prototype.isElementVisible = function() {
    return this.node.nodeType === Node.TEXT_NODE ? this.parent.visible : (
        this.css('display') !== "none" &&
        this.css('visibility') !== "hidden" &&
        !this.node.hasAttribute("data-html2canvas-ignore") &&
        (this.node.nodeName !== "INPUT" || this.node.getAttribute("type") !== "hidden")
    );
};

NodeContainer.prototype.css = function(attribute) {
    if (!this.computedStyles) {
        this.computedStyles = this.isPseudoElement ? this.parent.computedStyle(this.before ? ":before" : ":after") : this.computedStyle(null);
    }

    return this.styles[attribute] || (this.styles[attribute] = this.computedStyles[attribute]);
};

NodeContainer.prototype.prefixedCss = function(attribute) {
    var prefixes = ["webkit", "moz", "ms", "o"];
    var value = this.css(attribute);
    if (value === undefined) {
        prefixes.some(function(prefix) {
            value = this.css(prefix + attribute.substr(0, 1).toUpperCase() + attribute.substr(1));
            return value !== undefined;
        }, this);
    }
    return value === undefined ? null : value;
};

NodeContainer.prototype.computedStyle = function(type) {
    return this.node.ownerDocument.defaultView.getComputedStyle(this.node, type);
};

NodeContainer.prototype.cssInt = function(attribute) {
    var value = parseInt(this.css(attribute), 10);
    return (isNaN(value)) ? 0 : value; // borders in old IE are throwing 'medium' for demo.html
};

NodeContainer.prototype.cssFloat = function(attribute) {
    var value = parseFloat(this.css(attribute));
    return (isNaN(value)) ? 0 : value;
};

NodeContainer.prototype.fontWeight = function() {
    var weight = this.css("fontWeight");
    switch(parseInt(weight, 10)){
    case 401:
        weight = "bold";
        break;
    case 400:
        weight = "normal";
        break;
    }
    return weight;
};

NodeContainer.prototype.parseClip = function() {
    var matches = this.css('clip').match(this.CLIP);
    if (matches) {
        return {
            top: parseInt(matches[1], 10),
            right: parseInt(matches[2], 10),
            bottom: parseInt(matches[3], 10),
            left: parseInt(matches[4], 10)
        };
    }
    return null;
};

NodeContainer.prototype.parseBackgroundImages = function() {
    return this.backgroundImages || (this.backgroundImages = parseBackgrounds(this.css("backgroundImage")));
};

NodeContainer.prototype.cssList = function(property, index) {
    var value = (this.css(property) || '').split(',');
    value = value[index || 0] || value[0] || 'auto';
    value = value.trim().split(' ');
    if (value.length === 1) {
        value = [value[0], value[0]];
    }
    return value;
};

NodeContainer.prototype.parseBackgroundSize = function(bounds, image, index) {
    var size = this.cssList("backgroundSize", index);
    var width, height;

    if (isPercentage(size[0])) {
        width = bounds.width * parseFloat(size[0]) / 100;
    } else if (/contain|cover/.test(size[0])) {
        var targetRatio = bounds.width / bounds.height, currentRatio = image.width / image.height;
        return (targetRatio < currentRatio ^ size[0] === 'contain') ?  {width: bounds.height * currentRatio, height: bounds.height} : {width: bounds.width, height: bounds.width / currentRatio};
    } else {
        width = parseInt(size[0], 10);
    }

    if (size[0] === 'auto' && size[1] === 'auto') {
        height = image.height;
    } else if (size[1] === 'auto') {
        height = width / image.width * image.height;
    } else if (isPercentage(size[1])) {
        height =  bounds.height * parseFloat(size[1]) / 100;
    } else {
        height = parseInt(size[1], 10);
    }

    if (size[0] === 'auto') {
        width = height / image.height * image.width;
    }

    return {width: width, height: height};
};

NodeContainer.prototype.parseBackgroundPosition = function(bounds, image, index, backgroundSize) {
    var position = this.cssList('backgroundPosition', index);
    var left, top;

    if (isPercentage(position[0])){
        left = (bounds.width - (backgroundSize || image).width) * (parseFloat(position[0]) / 100);
    } else {
        left = parseInt(position[0], 10);
    }

    if (position[1] === 'auto') {
        top = left / image.width * image.height;
    } else if (isPercentage(position[1])){
        top =  (bounds.height - (backgroundSize || image).height) * parseFloat(position[1]) / 100;
    } else {
        top = parseInt(position[1], 10);
    }

    if (position[0] === 'auto') {
        left = top / image.height * image.width;
    }

    return {left: left, top: top};
};

NodeContainer.prototype.parseBackgroundRepeat = function(index) {
    return this.cssList("backgroundRepeat", index)[0];
};

NodeContainer.prototype.parseTextShadows = function() {
    var textShadow = this.css("textShadow");
    var results = [];

    if (textShadow && textShadow !== 'none') {
        var shadows = textShadow.match(this.TEXT_SHADOW_PROPERTY);
        for (var i = 0; shadows && (i < shadows.length); i++) {
            var s = shadows[i].match(this.TEXT_SHADOW_VALUES);
            results.push({
                color: s[0],
                offsetX: s[1] ? parseFloat(s[1].replace('px', '')) : 0,
                offsetY: s[2] ? parseFloat(s[2].replace('px', '')) : 0,
                blur: s[3] ? s[3].replace('px', '') : 0
            });
        }
    }
    return results;
};

