getWrapperAncestor = function(elt) {

	var parent = elt ;

	while (parent != null) {

    	if (CY.DOM.hasClass(parent, 'c-s')) 

    		return parent ;

    	parent = parent.parentNode ;

	}

	return null ; 

}

hasWrapperAncestor = function(elt) {

	return (getWrapperAncestor(elt) != null) ;

/*	var parent = elt ;

	while (parent != null) {

    	if (CY.DOM.hasClass(parent, 'c-s')) 

    		return true ;

    	parent = parent.parentNode ;

	}

	return false ;*/ 

}

// returns null or :

// {'text' : textcontent, 'start': {'elt':startNode, 'nbChar':startOffset(==number of characters to selection start in the start node},

// 'end': ....}

// the text attribute is informational having it empty doesn't mean selection is empty !!

// when selection starts/ends in/on a non textual element (<hr/> for example) we very often have anchorNode/focusNode == body elt

// TODO adapt this body case by considering offset ( cf. http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html)

getSelectionInfo  = function () {

	var startNode = null, endNode = null, startOffset = 0, endOffset = 0, text = '' ;

	if (window.getSelection) { // everything else than IE

		var userSelection = window.getSelection();

		if (userSelection.rangeCount > 0) {

			var range = userSelection.getRangeAt(0) ;

			text = range.toString() ;

			if (text != "")  {

				// selection occured from right to left ? :

				var r1 = document.createRange() ;r1.setStart(userSelection.anchorNode, userSelection.anchorOffset) ;r1.collapse(true) ;

				var r2 = document.createRange() ;r2.setEnd(userSelection.focusNode, userSelection.focusOffset) ;r2.collapse(false) ;

				var leftToRight = (r2.compareBoundaryPoints(2, r1) == 1) ; // 2 is for END_TO_END

//				CY.log("leftToRight : " + leftToRight) ;

				startNode = (leftToRight) ? userSelection.anchorNode.parentNode : userSelection.focusNode.parentNode ;  

				innerStartNode = (leftToRight) ? userSelection.anchorNode : userSelection.focusNode ;

				endNode = (leftToRight) ? userSelection.focusNode.parentNode : userSelection.anchorNode.parentNode;

				innerEndNode = (leftToRight) ? userSelection.focusNode : userSelection.anchorNode;

				startOffset = (leftToRight) ? userSelection.anchorOffset : userSelection.focusOffset;

				endOffset = (leftToRight) ? userSelection.focusOffset : userSelection.anchorOffset ;

				if (!hasWrapperAncestor(endNode) && hasWrapperAncestor(startNode)){

					var r3 = document.createRange() ;

					r3.setStart(innerStartNode, startOffset) ;

					var csStartAncestor = getWrapperAncestor(startNode) ;

					var next = csStartAncestor ;

					r3.setEndAfter(next) ;

					var ind = parseInt(csStartAncestor.id.substring('sv_'.length)) ;

					while(r3.toString().length < range.toString().length) {

							ind++ ;

							var node = CY.get("#sv_"+ind) ;

							if (node) {

								next = CY.Node.getDOMNode(node) ;

								r3.setEndAfter(next) ;

							}

							else 

								break ;

					}

					endNode = next.lastChild ;

					endOffset = CY.DOM.getText(endNode).length ;

				}

				else if (!hasWrapperAncestor(startNode) && hasWrapperAncestor(endNode)){

					var r3 = document.createRange() ;

					r3.setEnd(innerEndNode, endOffset) ;

					var csEndAncestor = getWrapperAncestor(endNode) ;

					var prev = csEndAncestor ;

					r3.setStartBefore(prev) ;

					var ind = parseInt(csEndAncestor.id.substring('sv_'.length)) ;

					while(r3.toString().length < range.toString().length) {

							ind-- ;

							var node = CY.get("#sv_"+ind) ;

							if (node) {

								prev = CY.Node.getDOMNode(node) ;

								r3.setStartBefore(prev) ;

							}

							else 

								break ;

					}

					startNode = prev.firstChild ;

					startOffset = 0 ;

				}

				else if (!hasWrapperAncestor(startNode) && !hasWrapperAncestor(endNode)){

					var textLength = text.length ;

					// gather nodes with id sv_xxxx as candidates for start ancestor

					var startNodeInds = [] ;

					for (var ind = 0 ;  ; ind++) {

						var svNode = CY.get("#sv_"+ind) ;

						if (svNode == null) {

							break;

						}

						else {

							var svText = svNode.get("text") ;

							if (text.indexOf(svText) == 0) {

								startNodeInds.push(ind) ;

							}

						}

					}

					// gather nodes with id sv_xxxx as candidates for end ancestor

					var endNodeInds = [] ;

					for (var ind = 0 ;  ; ind++) {

						var svNode = CY.get("#sv_"+ind) ;

						if (svNode == null) {

							break;

						}

						else {

							var svText = svNode.get("text") ;

							if (text.indexOf(svText) == (textLength - svText.length)) { // i.e. the selection exactly ends with svText

								endNodeInds.push(ind) ;

							}

						}

					}

					var stop = false ;

					for (var i = 0 ; i < startNodeInds.length ; i++) {

						for (var j = 0 ; j < endNodeInds.length ; j++) {

							var r4 = document.createRange() ;

							var s = CY.Node.getDOMNode(CY.get("#sv_"+startNodeInds[i])) ; var e = CY.Node.getDOMNode(CY.get("#sv_"+endNodeInds[j])) ;

							r4.setStartBefore(s) ; r4.setEndAfter(CY.Node.getDOMNode(e)) ;

							// does r4 starts after range start and r4 ends before range end ? 

							if ((-1 < r4.compareBoundaryPoints(0, range)) && (1 > r4.compareBoundaryPoints(2, range))) { 

								startNode = s.firstChild ;

								startOffset = 0 ;

								endNode = e.lastChild ;

								endOffset = CY.DOM.getText(e).length ;

								stop = true ; 

								break ;

							}

						}

						if (stop)

							break ;

					}							

				}				

				r1.detach() ;

				r2.detach() ;

			}

			else 

				return null ;

		}

		else 

			return null ;

	}

	else if (document.selection) { // IE case

		var rng = document.selection.createRange();

		if (rng.text.length == 0) 

			return null ;

		var el = rng.parentElement();

		// duplicate the range and collapse it to its start, to ask IE the parent element of the start textNode.		

		var rngStart = rng.duplicate();

		var rngEnd = rng.duplicate();

		rngStart.collapse(true); // collapse to start

		rngEnd.collapse(false);  // collapse to end

		startNode = rngStart.parentElement() ;

		while(rngStart.moveStart('character', -1) != 0) {

			if (rngStart.parentElement() != startNode)

				break ;

			startOffset++ ;

		}

		endNode = rngEnd.parentElement() ;

		while(rngEnd.moveEnd('character', -1) != 0) {

			if (rngEnd.parentElement() != endNode)

				break ;

			endOffset++ ;

		}

		text = rng.text ;

	}

	if (!hasWrapperAncestor(startNode) || !hasWrapperAncestor(endNode)){

		// CY.log('no wrapper on one end') ;

		return null ;

	}

	return {'text' : text, 'start' : {'elt':startNode, 'offset':startOffset}, 'end' : {'elt':endNode, 'offset':endOffset}} ;

}