upd

modules/app.nix

@@ -1,5 +1,5 @@
 {pkgs, ...}: {
-  imports = [
-    ../pkgs/delfin/default.nix
+  environment.systemPackages = with pkgs; [
+    delfin
   ];
 }

modules/desktop/display-manager.nix

@@ -5,5 +5,7 @@
     ../../pkgs/swww/default.nix
     ../../pkgs/waybar/default.nix
     ../../pkgs/wofi/default.nix
+    ../../pkgs/hypridle/default.nix
+    ../../pkgs/hyprlock/default.nix
   ];
 }

pkgs/delfin/default.nix

@@ -1,5 +0,0 @@
-{pkgs, ...}: {
-  environment.systemPackages = with pkgs; [
-    delfin
-  ];
-}

pkgs/hypridle/default.nix

@@ -0,0 +1,38 @@
+{...}: {
+  services.hypridle = {
+    enable = true;
+    settings = {
+      general = {
+        lock_cmd = "pidof hyprlock || hyprlock"; # avoid starting multiple hyprlock instances.
+        before_sleep_cmd = "loginctl lock-session"; # lock before suspend.
+        after_sleep_cmd = "hyprctl dispatch dpms on"; # avoid needing to press a key twice to turn on the display.
+      };
+
+      listener = [
+        # {
+        #   timeout = 150;
+        #   on-timeout = "brightnessctl -s set 10"; # set monitor backlight to minimum, avoid 0 on OLED monitor.
+        #   on-resume = "brightnessctl -r"; # restore monitor backlight.
+        # }
+        # {
+        #   timeout = 150;
+        #   on-timeout = "brightnessctl -sd rgb:kbd_backlight set 0"; # turn off keyboard backlight.
+        #   on-resume = "brightnessctl -rd rgb:kbd_backlight"; # turn on keyboard backlight.
+        # }
+        # {
+        #   timeout = 300;
+        #   on-timeout = "loginctl lock-session"; # lock screen when timeout has passed.
+        # }
+        # {
+        #   timeout = 330;
+        #   on-timeout = "hyprctl dispatch dpms off"; # screen off after 5.5min.
+        #   on-resume = "hyprctl dispatch dpms on && brightnessctl -r"; # screen on and restore brightness on resume.
+        # }
+        {
+          timeout = 1800;
+          on-timeout = "systemctl suspend"; # suspend PC after 30min.
+        }
+      ];
+    };
+  };
+}

pkgs/hyprlock/default.nix

@@ -0,0 +1,7 @@
+{...}: {
+  services.hyprlock = {
+    enable = true;
+    settings = {
+    };
+  };
+}

system/desktop/wayland.nix

@@ -1,6 +1,8 @@
 {pkgs, ...}: {
   environment.systemPackages = with pkgs; [
     wl-clipboard
+    hypridle
+    hyprlock
   ];
   programs.hyprland.enable = true;
   hardware = {