Add option to follow the system theme

The theme preference now an enum with 3 options:

  - light   => maps to libadwaita::ColorScheme::ForceLight
    The app uses the light theme - regardless of system prefs

  - dark    => maps to libadwaita::ColorScheme::ForceDark
    The app uses the dark theme - regardless of system prefs

  - system  => maps to libadwaita::ColorScheme::Default
    The Apps style follows the system theme preferences

data/dev.alextren.Spot.gschema.xml

@@ -9,10 +9,15 @@
     <value value="1" nick="160"/>
     <value value="2" nick="320"/>
   </enum>
+  <enum id="dev.alextren.Spot.ThemePref">
+    <value value="0" nick="light" />
+    <value value="1" nick="dark" />
+    <value value="2" nick="system" />
+  </enum>
   <schema id="dev.alextren.Spot" path="/dev/alextren/Spot/">
-    <key name='prefers-dark-theme' type='b'>
-      <default>true</default>
-      <summary>Prefer dark theme</summary>
+    <key name='theme-preference' enum='dev.alextren.Spot.ThemePref'>
+      <default>'system'</default>
+      <summary>The theme preference</summary>
     </key>
     <key name="window-width" type="i">
       <default>1080</default>

src/app/components/settings/settings.rs

@@ -168,30 +168,51 @@ impl SettingsWindow {
             .set_mapping(|value, _| value.get::<u32>().ok().map(|u| u.to_variant()))
             .build();
 
-        let theme = widget.theme.downcast_ref::<libadwaita::ComboRow>().unwrap();
+        let theme = widget
+            .theme
+            .downcast_ref::<libadwaita::ComboRow>()
+            .unwrap();
         settings
-            .bind("prefers-dark-theme", theme, "selected")
+            .bind("theme-preference", theme, "selected")
             .mapping(|variant, _| {
-                variant
-                    .get::<bool>()
-                    .map(|prefer_dark| if prefer_dark { 1 } else { 0 }.to_value())
+                variant.str().map(|s| {
+                    match s {
+                        "light" => 0,
+                        "dark" => 1,
+                        "system" => 2,
+                        _ => unreachable!(),
+                    }
+                    .to_value()
+                })
+            })
+            .set_mapping(|value, _| {
+                value.get::<u32>().ok().map(|u| {
+                    match u {
+                        0 => "light",
+                        1 => "dark",
+                        2 => "system",
+                        _ => unreachable!(),
+                    }
+                    .to_variant()
+                })
             })
-            .set_mapping(|value, _| value.get::<u32>().ok().map(|u| (u == 1).to_variant()))
             .build();
     }
 
     fn connect_theme_select(&self) {
         let widget = self.imp();
         let theme = widget.theme.downcast_ref::<libadwaita::ComboRow>().unwrap();
         theme.connect_selected_notify(|theme| {
-            let prefers_dark_theme = theme.selected() == 1;
+            debug!("Theme switched! --> value: {}", theme.selected());
             let manager = libadwaita::StyleManager::default();
 
-            manager.set_color_scheme(if prefers_dark_theme {
-                libadwaita::ColorScheme::PreferDark
-            } else {
-                libadwaita::ColorScheme::PreferLight
-            });
+            let pref = match theme.selected() {
+                0 => libadwaita::ColorScheme::ForceLight,
+                1 => libadwaita::ColorScheme::ForceDark,
+                _ => libadwaita::ColorScheme::Default,
+            };
+
+            manager.set_color_scheme(pref);
         });
     }
 

src/app/components/settings/settings.ui

@@ -62,6 +62,7 @@
                     <items>
                       <item translatable="yes">Light</item>
                       <item translatable="yes">Dark</item>
+                      <item translatable="yes">System</item>
                     </items>
                   </object>
                 </property>

src/main.rs

@@ -12,7 +12,6 @@ use gio::prelude::*;
 use gio::ApplicationFlags;
 use gio::SimpleAction;
 use gtk::prelude::*;
-use libadwaita::ColorScheme;
 
 mod api;
 mod app;
@@ -98,11 +97,7 @@ fn startup(settings: &settings::SpotSettings) {
         .expect("Could not load resources");
     gio::resources_register(&res);
 
-    manager.set_color_scheme(if settings.prefers_dark_theme {
-        ColorScheme::PreferDark
-    } else {
-        ColorScheme::PreferLight
-    });
+    manager.set_color_scheme(settings.theme_preference);
 
     let provider = gtk::CssProvider::new();
     provider.load_from_resource("/dev/alextren/Spot/app.css");

src/settings.rs

@@ -1,6 +1,7 @@
 use crate::player::{AudioBackend, SpotifyPlayerSettings};
 use gio::prelude::SettingsExt;
 use librespot::playback::config::Bitrate;
+use libadwaita::ColorScheme;
 
 const SETTINGS: &str = "dev.alextren.Spot";
 
@@ -73,17 +74,22 @@ impl SpotifyPlayerSettings {
 
 #[derive(Debug, Clone)]
 pub struct SpotSettings {
-    pub prefers_dark_theme: bool,
+    pub theme_preference: ColorScheme,
     pub player_settings: SpotifyPlayerSettings,
     pub window: WindowGeometry,
 }
 
 impl SpotSettings {
     pub fn new_from_gsettings() -> Option<Self> {
         let settings = gio::Settings::new(SETTINGS);
-        let prefers_dark_theme = settings.boolean("prefers-dark-theme");
+        let theme_preference = match settings.enum_("theme-preference") {
+            0 => Some(ColorScheme::ForceLight),
+            1 => Some(ColorScheme::ForceDark),
+            2 => Some(ColorScheme::Default),
+            _ => None,
+        }?;
         Some(Self {
-            prefers_dark_theme,
+            theme_preference,
             player_settings: SpotifyPlayerSettings::new_from_gsettings()?,
             window: WindowGeometry::new_from_gsettings(),
         })
@@ -93,7 +99,7 @@ impl SpotSettings {
 impl Default for SpotSettings {
     fn default() -> Self {
         Self {
-            prefers_dark_theme: true,
+            theme_preference: ColorScheme::PreferDark,
             player_settings: Default::default(),
             window: Default::default(),
         }