{ pkgs, config, lib, ... }:
{
  mkServer =
    { name
    , sourceType
    , description ? "Enable ${name} source, for null-ls."
    , package ? null
    , extraPackages ? [ ]
    , ...
    }:
    # returns a module
    { pkgs, config, lib, ... }@args:
      with lib;
      let
        helpers = import ../helpers.nix args;
        cfg = config.plugins.null-ls.sources.${sourceType}.${name};
        # does this evaluate package?
        packageOption = if package == null then { } else {
          package = mkOption {
            type = types.package;
            default = package;
            description = "Package to use for ${name} by null-ls";
          };
        };
      in
      {
        options.plugins.null-ls.sources.${sourceType}.${name} = {
          enable = mkEnableOption description;

          # TODO: withArgs can exist outside of the module in a generalized manner
          withArgs = mkOption {
            default = null;
            type = with types; nullOr str;
            description = ''Raw Lua code to be called with the with function'';
            # Not sure that it makes sense to have the same example for all servers
            # example = ''
            #   '\'{ extra_args = { "--no-semi", "--single-quote", "--jsx-single-quote" } }'\'
            # '';
          };
        } // packageOption;

        config = mkIf cfg.enable {
          # Does this evaluate package?
          extraPackages = extraPackages ++ optional (package != null) cfg.package;

          # Add source to list of sources
          plugins.null-ls.sourcesItems =
            let
              sourceItem = "${sourceType}.${name}";
              withArgs = if (isNull cfg.withArgs) then sourceItem else "${sourceItem}.with ${cfg.withArgs}";
              finalString = ''require("null-ls").builtins.${withArgs}'';
            in
            [ (helpers.mkRaw finalString) ];
        };
      };
}