system/modules/home-manager/services/lan-mouse/default.nix

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

let
  cfg = config.local.services.lan-mouse;

  connectionSettings = with lib; (types.submodule {
    options = {
      hostname = mkOption {
        type = types.str;
        default = "";
      };
      ips = mkOption {
        type = types.listOf types.str;
        default = [ ];
      };
      port = mkOption {
        type = types.int;
        default = 4242;
      };
      activateOnStartup = mkOption {
        type = types.bool;
        default = false;
      };
    };
  });

  # See: https://github.com/feschber/lan-mouse/blob/main/src/config.rs#L79
  lanMouseConfig = pkgs.writeText "config.toml" (
    let
      # List[str] -> str
      listOfStr = lib.concatMapStringsSep "," (val: "\"${val}\"");
    in
    ''
      port = ${toString cfg.settings.port}
      frontent = "${cfg.settings.frontend}"
    ''
    + lib.optionalString (cfg.settings.releaseBind != [ ]) ''
      release_bind = [${listOfStr cfg.settings.releaseBind}]
    ''
    + (builtins.concatStringsSep "\n"
      (lib.flip lib.mapAttrstoList cfg.settings.connections (key: value: ''
        [${key}]
        ips = [${listOfStr value.ips}]
        ${lib.optionalString (value.hostname != "") ''
          hostname = "${value.hostname}"
        ''}
        port = ${toString value.port}
        activate_on_startup = ${if value.activateOnStartup then "true" else "false"}
      ''
      ))
    )
  );
in
{
  options.local.services.lan-mouse = with lib; {
    enable = mkEnableOption "lan-mouse";
    settings = {
      releaseBind = mkOption {
        type = types.listOf types.str;
        default = [ ];
      };
      frontend = mkOption {
        type = types.enum [ "cli" "gtk" ];
        default = "gtk";
      };
      port = mkOption {
        type = types.int;
        default = 4242;
      };
      connections = mkOption {
        type = types.attrsOf connectionSettings;
        default = { };
      };
    };
  };

  config = lib.mkIf cfg.enable {
    programs.lan-mouse = {
      enable = true;
      # systemd = true;
      package = pkgs.unstable.lan-mouse;
    };

    xdg.configFile."lan-mouse/config.toml".source = lanMouseConfig;
  };
}