{ user ? throw "user argument is required" }: { config, lib, pkgs, ... }:

let
  hmConfig = config.home-manager.users."${user.name}";
in
{
  home-manager.users."${user.name}" = {
    gtk = {
      enable = true;

      theme = {
        package = pkgs.adw-gtk3;
        name = "adw-gtk3-dark";
      };

      gtk2.configLocation = "${hmConfig.xdg.configHome}/gtk-2.0/gtkrc";
      gtk3.extraCss = "@import './theme.css';";
      gtk4.extraCss = "@import './theme.css';";
    };

    programs.matugen.settings.templates = {
      gtk3 = {
        input_path = ./theme.css;
        output_path = "${hmConfig.xdg.configHome}/gtk-3.0/theme.css";
      };
      gtk4 = {
        input_path = ./theme.css;
        output_path = "${hmConfig.xdg.configHome}/gtk-4.0/theme.css";
      };
    };

    theme.extraConfig = "${lib.meta.getExe (pkgs.writeShellApplication {
      name = "theme-gtk";
      runtimeInputs = with pkgs; [ dconf ];
      text = ''
        MODE=$(cat "${hmConfig.theme.configDir}/mode")

        if [ "$MODE" = "light" ]; then
          GTK_THEME="adw-gtk3"
        else
          GTK_THEME="adw-gtk3-dark"
        fi

        dconf write /org/gnome/desktop/interface/gtk-theme "'$GTK_THEME'"
        dconf write /org/gnome/desktop/interface/color-scheme "'prefer-$MODE'"
      '';
      })} &";
  };
}