"use strict";

var _html2canvas = {},
previousElement,
computedCSS,
html2canvas;


function h2clog(a) {
    if (_html2canvas.logging && window.console && window.console.log) {
        window.console.log(a);
    }
}

_html2canvas.Util = {};

_html2canvas.Util.backgroundImage = function (src) {

    if (/data:image\/.*;base64,/i.test( src ) || /^(-webkit|-moz|linear-gradient|-o-)/.test( src )) {
        return src;
    }

    if (src.toLowerCase().substr( 0, 5 ) === 'url("') {
        src = src.substr( 5 );
        src = src.substr( 0, src.length - 2 );
    } else {
        src = src.substr( 4 );
        src = src.substr( 0, src.length - 1 );
    }

    return src;
};

_html2canvas.Util.parseBackgroundImage = function (value) {
    var rxBackgroundImage = /([a-z\-]+)\((("[^"]+)|([^)]+))\)/i,
        method, definition, prefix, prefix_i, block, results = [], 
        c, mode = 0, numParen = 0;

    var appendResult = function(){
        if(method) {
            if(definition.substr( 0, 1 ) === '"') {
                definition = definition.substr( 1, definition.length - 2 );
            }
            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,
                definition: definition,
                value: block
            });
        }
        method = 
            prefix =
            definition =
            block = '';
    };

    appendResult();
    for(var i = 0, ii = value.length; i<ii; i++) {
        c = value[i];
        switch(c) {
            case ' ':
            case '\t':
            case '\n':
            case '\r':
                if(mode == 0){
                    continue;
                }
                
            case '(':
                if(mode === 0) {
                    mode = 1;
                    block += c;
                    continue;
                } else {
                    numParen++;
                }
                break;

            case ')':
                if(mode === 1) {
                    if(numParen === 0) {
                        mode = 0;
                        block += c;
                        appendResult();
                        continue;
                    } else { 
                        numParen--; 
                    }
                }
                break;

            case ',':
                if(mode === 0) {
                    appendResult();
                    continue;
                }
                break;
        }

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

    return results;
};

_html2canvas.Util.Bounds = function getBounds (el) {
    var clientRect,
    bounds = {};

    if (el.getBoundingClientRect){
        clientRect = el.getBoundingClientRect();


        // TODO add scroll position to bounds, so no scrolling of window necessary
        bounds.top = clientRect.top;
        bounds.bottom = clientRect.bottom || (clientRect.top + clientRect.height);
        bounds.left = clientRect.left;

        // older IE doesn't have width/height, but top/bottom instead
        bounds.width = clientRect.width || (clientRect.right - clientRect.left);
        bounds.height = clientRect.height || (clientRect.bottom - clientRect.top);

        return bounds;

    }
};

_html2canvas.Util.getCSS = function (el, attribute) {
    // return $(el).css(attribute);

    var val;

    function toPX( attribute, val ) {
        var rsLeft = el.runtimeStyle && el.runtimeStyle[ attribute ],
        left,
        style = el.style;

        // Check if we are not dealing with pixels, (Opera has issues with this)
        // Ported from jQuery css.js
        // From the awesome hack by Dean Edwards
        // http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291

        // If we're not dealing with a regular pixel number
        // but a number that has a weird ending, we need to convert it to pixels

        if ( !/^-?[0-9]+\.?[0-9]*(?:px)?$/i.test( val ) && /^-?\d/.test( val ) ) {

            // Remember the original values
            left = style.left;

            // Put in the new values to get a computed value out
            if ( rsLeft ) {
                el.runtimeStyle.left = el.currentStyle.left;
            }
            style.left = attribute === "fontSize" ? "1em" : (val || 0);
            val = style.pixelLeft + "px";

            // Revert the changed values
            style.left = left;
            if ( rsLeft ) {
                el.runtimeStyle.left = rsLeft;
            }

        }

        if (!/^(thin|medium|thick)$/i.test( val )) {
            return Math.round(parseFloat( val )) + "px";
        }

        return val;

