[feature] Enable UI-customizable message layout

.hound.yml

@@ -2,3 +2,5 @@ ruby:
   config_file: .rubocop.yml
 haml:
   config_file: .haml-lint.yml
+eslint:
+  enabled: false

.rubocop-shared.yml

@@ -60,6 +60,9 @@ Style/IfUnlessModifier:
 Style/StringLiterals:
   Enabled: false
 
+Style/TrailingCommaInArguments:
+  Enabled: false
+
 TrailingCommaInHashLiteral:
   Enabled: false
 

Gemfile

@@ -118,6 +118,7 @@ group :test do
   gem 'codeclimate-test-reporter', '~> 0.6.0', require: nil
   gem 'rails-controller-testing' # Rails 4 fallback
   gem 'webmock', '~> 3.4'
+  gem 'timecop'
 
   # Adds support for Capybara system testing and selenium driver
   gem 'capybara', '>= 2.15'

Gemfile.lock

@@ -414,6 +414,7 @@ GEM
     thor (0.20.3)
     thread_safe (0.3.6)
     tilt (2.0.9)
+    timecop (0.9.1)
     turbolinks (5.2.0)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
@@ -505,6 +506,7 @@ DEPENDENCIES
   sprockets
   strip_attributes
   test-unit (~> 3.0)
+  timecop
   turbolinks (~> 5)
   uglifier (>= 1.3.0)
   valid_attribute

app/assets/javascripts/manage/application.js

@@ -3,6 +3,10 @@
 //= require popper
 //= require bootstrap
 //= require ../vendor/datatables.min
+//= require ../vendor/codemirror
+//= require ../vendor/codemirror-modes/htmlmixed
+//= require ../vendor/codemirror-modes/xml
+//= require ../vendor/codemirror-modes/css
 //= require selectize
 //= require_directory ./lib
 
@@ -18,6 +22,7 @@ function applicationReady() {
   setupSimpleMde();
   setupEmailEvents();
   setupManageForms();
+  setupCodeMirror();
 
   $.ajaxSetup({
     beforeSend: function(xhr) {

app/assets/javascripts/manage/lib/codeMirror.js

@@ -0,0 +1,9 @@
+function setupCodeMirror() {
+  $('[data-code-mirror-textarea]').each(function(i, element) {
+    var myCodeMirror = CodeMirror.fromTextArea(element, {
+      lineNumbers: true,
+      mode: 'htmlmixed',
+    });
+    myCodeMirror.setSize(null, window.innerHeight - 200);
+  });
+}