/**
* @author John Nesky <http://www.johnnesky.com>
* Bezier curves added by Quest Yarbrough <http://www.ezqueststudios.com>
* partially based on some code by Helen Triolo <http://flash-creations.com/notes/sample_svgtoflash.php>
* 
* This code is available under the LGPL license. <http://www.gnu.org/licenses/lgpl-3.0.txt>
*/
 
package 
{
  import Box2D.Dynamics.b2World;
  import Box2D.Common.Math.b2Vec2;
  import Box2D.Collision.Shapes.b2EdgeChainDef;
  import Box2D.Collision.Shapes.b2ShapeDef;
  import Box2D.Collision.Shapes.b2Shape;
  import b2Bezier;
  public class b2SVG
  {
 
    public static function parseSVG(svg: XML, world: b2World, RATIO:Number, useDefaultCurveResolution:Number): Array {
      var ns: Namespace = svg.namespace("");
      var useCurveThickness:Boolean = false;
      var resolution:Number;
 
      if (useDefaultCurveResolution > 0) {
        resolution = useDefaultCurveResolution; 
      } else {
        useCurveThickness = true;
      }
 
      var chainDef: b2EdgeChainDef = new b2EdgeChainDef();
      chainDef.friction = 0.5;
      chainDef.restitution = 0.0;
      for each (var path: XML in svg..ns::path)
      {
        if (useCurveThickness) resolution = Math.round(returnStrokeWidth(path.@style) * 10);
 
        // the entire path:
        var d: String = path.@d;
 
        // Inkscape, Illustrator, and other programs use slightly different
        // formats for the path, because the SVG specs are very flexible. This
        // puts some strain on the people who write path parsers (me!), but 
        // Helen Triolo's example illustrates an easy way to convert the path
        // to a consistent format and then break it up into an array:
 
        // replace whitespace with commas:
        var letter: String;
        for each (letter in [" ","\f","\n","\r","\t"])
          d = d.split(letter).join(",");
 
        // surround letters with commas:
        for each (letter in ["M","m","Z","z","L","l","H","h","V","v","C","c","S","s","Q","q","T","t","A","a"])
          d = d.split(letter).join("," + letter + ",");
 
        // insert commas before negative symbols:
        d = d.split("-").join(",-");
 
        // now get all tokens separated by commas:
        var args: Array = d.split(",");
 
        // remove empty strings:
        args = args.filter(filterEmptyString);
 
 
        var currentPosition: b2Vec2 = new b2Vec2(0,0);
        var control1: b2Vec2 = null;
        var control2: b2Vec2 = null;
        var control3: b2Vec2 = null;
        var prevControl: b2Vec2 = null;
        var prevCommand: String = null;
        var relative: Boolean = false;
        var curve: Array;
		var shapes: Array = new Array();
 
        chainDef.vertices.length = 0;
        var i: int = 0;
        while (true)
        {
          if (i == args.length) {
            // cleanup: If a path is incomplete, finish it without closing the loop
            //          and add it to the Box2D world.
            if (chainDef.vertices.length >= 2) {
              chainDef.vertexCount = chainDef.vertices.length;
              chainDef.isALoop = false;
              shapes.push(world.GetGroundBody().CreateShape(chainDef)); 
            }
            break;
          }
 
          var command: String = args[i];
          i++;
 
          switch (command)
          {
            case "Z":
            case "z":
              // closepath: If a path is incomplete, finish it, close the loop,
              //            and add it to the Box2D world. 
              if (chainDef.vertices.length >= 3) {
                chainDef.vertices.pop(); // the last vertex of the loop is redundant.
                chainDef.vertexCount = chainDef.vertices.length;
                chainDef.isALoop = true;
				shapes.push(world.GetGroundBody().CreateShape(chainDef));
              }
              chainDef.vertices.length = 0;
              chainDef.vertices.push(currentPosition);
              break;
            case "M":
            case "m":
              // moveto: If a path is incomplete, finish it without closing the loop
              //          and add it to the Box2D world.
              //          Start a new path.
              if (chainDef.vertices.length >= 2) {
                chainDef.vertexCount = chainDef.vertices.length;
                chainDef.isALoop = false;
                shapes.push(world.GetGroundBody().CreateShape(chainDef));
              }
              relative = (command == "m");
              if (relative) {
                currentPosition = new b2Vec2(currentPosition.x + args[i] / RATIO,
                                             currentPosition.y + args[i+1] / RATIO);
              } else {
                currentPosition = new b2Vec2(args[i] / RATIO, args[i+1] / RATIO);
              }
              i += 2;
              chainDef.vertices.length = 0;
              chainDef.vertices.push(currentPosition);
 