NodeContainer.prototype.parseTransform = function() {
    if (!this.transformData) {
        if (this.hasTransform()) {
            var offset = this.parseBounds();
            var origin = this.prefixedCss("transformOrigin").split(" ").map(removePx).map(asFloat);
            origin[0] += offset.left;
            origin[1] += offset.top;
            this.transformData = {
                origin: origin,
                matrix: this.parseTransformMatrix()
            };
        } else {
            this.transformData = {
                origin: [0, 0],
                matrix: [1, 0, 0, 1, 0, 0]
            };
        }
    }
    return this.transformData;
};

NodeContainer.prototype.parseTransformMatrix = function() {
    if (!this.transformMatrix) {
        var transform = this.prefixedCss("transform");
        var matrix = transform ? parseMatrix(transform.match(this.MATRIX_PROPERTY)) : null;
        this.transformMatrix = matrix ? matrix : [1, 0, 0, 1, 0, 0];
    }
    return this.transformMatrix;
};

NodeContainer.prototype.parseBounds = function() {
    return this.bounds || (this.bounds = this.hasTransform() ? offsetBounds(this.node) : getBounds(this.node));
};

NodeContainer.prototype.hasTransform = function() {
    return this.parseTransformMatrix().join(",") !== "1,0,0,1,0,0" || (this.parent && this.parent.hasTransform());
};

NodeContainer.prototype.getValue = function() {
    var value = this.node.value || "";
    value = (this.node.tagName === "SELECT") ? selectionValue(this.node) : value;
    return value.length === 0 ? (this.node.placeholder || "") : value;
};

NodeContainer.prototype.MATRIX_PROPERTY = /(matrix)\((.+)\)/;
NodeContainer.prototype.TEXT_SHADOW_PROPERTY = /((rgba|rgb)\([^\)]+\)(\s-?\d+px){0,})/g;
NodeContainer.prototype.TEXT_SHADOW_VALUES = /(-?\d+px)|(#.+)|(rgb\(.+\))|(rgba\(.+\))/g;
NodeContainer.prototype.CLIP = /^rect\((\d+)px,? (\d+)px,? (\d+)px,? (\d+)px\)$/;

function selectionValue(node) {
    var option = node.options[node.selectedIndex || 0];
    return option ? (option.text || "") : "";
}

function parseMatrix(match) {
    if (match && match[1] === "matrix") {
        return match[2].split(",").map(function(s) {
            return parseFloat(s.trim());
        });
    }
}

function isPercentage(value) {
    return value.toString().indexOf("%") !== -1;
}

function parseBackgrounds(backgroundImage) {
    var whitespace = ' \r\n\t',
        method, definition, prefix, prefix_i, block, results = [],
        mode = 0, numParen = 0, quote, args;
    var appendResult = function() {
        if(method) {
            if (definition.substr(0, 1) === '"') {
                definition = definition.substr(1, definition.length - 2);
            }
            if (definition) {
                args.push(definition);
            }
            if (method.substr(0, 1) === '-' && (prefix_i = method.indexOf('-', 1 ) + 1) > 0) {
                prefix = method.substr(0, prefix_i);
                method = method.substr(prefix_i);
            }
            results.push({
                prefix: prefix,
                method: method.toLowerCase(),
                value: block,
                args: args,
                image: null
            });
        }
        args = [];
        method = prefix = definition = block = '';
    };
    args = [];
    method = prefix = definition = block = '';
    backgroundImage.split("").forEach(function(c) {
        if (mode === 0 && whitespace.indexOf(c) > -1) {
            return;
        }
        switch(c) {
        case '"':
            if(!quote) {
                quote = c;
            } else if(quote === c) {
                quote = null;
            }
            break;
        case '(':
            if(quote) {
                break;
            } else if(mode === 0) {
                mode = 1;
                block += c;
                return;
            } else {
                numParen++;
            }
            break;
        case ')':
            if (quote) {
                break;
            } else if(mode === 1) {
                if(numParen === 0) {
                    mode = 0;
                    block += c;
                    appendResult();
                    return;
                } else {
                    numParen--;
                }
            }
            break;

        case ',':
            if (quote) {
                break;
            } else if(mode === 0) {
                appendResult();
                return;
            } else if (mode === 1) {
                if (numParen === 0 && !method.match(/^url$/i)) {
                    args.push(definition);
                    definition = '';
                    block += c;
                    return;
                }
            }
            break;
        }

        block += c;
        if (mode === 0) {
            method += c;
        } else {
            definition += c;
        }
    });

    appendResult();
    return results;
}

function removePx(str) {
    return str.replace("px", "");
}

function asFloat(str) {
    return parseFloat(str);
}

function getBounds(node) {
    if (node.getBoundingClientRect) {
        var clientRect = node.getBoundingClientRect();
        var width = node.offsetWidth == null ? clientRect.width : node.offsetWidth;
        return {
            top: clientRect.top,
            bottom: clientRect.bottom || (clientRect.top + clientRect.height),
            right: clientRect.left + width,
            left: clientRect.left,
            width:  width,
            height: node.offsetHeight == null ? clientRect.height : node.offsetHeight
        };
    }
    return {};
}

function offsetBounds(node) {
    var parent = node.offsetParent ? offsetBounds(node.offsetParent) : {top: 0, left: 0};

    return {
        top: node.offsetTop + parent.top,
        bottom: node.offsetTop + node.offsetHeight + parent.top,
        right: node.offsetLeft + parent.left + node.offsetWidth,
        left: node.offsetLeft + parent.left,
        width: node.offsetWidth,
        height: node.offsetHeight
    };
}