flake-module.nix

{ inputs, ... }:

{
  perSystem =
    { pkgs, lib, ... }:
    {
      apps = lib.mapAttrs' (host: cfg: {
        name = "deploy-${host}";
        value.program = toString (
          pkgs.writeShellScript "deploy-${host}" ''
            if [[ -n "$1" ]]; then 
              TASK="$1" 
            else 
              TASK="switch" 
            fi
            set -x
            ${lib.optionalString cfg.config.security.sudo.wheelNeedsPassword "export NIX_SSHOPTS=-tt"}
            ${
              lib.getExe (pkgs.nixos-rebuild.override { nix = pkgs.nixUnstable; })
            } "$TASK" -s --use-remote-sudo --fast --flake ${inputs.self}#${host} \
            --target-host ${cfg.config.networking.hostName}
          ''
        );
      }) inputs.self.nixosConfigurations;
    };
}