absolute ridiculousness

ridiculous.js

function getSelection()
  {
    // returns null, or a structure containing startPoint and endPoint,
    // each of which has node (a magicdom node), index, and maxIndex.  If the node
    // is a text node, maxIndex is the length of the text; else maxIndex is 1.
    // index is between 0 and maxIndex, inclusive.
    if (browser.msie)
    {
      var browserSelection;
      try
      {
        browserSelection = doc.selection;
      }
      catch (e)
      {}
      if (!browserSelection) return null;
      var origSelectionRange;
      try
      {
        origSelectionRange = browserSelection.createRange();
      }
      catch (e)
      {}
      if (!origSelectionRange) return null;
      var selectionParent = origSelectionRange.parentElement();
      if (selectionParent.ownerDocument != doc) return null;

      var newRange = function()
      {
        return doc.body.createTextRange();
      };

      var rangeForElementNode = function(nd)
      {
        var rng = newRange();
        // doesn't work on text nodes
        rng.moveToElementText(nd);
        return rng;
      };

      var pointFromCollapsedRange = function(rng)
      {
        var parNode = rng.parentElement();
        var elemBelow = -1;
        var elemAbove = parNode.childNodes.length;
        var rangeWithin = rangeForElementNode(parNode);

        if (rng.compareEndPoints("StartToStart", rangeWithin) === 0)
        {
          return {
            node: parNode,
            index: 0,
            maxIndex: 1
          };
        }
        else if (rng.compareEndPoints("EndToEnd", rangeWithin) === 0)
        {
          if (isBlockElement(parNode) && parNode.nextSibling)
          {
            // caret after block is not consistent across browsers
            // (same line vs next) so put caret before next node
            return {
              node: parNode.nextSibling,
              index: 0,
              maxIndex: 1
            };
          }
          return {
            node: parNode,
            index: 1,
            maxIndex: 1
          };
        }
        else if (parNode.childNodes.length === 0)
        {
          return {
            node: parNode,
            index: 0,
            maxIndex: 1
          };
        }

        for (var i = 0; i < parNode.childNodes.length; i++)
        {
          var n = parNode.childNodes.item(i);
          if (!isNodeText(n))
          {
            var nodeRange = rangeForElementNode(n);
            var startComp = rng.compareEndPoints("StartToStart", nodeRange);
            var endComp = rng.compareEndPoints("EndToEnd", nodeRange);
            if (startComp >= 0 && endComp <= 0)
            {
              var index = 0;
              if (startComp > 0)
              {
                index = 1;
              }
              return {
                node: n,
                index: index,
                maxIndex: 1
              };
            }
            else if (endComp > 0)
            {
              if (i > elemBelow)
              {
                elemBelow = i;
                rangeWithin.setEndPoint("StartToEnd", nodeRange);
              }
            }
            else if (startComp < 0)
            {
              if (i < elemAbove)
              {
                elemAbove = i;
                rangeWithin.setEndPoint("EndToStart", nodeRange);
              }
            }
          }
        }
        if ((elemAbove - elemBelow) == 1)
        {
          if (elemBelow >= 0)
          {
            return {
              node: parNode.childNodes.item(elemBelow),
              index: 1,
              maxIndex: 1
            };
          }
          else
          {
            return {
              node: parNode.childNodes.item(elemAbove),
              index: 0,
              maxIndex: 1
            };
          }
        }
        var idx = 0;
        var r = rng.duplicate();
        // infinite stateful binary search! call function for values 0 to inf,
        // expecting the answer to be about 40.  return index of smallest
        // true value.
        var indexIntoRange = binarySearchInfinite(40, function(i)
        {
          // the search algorithm whips the caret back and forth,
          // though it has to be moved relatively and may hit
          // the end of the buffer
          var delta = i - idx;
          var moved = Math.abs(r.move("character", -delta));
          // next line is work-around for fact that when moving left, the beginning
          // of a text node is considered to be after the start of the parent element:
          if (r.move("character", -1)) r.move("character", 1);
          if (delta < 0) idx -= moved;
          else idx += moved;
          return (r.compareEndPoints("StartToStart", rangeWithin) <= 0);
        });
        // iterate over consecutive text nodes, point is in one of them
        var textNode = elemBelow + 1;
        var indexLeft = indexIntoRange;
        while (textNode < elemAbove)
        {
          var tn = parNode.childNodes.item(textNode);
          if (indexLeft <= tn.nodeValue.length)
          {
            return {
              node: tn,
              index: indexLeft,
              maxIndex: tn.nodeValue.length
            };
          }
          indexLeft -= tn.nodeValue.length;
          textNode++;
        }
        var tn = parNode.childNodes.item(textNode - 1);
        return {
          node: tn,
          index: tn.nodeValue.length,
          maxIndex: tn.nodeValue.length
        };
      };

