WIP: Handle buffer change events correctly with respect to folded lines

We're handling changes that straddle the start row and are in the middle of the fold, but we're still screwing up when the old range straddles the end row.

src/app/fold.coffee

@@ -15,18 +15,19 @@ class Fold
   destroy: ->
     @renderer.destroyFold(this)
 
+  inspect: ->
+    "Fold(#{@startRow}, #{@endRow})"
+
   getBufferDelta: ->
     new Point(@endRow - @startRow + 1, 0)
 
   handleBufferChange: (event) ->
     oldStartRow = @startRow
 
-    { oldRange } = event
-    if oldRange.start.row <= @startRow and oldRange.end.row >= @endRow
-      @renderer.unregisterFold(oldStartRow, this)
+    if @isContainedByRange(event.oldRange)
+      @renderer.unregisterFold(@startRow, this)
       return
 
-    changeInsideFold = @startRow <= oldRange.start.row and @endRow >= oldRange.end.row
     @updateStartRow(event)
     @updateEndRow(event)
 
@@ -34,18 +35,34 @@ class Fold
       @renderer.unregisterFold(oldStartRow, this)
       @renderer.registerFold(@startRow, this)
 
-    changeInsideFold
+  isContainedByRange: (range) ->
+    range.start.row <= @startRow and @endRow <= range.end.row
 
   updateStartRow: (event) ->
     { newRange, oldRange } = event
-    return if oldRange.start.row >= @startRow
 
-    deltaFromOldRangeEndRow = @startRow - oldRange.end.row
-    @startRow = newRange.end.row + deltaFromOldRangeEndRow
+    if oldRange.end.row < @startRow
+      delta = newRange.end.row - oldRange.end.row
+    else if newRange.end.row < @startRow
+      delta = newRange.end.row - @startRow
+    else
+      delta = 0
+
+    console.log "start row delta", delta
+
+    @startRow += delta
 
   updateEndRow: (event) ->
     { newRange, oldRange } = event
-    return if oldRange.start.row > @endRow
 
-    deltaFromOldRangeEndRow = @endRow - oldRange.end.row
-    @endRow = newRange.end.row + deltaFromOldRangeEndRow
+    if oldRange.end.row <= @endRow
+      delta = newRange.end.row - oldRange.end.row
+    else if newRange.end.row <= @endRow
+      console.log "newRange.end.row", newRange.end.row, " - @endRow", @endRow
+      delta = newRange.end.row - @endRow
+    else
+      delta = 0
+
+    console.log "end row delta", delta
+
+    @endRow += delta

src/app/renderer.coffee

@@ -111,12 +111,15 @@ class Renderer
     @handleHighlighterChange(@lastHighlighterChangeEvent)
 
   handleHighlighterChange: (e) ->
-    { oldRange, newRange } = e
+    oldRange = @bufferRangeForScreenRange(@screenRangeForBufferRange(e.oldRange.copy()))
+    newRange = @bufferRangeForScreenRange(@screenRangeForBufferRange(e.newRange.copy()))
 
     oldScreenRange = @screenLineRangeForBufferRange(oldRange)
+
     newScreenLines = @buildLinesForBufferRows(newRange.start.row, newRange.end.row)
     @lineMap.replaceScreenRows oldScreenRange.start.row, oldScreenRange.end.row, newScreenLines
     newScreenRange = @screenLineRangeForBufferRange(newRange)
+    console.log "New Screen Range", newScreenRange.inspect()
 
     @trigger 'change', { oldRange: oldScreenRange, newRange: newScreenRange, bufferChanged: true }
 
@@ -176,6 +179,7 @@ class Renderer
     @foldsById[fold.id] = fold
 
   unregisterFold: (bufferRow, fold) ->
+    console.log "unregistering fold", fold.id
     folds = @activeFolds[bufferRow]
     _.remove(folds, fold)
     delete @foldsById[fold.id]