{
  inputs = {
    nixpkgs.url = "nixpkgs/nixos-unstable";
    agenix = {
      url = "github:ryantm/agenix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, agenix, ... }:
    let 
      lib = nixpkgs.lib; 
      proj_root = ./../..;
      # TODO: Change respectively to the system or make a nix shell to alias `nix run github:ryantm/agenix -- `
      base_modules = [
        agenix.nixosModule
        {
          age.secrets.s3fs = {
            file = ./secrets/s3fs.age;
            # mode = "600";  # owner + group only
            # owner = "hungtr";
            # group = "users";
          };
          age.secrets."s3fs.digital-garden" = {
            file = ./secrets/s3fs.digital-garden.age;
          };
          age.secrets._nhitrl_cred = {
            file = ./secrets/_nhitrl.age;
          };
          environment.systemPackages = [agenix.defaultPackage.x86_64-linux];
        }
      ];
    in {
      # Windows with NixOS WSL
      nixosConfigurations.Felia = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = base_modules ++ [
          ./wsl-configuration.nix
          {
            system.stateVersion = "22.05";
          }
        ];
        specialArgs = {
          # includeHardware = false;
          hostname = "Felia";
          _services.openssh = {
            permitRootLogin = "no";
            enable = true;
          };
        };
      };
      nixosConfigurations.lizzi = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = base_modules ++ [
          ./configuration.nix
          {
            system.stateVersion = "22.05";
          }
        ];
        specialArgs = {
          hostname = "lizzi";
          _networking = {
            interfaces.eth1.ipv4.addresses = [{
              address = "71.0.0.1";
              prefixLength = 24;
            }];
            firewall = {
              enable = true;
              allowedTCPPorts = [ 80 443 22 ];
            };
            useDHCP = false;
            # required so that we get IP address from linode
            interfaces.eth0.useDHCP = true;
          };
          _boot.loader.grub.enable = true;
          _boot.loader.grub.version = 2;
          _services.openssh = {
            permitRootLogin = "no";
            enable = true;
          };
          _services.gitea = {
            enable = true;
            stateDir = "/gitea";
            rootUrl = "https://git.pegasust.com";
            settings = {
              repository = {
                "ENABLE_PUSH_CREATE_USER" = true;
                "ENABLE_PUSH_CREATE_ORG" = true;
              };
            };
          };
          # Highly suspect that thanks to nginx, ipv6 is disabled?
          _services.nginx = {
            enable = true;
            clientMaxBodySize = "100m"; # Allow big file transfers over git :^)
            recommendedGzipSettings = true;
            recommendedOptimisation = true;
            recommendedProxySettings = true;
            recommendedTlsSettings = true;
            virtualHosts."git.pegasust.com" = {
              # Gitea hostname
              sslCertificate = "/var/lib/acme/git.pegasust.com/fullchain.pem";
              sslCertificateKey = "/var/lib/acme/git.pegasust.com/key.pem";
              forceSSL = true; # Runs on port 80 and 443
              locations."/".proxyPass = "http://localhost:3000/"; # Proxy to Gitea
            };
          };
        };
      };
      # Generic machine
      nixosConfigurations.pixi = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = base_modules ++ [
          ./configuration.nix
          {
            system.stateVersion = "22.05";
          }
        ];
        specialArgs = {
          hostname = "pixi";
          _networking = {
