{ config, lib, pkgs, ... }:
let
  cfg = config.programs.hyprscrolling;
  # Render plugin settings into:
  # plugin:hyprscrolling {
  #   key = value
  # }
  #
  # Values:
  # - strings become "..."
  # - bools become true/false
  # - ints/floats stay numeric
  # - lists become [ a b c ] (Hyprland-style arrays)
  renderValue =
    v:
    if lib.isString v then "\"${v}\""
    else if lib.isBool v then (if v then "true" else "false")
    else if lib.isInt v || lib.isFloat v then toString v
    else if lib.isList v then
      "[ " + (lib.concatStringsSep " " (map renderValue v)) + " ]"
    else
      throw "programs.hyprscrolling.settings: unsupported value type: ${builtins.typeOf v}";

  renderSettings =
    settings:
    let
      lines = lib.mapAttrsToList (k: v: "  ${k} = ${renderValue v}") settings;
    in
      if settings == { } then ""
      else ''
        plugin:hyprscrolling {
        ${lib.concatStringsSep "\n" lines}
        }
      '';

  defaultPluginPkg =
    # In nixpkgs this is typically available as pkgs.hyprlandPlugins.hyprscrolling
    # (names may vary by channel; override via programs.hyprscrolling.pluginPackage if needed).
    (pkgs.hyprlandPlugins.hyprscrolling or null);

in
{
  options.programs.hyprscrolling = {
    enable = lib.mkEnableOption "Hyprland hyprscrolling (scrolling layout) plugin";

    pluginPackage = lib.mkOption {
      type = lib.types.nullOr lib.types.package;
      default = defaultPluginPkg;
      description = ''
        Package that provides the hyprscrolling plugin.
        Defaults to pkgs.hyprlandPlugins.hyprscrolling when available.
      '';
    };

    setAsDefaultLayout = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Whether to set `general:layout = scrolling` in Hyprland.";
    };
    settings = lib.mkOption {
      type = lib.types.attrs;
      default = { };
      example = {
        # Example keys (actual keys depend on plugin version)
        # See hyprscrolling README for supported options.
        # swipe_fingers = 3;
        # natural_scroll = true;
      };
      description = ''
        Attribute set rendered into a `plugin:hyprscrolling { ... }` block.
        Keys/values must match hyprscrolling config options.
      '';
    };

    extraConfig = lib.mkOption {
      type = lib.types.lines;
      default = "";
      description = "Extra Hyprland config appended after the generated plugin config.";
    };
  };

  config = lib.mkIf cfg.enable {
    assertions = [
      {
        assertion = config.wayland.windowManager.hyprland.enable or false;
        message = "programs.hyprscrolling.enable requires wayland.windowManager.hyprland.enable = true;";
      }
      {
        assertion = cfg.pluginPackage != null;
        message = ''
          Could not find a default hyprscrolling plugin package in this nixpkgs.
          Set programs.hyprscrolling.pluginPackage explicitly (either from pkgs or a flake input).
        '';
      }
    ];

    wayland.windowManager.hyprland = {
      plugins = [ cfg.pluginPackage ];

      extraConfig = lib.mkAfter ''
        ${lib.optionalString cfg.setAsDefaultLayout "general { layout = scrolling }"}

        ${renderSettings cfg.settings}

        ${cfg.extraConfig}
      '';
    };
  };
}