{ lib, ... }:
let
  mkNullableOption =
    type:
    lib.mkOption {
      inherit type;
      default = null;
    };

  emailType = lib.types.submodule (
    { ... }:
    {
      options = {
        address = lib.mkOption {
          type = lib.types.str;
        };

        primary = lib.mkOption {
          type = lib.types.bool;
        };

        type = lib.mkOption {
          type = lib.types.str;
        };
      };
    }
  );

  userType = lib.types.submodule (
    { config, ... }:
    {
      options = {
        name = lib.mkOption {
          type = lib.types.str;
        };

        realName = lib.mkOption {
          type = lib.types.str;
        };

        homeDirectory = lib.mkOption {
          type = lib.types.str;
        };

        terminalPackageAttr = lib.mkOption {
          type = lib.types.str;
        };

        nixosConfigurationPath = lib.mkOption {
          type = lib.types.str;
          default = "${config.homeDirectory}/.config/nixos";
        };

        emails = lib.mkOption {
          type = lib.types.attrsOf emailType;
        };
      };
    }
  );

  displayModeType = lib.types.submodule (
    { ... }:
    {
      options = {
        width = lib.mkOption {
          type = lib.types.int;
        };

        height = lib.mkOption {
          type = lib.types.int;
        };

        refresh = lib.mkOption {
          type = lib.types.float;
        };
      };
    }
  );

  displayType = lib.types.submodule (
    { ... }:
    {
      options = {
        primary = lib.mkOption {
          type = lib.types.bool;
          default = false;
        };

        x = lib.mkOption {
          type = lib.types.int;
        };

        y = lib.mkOption {
          type = lib.types.int;
        };

        scale = lib.mkOption {
          type = lib.types.nullOr lib.types.float;
          default = null;
        };

        mode = lib.mkOption {
          type = lib.types.nullOr displayModeType;
          default = null;
        };
      };
    }
  );

  mouseInputType = lib.types.submodule (
    { ... }:
    {
      options = {
        accelProfile = mkNullableOption (lib.types.nullOr (lib.types.enum [
          "adaptive"
          "flat"
        ]));
        accelSpeed = mkNullableOption (lib.types.nullOr lib.types.float);
        leftHanded = mkNullableOption (lib.types.nullOr lib.types.bool);
        middleEmulation = mkNullableOption (lib.types.nullOr lib.types.bool);
        naturalScrolling = mkNullableOption (lib.types.nullOr lib.types.bool);
        scrollMethod = mkNullableOption (lib.types.nullOr (lib.types.enum [
          "no-scroll"
          "two-finger"
          "edge"
          "on-button-down"
        ]));
      };
    }
  );

  touchpadInputType = lib.types.submodule (
    { ... }:
    {
      options = {
        accelProfile = mkNullableOption (lib.types.nullOr (lib.types.enum [
          "adaptive"
          "flat"
        ]));
        accelSpeed = mkNullableOption (lib.types.nullOr lib.types.float);
        clickMethod = mkNullableOption (lib.types.nullOr (lib.types.enum [
          "button-areas"
          "clickfinger"
        ]));
        disableWhileTyping = mkNullableOption (lib.types.nullOr lib.types.bool);
        leftHanded = mkNullableOption (lib.types.nullOr lib.types.bool);
        middleEmulation = mkNullableOption (lib.types.nullOr lib.types.bool);
        naturalScrolling = mkNullableOption (lib.types.nullOr lib.types.bool);
        scrollMethod = mkNullableOption (lib.types.nullOr (lib.types.enum [
          "no-scroll"
          "two-finger"
          "edge"
          "on-button-down"
        ]));
        tapping = mkNullableOption (lib.types.nullOr lib.types.bool);
      };
    }
  );

  inputType = lib.types.submodule (
    { ... }:
    {
      options = {
        mouse = lib.mkOption {
          type = mouseInputType;
          default = { };
        };

        touchpad = lib.mkOption {
          type = touchpadInputType;
          default = { };
        };
      };
    }
  );

  hostType = lib.types.submodule (
    { ... }:
    {
      options = {
        name = lib.mkOption {
          type = lib.types.str;
        };

        displays = lib.mkOption {
          type = lib.types.attrsOf displayType;
          default = { };
        };

        input = lib.mkOption {
          type = inputType;
          default = { };
        };

        users = lib.mkOption {
          type = lib.types.attrsOf userType;
          default = { };
        };
      };
    }
  );
in
{
  flake.modules.nixos.meta = {
    options.meta.host = lib.mkOption {
      type = hostType;
    };
  };

  flake.modules.homeManager.meta = {
    options.meta = {
      host = lib.mkOption {
        type = lib.types.nullOr hostType;
        default = null;
      };

      user = lib.mkOption {
        type = lib.types.nullOr userType;
        default = null;
      };
    };
  };
}