{ pkgs, lib, ... }:
let
  inherit (lib)
    singleton
    getExe;
in
{
  systemd.user.services.wallpaper = {
    Unit = {
      Description = "Applies wallpaper";
      After = singleton "graphical-session-pre.target";
      PartOf = singleton "graphical-session.target";
    };

    Service = {
      Type = "oneshot";
      ExecStart = pkgs.writeShellScript "apply-wallpaper" ''
        if [[ -f "$HOME/.config/wallpaper" ]]
        then
          ${getExe pkgs.feh} --no-fehbg --bg-fill "$HOME/.config/wallpaper"
        else
          ${getExe pkgs.feh} --no-fehbg --bg-fill ${./default.png}
        fi
      '';
    };

    Install.WantedBy = singleton "graphical-session.target";
  };
}