Base the screen range of the selection view on the selection model

spec/app/selection-spec.coffee

@@ -17,8 +17,8 @@ describe "Selection", ->
     it "places the anchor at the start of the range and the cursor at the end", ->
       range = new Range({row: 2, column: 7}, {row: 3, column: 18})
       selection.setBufferRange(range)
-      expect(selection.anchor.getScreenPosition()).toEqual range.start
-      expect(selection.cursor.getScreenPosition()).toEqual range.end
+      expect(selection.selection.anchor.getScreenPosition()).toEqual range.start
+      expect(selection.selection.cursor.getScreenPosition()).toEqual range.end
 
   describe ".deleteSelectedText()", ->
     describe "when nothing is selected", ->

src/app/cursor-view.coffee

@@ -14,7 +14,6 @@ class CursorView extends View
   hidden: false
 
   initialize: (@cursor, @editor) ->
-
     @cursor.on 'change-screen-position', (position, options) =>
       @updateAppearance()
       unless options.bufferChange

src/app/edit-session.coffee

@@ -32,7 +32,8 @@ class EditSession
     @addCursorAtScreenPosition([0, 0])
 
     @buffer.on "change.edit-session-#{@id}", (e) =>
-      @moveCursors (cursor) -> cursor.handleBufferChange(e)
+      for selection in @getSelections()
+        selection.handleBufferChange(e)
 
     @renderer.on "change.edit-session-#{@id}", (e) =>
       @trigger 'screen-lines-change', e
@@ -107,7 +108,7 @@ class EditSession
     cursor
 
   addSelectionForCursor: (cursor) ->
-    selection = new Selection(cursor)
+    selection = new Selection(editSession: this, cursor: cursor)
     @selections.push(selection)
     @trigger 'add-selection', selection
     selection

src/app/selection-view.coffee

@@ -16,6 +16,9 @@ class SelectionView extends View
   initialize: ({@editor, @selection} = {}) ->
     @cursor = @selection.cursor
     @regions = []
+    @selection.view = this
+    @selection.on 'change-screen-range', =>
+      @updateAppearance()
 
   handleBufferChange: (e) ->
     return unless @anchor
@@ -28,17 +31,16 @@ class SelectionView extends View
     @anchor.setScreenPosition @cursor.getScreenPosition()
 
   isEmpty: ->
-    @getBufferRange().isEmpty()
+    @selection.isEmpty()
 
   isReversed: ->
-    not @isEmpty() and @cursor.getBufferPosition().isLessThan(@anchor.getBufferPosition())
+    @selection.isReversed()
 
   intersectsWith: (otherSelection) ->
     @getScreenRange().intersectsWith(otherSelection.getScreenRange())
 
   clearSelection: ->
-    @anchor = null
-    @updateAppearance()
+    @selection.clear()
 
   updateAppearance: ->
     return unless @cursor
@@ -60,7 +62,6 @@ class SelectionView extends View
         @appendRegion(rowSpan - 1, { row: range.start.row + 1, column: 0}, null)
       @appendRegion(1, { row: range.end.row, column: 0 }, range.end)
 
-
   appendRegion: (rows, start, end) ->
     { lineHeight, charWidth } = @editor
     css = @editor.pixelPositionForScreenPosition(start)
@@ -79,21 +80,13 @@ class SelectionView extends View
     @regions = []
 
   getScreenRange: ->
-    if @anchor
-      new Range(@anchor.getScreenPosition(), @cursor.getScreenPosition())
-    else
-      new Range(@cursor.getScreenPosition(), @cursor.getScreenPosition())
+    @selection.getScreenRange()
 
-  setScreenRange: (range, {reverse}={}) ->
-    range = Range.fromObject(range)
-    { start, end } = range
-    [start, end] = [end, start] if reverse
-
-    @cursor.setScreenPosition(start)
-    @modifySelection => @cursor.setScreenPosition(end)
+  setScreenRange: (range, options)->
+    @selection.setScreenRange(range, options)
 
   getBufferRange: ->
-    @editor.bufferRangeForScreenRange(@getScreenRange())
+    @selection.getBufferRange()
 
   setBufferRange: (bufferRange, options) ->
     @setScreenRange(@editor.screenRangeForBufferRange(bufferRange), options)
@@ -182,10 +175,7 @@ class SelectionView extends View
     super
 
   modifySelection: (fn) ->
-    @placeAnchor()
-    @retainSelection = true
-    fn()
-    @retainSelection = false
+    @selection.modifySelection(fn)
 
   selectWord: ->
     @setBufferRange(@cursor.getCurrentWordBufferRange())

src/app/selection.coffee

@@ -1,3 +1,69 @@
+Range = require 'range'
+Anchor = require 'new-anchor'
+EventEmitter = require 'event-emitter'
+_ = require 'underscore'
+
 module.exports =
 class Selection
-  constructor: (@cursor) ->
+  anchor: null
+
+  constructor: ({@cursor, @editSession}) ->
+    @cursor.on 'change-screen-position', (e) =>
+      @trigger 'change-screen-range', @getScreenRange() unless e.bufferChanged
+
+  getScreenRange: ->
+    if @anchor
+      new Range(@anchor.getScreenPosition(), @cursor.getScreenPosition())
+    else
+      new Range(@cursor.getScreenPosition(), @cursor.getScreenPosition())
+
+  setScreenRange: (screenRange, options={})->
+    screenRange = Range.fromObject(screenRange)
+    { start, end } = screenRange
+    [start, end] = [end, start] if options.reverse
+
+    @modifyScreenRange =>
+      @placeAnchor() unless @anchor
+      @modifySelection =>
+        @anchor.setScreenPosition(start)
+        @cursor.setScreenPosition(end)
+
+  getBufferRange: ->
+    if @anchor
+      new Range(@anchor.getBufferPosition(), @cursor.getBufferPosition())
+    else
+      new Range(@cursor.getBufferPosition(), @cursor.getBufferPosition())
+
+  clear: ->
+    @modifyScreenRange => @anchor = null
+
+  isEmpty: ->
+    @getBufferRange().isEmpty()
+
+  isReversed: ->
+    not @isEmpty() and @cursor.getBufferPosition().isLessThan(@anchor.getBufferPosition())
+
+  handleBufferChange: (e) ->
+    @modifyScreenRange =>
+      @anchor?.handleBufferChange(e)
+      @cursor.handleBufferChange(e)
+
+  modifySelection: (fn) ->
+    @retainSelection = true
+    @view?.retainSelection = true
+    @placeAnchor() unless @anchor
+    fn()
+    @retainSelection = false
+    @view?.retainSelection = false
+
+  modifyScreenRange: (fn) ->
+    oldScreenRange = @getScreenRange()
+    fn()
+    newScreenRange = @getScreenRange()
+    @trigger 'change-screen-range', newScreenRange unless oldScreenRange.isEqual(newScreenRange)
+
+  placeAnchor: ->
+    @anchor = new Anchor(@editSession)
+    @anchor.setScreenPosition(@cursor.getScreenPosition())
+
+_.extend Selection.prototype, EventEmitter