/**
 * Package: svgedit.utilities
 *
 * Licensed under the Apache License, Version 2
 *
 * Copyright(c) 2010 Alexis Deveria
 * Copyright(c) 2010 Jeff Schiller
 */

// Dependencies:
// 1) jQuery
// 2) browser.js
// 3) svgtransformlist.js

var svgedit = svgedit || {};

(function() {

if (!svgedit.utilities) {
  svgedit.utilities = {};
}

// Constants

// String used to encode base64.
var KEYSTR = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
var SVGNS = 'http://www.w3.org/2000/svg';
var XLINKNS = 'http://www.w3.org/1999/xlink';
var XMLNS = "http://www.w3.org/XML/1998/namespace";

// Much faster than running getBBox() every time
var visElems = 'a,circle,ellipse,foreignObject,g,image,line,path,polygon,polyline,rect,svg,text,tspan,use';
var visElems_arr = visElems.split(',');
//var hidElems = 'clipPath,defs,desc,feGaussianBlur,filter,linearGradient,marker,mask,metadata,pattern,radialGradient,stop,switch,symbol,title,textPath';

var editorContext_ = null;
var domdoc_ = null;
var domcontainer_ = null;
var svgroot_ = null;

svgedit.utilities.init = function(editorContext) {
  editorContext_ = editorContext;
  domdoc_ = editorContext.getDOMDocument();
  domcontainer_ = editorContext.getDOMContainer();
  svgroot_ = editorContext.getSVGRoot();
};

// Function: svgedit.utilities.toXml
// Converts characters in a string to XML-friendly entities.
//
// Example: "&" becomes "&amp;"
//
// Parameters:
// str - The string to be converted
//
// Returns:
// The converted string
svgedit.utilities.toXml = function(str) {
  return $('<p/>').text(str).html();
};
  
// Function: svgedit.utilities.fromXml
// Converts XML entities in a string to single characters. 
// Example: "&amp;" becomes "&"
//
// Parameters:
// str - The string to be converted
//
// Returns: 
// The converted string
svgedit.utilities.fromXml = function(str) {
  return $('<p/>').html(str).text();
};

// This code was written by Tyler Akins and has been placed in the
// public domain.  It would be nice if you left this header intact.
// Base64 code from Tyler Akins -- http://rumkin.com

// schiller: Removed string concatenation in favour of Array.join() optimization,
//           also precalculate the size of the array needed.

// Function: svgedit.utilities.encode64
// Converts a string to base64
svgedit.utilities.encode64 = function(input) {
  // base64 strings are 4/3 larger than the original string
//  input = svgedit.utilities.encodeUTF8(input); // convert non-ASCII characters
  input = svgedit.utilities.convertToXMLReferences(input);
  if(window.btoa) return window.btoa(input); // Use native if available
  var output = new Array( Math.floor( (input.length + 2) / 3 ) * 4 );
  var chr1, chr2, chr3;
  var enc1, enc2, enc3, enc4;
  var i = 0, p = 0;

  do {
    chr1 = input.charCodeAt(i++);
    chr2 = input.charCodeAt(i++);
    chr3 = input.charCodeAt(i++);

    enc1 = chr1 >> 2;
    enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
    enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
    enc4 = chr3 & 63;

    if (isNaN(chr2)) {
      enc3 = enc4 = 64;
    } else if (isNaN(chr3)) {
      enc4 = 64;
    }

    output[p++] = KEYSTR.charAt(enc1);
    output[p++] = KEYSTR.charAt(enc2);
    output[p++] = KEYSTR.charAt(enc3);
    output[p++] = KEYSTR.charAt(enc4);
  } while (i < input.length);

  return output.join('');
};

// Function: svgedit.utilities.decode64
// Converts a string from base64
svgedit.utilities.decode64 = function(input) {
  if(window.atob) return window.atob(input);
  var output = "";
  var chr1, chr2, chr3 = "";
  var enc1, enc2, enc3, enc4 = "";
  var i = 0;

   // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
   input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

   do {
    enc1 = KEYSTR.indexOf(input.charAt(i++));
    enc2 = KEYSTR.indexOf(input.charAt(i++));
    enc3 = KEYSTR.indexOf(input.charAt(i++));
    enc4 = KEYSTR.indexOf(input.charAt(i++));

    chr1 = (enc1 << 2) | (enc2 >> 4);
    chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
    chr3 = ((enc3 & 3) << 6) | enc4;

    output = output + String.fromCharCode(chr1);

    if (enc3 != 64) {
       output = output + String.fromCharCode(chr2);
    }
    if (enc4 != 64) {
       output = output + String.fromCharCode(chr3);
    }

    chr1 = chr2 = chr3 = "";
    enc1 = enc2 = enc3 = enc4 = "";

   } while (i < input.length);
   return unescape(output);
};

// Currently not being used, so commented out for now
// based on http://phpjs.org/functions/utf8_encode:577
// codedread:does not seem to work with webkit-based browsers on OSX
//    "encodeUTF8": function(input) {
//      //return unescape(encodeURIComponent(input)); //may or may not work
//      var output = '';
//      for (var n = 0; n < input.length; n++){
//        var c = input.charCodeAt(n);
//        if (c < 128) {
//          output += input[n];
//        }
//        else if (c > 127) {
//          if (c < 2048){
//            output += String.fromCharCode((c >> 6) | 192);
//          } 
//          else {
//            output += String.fromCharCode((c >> 12) | 224) + String.fromCharCode((c >> 6) & 63 | 128);
//          }
//          output += String.fromCharCode((c & 63) | 128);
//        }
//      }
//      return output;
//    },

// Function: svgedit.utilities.convertToXMLReferences 
// Converts a string to use XML references
svgedit.utilities.convertToXMLReferences = function(input) {
  var output = '';
  for (var n = 0; n < input.length; n++){
    var c = input.charCodeAt(n);
    if (c < 128) {
      output += input[n];
    } else if(c > 127) {
      output += ("&#" + c + ";");
    }
  }
  return output;
};

// Function: svgedit.utilities.text2xml
// Cross-browser compatible method of converting a string to an XML tree
// found this function here: http://groups.google.com/group/jquery-dev/browse_thread/thread/c6d11387c580a77f
svgedit.utilities.text2xml = function(sXML) {
  if(sXML.indexOf('<svg:svg') >= 0) {
    sXML = sXML.replace(/<(\/?)svg:/g, '<$1').replace('xmlns:svg', 'xmlns');
  }

  var out;
  try{
    var dXML = (window.DOMParser)?new DOMParser():new ActiveXObject("Microsoft.XMLDOM");
    dXML.async = false;
  } catch(e){ 
    throw new Error("XML Parser could not be instantiated"); 
  };
  try{
    if(dXML.loadXML) out = (dXML.loadXML(sXML))?dXML:false;
    else out = dXML.parseFromString(sXML, "text/xml");
  }
  catch(e){ throw new Error("Error parsing XML string"); };
  return out;
};

// Function: svgedit.utilities.bboxToObj
// Converts a SVGRect into an object.
// 
// Parameters:
// bbox - a SVGRect
// 
// Returns:
// An object with properties names x, y, width, height.
svgedit.utilities.bboxToObj = function(bbox) {
  return {
    x: bbox.x,
    y: bbox.y,
    width: bbox.width,
    height: bbox.height
  }
};

// Function: svgedit.utilities.walkTree
// Walks the tree and executes the callback on each element in a top-down fashion
//
// Parameters:
// elem - DOM element to traverse
// cbFn - Callback function to run on each element
svgedit.utilities.walkTree = function(elem, cbFn){
  if (elem && elem.nodeType == 1) {
    cbFn(elem);
    var i = elem.childNodes.length;
    while (i--) {
      svgedit.utilities.walkTree(elem.childNodes.item(i), cbFn);
    }
  }
};

