[audio] Adds script to inhibit sleep while media is playing.

home-manager/features/audio.nix

@@ -1,7 +1,41 @@
 { pkgs, ... }:
+with pkgs;
+let
+  # A script that runs as long as media is playing.
+  isMediaPlaying = writeShellApplication {
+    name = "isMediaPlaying";
+    runtimeInputs = [
+      playerctl
+    ];
+    text = ''
+      set -e
+
+      while [ "$(playerctl status)" = "Playing" ]; do
+        echo -n "."
+        sleep 1
+      done
+    '';
+  };
+  # A script that prevents the system from going to sleep while media is playing
+  mediaCaffeine = writeShellApplication {
+    name = "media-caffeine";
+    runtimeInputs = [
+      isMediaPlaying
+      systemd
+    ];
+    text = ''
+      set -e
+
+      systemd-inhibit --what=sleep --why="Media is playing" --mode=block isMediaPlaying
+    '';
+  };
+in
 {
   home.packages = with pkgs; [
     pulseaudio # for pactl and other tools
     pavucontrol # GUI volume control with lots of options
+
+    mediaCaffeine
   ];
+
 }