"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.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;
};


_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;
};