            # interfaces.eth1.ipv4.addresses = [{
            #   address = "71.0.0.1";
            #   prefixLength = 24;
            # }];
            firewall = {
              enable = false;
              allowedTCPPorts = [ 80 443 22 ];
            };
            useDHCP = false;
            # interfaces.eth0.useDHCP = true;
          };
          _boot.loader.grub.enable = true;
          _boot.loader.grub.version = 2;
          _services.openssh = {
            permitRootLogin = "no";
            enable = true;
          };
          _services.gitea = {
            enable = true;
            stateDir = "/gitea";
            rootUrl = "https://git.pegasust.com";
            settings = {
              repository = {
                "ENABLE_PUSH_CREATE_USER" = true;
                "ENABLE_PUSH_CREATE_ORG" = true;
              };
            };
          };
          _services.nginx = {
            enable = true;
            clientMaxBodySize = "100m"; # Allow big file transfers over git :^)
            recommendedGzipSettings = true;
            recommendedOptimisation = true;
            recommendedProxySettings = true;
            recommendedTlsSettings = true;
            virtualHosts."git.pegasust.com" = {
              # Gitea hostname
              sslCertificate = "/var/lib/acme/git.pegasust.com/fullchain.pem";
              sslCertificateKey = "/var/lib/acme/git.pegasust.com/key.pem";
              forceSSL = true; # Runs on port 80 and 443
              locations."/".proxyPass = "http://localhost:3000/"; # Proxy to Gitea
            };
          };
        };
      };
      nixosConfigurations.nyx = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = base_modules ++ [
          ./configuration.nix
          {
            system.stateVersion = "22.05";
          }
        ];
        specialArgs = {
          hostname = "nyx";
          _networking = {
            enableIPv6 = false;
            interfaces.eth1.ipv4.addresses = [{
              address = "71.0.0.2";
              prefixLength = 24;
            }];
            firewall.enable = true;
            useDHCP = false;
            interfaces.eth0.useDHCP = true;
          };
          _boot.loader.grub.enable = true;
          _boot.loader.grub.version = 2;
          _services.openssh = {
            permitRootLogin = "no";
            enable = true;
          };
        };
      };
      nixosConfigurations.nixos = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = base_modules ++ [
          ./configuration.nix
          {
            system.stateVersion = "22.05";
          }
        ];
        specialArgs = {
          hostname = "nixos";
        };
      };
      nixosConfigurations.bao = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
	      specialArgs.hostname = "bao";
        modules = base_modules ++ [
          ./configuration.nix
          # automount using s3fs
          ({config, pkgs, lib, ...}: {
            environment.systemPackages = [pkgs.s3fs pkgs.cifs-utils]; # s3fs-fuse
            # Sadly, autofs uses systemd, so we can't put it in home-manager
            # HACK: need to store secret somewhere so that root can access this
            # because autofs may run as root for now, we enforce putting the secret in this monorepo
            # services.rpcbind.enable = true;
            services.autofs = let 
              # confToBackendArg {lol="what"; empty=""; name_only=null;} -> "lol=what,empty=,name_only"
              # TODO: change null -> true/false. This allows overriding & better self-documentation
              confToBackendArg = conf: (lib.concatStringsSep ","
                (lib.mapAttrsToList (name: value: "${name}${lib.optionalString (value != null) "=${value}"}") conf));

