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

let
  cfg = config.aux.system.services.duplicacy-web;
  duplicacy-web = pkgs.callPackage ../../packages/duplicacy-web.nix { inherit pkgs lib; };
in
with lib;
rec {
  options = {
    aux.system.services.duplicacy-web = {
      enable = mkEnableOption (mdDoc "Enables duplicacy-web");
      autostart = mkOption {
        default = true;
        type = types.bool;
        description = "Whether to auto-start duplicacy-web on boot";
      };

      environment = mkOption {
        default = "";
        type = types.str;
        description = "Environment where duplicacy-web stores its config files";
      };
    };
  };

  config = lib.mkIf cfg.enable {
    nixpkgs.config.allowUnfree = true;
    environment.systemPackages = [ duplicacy-web ];

    networking.firewall.allowedTCPPorts = [ 3875 ];

    # Install systemd service.
    systemd.services.duplicacy-web = {
      enable = true;
      wants = [ "network-online.target" ];
      after = [
        "syslog.target"
        "network-online.target"
      ];
      description = "Start the Duplicacy backup service and web UI";
      serviceConfig = {
        Type = "simple";
        ExecStart = ''${duplicacy-web}/duplicacy-web'';
        Restart = "on-failure";
        RestartSrc = 10;
        KillMode = "process";
      };
      environment = {
        HOME = cfg.environment;
      };
    } // lib.optionalAttrs (!cfg.autostart) { wantedBy = lib.mkForce [ ]; };
  };
}