{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-24.05";
    nixpkgs-unstable.url = "github:nixos/nixpkgs/nixos-unstable";
    home-manager = {
      url = "github:nix-community/home-manager/release-24.05";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    agenix = {
      url = "github:ryantm/agenix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs =
    { self
    , nixpkgs
    , nixpkgs-unstable
    , home-manager
    , agenix
    , ...
    } @ inputs:
    let
      inherit (self) outputs;
    in
    {
      overlays = import ./overlays { inherit inputs; };

      nixosConfigurations = {
        woodpecker = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            # Base configuration and modules.
            ./modules/bspwm
            ./modules/fstrim
            ./modules/libvirtd
            ./modules/nvidia
            ./modules/pipewire
            ./modules/steam
            ./modules/wireshark

            # System configuration.
            ./hosts/workstations
            ./hosts/workstations/woodpecker

            # User configuration.
            ./users/tdback
            home-manager.nixosModules.home-manager {
              home-manager = {
                useGlobalPkgs = true;
                useUserPackages = true;
                users.tdback = import ./users/tdback/dots.nix;
                extraSpecialArgs = { inherit inputs; };
              };
            }
          ];
          specialArgs = { inherit inputs outputs; };
        };

        sparrow = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            # Base configuration and modules.
            ./modules/bspwm
            ./modules/pipewire
            ./modules/vpn

            # System configuration.
            ./hosts/workstations
            ./hosts/workstations/sparrow

            # User configuration.
            ./users/tdback
            home-manager.nixosModules.home-manager {
              home-manager = {
                useGlobalPkgs = true;
                useUserPackages = true;
                users.tdback = import ./users/tdback/dots.nix;
                extraSpecialArgs = { inherit inputs; };
              };
            }
          ];
          specialArgs = { inherit inputs outputs; };
        };

        raindog = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            # Base configuration and modules.
            ./containers/pihole
            ./modules/motd
            ./modules/podman
            ./modules/searx
            ./modules/ssh

            # System configuration.
            ./hosts/servers
            ./hosts/servers/raindog

            # User configuration.
            ./users/tdback
          ];
          specialArgs = { inherit inputs outputs; };
        };

        oasis = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            # Base configuration and modules.
            ./modules/forgejo
            ./modules/motd
            ./modules/podman
            ./modules/proxy
            ./modules/pushover
            ./modules/sftpgo
            ./modules/ssh
            ./modules/wireguard
            ./modules/zfs

            # System configuration and secrets.
            ./hosts/servers
            ./hosts/servers/oasis
            agenix.nixosModules.default

            # User configuration.
            ./users/tdback
          ];
          specialArgs = { inherit inputs outputs; };
        };

        hive = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            # Base configuration and modules.
            ./modules/fediverse
            ./modules/mealie
            ./modules/motd
            ./modules/proxy
            ./modules/ssh
            ./modules/wireguard

            # System configuration.
            ./hosts/servers
            ./hosts/servers/hive

            # User configuration.
            ./users/tdback
          ];
          specialArgs = { inherit inputs outputs; };
        };

        eden = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            # Base configuration and modules.
            ./containers/freshrss
            ./containers/jellyfin
            ./containers/navidrome
            ./containers/pinchflat
            ./containers/stirling-pdf
            ./containers/vaultwarden
            ./containers/watchtower
            ./modules/immich
            ./modules/motd
            ./modules/podman
            ./modules/proxy
            ./modules/pushover
            ./modules/ssh
            ./modules/wireguard
            ./modules/zfs

            # System configuration and secrets.
            ./hosts/servers
            ./hosts/servers/eden
            agenix.nixosModules.default

            # User configuration.
            ./users/tdback
          ];
          specialArgs = { inherit inputs outputs; };
        };
      };
    };
}