              # mount_dest: path ("wow")
              # backend_args: nix attrs representing the arguments to be passed to s3fs 
              #    ({"-fstype" = "fuse"; "use_cache" = "/tmp";})
              # bucket: bucket name (hungtr-hot)
              #     NOTE: s3 custom provider will be provided inside
              #    backend_args, so just put the bucket name here
              #
              #-> "${mount_dest} ${formatted_args} ${s3fs-bin}#${bucket}"
              autofs-s3fs_entry = {
                mount_dest,
                backend_args? {"-fstype" = "fuse";}, 
                bucket
              }@inputs: let
                s3fs-exec = "${pkgs.s3fs}/bin/s3fs";
              in "${mount_dest} ${confToBackendArg backend_args} :${s3fs-exec}\#${bucket}";
              personalStorage = [
                # hungtr-hot @ phoenix is broken :)
                # (autofs-s3fs_entry {
                #   mount_dest = "hot";
                #   backend_args = {
                #     "-fstype" = "fuse";
                #     use_cache = "/tmp";
                #     del_cache = null;
                #     allow_other = null;
                #     url = ''"https://f5i0.ph.idrivee2-32.com"'';
                #     # TODO: builtins.readFile requires a Git-controlled file
                #     passwd_file = config.age.secrets.s3fs.path;
                #     dbglevel = "debug"; # enable this for better debugging info in journalctl
                #     uid = "1000"; # default user
                #     gid = "100";  # users
                #     umask="003";  # others read only, fully shared for users group
                #     # _netdev = null; # ignored by s3fs (https://github.com/s3fs-fuse/s3fs-fuse/blob/master/src/s3fs.cpp#L4910)
                #   };
                #   bucket = "hungtr-hot";
                # })
                (autofs-s3fs_entry {
                  mount_dest = "garden";
                  backend_args = {
                    "-fstype" = "fuse";
                    use_cache = "/tmp";
                    del_cache = null;
                    allow_other = null;
                    url = "https://v5h5.la11.idrivee2-14.com";
                    passwd_file = config.age.secrets."s3fs.digital-garden".path;
                    dbglevel = "debug"; # enable this for better debugging info in journalctl
                    uid = "1000"; # default user
                    gid = "100";  # users
                    umask="003";  # others read only, fully shared for users group
                  };
                  bucket = "digital-garden";
                })
                (let args = {
                  "-fstype" = "cifs";
                  credentials = config.age.secrets._nhitrl_cred.path;
                  user = null;
                  uid = "1001";
                  gid = "100";
                  dir_mode = "0777";
                  file_mode = "0777";
                };
                in "felia_d ${confToBackendArg args} ://felia.coati-celsius.ts.net/d")
                (let args = {
                  "-fstype" = "cifs";
                  credentials = config.age.secrets._nhitrl_cred.path;
                  user = null;
                  uid = "1001";
                  gid = "100";
                  dir_mode = "0777";
                  file_mode = "0777";
                };
                in "felia_f ${confToBackendArg args} ://felia.coati-celsius.ts.net/f")
              ];
              persoConf = pkgs.writeText "auto.personal" (builtins.concatStringsSep "\n" personalStorage);
            in {
              enable = true;
              # Creates /perso directory with every subdirectory declared by ${personalStorage}
              # as of now (might be stale), /perso/hot is the only mount accessible
              # that is also managed by s3fs
              autoMaster = ''
                /perso file:${persoConf}
              '';
              timeout = 30; # default: 600, 600 seconds (10 mins) of inactivity => unmount
              # debug = true; # writes to more to journalctl
            };
          })
          # GPU, sound, networking stuffs
          ({ config, pkgs, lib, ... }:
          let
            gpu_pkgs = [ pkgs.clinfo pkgs.lshw pkgs.glxinfo pkgs.pciutils pkgs.vulkan-tools ];
            gpu_conf = {
              # openCL
              hardware.opengl = {
                enable = true;
                extraPackages = let 
                  inherit (pkgs) rocm-opencl-icd rocm-opencl-runtime;
                  in [rocm-opencl-icd rocm-opencl-runtime];
                # Vulkan
                driSupport = true;
                driSupport32Bit = true;
                package = pkgs.mesa.drivers;
                package32 = pkgs.pkgsi686Linux.mesa.drivers;
              };
            };
            amd_rx470 = {
              # early amd gpu usage
              # boot.initrd.kernelModules = ["amdgpu"];
              services.xserver.enable = true;
              services.xserver.videoDrivers = ["amdgpu"];
            };
            nv_rtx3060 = {
              nixpkgs.config.allowUnfree = true;
              services.xserver.enable = true;
              services.xserver.videoDrivers = ["nvidia"];
              hardware.nvidia.package = config.boot.kernelPackages.nvidiaPackages.stable;
            };
            systemPackages = [] ++ gpu_pkgs;
          in
          lib.recursiveUpdate gpu_conf (lib.recursiveUpdate nv_rtx3060 {
            # Use UEFI
            boot.loader.systemd-boot.enable = true;

