{ config, pkgs, lib, ... }:
with builtins // lib;
let
  cfg = config.kfmon;
  ini = pkgs.formats.ini {};
in {
  options.kfmon = {
    enable = mkEnableOption "KFMon";

    package = mkPackageOption pkgs "kfmon" {};

    path = mkOption {
      type = types.str;
      readOnly = true;
      internal = true;
      default = ".adds/kfmon";
    };

    devicePath = mkOption {
      type = types.str;
      readOnly = true;
      internal = true;
      default = "/mnt/onboard/${cfg.path}";
    };

    file = mkOption {
      default = {};
      type = types.attrsOf (types.submodule (pkgs.callPackage ../lib/file-type.nix {}));
      apply = filterAttrs (_: v: v.enable);
    };

    _createdFiles = mkOption {
      type = types.package;
      internal = true;
      readOnly = true;
      default = pkgs.buildEnv {
        name = "kfmon-files-created";
        paths = mapAttrsToList (_: v: v._package) cfg.file;
        extraPrefix = cfg.devicePath;
      };
    };

    finalPackage = mkOption {
      type = types.package;
      internal = true;
      readOnly = true;
      default = pkgs.mergePaths {
        name = "kfmon-package";
        paths = [
          (pkgs.linkFarm "kfmon" [{
            name = removePrefix "/" cfg.devicePath;
            path = cfg.package.out;
          }])
          cfg._createdFiles
          cfg.package.KoboRoot
        ];
      };
    };

    # _allFiles = mkOption {
    #   type = types.package;
    #   internal = true;
    #   readOnly = true;
    #   default = pkgs.symlinkJoin {
    #     name = "kfmon-files";
    #     paths = mapAttrsToList (v: v._package) cfg.file;
    #   };
    # };

    configs = mkOption {
      type = types.attrsOf ini.type;
      default = {};
      description = ''
        KFMon .ini config files. Do not touch this unless you know what you're doing!
      '';
    };
  };

  config = mkMerge [
    {
      info.kfmon = cfg.enable;

      kfmon.file = mapAttrs' (n: v: {
        name = "kfmon-config-${n}";
        value = {
          text = generators.toINI {} v;
          target =
            let
              fixedN = if isSuffix ".ini" n then n else "${n}.ini";
            in "config/${fixedN}";
        };
      });
    }
    (mkIf cfg.enable {
      koboroot.include = singleton cfg.finalPackage;
      # koboroot.include = [
      #   (pkgs.linkFarm [{
      #     name = cfg.devicePath;
      #     path = cfg._allFiles;
      #   }])
      #   cfg.package.KoboRoot
      # ];
    })
  ];
}