      var selection = {};
      if (origSelectionRange.compareEndPoints("StartToEnd", origSelectionRange) === 0)
      {
        // collapsed
        var pnt = pointFromCollapsedRange(origSelectionRange);
        selection.startPoint = pnt;
        selection.endPoint = {
          node: pnt.node,
          index: pnt.index,
          maxIndex: pnt.maxIndex
        };
      }
      else
      {
        var start = origSelectionRange.duplicate();
        start.collapse(true);
        var end = origSelectionRange.duplicate();
        end.collapse(false);
        selection.startPoint = pointFromCollapsedRange(start);
        selection.endPoint = pointFromCollapsedRange(end);
/*if ((!selection.startPoint.node.isText) && (!selection.endPoint.node.isText)) {
  console.log(selection.startPoint.node.uniqueId()+","+
    selection.startPoint.index+" / "+
    selection.endPoint.node.uniqueId()+","+
    selection.endPoint.index);
	}*/
      }
      return selection;
    }
    else
    {
      // non-IE browser
      var browserSelection = window.getSelection();
      if (browserSelection && browserSelection.type != "None" && browserSelection.rangeCount !== 0)
      {
        var range = browserSelection.getRangeAt(0);

        function isInBody(n)
        {
          while (n && !(n.tagName && n.tagName.toLowerCase() == "body"))
          {
            n = n.parentNode;
          }
          return !!n;
        }

        function pointFromRangeBound(container, offset)
        {
          if (!isInBody(container))
          {
            // command-click in Firefox selects whole document, HEAD and BODY!
            return {
              node: root,
              index: 0,
              maxIndex: 1
            };
          }
          var n = container;
          var childCount = n.childNodes.length;
          if (isNodeText(n))
          {
            return {
              node: n,
              index: offset,
              maxIndex: n.nodeValue.length
            };
          }
          else if (childCount === 0)
          {
            return {
              node: n,
              index: 0,
              maxIndex: 1
            };
          }
          // treat point between two nodes as BEFORE the second (rather than after the first)
          // if possible; this way point at end of a line block-element is treated as
          // at beginning of next line
          else if (offset == childCount)
          {
            var nd = n.childNodes.item(childCount - 1);
            var max = nodeMaxIndex(nd);
            return {
              node: nd,
              index: max,
              maxIndex: max
            };
          }
          else
          {
            var nd = n.childNodes.item(offset);
            var max = nodeMaxIndex(nd);
            return {
              node: nd,
              index: 0,
              maxIndex: max
            };
          }
        }
        var selection = {};
        selection.startPoint = pointFromRangeBound(range.startContainer, range.startOffset);
        selection.endPoint = pointFromRangeBound(range.endContainer, range.endOffset);
        selection.focusAtStart = (((range.startContainer != range.endContainer) || (range.startOffset != range.endOffset)) && browserSelection.anchorNode && (browserSelection.anchorNode == range.endContainer) && (browserSelection.anchorOffset == range.endOffset));

        if(selection.startPoint.node.ownerDocument !== window.document){
          return null;
        }

        return selection;
      }
      else return null;
    }
  }