self:
{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.programs.nova-shell;

  stylixAvailable = config ? lib && config.lib ? stylix;

  stylixTheme =
    let
      c = config.lib.stylix.colors.withHashtag;
      f = config.stylix.fonts;
    in
    {
      colors = {
        inherit (c)
          base00
          base01
          base02
          base03
          base04
          base05
          base06
          base07
          base08
          base09
          base0A
          base0B
          base0C
          base0D
          base0E
          base0F
          ;
      };
      fontFamily = f.sansSerif.name;
      fontSize = f.sizes.desktop;
      barOpacity = 1.0 - config.stylix.opacity.desktop;
      iconFontFamily = "Symbols Nerd Font";
    };
in
{
  options.programs.nova-shell = {
    enable = lib.mkEnableOption "nova-shell Quickshell bar";

    package = lib.mkOption {
      type = lib.types.package;
      default = self.packages.${pkgs.stdenv.hostPlatform.system}.default;
      description = "nova-shell package to use.";
    };

    modules =
      let
        moduleOpt =
          name: extra:
          lib.mkOption {
            default = { };
            description = "Configuration for the ${name} module.";
            type = lib.types.submodule {
              options = {
                enable = lib.mkOption {
                  type = lib.types.bool;
                  default = true;
                  description = "Enable the ${name} module.";
                };
              }
              // extra;
            };
          };
        intervalOpt = default: {
          interval = lib.mkOption {
            type = lib.types.int;
            inherit default;
            description = "Polling interval in milliseconds.";
          };
        };
        simpleModules = lib.genAttrs [
          "workspaces"
          "tray"
          "windowTitle"
          "clock"
          "notifications"
          "mpris"
          "volume"
          "idleInhibitor"
          "power"
        ] (name: moduleOpt name { });
      in
      simpleModules
      // {
        bluetooth = moduleOpt "bluetooth" (intervalOpt 5000);
        network = moduleOpt "network" (intervalOpt 5000);
        powerProfile = moduleOpt "powerProfile" (intervalOpt 5000);
        cpu = moduleOpt "cpu" (intervalOpt 1000);
        memory = moduleOpt "memory" (intervalOpt 2000);
        disk = moduleOpt "disk" (intervalOpt 30000);
        backlight = moduleOpt "backlight" {
          step = lib.mkOption {
            type = lib.types.int;
            default = 5;
            description = "Brightness adjustment step (%).";
          };
        };
        temperature = moduleOpt "temperature" (
          (intervalOpt 2000)
          // {
            warm = lib.mkOption {
              type = lib.types.int;
              default = 60;
              description = "Temperature threshold for warm state (°C).";
            };
            hot = lib.mkOption {
              type = lib.types.int;
              default = 80;
              description = "Temperature threshold for hot state (°C).";
            };
          }
        );
        battery = moduleOpt "battery" {
          warning = lib.mkOption {
            type = lib.types.int;
            default = 25;
            description = "Battery percentage for warning notification.";
          };
          critical = lib.mkOption {
            type = lib.types.int;
            default = 15;
            description = "Battery percentage for critical notification and blink.";
          };
        };
        weather = moduleOpt "weather" (
          (intervalOpt 3600000)
          // {
            args = lib.mkOption {
              type = lib.types.listOf lib.types.str;
              default = [ "--nerd" ];
              description = "Arguments passed to wttrbar.";
              example = [
                "--nerd"
                "--location"
                "Berlin"
              ];
            };
          }
        );
      };

    theme = lib.mkOption {
      type = lib.types.attrsOf lib.types.anything;
      default = { };
      description = ''
        Theme overrides written to `$XDG_CONFIG_HOME/nova-shell/theme.json`.
        Keys: colors (base00-base0F), fontFamily, iconFontFamily, fontSize,
        barOpacity, barHeight, barPadding, barSpacing, moduleSpacing, radius.
        Automatically populated from stylix when it is available.
      '';
    };

    systemd = {
      enable = lib.mkOption {
        type = lib.types.bool;
        default = true;
        description = "Run nova-shell as a systemd user service.";
      };
      target = lib.mkOption {
        type = lib.types.str;
        default = "graphical-session.target";
        description = "Systemd target to bind the service to.";
      };
    };
  };

  config = lib.mkIf cfg.enable {
    home.packages = [
      self.packages.${pkgs.stdenv.hostPlatform.system}.nova-shell-cli
      pkgs.nerd-fonts.symbols-only
    ]
    ++ lib.optional cfg.modules.weather.enable pkgs.wttrbar
    ++ lib.optional cfg.modules.mpris.enable pkgs.cava;

    xdg.configFile."nova-shell/modules.json".source =
      (pkgs.formats.json { }).generate "nova-shell-modules.json"
        cfg.modules;

    xdg.configFile."nova-shell/theme.json".source =
      let
        stylixDefaults = if stylixAvailable then stylixTheme else { };
        finalTheme = lib.recursiveUpdate stylixDefaults cfg.theme;
      in
      (pkgs.formats.json { }).generate "nova-shell-theme.json" finalTheme;

    systemd.user.services.nova-shell = lib.mkIf cfg.systemd.enable {
      Unit = {
        Description = "nova-shell Quickshell bar";
        PartOf = [ cfg.systemd.target ];
        After = [ cfg.systemd.target ];
      };
      Service = {
        ExecStart = lib.getExe cfg.package;
        Restart = "on-failure";
        Slice = "session.slice";
      };
      Install.WantedBy = [ cfg.systemd.target ];
    };
  };
}