Initial commit, added all backend files

web/dart/theme.dart

@@ -0,0 +1,53 @@
+import 'dart:html';
+
+class Theme {
+  String _name;
+  String _icon;
+
+  Theme(String t_name, String t_icon) {
+    _name = t_name;
+    _icon = t_icon;
+  }
+
+  String getIcon() => _icon;
+  String getName() => _name;
+}
+
+final themes = {
+  'light': Theme('light', 'fa-sun'),
+  'dark': Theme('dark', 'fa-lightbulb'),
+  'black': Theme('black', 'fa-moon')
+};
+
+final localStorage = window.localStorage;
+
+var currentTheme = themes[localStorage['theme']];
+
+void enableThemeChanger() {
+  final darkBtn = querySelector('#darkBtn');
+  final lightBtn = querySelector('#lightBtn');
+  final blackBtn = querySelector('#blackBtn');
+
+  lightBtn.onClick.listen((_) => switchTheme(themes['light']));
+  darkBtn.onClick.listen((_) => switchTheme(themes['dark']));
+  blackBtn.onClick.listen((_) => switchTheme(themes['black']));
+}
+
+Future<void> setTheme() async {
+  if (currentTheme == null) {
+    currentTheme = themes['light'];
+    localStorage['theme'] = currentTheme.getName();
+  }
+  querySelector('body')
+    ..classes.clear()
+    ..classes.add(currentTheme.getName());
+}
+
+void switchTheme(Theme currentTheme) {
+  // Set HTML theme
+  querySelector('body')
+    ..classes.clear()
+    ..classes.add(currentTheme.getName());
+  // Set storage theme
+  localStorage['theme'] = currentTheme.getName();
+}