{
  lib,
  ...
}:
let
  inherit (lib) types mkOption;
in
with types;
{
  options = {
    runtime-environments = mkOption {
      description = "Collection of runtime environments into which applications can be deployed";
      type = attrsOf (attrTag {
        nixos = mkOption {
          description = "A single NixOS machine";
          type = submodule {
            options = {
              module = mkOption {
                description = "The NixOS module describing the base configuration for that machine";
                type = deferredModule;
              };
            };
          };
        };
      });
    };
    applications = mkOption {
      description = "Collection of Fediversity applications";
      type = attrsOf (submoduleWith {
        modules = [
          {
            options = {
              module = mkOption {
                description = "The NixOS module for that application, for configuring that application";
                type = deferredModule;
              };
            };
          }
        ];
      });
    };
  };
}