use ace modelist extension to auto-detect mode

services/web/app/views/project/editor/editor.jade

@@ -35,7 +35,8 @@ div.full-size(
 			resize-on="layout:main:resize,layout:pdf:resize",
 			annotations="pdf.logEntryAnnotations[editor.open_doc_id]",
 			read-only="!permissions.write",
-			on-ctrl-enter="recompileViaKey"
+			file-name="editor.open_doc_name",
+			on-ctrl-enter="recompileViaKey",
 			syntax-validation="settings.syntaxValidation"
 		)
 

services/web/public/coffee/ide/editor/EditorManager.coffee

@@ -8,6 +8,7 @@ define [
 			@$scope.editor = {
 				sharejs_doc: null
 				open_doc_id: null
+				open_doc_name: null
 				opening: true
 			}
 
@@ -59,6 +60,7 @@ define [
 				return
 
 			@$scope.editor.open_doc_id = doc.id
+			@$scope.editor.open_doc_name = doc.name
 
 			@ide.localStorage "doc.open_id.#{@$scope.project_id}", doc.id
 			@ide.fileTreeManager.selectEntity(doc)

services/web/public/coffee/ide/editor/directives/aceEditor.coffee

@@ -2,14 +2,16 @@ define [
 	"base"
 	"ace/ace"
 	"ace/ext-searchbox"
+	"ace/ext-modelist"
 	"ide/editor/directives/aceEditor/undo/UndoManager"
 	"ide/editor/directives/aceEditor/auto-complete/AutoCompleteManager"
 	"ide/editor/directives/aceEditor/spell-check/SpellCheckManager"
 	"ide/editor/directives/aceEditor/highlights/HighlightsManager"
 	"ide/editor/directives/aceEditor/cursor-position/CursorPositionManager"
 	"ide/editor/directives/aceEditor/track-changes/TrackChangesManager"
-], (App, Ace, SearchBox, UndoManager, AutoCompleteManager, SpellCheckManager, HighlightsManager, CursorPositionManager, TrackChangesManager) ->
+], (App, Ace, SearchBox, ModeList, UndoManager, AutoCompleteManager, SpellCheckManager, HighlightsManager, CursorPositionManager, TrackChangesManager) ->
 	EditSession = ace.require('ace/edit_session').EditSession
+	ModeList = ace.require('ace/ext/modelist')
 
 	# set the path for ace workers if using a CDN (from editor.jade)
 	if window.aceWorkerPath != ""
@@ -42,7 +44,8 @@ define [
 				text: "="
 				readOnly: "="
 				annotations: "="
-				navigateHighlights: "=",
+				navigateHighlights: "="
+				fileName: "="
 				onCtrlEnter: "="
 				syntaxValidation: "="
 			}
@@ -221,8 +224,16 @@ define [
 					session = editor.getSession()
 					if session?
 						session.destroy()
-					editor.setSession(new EditSession(lines, "ace/mode/latex"))
-					resetSession()
+
+					# see if we can lookup a suitable mode from ace
+					# but fall back to text by default
+					try
+						mode = ModeList.getModeForPath(scope.fileName).mode
+					catch
+						mode = "ace/mode/text"
+
+					editor.setSession(new EditSession(lines, mode))
+
 					session = editor.getSession()
 
 					doc = session.getDocument()