"use strict";

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

_html2canvas.Util = {};

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

_html2canvas.Util.trimText = (function(isNative){
  return function(input) {
    return isNative ? isNative.apply(input) : ((input || '') + '').replace( /^\s+|\s+$/g , '' );
  };
})(String.prototype.trim);

_html2canvas.Util.asFloat = function(v) {
  return parseFloat(v);
};

(function() {
  // TODO: support all possible length values
  var TEXT_SHADOW_PROPERTY = /((rgba|rgb)\([^\)]+\)(\s-?\d+px){0,})/g;
  var TEXT_SHADOW_VALUES = /(-?\d+px)|(#.+)|(rgb\(.+\))|(rgba\(.+\))/g;
  _html2canvas.Util.parseTextShadows = function (value) {
    if (!value || value === 'none') {
      return [];
    }

    // find multiple shadow declarations
    var shadows = value.match(TEXT_SHADOW_PROPERTY),
      results = [];
    for (var i = 0; shadows && (i < shadows.length); i++) {
      var s = shadows[i].match(TEXT_SHADOW_VALUES);
      results.push({
        color: s[0],
        offsetX: s[1] ? s[1].replace('px', '') : 0,
        offsetY: s[2] ? s[2].replace('px', '') : 0,
        blur: s[3] ? s[3].replace('px', '') : 0
      });
    }
    return results;
  };
})();


_html2canvas.Util.parseBackgroundImage = function (value) {
    var whitespace = ' \r\n\t',
        method, definition, prefix, prefix_i, block, results = [],
        c, 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
            });
        }
        args = []; //for some odd reason, setting .length = 0 didn't work in safari
        method =
            prefix =
            definition =
            block = '';
    };

    appendResult();
    for(var i = 0, ii = value.length; i<ii; i++) {
        c = value[i];
        if(mode === 0 && whitespace.indexOf( c ) > -1){
            continue;
        }
        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;
                    continue;
                } else {
                    numParen++;
                }
                break;

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

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

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

    return results;
};

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

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

    bounds.width = element.offsetWidth;
    bounds.height = element.offsetHeight;
  }

  return bounds;
};

// TODO ideally, we'd want everything to go through this function instead of Util.Bounds,
// but would require further work to calculate the correct positions for elements with offsetParents
_html2canvas.Util.OffsetBounds = function (element) {
  var parent = element.offsetParent ? _html2canvas.Util.OffsetBounds(element.offsetParent) : {top: 0, left: 0};

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

function toPX(element, attribute, value ) {
    var rsLeft = element.runtimeStyle && element.runtimeStyle[attribute],
        left,
        style = element.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( value ) && /^-?\d/.test(value) ) {
        // Remember the original values
        left = style.left;

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

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

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

    return value;
}

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

function parseBackgroundSizePosition(value, element, attribute, index) {
    value = (value || '').split(',');
    value = value[index || 0] || value[0] || 'auto';
    value = _html2canvas.Util.trimText(value).split(' ');
    if(attribute === 'backgroundSize' && (value[0] && value[0].match(/^(cover|contain|auto)$/))) {
        return value;
    } else {
        value[0] = (value[0].indexOf( "%" ) === -1) ? toPX(element, attribute + "X", value[0]) : value[0];
        if(value[1] === undefined) {
            if(attribute === 'backgroundSize') {
                value[1] = 'auto';
                return value;
            } else {
                // IE 9 doesn't return double digit always
                value[1] = value[0];
            }
        }
        value[1] = (value[1].indexOf("%") === -1) ? toPX(element, attribute + "Y", value[1]) : value[1];
    }
    return value;
}

_html2canvas.Util.getCSS = function (element, attribute, index) {
    if (previousElement !== element) {
      computedCSS = document.defaultView.getComputedStyle(element, null);
    }

    var value = computedCSS[attribute];

    if (/^background(Size|Position)$/.test(attribute)) {
        return parseBackgroundSizePosition(value, element, attribute, index);
    } else if (/border(Top|Bottom)(Left|Right)Radius/.test(attribute)) {
      var arr = value.split(" ");
      if (arr.length <= 1) {
          arr[1] = arr[0];
      }
      return arr.map(asInt);
    }

  return value;
};

_html2canvas.Util.resizeBounds = function( current_width, current_height, target_width, target_height, stretch_mode ){
  var target_ratio = target_width / target_height,
    current_ratio = current_width / current_height,
    output_width, output_height;

  if(!stretch_mode || stretch_mode === 'auto') {
    output_width = target_width;
    output_height = target_height;
  } else if(target_ratio < current_ratio ^ stretch_mode === 'contain') {
    output_height = target_height;
    output_width = target_height * current_ratio;
  } else {
    output_width = target_width;
    output_height = target_width / current_ratio;
  }

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

_html2canvas.Util.BackgroundPosition = function(element, bounds, image, imageIndex, backgroundSize ) {
    var backgroundPosition =  _html2canvas.Util.getCSS(element, 'backgroundPosition', imageIndex),
        leftPosition,
        topPosition;
    if (backgroundPosition.length === 1){
        backgroundPosition = [backgroundPosition[0], backgroundPosition[0]];
    }

    if (backgroundPosition[0].toString().indexOf("%") !== -1){
        leftPosition = (bounds.width - (backgroundSize || image).width) * (parseFloat(backgroundPosition[0]) / 100);
    } else {
        leftPosition = parseInt(backgroundPosition[0], 10);
    }

    if (backgroundPosition[1] === 'auto') {
        topPosition = leftPosition / image.width * image.height;
    } else if (backgroundPosition[1].toString().indexOf("%") !== -1){
        topPosition =  (bounds.height - (backgroundSize || image).height) * parseFloat(backgroundPosition[1]) / 100;
    } else {
        topPosition = parseInt(backgroundPosition[1], 10);
    }

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

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

_html2canvas.Util.BackgroundSize = function(element, bounds, image, imageIndex) {
    var backgroundSize =  _html2canvas.Util.getCSS(element, 'backgroundSize', imageIndex),
        width,
        height;

    if (backgroundSize.length === 1){
        backgroundSize = [backgroundSize[0], backgroundSize[0]];
    }

    if (backgroundSize[0].toString().indexOf("%") !== -1){
        width = bounds.width * parseFloat(backgroundSize[0]) / 100;
    } else if(backgroundSize[0] === 'auto') {
        width = image.width;
    } else {
        if (/contain|cover/.test(backgroundSize[0])) {
            var resized = _html2canvas.Util.resizeBounds(image.width, image.height, bounds.width, bounds.height, backgroundSize[0]);
            return {width: resized.width, height: resized.height};
        } else {
            width = parseInt(backgroundSize[0], 10);
        }
    }

    if(backgroundSize[1] === 'auto') {
        height = width / image.width * image.height;
    } else if (backgroundSize[1].toString().indexOf("%") !== -1){
        height =  bounds.height * parseFloat(backgroundSize[1]) / 100;
    } else {
        height = parseInt(backgroundSize[1],10);
    }


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

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

_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) {
    _html2canvas.Util.log("html2canvas.Util.Children failed with exception: " + ex.message);
    children = [];
  }
  return children;
};

_html2canvas.Util.isTransparent = function(backgroundColor) {
  return (!backgroundColor || backgroundColor === "transparent" || backgroundColor === "rgba(0, 0, 0, 0)");
};