              // According to the SVG spec, a moveto command can be implicitly followed
              // by lineto coordinates. So there is no "break" here.
            case "L":
            case "l":
              // lineto: a series of straight lines. Keep parsing until you hit a non-number. 
              if (command == "l") relative = true;
              else if (command == "L") relative = false;
              while (!isNaN(parseFloat(args[i])))
              {
                if (relative) {
                  currentPosition = new b2Vec2(currentPosition.x + args[i] / RATIO,
                                               currentPosition.y + args[i+1] / RATIO);
                } else {
                  currentPosition = new b2Vec2(args[i] / RATIO, args[i+1] / RATIO);
                }
                i += 2;
                chainDef.vertices.push(currentPosition);
              }
              break;
            case "H":
            case "h":
              // horizontal lineto: a series of horizontal lines. 
              //                    keep parsing until you hit a non-number. 
              //                    Box2D works much better if adjacent parallel lines
              //                    are merged into one, so I'll go ahead and merge them.
              relative = (command == "h");
              do
              {
                if (relative) {
                  currentPosition = new b2Vec2(currentPosition.x + args[i] / RATIO,
                                               currentPosition.y);
                } else {
                  currentPosition = new b2Vec2(args[i] / RATIO, currentPosition.y);
                }
                i++;
              } while (!isNaN(parseFloat(args[i])));
              chainDef.vertices.push(currentPosition);
              break;
            case "V":
            case "v":
              // vertical lineto: a series of vertical lines. 
              //                  keep parsing until you hit a non-number. 
              //                  Box2D works much better if adjacent parallel lines
              //                  are merged into one, so I'll go ahead and merge them.
              relative = (command == "v");
              do
              {
                if (relative) {
                  currentPosition = new b2Vec2(currentPosition.x,
                                               currentPosition.y + args[i] / RATIO);
                } else {
                  currentPosition = new b2Vec2(currentPosition.x, args[i] / RATIO);
                }
                i++;
              } while (!isNaN(parseFloat(args[i])));
              chainDef.vertices.push(currentPosition);
              break;
            case "C":
            case "c":
              // curveto
              relative = (command == "c");
              do
              {
                if (relative) {
                  control1 = new b2Vec2(currentPosition.x + args[i] / RATIO,
                                        currentPosition.y + args[i+1] / RATIO);
                  control2 = new b2Vec2(currentPosition.x + args[i+2] / RATIO,
                                        currentPosition.y + args[i+3] / RATIO);
                  control3 = new b2Vec2(currentPosition.x + args[i+4] / RATIO,
                                        currentPosition.y + args[i+5] / RATIO);
                } else {
                  control1 = new b2Vec2(args[i] / RATIO, args[i+1] / RATIO);
                  control2 = new b2Vec2(args[i+2] / RATIO, args[i+3] / RATIO);
                  control3 = new b2Vec2(args[i+4] / RATIO, args[i+5] / RATIO);
                }
                i += 6;
 
                curve = b2Bezier.parseCurve([currentPosition, control1, control2, control3], resolution);
                curve.shift(); // the first point is redundant, "currentPosition" is already added.
                chainDef.vertices = chainDef.vertices.concat(curve);
 
                currentPosition = control3;
              } while (!isNaN(parseFloat(args[i])));
 
              prevControl = control2;
              break;
            case "S":
            case "s":
              // shorthand curveto
              relative = (command == "s");
              do
              {
                if (prevCommand == "C" || prevCommand == "c" || prevCommand == "S" || prevCommand == "s")
                {
                  control1 = new b2Vec2(currentPosition.x*2 - prevControl.x,
                                        currentPosition.y*2 - prevControl.y);
                } else {
                  control1 = new b2Vec2(currentPosition.x,
                                        currentPosition.y);
                }
                if (relative) {
                  control2 = new b2Vec2(currentPosition.x + args[i] / RATIO,
                                        currentPosition.y + args[i+1] / RATIO);
                  control3 = new b2Vec2(currentPosition.x + args[i+2] / RATIO,
                                        currentPosition.y + args[i+3] / RATIO);
                } else {
                  control2 = new b2Vec2(args[i] / RATIO, args[i+1] / RATIO);
                  control3 = new b2Vec2(args[i+2] / RATIO, args[i+3] / RATIO);
                }
                i += 4;
 
                curve = b2Bezier.parseCurve([currentPosition, control1, control2, control3], resolution);
                curve.shift(); // the first point is redundant, "currentPosition" is already added.
                chainDef.vertices = chainDef.vertices.concat(curve);
 
                currentPosition = control3;
                prevControl = control2;
                prevCommand = command;
 
