{ config, pkgs, lib, ... }:
let
  cfg = config.services.nncp;
  settingsFormat = pkgs.formats.json { };
in
{
  options.services.nncp = {
    daemon = {
      enable = lib.mkEnableOption "NNCP Daemon";
      port = lib.mkOption {
        type = lib.types.port;
      };
    };
    caller = {
      enable = lib.mkEnableOption "NNCP Caller";
    };
    configFile = lib.mkOption {
      type = lib.types.path;
      default = settingsFormat.generate "nncp.hjson" cfg.settings;
    };
    dataDir = lib.mkOption {
      type = lib.types.path;
      default = "/var/lib/nncp";
    };
    user = lib.mkOption {
      type = lib.types.str;
      default = "nncp";
    };
    group = lib.mkOption {
      type = lib.types.str;
      default = "nncp";
    };
    settings = lib.mkOption {
    };
  };
  config = {
    systemd.tmpfiles.rules = lib.mkIf (cfg.daemon.enable || cfg.caller.enable) [
      "d '${cfg.dataDir}' 0770 ${cfg.user} ${cfg.group}"
      "Z '${cfg.dataDir}' 0770 ${cfg.user} ${cfg.group}"
      "d '/var/spool/nncp' 0770 ${cfg.user} ${cfg.group}"
      "Z '/var/spool/nncp' 0770 ${cfg.user} ${cfg.group}"
    ];
    systemd.paths."nncp-watcher" = lib.mkIf (cfg.daemon.enable || cfg.caller.enable) {
      wantedBy = [ "multi-user.target" ];
      pathConfig = {
        PathModified = "/run/keys/nncp";
        Unit = "nncp-reloader.service";
      };
    };
    systemd.services."nncp-reloader" = lib.mkIf (cfg.daemon.enable || cfg.caller.enable) {
      after = [ "networking.target" ];
      script = ''
             exec ${pkgs.nncp}/bin/nncp-cfgdir -cfg ${cfg.configFile} -dump ${cfg.dataDir}
             exec systemd-tmpfiles --create
      '';
      serviceConfig = {
        Type = "oneshot";
        WorkingDirectory = "${cfg.dataDir}";
      };
    };
    systemd.services.nncp-daemon = lib.mkIf cfg.daemon.enable {
      # wantedBy = [ "multi-user.target" ];
      after = [ "nncp-reloader.service" ];
      description = "Node to Node Copy Protocol Daemon";
      serviceConfig = {
        # DynamicUser = true;
        User = cfg.user;
        Group = cfg.group;
        ExecStart = ''${pkgs.nncp}/bin/nncp-daemon -autotoss -noprogress -bind "0.0.0.0:${toString cfg.daemon.port}" -cfg ${cfg.dataDir}'';
        Restart = "always";
        Type = "simple";
        RestartSec = 1;
        StateDirectory = "nncp";
        WorkingDirectory = "${cfg.dataDir}";
      };
    };
    systemd.services.nncp-caller = lib.mkIf cfg.caller.enable {
      # wantedBy = [ "multi-user.target" ];
      after = [ "nncp-reloader.service" ];
      description = "Node to Node Copy Protocol Caller";
      serviceConfig = {
        # DynamicUser = true;
        User = cfg.user;
        Group = cfg.group;
        ExecStart = ''${pkgs.nncp}/bin/nncp-caller -autotoss -noprogress -cfg ${cfg.dataDir}'';
        Restart = "always";
        Type = "simple";
        RestartSec = 1;
        StateDirectory = "nncp";
        WorkingDirectory = "${cfg.dataDir}";
      };
    };
    users.users = lib.mkIf (cfg.user == "nncp") {
      nncp = {
        description = "NNCP daemon user";
        isSystemUser = true;
        group = cfg.group;
        home = cfg.dataDir;
      };
    };
    users.groups = lib.mkIf (cfg.group == "nncp") { nncp = { }; };
  };
}