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}} ;
}