home/wayland/swayidle: suspend idle system on battery

1 files changed, 48 insertions, 3 deletions

diff --git a/home/wayland/modules/sway/swayidle.nix b/home/wayland/modules/sway/swayidle.nix
index 1aa16c5..abb3a10 100644
--- a/home/wayland/modules/sway/swayidle.nix
+++ b/home/wayland/modules/sway/swayidle.nix
@@ -2,14 +2,51 @@
   swaylock = lib.getExe config.programs.swaylock.package;
   brightnessctl = lib.getExe pkgs.brightnessctl;
   swaymsg = "${pkgs.sway}/bin/swaymsg";
+
+  minute = 60; # seconds
+  suspend_timeout = minute * 60;
+  suspend_on_battery = pkgs.writeShellApplication {
+    name = "suspend_on_battery";
+    runtimeInputs = with pkgs; [ gnugrep systemd sudo coreutils ];
+    text = let
+      sudo = "/run/wrappers/bin/sudo";
+    in ''
+      is_discharging() {
+	  grep -qFx \
+	      'POWER_SUPPLY_STATUS=Discharging' \
+	      /sys/class/power_supply/*/uevent
+      }
+
+      was_charging=false
+      while true; do
+	  if is_discharging; then
+	      if [ $was_charging = true ]; then
+		  sleep ${builtins.toString suspend_timeout}
+	      fi
+
+	      if is_discharging; then
+		  ${sudo} systemctl suspend-then-hibernate
+	      fi
+	  fi
+
+	  was_charging=true
+	  sleep 10
+      done
+    '';
+  };
 in {
+  systemd.user.services.suspend_on_battery = {
+    Unit.Description = "Suspend on battery";
+    Service.ExecStart = lib.getExe suspend_on_battery;
+  };
+
   services.swayidle = {
     enable = true;
     systemdTarget = "sway-session.target";
 
     timeouts = [
       {
-	timeout = 250;
+	timeout = minute * 4;
 	command =
 	  "${brightnessctl} --save; "
 	  + "${brightnessctl} set 10%-";
@@ -17,12 +54,12 @@ in {
       }
 
       {
-	timeout = 300;
+	timeout = minute * 5;
 	command = swaylock;
       }
 
       {
-	timeout = 600;
+	timeout = minute * 10;
 	command =
 	  "${swaymsg} --type command 'output * dpms off'; "
 	  + "${brightnessctl} -c leds -d platform::kbd_backlight --save; "
@@ -31,6 +68,14 @@ in {
 	  "${brightnessctl} -c leds -d platform::kbd_backlight --restore; "
 	  + "${swaymsg} --type command 'output * dpms on'";
       }
+
+      {
+	timeout = suspend_timeout;
+	command =
+	  "${pkgs.systemd}/bin/systemctl --user start suspend_on_battery";
+	resumeCommand =
+	  "${pkgs.systemd}/bin/systemctl --user stop suspend_on_battery";
+      }
     ];
   };
 }