{
  description = "A very basic flake";

  inputs = {
    deploy-rs = {
      url = "github:serokell/deploy-rs";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    image-builder.url = "git+https://git.asonix.dog/asonix/nixos-aarch64-images";
    nixpkgs.url = "github:nixos/nixpkgs/master";
    sops-nix = {
      url = "github:Mic92/sops-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

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

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

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

      sharedModule = {
        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;

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

        environment.systemPackages = with pkgs; [
          bottom
          btrbk
          cryptsetup
          htop
        ];

        sops = {
          age.keyFile = "/home/asonix/.config/sops/age/keys.txt";
          age.generateKey = true;
          secrets.private_key = {
            format = "yaml";
            sopsFile = ./secrets/btrbk.yaml;
          };
          secrets.nextcloudKeyFile = {
            format = "binary";
            sopsFile = ./secrets/nextcloudKeyFile.bin;
          };
          secrets.redtailKeyFile = {
            format = "binary";
            sopsFile = ./secrets/redtailKeyFile.bin;
          };
          secrets.whitestormKeyFile = {
            format = "binary";
            sopsFile = ./secrets/whitestormKeyFile.bin;
          };
        };
      };

      btrbkModule = ({ primaryIp ? null, mountDir, subvolumes }: { config, ... }:
        let
          primary = {
            snapshot_preserve_min = "2d";
            snapshot_preserve = "35d 20w 12m";
            transaction_log = "/var/log/btrbk.log";
            volume = {
              "${mountDir}" = btrbkPrimary {
                inherit subvolumes;
              };
            };
          };
          secondary = {
            backend_remote = "btrfs-progs-sudo";
            ssh_identity = config.sops.secrets.private_key.path;
            ssh_user = "btrbk";
            stream_buffer = "512m";
            stream_compress = "gzip";
            stream_compress_level = "default";
            stream_compress_threads = "default";
            target_preserve = "24h 7d";
            target_preserve_min = "24h";
            transaction_log = "/var/log/btrbk.log";
            volume = {
              "ssh://${primaryIp}${mountDir}" = btrbkSecondary {
                targetDir = "${mountDir}/@snapshots";
                inherit subvolumes;
              };
            };
          };
          selected = if primaryIp == null then primary else secondary;
        in
        {
          services.btrbk = {
            sshAccess = [
              {
                key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHTqU3EvTgY5/e9m6YyQWypQPK58t9iPmPnPYAvnODGB asonix@lionheart";
                roles = [ "source" "info" "send" ];
              }
            ];
            extraPackages = with pkgs; [ gzip ];
            instances.btrbk = {
              onCalendar = "hourly";
              settings = selected;
            };
          };
        }
      );

      makeDockerConfig = { hostname, extraModules ? [ ] }:
        with image-builder.packages.aarch64-linux.modules;
        nixpkgs.lib.nixosSystem {
          system = "aarch64-linux";
          modules = [
            sops-nix.nixosModules.sops
            sharedModule
            userModule
            ({ config, ... }: {
              environment.systemPackages = with pkgs; [
                docker
                docker-compose
              ];

              networking.hostName = hostname;

              virtualisation.docker.enable = true;
            })
          ] ++ extraModules;
        };

      makeNextcloudConfig = { hostname, primaryIp ? null }:
        with image-builder.packages.aarch64-linux.modules;
        let
          mountDir = "/btrfs/hdd";
        in
        makeDockerConfig {
          inherit hostname;

          extraModules = [
            rockPro64v2
            (btrbkModule {
              inherit mountDir primaryIp;

              subvolumes = [
                "@nc-config"
                "@nc-data"
                "@postgres"
                "@redis"
                "@gitea"
                "@gitea-conf"
                "@pihole"
                "@papermc"
                "@docker-cfg"
                "@garage"
                "@garage-config"
              ];
            })
            ({ config, ... }: {
              environment.etc.crypttab = {
                enable = true;
                text = ''
                  cryptdrive1 /dev/sda1 ${config.sops.secrets.nextcloudKeyFile.path} luks
                  cryptdrive2 /dev/sdb1 ${config.sops.secrets.nextcloudKeyFile.path} luks
                  cryptdrive3 /dev/sdc1 ${config.sops.secrets.nextcloudKeyFile.path} luks
                '';
              };

              fileSystems."${mountDir}" = {
                device = "/dev/mapper/cryptdrive1";
                fsType = "btrfs";
                options = [ "defaults" "compress=zstd" "rw" ];
              };
            })
          ];
        };

      makePostgresConfig = { hostname, keyFile, primaryIp ? null }:
        with image-builder.packages.aarch64-linux.modules;
        let
          mountDir = "/btrfs/ssd";
        in
        makeDockerConfig {
          inherit hostname;

          extraModules = [
            rock64
            (btrbkModule {
              inherit mountDir primaryIp;

              subvolumes = [
                "postgres"
                "postgres-cfg"
              ];
            })
            ({ config, ... }:
              let
                keyFilePath = config.sops.secrets."${keyFile}".path;
              in
              {
                environment.etc.crypttab = {
                  enable = true;
                  text = ''
                    cryptdrive1 /dev/sda1 ${keyFilePath} luks
                  '';
                };

                fileSystems."${mountDir}" = {
                  device = "/dev/mapper/cryptdrive1";
                  fsType = "btrfs";
                  options = [ "defaults" "compress=zstd" "rw" ];
                };
              })
          ];
        };

      deployer = { hostname, configuration }: {
        hostname = hostname;
        profiles.system = {
          sshUser = "asonix";
          user = "root";
          magicRollback = false;
          sshOpts = [
            "-i"
            "/home/asonix/.ssh/kube-rsa"
            "-t"
          ];
          path = deploy-rs.lib.aarch64-linux.activate.nixos configuration;
        };
      };
    in
    {
      nixosConfigurations = {
        nextcloud1 = makeNextcloudConfig {
          hostname = "nextcloud1";
          # primaryIp = "192.168.20.28";
        };

        nextcloud2 = makeNextcloudConfig {
          hostname = "nextcloud2";
          primaryIp = "192.168.20.21";
        };

        redtail1 = makePostgresConfig {
          hostname = "redtail1";
          keyFile = "redtailKeyFile";
          primaryIp = "192.168.20.24";
        };

        redtail2 = makePostgresConfig {
          hostname = "redtail2";
          keyFile = "redtailKeyFile";
          # primaryIp = "192.168.20.23";
        };

        whitestorm1 = makePostgresConfig {
          hostname = "whitestorm1";
          keyFile = "whitestormKeyFile";
          # primaryIp = "192.168.20.11";
        };

        whitestorm2 = makePostgresConfig {
          hostname = "whitestorm2";
          keyFile = "whitestormKeyFile";
          primaryIp = "192.168.20.26";
        };
      };

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