add basic system theme option

psst-gui/src/data/config.rs

@@ -240,6 +240,7 @@ impl Default for AudioQuality {
 pub enum Theme {
     Light,
     Dark,
+    System
 }
 
 impl Default for Theme {

psst-gui/src/ui/preferences.rs

@@ -157,7 +157,7 @@ fn general_tab_widget() -> impl Widget<AppState> {
         .with_child(Label::new("Theme").with_font(theme::UI_FONT_MEDIUM))
         .with_spacer(theme::grid(2.0))
         .with_child(
-            RadioGroup::column(vec![("Light", Theme::Light), ("Dark", Theme::Dark)])
+            RadioGroup::column(vec![("Light", Theme::Light), ("Dark", Theme::Dark), ("System", Theme::System)])
                 .lens(AppState::config.then(Config::theme)),
         );
 

psst-gui/src/ui/theme.rs

@@ -46,6 +46,7 @@ pub fn setup(env: &mut Env, state: &AppState) {
     match state.config.theme {
         Theme::Light => setup_light_theme(env),
         Theme::Dark => setup_dark_theme(env),
+        Theme::System => setup_system_theme(env),
     };
 
     env.set(WINDOW_BACKGROUND_COLOR, env.get(GREY_700));
@@ -69,6 +70,11 @@ pub fn setup(env: &mut Env, state: &AppState) {
             env.set(BUTTON_LIGHT, env.get(GREY_600));
             env.set(BUTTON_DARK, env.get(GREY_700));
         }
+        //TODO: fix this?
+        Theme::System => {
+            env.set(BUTTON_LIGHT, env.get(GREY_600));
+            env.set(BUTTON_DARK, env.get(GREY_700));
+        }
     }
 
     env.set(BORDER_LIGHT, env.get(GREY_400));
@@ -165,3 +171,12 @@ fn setup_dark_theme(env: &mut Env) {
     env.set(LINK_ACTIVE_COLOR, Color::rgba(1.0, 1.0, 1.0, 0.025));
     env.set(LINK_COLD_COLOR, Color::rgba(1.0, 1.0, 1.0, 0.0));
 }
+
+fn setup_system_theme(env: &mut Env) {
+    let current_theme = dark_light::detect();
+    if current_theme == dark_light::Mode::Dark {
+        setup_dark_theme(env);
+    } else {
+        setup_light_theme(env);
+    }
+}