{
  description = "A very basic flake";

  inputs = {
    deploy-rs.url = "github:serokell/deploy-rs";
    nixpkgs.url = "github:nixos/nixpkgs/master";
    image-builder.url = "git+https://git.asonix.dog/asonix/nixos-aarch64-images";
  };

  outputs = { self, deploy-rs, image-builder, nixpkgs }:
    let
      pkgs = import nixpkgs {
        system = "aarch64-linux";
      };

      btrbkPrimary = { subvolumes ? [ ] }: {
        snapshot_dir = "@snapshots";
        subvolume = builtins.foldl'
          (acc: subvol: acc // {
            ${subvol} = { };
          })
          { }
          subvolumes;
      };

      btrbkSecondary = { target-dir, subvolumes ? [ ] }: {
        target = "send-receive ${target-dir}";
        subvolume = builtins.foldl'
          (acc: subvol: acc // {
            ${subvol} = {
              snapshot_dir = "@snapshots";
              snapshot_preserve_min = "all";
              snapshot_create = "no";
            };
          })
          { }
          subvolumes;
      };

      nextcloudSubvolumes = [
        "@nc-config"
        "@nc-data"
        "@postgres"
        "@redis"
        "@gitea"
        "@gitea-conf"
        "@pihole"
        "@papermc"
        "@docker-cfg"
        "@garage"
        "@garage-config"
      ];

      sharedModule = { extraPackages ? [ ] }: {
        services.openssh.settings.PasswordAuthentication = false;

        # Use the extlinux boot loader. (NixOS wants to enable GRUB by default)
        boot.loader.grub.enable = false;
        # Enables the generation of /boot/extlinux/extlinux.conf
        boot.loader.generic-extlinux-compatible.enable = true;

        users.users.asonix = {
          isNormalUser = true;
          description = "Tavi";
          extraGroups = [ "wheel" ];
          openssh.authorizedKeys.keys = [
            "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQD3+mNUlokSKZQNXJAuGm2LCHelKuElWLJArzIYZQYEPbrFaE+J8VtfNbMMD1qVI21ksfcqvFQW4aiP4+BFDxTOGW0uBmUHWKxkyyU39y2yhnsa+svwwIooc+Iwkxw0atzSMEBb94UaZlq9cKMSnG9RGeRFqfYnW2s49wpU79wk6zEFUuOHCMKn4R7zqkPac7IyjxZeKlspY3fOasNH4zyrkbhEOlvrwEOdRNTRNCWWzDcinIVZjfmErHlSynshx9yLnCGkLBxHSxgI2TVyR3RlQ3aGbHtB3QN5X7/T/dwXJFJ11P1Q2bC3XP3hHCogDqXcPvDTFSQEM/mZuFcKNbsn asonix@asonix-tower"
          ];
        };

        fileSystems."/" =
          {
            device = "/dev/disk/by-uuid/44444444-4444-4444-8888-888888888888";
            fsType = "ext4";
          };

        environment.systemPackages = with pkgs; [
          btrbk
        ] ++ extraPackages;

        services.btrbk = {
          sshAccess = [
            {
              key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHTqU3EvTgY5/e9m6YyQWypQPK58t9iPmPnPYAvnODGB asonix@lionheart";
              roles = [ "source" "info" "send" ];
            }
          ];
          extraPackages = with pkgs; [ xz ];
          instances.btrbk.settings = {
            transaction_log = "/var/log/btrbk.log";
            stream_buffer = "512m";
            snapshot_preserve_min = "2d";
            snapshot_preserve = "35d 20w 12m";
            target_preserve_min = "24h";
            target_preserve = "24h 7d";
            archive_preserve_min = "latest";
            archive_preserve = "12m 10y";
            ssh_user = "btrbk";
            ssh_identity = "/etc/btrbk/ssh/backup-ssh-key";
            backend_remote = "btrfs-progs-sudo";
          };
        };
      };

      makeDockerConfig = { hostName, volume }: nixpkgs.lib.nixosSystem {
        system = "aarch64-linux";
        modules = [
          image-builder.packages.aarch64-linux.modules.rockPro64v2
          (sharedModule
            {
              extraPackages = with pkgs; [
                docker
                docker-compose
              ];
            })
          {
            networking.hostName = hostName;

            virtualisation.docker.enable = true;

            services.btrbk.instances.btrbk.settings.volume = volume;
          }
        ];
      };

      deployer = { hostname, configuration }: {
        hostname = hostname;
        profiles.system = {
          user = "root";
          sshOpts = [
            "-i"
            "/home/asonix/.ssh/nix-installer"
          ];
          path = deploy-rs.lib.aarch64-linux.activate.nixos configuration;
        };
      };
    in
    {
      nixosConfigurations.nextcloud1 = makeDockerConfig {
        hostName = "nextcloud1";
        volume = {
          # "ssh://192.168.20.28/btrfs/hdd" = btrbkSecondary {
          #   target-dir = "/btrfs/hdd/@snapshots";
          #   subvolumes = nextcloudSubvolumes;
          # };
          "/btrfs/hdd" = btrbkPrimary {
            subvolumes = nextcloudSubvolumes;
          };
        };
      };

      nixosConfigurations.nextcloud2 =
        makeDockerConfig {
          hostName = "nextcloud2";
          volume = {
            "ssh://192.168.20.21/btrfs/hdd" = btrbkSecondary {
              target-dir = "/btrfs/hdd/@snapshots";
              subvolumes = nextcloudSubvolumes;
            };
            # "/btrfs/hdd" = btrbkPrimary {
            #   subvolumes = nextcloudSubvolumes;
            # };
          };
        };

      deploy.nodes.nextcloud2 = deployer {
        hostname = "192.168.20.28";
        configuration = self.nixosConfigurations.nextcloud2;
      };
    };
}