Set power profiles based on whether the device is running on battery

data/io.elementary.settings-daemon.gschema.xml

@@ -88,4 +88,17 @@
       <description>How often to check for updates in seconds.</description>
     </key>
   </schema>
+
+  <schema path="/io/elementary/settings-daemon/power/" id="io.elementary.settings-daemon.power">
+    <key type="s" name="profile-plugged-in">
+      <default>"balanced"</default>
+      <summary>Power profile to use when plugged in</summary>
+      <description></description>
+    </key>
+    <key type="s" name="profile-on-battery">
+      <default>"balanced"</default>
+      <summary>Power profile to use on battery</summary>
+      <description></description>
+    </key>
+  </schema>
 </schemalist>

src/Application.vala

@@ -13,13 +13,13 @@ public sealed class SettingsDaemon.Application : Gtk.Application {
 
     private Backends.KeyboardSettings keyboard_settings;
     private Backends.MouseSettings mouse_settings;
-
     private Backends.InterfaceSettings interface_settings;
     private Backends.NightLightSettings night_light_settings;
     private Backends.PrefersColorSchemeSettings prefers_color_scheme_settings;
     private Backends.AccentColorManager accent_color_manager;
 
     private Backends.Housekeeping housekeeping;
+    private Backends.PowerProfilesSync power_profiles_sync;
 
     private const string FDO_ACCOUNTS_NAME = "org.freedesktop.Accounts";
     private const string FDO_ACCOUNTS_PATH = "/org/freedesktop/Accounts";
@@ -55,6 +55,7 @@ public sealed class SettingsDaemon.Application : Gtk.Application {
         base.startup ();
 
         housekeeping = new Backends.Housekeeping ();
+        power_profiles_sync = new Backends.PowerProfilesSync ();
 
         var check_firmware_updates_action = new GLib.SimpleAction ("check-firmware-updates", null);
         check_firmware_updates_action.activate.connect (check_firmware_updates);

src/Backends/PowerProfilesSync.vala

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2024 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+public class SettingsDaemon.Backends.PowerProfilesSync : GLib.Object {
+    [DBus (name = "org.freedesktop.UPower")]
+    private interface UPower : GLib.DBusProxy {
+        public abstract bool on_battery { get; }
+    }
+
+    [DBus (name = "net.hadess.PowerProfiles")]
+    private interface PowerProfile : GLib.DBusProxy {
+        public abstract HashTable<string, Variant>[] profiles { owned get; }
+        public abstract string active_profile { owned get; set; }
+    }
+
+    private const string PROFILE_PLUGGED_IN = "profile-plugged-in";
+    private const string PROFILE_ON_BATTERY = "profile-on-battery";
+
+    private GLib.Settings settings;
+    private UPower? upower = null;
+    private PowerProfile? power_profiles_daemon = null;
+
+    construct {
+        settings = new GLib.Settings ("io.elementary.settings-daemon.power");
+
+        Bus.watch_name (BusType.SYSTEM, "org.freedesktop.UPower", BusNameWatcherFlags.NONE, on_upower_watch, on_upower_unwatch);
+        Bus.watch_name (BusType.SYSTEM, "net.hadess.PowerProfiles", BusNameWatcherFlags.NONE, on_ppd_watch, on_ppd_unwatch);
+
+        settings.changed.connect (update_profile);
+    }
+
+    private void on_upower_watch (GLib.DBusConnection connection) {
+        connection.get_proxy.begin<UPower> (
+            "org.freedesktop.UPower", "/org/freedesktop/UPower", NONE, null,
+            (obj, res) => {
+                try {
+                    upower = ((GLib.DBusConnection) obj).get_proxy.end<UPower> (res);
+                    debug ("Connected to UPower");
+
+                    update_profile ();
+
+                    upower.g_properties_changed.connect ((changed_properties) => {
+                        for (int i = 0; i < changed_properties.n_children (); i++) {
+                            unowned string property;
+                            changed_properties.get_child (i, "{&sv}", out property, null);
+                            if (property == "OnBattery") {
+                                update_profile ();
+                                break;
+                            }
+                        }
+                    });
+                } catch (Error e) {
+                    critical (e.message);
+                    upower = null;
+                }
+            }
+        );
+    }
+
+    private void on_upower_unwatch (GLib.DBusConnection connection) {
+        upower = null;
+        critical ("Lost connection to UPower");
+    }
+
+    private void on_ppd_watch (GLib.DBusConnection connection) {
+        connection.get_proxy.begin<PowerProfile> (
+            "net.hadess.PowerProfiles", "/net/hadess/PowerProfiles", NONE, null,
+            (obj, res) => {
+                try {
+                    power_profiles_daemon = ((GLib.DBusConnection) obj).get_proxy.end<PowerProfile> (res);
+                    debug ("Connected to power profiles daemon");
+
+                    update_profile ();
+                } catch (Error e) {
+                    critical (e.message);
+                    power_profiles_daemon = null;
+                }
+            }
+        );
+    }
+
+    private void on_ppd_unwatch (GLib.DBusConnection connection) {
+        power_profiles_daemon = null;
+        critical ("Lost connection to power profiles daemon");
+    }
+
+    private void update_profile () {
+        if (power_profiles_daemon == null || upower == null) {
+            return;
+        }
+
+        var profile_to_set = settings.get_string (upower.on_battery ? PROFILE_ON_BATTERY : PROFILE_PLUGGED_IN);
+
+        var found_profile = false;
+        var profiles = power_profiles_daemon.profiles;
+        for (int i = 0; i < profiles.length; i++) {
+            if (profiles[i].get ("Profile").get_string () == profile_to_set) {
+                found_profile = true;
+                break;
+            }
+        }
+
+        if (found_profile) {
+            power_profiles_daemon.active_profile = profile_to_set;
+        } else {
+            warning ("Couldn't set power profile to %s", profile_to_set);
+        }
+    }
+}

src/meson.build

@@ -7,6 +7,7 @@ sources = files(
     'Backends/KeyboardSettings.vala',
     'Backends/MouseSettings.vala',
     'Backends/NightLightSettings.vala',
+    'Backends/PowerProfilesSync.vala',
     'Backends/PrefersColorSchemeSettings.vala',
     'Backends/SystemUpdate.vala',
     'Utils/SunriseSunsetCalculator.vala',