// Function: svgedit.utilities.walkTreePost
// Walks the tree and executes the callback on each element in a depth-first fashion
// TODO: FIXME: Shouldn't this be calling walkTreePost?
//
// Parameters:
// elem - DOM element to traverse
// cbFn - Callback function to run on each element
svgedit.utilities.walkTreePost = function(elem, cbFn) {
  if (elem && elem.nodeType == 1) {
    var i = elem.childNodes.length;
    while (i--) {
      svgedit.utilities.walkTree(elem.childNodes.item(i), cbFn);
    }
    cbFn(elem);
  }
};

// Function: svgedit.utilities.getUrlFromAttr
// Extracts the URL from the url(...) syntax of some attributes.  
// Three variants:
//  * <circle fill="url(someFile.svg#foo)" />
//  * <circle fill="url('someFile.svg#foo')" />
//  * <circle fill='url("someFile.svg#foo")' />
//
// Parameters:
// attrVal - The attribute value as a string
// 
// Returns:
// String with just the URL, like someFile.svg#foo
svgedit.utilities.getUrlFromAttr = function(attrVal) {
  if (attrVal) {    
    // url("#somegrad")
    if (attrVal.indexOf('url("') === 0) {
      return attrVal.substring(5,attrVal.indexOf('"',6));
    }
    // url('#somegrad')
    else if (attrVal.indexOf("url('") === 0) {
      return attrVal.substring(5,attrVal.indexOf("'",6));
    }
    else if (attrVal.indexOf("url(") === 0) {
      return attrVal.substring(4,attrVal.indexOf(')'));
    }
  }
  return null;
};

// Function: svgedit.utilities.getHref
// Returns the given element's xlink:href value
svgedit.utilities.getHref = function(elem) {
  if (elem) return elem.getAttributeNS(XLINKNS, "href");
}

// Function: svgedit.utilities.setHref
// Sets the given element's xlink:href value
svgedit.utilities.setHref = function(elem, val) {
  elem.setAttributeNS(XLINKNS, "xlink:href", val);
}

// Function: findDefs
// Parameters:
// svgElement - The <svg> element.
//
// Returns:
// The document's <defs> element, create it first if necessary
svgedit.utilities.findDefs = function(svgElement) {
  var svgElement = editorContext_.getSVGContent().documentElement;
  var defs = svgElement.getElementsByTagNameNS(SVGNS, "defs");
  if (defs.length > 0) {
    defs = defs[0];
  }
  else {
    // first child is a comment, so call nextSibling
    defs = svgElement.insertBefore( svgElement.ownerDocument.createElementNS(SVGNS, "defs" ), svgElement.firstChild.nextSibling);
  }
  return defs;
};

// TODO(codedread): Consider moving the next to functions to bbox.js

// Function: svgedit.utilities.getPathBBox
// Get correct BBox for a path in Webkit
// Converted from code found here:
// http://blog.hackers-cafe.net/2009/06/how-to-calculate-bezier-curves-bounding.html
// 
// Parameters:
// path - The path DOM element to get the BBox for
//
// Returns:
// A BBox-like object
svgedit.utilities.getPathBBox = function(path) {
  var seglist = path.pathSegList;
  var tot = seglist.numberOfItems;
  
  var bounds = [[], []];
  var start = seglist.getItem(0);
  var P0 = [start.x, start.y];

  for(var i=0; i < tot; i++) {
    var seg = seglist.getItem(i);

    if(typeof seg.x == 'undefined') continue;

    // Add actual points to limits
    bounds[0].push(P0[0]);
    bounds[1].push(P0[1]);
    
    if(seg.x1) {
      var P1 = [seg.x1, seg.y1],
        P2 = [seg.x2, seg.y2],
        P3 = [seg.x, seg.y];

      for(var j=0; j < 2; j++) {

        var calc = function(t) {
          return Math.pow(1-t,3) * P0[j] 
            + 3 * Math.pow(1-t,2) * t * P1[j]
            + 3 * (1-t) * Math.pow(t,2) * P2[j]
            + Math.pow(t,3) * P3[j];
        };

