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

with lib;

let
  inputs = mkOption {
    description = "List of packages to build a ROM store with.";
    type = types.listOf types.package;
  };
in {

  options.genode.init = {
    inherit inputs;

    configFile = mkOption {
      description = ''
        Dhall configuration of this init instance after children have been merged.
      '';
      type = types.path;
    };

    baseConfig = mkOption {
      description =
        "Dhall configuration of this init instance before merging children.";
      type = types.str;
      default = ''
        let Genode = env:DHALL_GENODE

        in  Genode.Init::{
            , routes =
              [ Genode.Init.ServiceRoute.parent "File_system"
              , Genode.Init.ServiceRoute.parent "Rtc"
              , Genode.Init.ServiceRoute.parent "Timer"
              , Genode.Init.ServiceRoute.parent "IRQ"
              , Genode.Init.ServiceRoute.parent "IO_MEM"
              , Genode.Init.ServiceRoute.parent "IO_PORT"
              ]
            }
      '';
    };

    children = mkOption {
      default = { };
      type = with types;
        attrsOf (submodule {
          options = {
            inherit inputs;
            configFile = mkOption {
              type = types.path;
              description = ''
                Dhall configuration of child.
                See https://git.sr.ht/~ehmry/dhall-genode/tree/master/Init/Child/Type
              '';
            };
          };
        });
    };

    subinits = mkOption {
      default = { };
      type = with types;
        attrsOf (submodule {
          options = {
            inherit inputs;
            configFile = mkOption {
              type = types.path;
              description = ''
                Dhall configuration of child init.
                See https://git.sr.ht/~ehmry/dhall-genode/tree/master/Init/Type
              '';
            };
          };
        });
    };

  };

  config = {

    genode.init.inputs = with builtins;
      [ pkgs.genodePackages.report_rom ] ++ concatLists (catAttrs "inputs"
        ((attrValues config.genode.init.children)
          ++ (attrValues config.genode.init.subinits)));

    # TODO: convert the subinits to children

    genode.init.configFile = pkgs.writeText "init.dhall" ''
      let Genode = env:DHALL_GENODE
      let baseConfig = ${config.genode.init.baseConfig}

      in baseConfig with children = baseConfig.children # toMap {${
        concatMapStrings (name:
          ", `${name}` = (${
            config.genode.init.children.${name}.configFile
          } : Genode.Init.Child.Type)")
        (builtins.attrNames config.genode.init.children)
      } ${
        concatMapStrings (name: ''
          , `${name}` =
            Genode.Init.toChild
              (${
                config.genode.init.subinits.${name}.configFile
              } : Genode.Init.Type)
              Genode.Init.Attributes.default
        '') (builtins.attrNames config.genode.init.subinits)
      } }
    '';

  };

}