    }


    if ( window.getComputedStyle ) {
        if ( previousElement !== el ) {
            computedCSS = document.defaultView.getComputedStyle(el, null);
        }
        val = computedCSS[ attribute ];

        if ( attribute === "backgroundPosition" ) {

            val = (val.split(",")[0] || "0 0").split(" ");

            val[ 0 ] = ( val[0].indexOf( "%" ) === -1 ) ? toPX(  attribute + "X", val[ 0 ] ) : val[ 0 ];
            val[ 1 ] = ( val[1] === undefined ) ? val[0] : val[1]; // IE 9 doesn't return double digit always
            val[ 1 ] = ( val[1].indexOf( "%" ) === -1 ) ? toPX(  attribute + "Y", val[ 1 ] ) : val[ 1 ];
        } else if ( /border(Top|Bottom)(Left|Right)Radius/.test( attribute) ) {
            var arr = val.split(" ");
            if ( arr.length <= 1 ) {
                arr[ 1 ] = arr[ 0 ];
            }
            arr[ 0 ] = parseInt( arr[ 0 ], 10 );
            arr[ 1 ] = parseInt( arr[ 1 ], 10 );
            val = arr;
        }

    } else if ( el.currentStyle ) {
        // IE 9>
        if (attribute === "backgroundPosition") {
            // Older IE uses -x and -y
            val = [ toPX(  attribute + "X", el.currentStyle[ attribute + "X" ]  ), toPX(  attribute + "Y", el.currentStyle[ attribute + "Y" ]  ) ];
        } else {

            val = toPX(  attribute, el.currentStyle[ attribute ]  );

            if (/^(border)/i.test( attribute ) && /^(medium|thin|thick)$/i.test( val )) {
                switch (val) {
                    case "thin":
                        val = "1px";
                        break;
                    case "medium":
                        val = "0px"; // this is wrong, it should be 3px but IE uses medium for no border as well.. TODO find a work around
                        break;
                    case "thick":
                        val = "5px";
                        break;
                }
            }
        }



    }




    return val;



//return $(el).css(attribute);


};


_html2canvas.Util.BackgroundPosition = function ( el, bounds, image ) {
    // TODO add support for multi image backgrounds

    var bgposition =  _html2canvas.Util.getCSS( el, "backgroundPosition" ) ,
    topPos,
    left,
    percentage,
    val;

    if (bgposition.length === 1){
        val = bgposition;

        bgposition = [];

        bgposition[0] = val;
        bgposition[1] = val;
    }



    if (bgposition[0].toString().indexOf("%") !== -1){
        percentage = (parseFloat(bgposition[0])/100);
        left =  ((bounds.width * percentage)-(image.width*percentage));

    }else{
        left = parseInt(bgposition[0],10);
    }

    if (bgposition[1].toString().indexOf("%") !== -1){

        percentage = (parseFloat(bgposition[1])/100);
        topPos =  ((bounds.height * percentage)-(image.height*percentage));
    }else{
        topPos = parseInt(bgposition[1],10);
    }




    return {
        top: topPos,
        left: left
    };

};

_html2canvas.Util.Extend = function (options, defaults) {
    for (var key in options) {
        if (options.hasOwnProperty(key)) {
            defaults[key] = options[key];
        }
    }
    return defaults;
};


/*
 * Derived from jQuery.contents()
 * Copyright 2010, John Resig
 * Dual licensed under the MIT or GPL Version 2 licenses.
 * http://jquery.org/license
 */
_html2canvas.Util.Children = function( elem ) {


    var children;
    try {

        children = (elem.nodeName && elem.nodeName.toUpperCase() === "IFRAME") ?
        elem.contentDocument || elem.contentWindow.document : (function( array ){
            var ret = [];

            if ( array !== null ) {

                (function( first, second ) {
                    var i = first.length,
                    j = 0;

                    if ( typeof second.length === "number" ) {
                        for ( var l = second.length; j < l; j++ ) {
                            first[ i++ ] = second[ j ];
                        }

                    } else {
                        while ( second[j] !== undefined ) {
                            first[ i++ ] = second[ j++ ];
                        }
                    }

                    first.length = i;

                    return first;
                })( ret, array );

            }

            return ret;
        })( elem.childNodes );

    } catch (ex) {
        h2clog("html2canvas.Util.Children failed with exception: " + ex.message);
        children = [];
    }
    return children;
};