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

let
  defaultUser = "lnbits";
  cfg = config.services.lnbits;
  inherit (lib) mkOption mkIf types optionalAttrs;
in

{
  options = {
    services.lnbits = {
      enable = mkOption {
        default = false;
        type = types.bool;
        description = ''
          Whether to enable the lnbits service
        '';
      };
      openFirewall = mkOption {
        type = types.bool;
        default = false;
        description = ''
          Whether to open the ports used by lnbits in the firewall for the server
        '';
      };
      package = mkOption {
        type = types.package;
        default = pkgs.lnbits;
        description = ''
          The lnbits package to use.
        '';
      };
      stateDir = mkOption {
        type = types.path;
        default = "/var/lib/lnbits";
        description = ''
          The lnbits state directory which LNBITS_DATA_FOLDER will be set to
        '';
      };
      host = mkOption {
        type = types.str;
        default = "127.0.0.1";
        description = ''
          The host to bind to
        '';
      };
      port = mkOption {
        type = types.port;
        default = 8231;
        description = ''
          The port to run on
        '';
      };
      user = mkOption {
        type = types.str;
        default = "lnbits";
        description = "user to run lnbits as";
      };
      group = mkOption {
        type = types.str;
        default = "lnbits";
        description = "group to run lnbits as";
      };
    };
  };

  config = mkIf cfg.enable {
    users.users = optionalAttrs (cfg.user == defaultUser) {
      ${defaultUser} = {
        isSystemUser = true;
        group = defaultUser;
      };
    };

    users.groups = optionalAttrs (cfg.group == defaultUser) {
      ${defaultUser} = { };
    };

    systemd.tmpfiles.rules = [
      "d ${cfg.stateDir}                            0700 ${cfg.user} ${cfg.group} - -"
    ];

    systemd.services.lnbits = {
      enable = true;
      description = "lnbits";
      wantedBy = [ "multi-user.target" ];
      after = [ "network-online.target" ];
      environment = {
        LNBITS_DATA_FOLDER = "${cfg.stateDir}";
      };
      serviceConfig = {
        User = cfg.user;
        Group = cfg.group;
        WorkingDirectory = "${cfg.package.src}";
        StateDirectory = "${cfg.stateDir}";
        ExecStart = "${lib.getExe cfg.package} --port ${toString cfg.port} --host ${cfg.host}";
        Restart = "always";
        PrivateTmp = true;
      };
    };
    networking.firewall = mkIf cfg.openFirewall {
      allowedTCPPorts = [ cfg.port ];
    };
  };
}