{ lib }:
let
  checkType = lib.types.submodule {
    options = {
      assertion = lib.mkOption {
        type = lib.types.functionTo lib.types.bool;
        description = ''
          Predicate run against this registry's flattened collected entries.
        '';
      };

      message = lib.mkOption {
        type = lib.types.str;
        description = ''
          Error message shown when this registry validation check fails.
        '';
      };
    };
  };
in
{
  options = {
    type = lib.mkOption {
      type = lib.types.raw;
      description = ''
        NixOS option type for one registry entry.
      '';
    };

    replicate = lib.mkOption {
      type = lib.types.bool;
      default = false;
      description = ''
        Whether collected entries are merged and published under every host key.
      '';
    };

    checks = lib.mkOption {
      type = lib.types.listOf checkType;
      default = [ ];
      description = ''
        Validation checks for this registry's flattened collected entries.
      '';
    };
  };
}