/**
* Cornerz 0.6 - Bullet Proof Corners
* Jonah Fox (jonah@parkerfox.co.uk) 2008
*
* Usage: $('.myclass').curve(options)
* options is a hash with the following parameters. Bracketed is the default
*   radius (10)
*   borderWidth (read from BorderTopWidth or 0)
*   background ("white"). Note that this is not calculated from the HTML as it is expensive
*   borderColor (read from BorderTopColor)
*   corners ("tl br tr bl"). Specify which borders
*   fixIE ("padding") - attmepts to fix IE by incrementing the property by 1 if the outer width/height is odd.

CHANGELIST from  v0.4

0.5 - Now attempts to fix the odd dimension problem in IE
0.6 - Added semicolons for packing and fixed a problem with odd border width's in IE

*/

;(function($){

  if($.browser.msie && document.namespaces["v"] == null) {
    document.namespaces.add("v", "urn:schemas-microsoft-com:vml");
    var ss = document.createStyleSheet().owningElement;
    ss.styleSheet.cssText = "v\\:*{behavior:url(#default#VML);}"
  }

  $.fn.cornerz = function(options){

    function canvasCorner(t,l, r,bw,bc,bg){
            var sa,ea,cw,sx,sy,x,y, p = 1.57, css="position:absolute;";
            if(t)
                    {sa=-p; sy=r; y=0; css+="top:-"+bw+"px;";  }
            else
                    {sa=p; sy=0; y=r; css+="bottom:-"+bw+"px;"; }
            if(l)
                    {ea=p*2; sx=r; x=0;        css+="left:-"+bw+"px;"}
            else
                    {ea=0; sx=0; x=r; css+="right:-"+bw+"px;";        }

            var canvas=$("<canvas width="+r+"px height="+ r +"px style='" + css+"' ></canvas>");
            var ctx=canvas[0].getContext('2d');
            ctx.beginPath();
            ctx.lineWidth=bw*2;
            ctx.arc(sx,sy,r,sa,ea,!(t^l));
            ctx.strokeStyle=bc;
            ctx.stroke();
            ctx.lineWidth = 0;
            ctx.lineTo(x,y);
            ctx.fillStyle=bg;
            ctx.fill();
            return canvas;
    };

    function canvasCorners(corners, r, bw,bc,bg) {
            var hh = $("<div style='display: inherit' />"); // trying out style='float:left'
            $.each(corners.split(" "), function() {
              hh.append(canvasCorner(this[0]=="t",this[1]=="l", r,bw,bc,bg));
            });
            return hh;
    };

    function vmlCurve(r,b,c,m,ml,mt, right_fix) {
        var l = m-ml-right_fix;
        var t = m-mt;
        return "<v:arc filled='False' strokeweight='"+b+"px' strokecolor='"+c+"' startangle='0' endangle='361' style=' top:" + t +"px;left: "+ l + ";width:" + r+ "px; height:" + r+ "px' />";
    }


    function vmlCorners(corners, r, bw, bc, bg, w) {
      var h ="<div style='text-align:left; '>";
      $.each($.trim(corners).split(" "), function() {
        var css,ml=1,mt=1,right_fix=0;
        if(this.charAt(0)=="t") {
          css="top:-"+bw+"px;";
        }
        else {
          css= "bottom:-"+bw+"px;";
          mt=r+1;
        }
        if(this.charAt(1)=="l")
          css+="left:-"+bw+"px;";
        else {
          css +="right:-"+(bw)+"px; "; // odd width gives wrong margin?
           ml=r;
           right_fix = 1;
        }

        h+="<div style='"+css+"; position: absolute; overflow:hidden; width:"+ r +"px; height: " + r + "px;'>";
        h+= "<v:group  style='width:1000px;height:1000px;position:absolute;' coordsize='1000,1000' >";
        h+= vmlCurve(r*3,r+bw,bg, -r/2,ml,mt,right_fix);
        if(bw>0)
          h+= vmlCurve(r*2-bw,bw,bc, Math.floor(bw/2+0.5),ml,mt,right_fix);
        h+="</v:group>";
        h+= "</div>";
      });
      h += "</div>";

      return h;
    };

    var settings = {
      corners : "tl tr bl br",
      radius : 10,
      background: "white",
      borderWidth: 0,
      fixIE: true };
    $.extend(settings, options || {});

    var incrementProperty = function(elem, prop, x) {
      var y = parseInt(elem.css(prop)) || 0 ;
      elem.css(prop, x+y);
    }


    return this.each(function() {

      var $$ = $(this);
      var r = settings.radius*1.0;
      var bw = (settings.borderWidth || parseInt($$.css("borderTopWidth")) || 0)*1.0;
      var bg = settings.background;
      var bc = settings.borderColor;
      bc = bc || ( bw > 0 ? $$.css("borderTopColor") : bg);

      var cs = settings.corners;

      if($.browser.msie) {//need to use innerHTML rather than jQuery
        h = vmlCorners(cs,r,bw,bc,bg, $(this).width() );
        this.innerHTML += h;

      }
      else  //canvasCorners returns a DOM element
        $$.append(canvasCorners(cs,r,bw,bc,bg));


      if(this.style.position != "absolute")
        this.style.position = "relative";

       this.style.zoom = 1; // give it a layout in IE

       if($.browser.msie && settings.fixIE) {
          var ow = $$.outerWidth();
          var oh = $$.outerHeight();

          if(ow%2 == 1) {
            incrementProperty($$, "padding-right", 1);
            incrementProperty($$, "margin-right", 1);
          }

          if(oh%2 == 1) {
            incrementProperty($$, "padding-bottom", 1);
            incrementProperty($$, "margin-bottom", 1);
          }
        }

      }

    );

  }
})(jQuery);