              } while (!isNaN(parseFloat(args[i])));
 
              break;
            case "Q":
            case "q":
            case "T":
            case "t":
            case "A":
            case "a":
              throw new Error("TODO: Unimplemented path command: " + command);
              break;
          }
          prevCommand = command;
        }
      }
	  return shapes;
    }
 
    private static function filterEmptyString(item: *, index: int, array: Array): Boolean {
      return item != "";
    }
 
    public static function returnStrokeWidth(pathS:String):Number
    {
      var bar:Array;
      bar = (pathS.replace("px", "")).split(";"); //get rid of px in line-width and split
      return Number(bar[3].slice(13, bar[3].length));
    }
 
  }
 
}

package  
{
	import Box2D.Common.Math.b2Vec2;
 
	/** 
	 * ...This class accepts an Array of four b2vec2s (corresponding to the SVG format of Bezier curves) and outputs an array of b2vec2s
	 * The returned array contains all of the points that should be declared in an edgeChain version of the curve
	 * This is a Flash port of the C++ version at http://www.box2d.org/forum/viewtopic.php?p=9865#p9865
	 * The math for transforming a Bezien curve is found at http://www.niksula.cs.hut.fi/~hkankaan/Homepages/bezierfast.html
	 * Thanks to Shaktool off the Box2D forums for the help
	 * 
	 * Quest Yarbrough/Ezion <www.ezqueststudios.com>
	 */
	public class b2Bezier 
	{
 
		//Resolution is the number of lines to segment the curve into
		//cPoints must be structured like below.
		//cPoints[0] = starting point
		//cPoints[1] = starting point control point
		//cPoints[2] = end point control point
		//cPoints[3] = end point
 
		public static function parseCurve(cPoints:Array, resolution:Number) 
		{
			if (resolution == 0) {
				return null;
			}
 
			var f:b2Vec2, fd:b2Vec2, fdd:b2Vec2, fddd:b2Vec2, fdd_per_2:b2Vec2, fddd_per_2:b2Vec2, fddd_per_6:b2Vec2;
			f = new b2Vec2(); fd = new b2Vec2(); fdd = new b2Vec2(); fddd = new b2Vec2();
			fdd_per_2 = new b2Vec2(); fddd_per_2 = new b2Vec2(); fddd_per_6 = new b2Vec2();
 
			var t:Number = 1.0 / resolution;
			var t2:Number = t * t;
 
			//I've tried to optimize the amount of
			//multiplications here, but these are exactly
			//the same formulas that were derived earlier
			//for f(0), f'(0)*t etc.
 
			f.x = cPoints[0].x;
			f.y = cPoints[0].y;
 
			fd.x = 3.0 * t * (cPoints[1].x - cPoints[0].x);
			fd.y = 3.0 * t * (cPoints[1].y - cPoints[0].y);
 
			fdd_per_2.x = 3.0 * t2 * (cPoints[0].x - 2.0 * cPoints[1].x + cPoints[2].x);
			fdd_per_2.y = 3.0 * t2 * (cPoints[0].y - 2.0 * cPoints[1].y + cPoints[2].y);
 
			fddd_per_2.x = 3.0 * t2 * t * (3.0 * (cPoints[1].x - cPoints[2].x) + cPoints[3].x - cPoints[0].x);
			fddd_per_2.y = 3.0 * t2 * t * (3.0 * (cPoints[1].y - cPoints[2].y) + cPoints[3].y - cPoints[0].y);
 
			fddd.x = fddd_per_2.x + fddd_per_2.x;
			fddd.y = fddd_per_2.y + fddd_per_2.y;
 
			fdd.x = fdd_per_2.x + fdd_per_2.x;
			fdd.y = fdd_per_2.y + fdd_per_2.y;
 
			fddd_per_6.x = (1.0 / 3) * fddd_per_2.x;
			fddd_per_6.y = (1.0 / 3) * fddd_per_2.y;
 
			var ret:Array = new Array(resolution);
 
			if (!ret) {
				return null;
			}
 
			for (var loop = 0; loop < resolution - 1; loop += 1) {
				ret[loop] = new b2Vec2();
				ret[loop].x = f.x;
				ret[loop].y = f.y;
 
				f.x = f.x + fd.x + fdd_per_2.x + fddd_per_6.x;
				f.y = f.y + fd.y + fdd_per_2.y + fddd_per_6.y;
 
				fd.x = fd.x + fdd.x + fddd_per_2.x;
				fd.y = fd.y + fdd.y + fddd_per_2.y;
 
				fdd.x = fdd.x + fddd.x;
				fdd.y = fdd.y + fddd.y;
 
				fdd_per_2.x = fdd_per_2.x + fddd_per_2.x;
				fdd_per_2.y = fdd_per_2.y + fddd_per_2.y;
			}
 
			ret[ret.length - 1] = new b2Vec2(cPoints[3].x, cPoints[3].y); //last vertice not added by C++ version
 
			return ret;
		}
 
	}
 
}