{ config, tmpLib, pkgs, lib, ... }:

let
  inherit (tmpLib) mkTmpFile;

  upperConfig = config;
  enabledInstances = lib.lists.filter (instance: config.tmpfiles.instances.files != []) config.tmpfiles.instances;
in {
  options = {
    tmpfiles = {
      # selfManagement = {
      #   enable = lib.mkEnableOption "tmpfiles self management";
      #   targetDir = lib.mkOption {
      #     type = lib.types.str;
      #   };

      #   managedInstances = lib.mkOption {
      #     type = lib.types.listOf lib.types.str;
      #   };

      #   configurationPackage = lib.mkOption {
      #     type = lib.types.package;
      #     description = ''
      #       This package contains the tmpfiles configuration package
      #     '';
      #   };
      # };

      defaultUser = lib.mkOption {
        type = lib.types.nullOr lib.types.str;
      };
      defaultGroup = lib.mkOption {
        type = lib.types.nullOr lib.types.str;
      };

      instances = lib.mkOption {
        type = lib.types.attrsOf (lib.types.submodule( { name, config, ... }: {
          options = {
            files = lib.mkOption {
              type = lib.types.listOf tmpLib.tmpFileType;
            };

            priority = lib.mkOption {
              type = lib.types.str;
              default = "100";
            };

            configurationFileLines = lib.mkOption {
              type = lib.types.listOf lib.types.str;
            };

            configurationPackage = lib.mkOption {
              type = lib.types.package;
              description = ''
                This package contains the tmpfiles configuration package
              '';
            };

            activationPackage = lib.mkOption {
              type = lib.types.package;
              description = ''
                This package contains a script for activation of the tmp files using `systemd-tmpfiles`
              '';
            };
          };

          config = let
            tmpFiles = lib.lists.filter (file: file.enable) config.files;
            tmpFilesPath = "/share/user-tmpfiles.d/${config.priority}-tmpactivator-${name}.conf";
          in {
            configurationFileLines = builtins.map (file: (tmpLib.mkTmpFile ({
              type = file.type;
              target = file.target;
              mode = file.mode;
              user = if file.user == null then upperConfig.tmpfiles.defaultUser else file.user;
              group = if file.group == null then upperConfig.tmpfiles.defaultGroup else file.group;
              contents = if file.source != null then file.source else file.text;
            }))) tmpFiles;

            configurationPackage = pkgs.writeTextFile {
              name = "${builtins.baseNameOf tmpFilesPath}";
              destination = "${tmpFilesPath}";
              text = lib.concatStringsSep "\n" config.configurationFileLines;
            };

            activationPackage = pkgs.symlinkJoin {
              name = "tmpfiles-activation";

              paths = [
                (pkgs.writeShellScriptBin "activate" ''
                  systemd-tmpfiles --create "${config.configurationPackage}/${tmpFilesPath}"
                '')
                (pkgs.writeShellScriptBin "deactivate" ''
                  systemd-tmpfiles --remove "${config.configurationPackage}/${tmpFilesPath}"
                '')
                config.configurationPackage
              ];
            };
          };
        }));
      };
    };
  };

  # config = lib.mkMerge [
    # (lib.mkIf config.tmpfiles.selfManagement.enable {
    #   tmpfiles.selfManagement.configurationPackage = pkgs.writeTextFile {
    #     name = "99-tmpactivator.conf";
    #     destination = "/share/user-tmpfiles.d/99-tmpactivator.conf";
    #     text = ''
    #       L+ ${config.tmpfiles.selfManagement.targetDir}/100-tmpactivator-files.conf - - - - ${config.tmpfiles.configurationPackage}/share/user-tmpfiles.d/100-tmpactivator-files.conf
    #       r ${config.tmpfiles.selfManagement.targetDir}/100-tmpactivator-files.conf - - - - -
    #     '';
    #   };

    #   tmpfiles.activationPackage = pkgs.symlinkJoin {
    #     name = "tmpfiles-activation";

    #     paths = [
    #       (pkgs.writeShellScriptBin "activate" ''
    #         systemd-tmpfiles --create "${config.tmpfiles.selfManagement.configurationPackage}/share/user-tmpfiles.d/99-tmpactivator.conf"
    #         systemd-tmpfiles --create "${config.tmpfiles.configurationPackage}/share/user-tmpfiles.d/100-tmpactivator-files.conf"
    #       '')
    #       (pkgs.writeShellScriptBin "deactivate" ''
    #         systemd-tmpfiles --remove "${config.tmpfiles.configurationPackage}/share/user-tmpfiles.d/100-tmpactivator-files.conf"
    #         systemd-tmpfiles --remove "${config.tmpfiles.selfManagement.configurationPackage}/share/user-tmpfiles.d/99-tmpactivator.conf"
    #       '')
    #       config.tmpfiles.configurationPackage
    #       config.tmpfiles.selfManagement.configurationPackage
    #     ];
    #   };
    # })

    # {
      # assertions = builtins.map
      #   (file: {
      #     assertion = file.source == null || file.text == null;
      #     message = "Either text or source can be set, not both.";
      #   })
      # tmpFiles;
      #
    # }
  # ];
}