nixos/pkgs/writeXrandrScriptBin/default.nix

{ lib, writeShellScriptBin, xrandr }:
let
  inherit (builtins) getAttr hasAttr isAttrs concatStringsSep;
  inherit (lib) assertMsg lists escapeShellArgs getExe;
  inherit (lib.attrsets) mapAttrsToList;
  inherit (lib.cli) toGNUCommandLine;
in
name: config:
assert assertMsg (isAttrs config)
  "config should be an attrs, found ${lib.typeOf config}";
let
  isPrimary = config:
    (hasAttr "primary" config) && (getAttr "primary" config);

  getArgList = output: config:
    (escapeShellArgs (lists.flatten [
      (toGNUCommandLine { } { inherit output; })
      (lists.optional (isPrimary config) "--primary")
      (toGNUCommandLine { } config)
    ]));

  args = mapAttrsToList getArgList config;
in
writeShellScriptBin name ''
  ${getExe xrandr} \
    ${concatStringsSep " \\\n  " args}
''