        var b = 6 * P0[j] - 12 * P1[j] + 6 * P2[j];
        var a = -3 * P0[j] + 9 * P1[j] - 9 * P2[j] + 3 * P3[j];
        var c = 3 * P1[j] - 3 * P0[j];
        
        if(a == 0) {
          if(b == 0) {
            continue;
          }
          var t = -c / b;
          if(0 < t && t < 1) {
            bounds[j].push(calc(t));
          }
          continue;
        }
        
        var b2ac = Math.pow(b,2) - 4 * c * a;
        if(b2ac < 0) continue;
        var t1 = (-b + Math.sqrt(b2ac))/(2 * a);
        if(0 < t1 && t1 < 1) bounds[j].push(calc(t1));
        var t2 = (-b - Math.sqrt(b2ac))/(2 * a);
        if(0 < t2 && t2 < 1) bounds[j].push(calc(t2));
      }
      P0 = P3;
    } else {
      bounds[0].push(seg.x);
      bounds[1].push(seg.y);
    }
  }
  
  var x = Math.min.apply(null, bounds[0]);
  var w = Math.max.apply(null, bounds[0]) - x;
  var y = Math.min.apply(null, bounds[1]);
  var h = Math.max.apply(null, bounds[1]) - y;
  return {
    'x': x,
    'y': y,
    'width': w,
    'height': h
  };
};

// Function: groupBBFix
// Get the given/selected element's bounding box object, checking for
// horizontal/vertical lines (see issue 717)
// Note that performance is currently terrible, so some way to improve would
// be great.
//
// Parameters: 
// selected - Container or <use> DOM element
function groupBBFix(selected) {
  if(svgedit.browser.supportsHVLineContainerBBox()) {
    try { return selected.getBBox();} catch(e){} 
  }
  var ref = $.data(selected, 'ref');
  var matched = null;
  
  if(ref) {
    var copy = $(ref).children().clone().attr('visibility', 'hidden');
    $(svgroot_).append(copy);
    matched = copy.filter('line, path');
  } else {
    matched = $(selected).find('line, path');
  }
  
  var issue = false;
  if(matched.length) {
    matched.each(function() {
      var bb = this.getBBox();
      if(!bb.width || !bb.height) {
        issue = true;
      }
    });
    if(issue) {
      var elems = ref ? copy : $(selected).children();
      ret = getStrokedBBox(elems);
    } else {
      ret = selected.getBBox();
    }
  } else {
    ret = selected.getBBox();
  }
  if(ref) {
    copy.remove();
  }
  return ret;
}

// Function: svgedit.utilities.getBBox
// Get the given/selected element's bounding box object, convert it to be more
// usable when necessary
//
// Parameters:
// elem - Optional DOM element to get the BBox for
svgedit.utilities.getBBox = function(elem) {
  var selected = elem || editorContext_.getSelectedElements()[0];
  if (elem.nodeType != 1) return null;
  var ret = null;
  var elname = selected.nodeName;
  
  switch ( elname ) {
  case 'text':
    if(selected.textContent === '') {
      selected.textContent = 'a'; // Some character needed for the selector to use.
      ret = selected.getBBox();
      selected.textContent = '';
    } else {
      try { ret = selected.getBBox();} catch(e){}
    }
    break;
  case 'path':
    if(!svgedit.browser.supportsPathBBox()) {
      ret = svgedit.utilities.getPathBBox(selected);
    } else {
      try { ret = selected.getBBox();} catch(e){}
    }
    break;
  case 'g':
  case 'a':
    ret = groupBBFix(selected);
    break;
  default:

    if(elname === 'use') {
      ret = groupBBFix(selected, true);
    }
    
    if(elname === 'use') {
      if(!ret) ret = selected.getBBox();
      //if(!svgedit.browser.isWebkit()) {
      //  var bb = {};
      //  bb.width = ret.width;
      //  bb.height = ret.height;
      //  bb.x = ret.x + parseFloat(selected.getAttribute('x')||0);
      //  bb.y = ret.y + parseFloat(selected.getAttribute('y')||0);
      //  ret = bb;
      //}
    } else if(~visElems_arr.indexOf(elname)) {
      try { ret = selected.getBBox();} 
      catch(e) { 
        // Check if element is child of a foreignObject
        var fo = $(selected).closest("foreignObject");
        if(fo.length) {
          try {
            ret = fo[0].getBBox();
          } catch(e) {
            ret = null;
          }
        } else {
          ret = null;
        }
      }
    }
  }
  
  if(ret) {
    ret = svgedit.utilities.bboxToObj(ret);
  }

  // get the bounding box from the DOM (which is in that element's coordinate system)
  return ret;
};