            networking.hostName = "bao"; # Define your hostname.
            # Pick only one of the below networking options.
            # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
            networking.networkmanager.enable = true;  # Easiest to use and most distros use this by default.

            # Enable the X11 windowing system.
            services.xserver.enable = true;
            # KDE & Plasma 5
            services.xserver.displayManager.sddm.enable = true;
            services.xserver.desktopManager.plasma5 = {
              enable = true;
              excludePackages = let plasma5 = pkgs.libsForQt5; in [
                plasma5.elisa       # audio viewer
                plasma5.konsole     # I use alacritty instaed
                plasma5.plasma-browser-integration
                plasma5.print-manager # will enable if I need
                plasma5.khelpcenter   # why not just write manpages instead :(
                # plasma5.ksshaskpass   # pls just put prompts on my dear terminal
              ];
            };
            
            # disables KDE's setting of askpassword
            programs.ssh.askPassword = "";  
            programs.ssh.enableAskPassword = false;

            time.timeZone = "America/Phoenix";
            # Configure keymap in X11
            services.xserver.layout = "us";
            # services.xserver.xkbOptions = {
            #   "eurosign:e";
            #   "caps:escape" # map caps to escape.
            # };

            # Enable CUPS to print documents.
            # services.printing.enable = true;

            # Enable sound. (pulse audio)
            sound.enable = true;
            programs.dconf.enable = true;
            hardware.pulseaudio.enable = true;
            hardware.pulseaudio.support32Bit = true;
            nixpkgs.config.pulseaudio = true;
            hardware.pulseaudio.extraConfig = "load-module module-combine-sink";

            # Sound: pipewire
            # sound.enable = false;
            # hardware.pulseaudio.enable = false;
            # services.pipewire = {
            #   enable = true;
            #   alsa.enable = true;
            #   alsa.support32Bit = true;
            #   pulse.enable = true;
            #   # Might want to use JACK in the future
            #   jack.enable = true;
            # };
            #
            # security.rtkit.enable = true;


            # Enable touchpad support (enabled default in most desktopManager).
            # services.xserver.libinput.enable = true;

            # Define a user account. Don't forget to set a password with ‘passwd’.
            # users.users.alice = {
            #   isNormalUser = true;
            #   extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
            #   packages = with pkgs; [
            #     firefox
            #     thunderbird
            #   ];
            # };
            # Just an initial user to get this started lol
            users.users.user = {
              initialPassword = "pw123";
              extraGroups = [ "wheel" "networkmanager" "audio"];
              isNormalUser = true;
            };

            # List packages installed in system profile. To search, run:
            # $ nix search wget
            environment.systemPackages = with pkgs; [
              neovim 
              wget
            ] ++ systemPackages;

            # Some programs need SUID wrappers, can be configured further or are
            # started in user sessions.
            # programs.mtr.enable = true;
            # programs.gnupg.agent = {
            #   enable = true;
            #   enableSSHSupport = true;
            # };

            # List services that you want to enable:

            # Enable the OpenSSH daemon.
            services.openssh.enable = true;

            # Open ports in the firewall.
            # networking.firewall.allowedTCPPorts = [ ... ];
            # networking.firewall.allowedUDPPorts = [ ... ];
            # Or disable the firewall altogether.
            # networking.firewall.enable = false;

            # Copy the NixOS configuration file and link it from the resulting system
            # (/run/current-system/configuration.nix). This is useful in case you
            # accidentally delete configuration.nix.
            # system.copySystemConfiguration = true;

            # This value determines the NixOS release from which the default
            # settings for stateful data, like file locations and database versions
            # on your system were taken. It‘s perfectly fine and recommended to leave
            # this value at the release version of the first install of this system.
            # Before changing this value read the documentation for this option
            # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
            system.stateVersion = "22.11"; # Did you read the comment?
          }))
        ];
      };
    };
}