{ config, lib, ... }:
let
  types = lib.types;

  metaOptions = {
    name = lib.mkOption { type = types.str; };
    description = lib.mkOption {
      default = null;
      type = types.nullOr types.str;
    };
    icon = lib.mkOption {
      default = null;
      type = types.nullOr types.str;
    };
  };
  metaOptionsWith = name: {
    name = lib.mkOption {
      type = types.str;
      default = name;
    };
    description = lib.mkOption {
      default = null;
      type = types.nullOr types.str;
    };
    icon = lib.mkOption {
      default = null;
      type = types.nullOr types.str;
    };
  };

  moduleConfig = lib.mkOption {
    default = { };
    type = types.attrsOf types.anything;
  };

  importsOption = lib.mkOption {
    description = ''
      List of imported '.nix' files.

      Each filename must be a string and is interpreted relative to the 'directory' passed to buildClan.
      The import only happens if the machine is part of the service or role.

      ## Example

      To import the `special.nix` file

      ```
      . Clan Directory
      ├── flake.nix
      ...
      └── modules
          ├── special.nix
          └── ...
      ```

      ```nix
      {
        imports = [ "modules/special.nix" ];
      }
      ```

    '';
    default = [ ];
    type = types.listOf types.str;
  };
in
{
  imports = [ ./assertions.nix ];
  options = {
    assertions = lib.mkOption {
      type = types.listOf types.unspecified;
      internal = true;
      visible = false;
      default = [ ];
    };
    meta = metaOptions;

    machines = lib.mkOption {
      default = { };
      type = types.attrsOf (
        types.submodule (
          { name, ... }:
          {
            options = {
              inherit (metaOptionsWith name) name description icon;

              tags = lib.mkOption {

                default = [ ];
                apply = lib.unique;
                type = types.listOf types.str;
              };
              system = lib.mkOption {
                default = null;
                type = types.nullOr types.str;
              };
              deploy.targetHost = lib.mkOption {
                description = "Configuration for the deployment of the machine";
                default = null;
                type = types.nullOr types.str;
              };
            };
          }
        )
      );
    };

    services = lib.mkOption {
      default = { };
      type = types.attrsOf (
        types.attrsOf (
          types.submodule (
            { name, ... }:
            {
              options.meta = metaOptionsWith name;
              options.imports = importsOption;
              options.config = moduleConfig;
              options.machines = lib.mkOption {
                default = { };
                type = types.attrsOf (
                  types.submodule {
                    options.imports = importsOption;
                    options.config = moduleConfig;
                  }
                );
              };
              options.roles = lib.mkOption {
                default = { };
                type = types.attrsOf (
                  types.submodule {
                    options.machines = lib.mkOption {
                      default = [ ];
                      type = types.listOf types.str;
                    };
                    options.tags = lib.mkOption {
                      default = [ ];
                      apply = lib.unique;
                      type = types.listOf types.str;
                    };
                    options.config = moduleConfig;
                    options.imports = importsOption;
                  }
                );
              };
            }
          )
        )
      );
    };
  };
}