// Function: svgedit.utilities.getRotationAngle
// Get the rotation angle of the given/selected DOM element
//
// Parameters:
// elem - Optional DOM element to get the angle for
// to_rad - Boolean that when true returns the value in radians rather than degrees
//
// Returns:
// Float with the angle in degrees or radians
svgedit.utilities.getRotationAngle = function(elem, to_rad) {
  var selected = elem || editorContext_.getSelectedElements()[0];
  // find the rotation transform (if any) and set it
  var tlist = svgedit.transformlist.getTransformList(selected);
  if(!tlist) return 0; // <svg> elements have no tlist
  var N = tlist.numberOfItems;
  for (var i = 0; i < N; ++i) {
    var xform = tlist.getItem(i);
    if (xform.type == 4) {
      return to_rad ? xform.angle * Math.PI / 180.0 : xform.angle;
    }
  }
  return 0.0;
};

// Function: getElem
// Get a DOM element by ID within the SVG root element.
//
// Parameters:
// id - String with the element's new ID
if (svgedit.browser.supportsSelectors()) {
  svgedit.utilities.getElem = function(id) {
    // querySelector lookup
    return svgroot_.querySelector('#'+id);
  };
} else if (svgedit.browser.supportsXpath()) {
  svgedit.utilities.getElem = function(id) {
    // xpath lookup
    return domdoc_.evaluate(
      'svg:svg[@id="svgroot"]//svg:*[@id="'+id+'"]',
      domcontainer_, 
      function() { return "http://www.w3.org/2000/svg"; },
      9,
      null).singleNodeValue;
  };
} else {
  svgedit.utilities.getElem = function(id) {
    // jQuery lookup: twice as slow as xpath in FF
    return $(svgroot_).find('[id=' + id + ']')[0];
  };
}

// Function: assignAttributes
// Assigns multiple attributes to an element.
//
// Parameters: 
// node - DOM element to apply new attribute values to
// attrs - Object with attribute keys/values
// suspendLength - Optional integer of milliseconds to suspend redraw
// unitCheck - Boolean to indicate the need to use svgedit.units.setUnitAttr
svgedit.utilities.assignAttributes = function(node, attrs, suspendLength, unitCheck) {

  for (var i in attrs) {
    var ns = (i.substr(0,4) === "xml:" ? XMLNS : 
      i.substr(0,6) === "xlink:" ? XLINKNS : null);

    if(node) {
      if(ns) {
        node.setAttributeNS(ns, i, attrs[i]);
      } else if(!unitCheck) {
        if(i == 'transform' && (attrs[i] == 0 || attrs[i] == null)) return;
        node.setAttribute(i, attrs[i]);
      } else {
        svgedit.units.setUnitAttr(node, i, attrs[i]);
      }
    }  
  }
};

// Function: cleanupElement
// Remove unneeded (default) attributes, makes resulting SVG smaller
//
// Parameters:
// element - DOM element to clean up
svgedit.utilities.cleanupElement = function(element) {
  var defaults = {
    'fill-opacity':1,
    'stop-opacity':1,
    'opacity':1,
    'stroke':'none',
    'stroke-dasharray':'none',
    'stroke-linejoin':'miter',
    'stroke-linecap':'butt',
    'stroke-opacity':1,
    'stroke-width':1,
    'rx':0,
    'ry':0
  }
  
  for(var attr in defaults) {
    var val = defaults[attr];
    if(element.getAttribute(attr) == val) {
      element.removeAttribute(attr);
    }
  }
  
};


})();