{
  description = "NixOS + Home Manager configuration of chayleaf";

  inputs = {
    nix-community-infra.url = "github:nix-community/infra";
    nixpkgs-kernel.url = "github:NixOS/nixpkgs/a58bc8ad779655e790115244571758e8de055e3d";
    nixpkgs.url = "github:chayleaf/nixpkgs/ci";
    nixvim.url = "github:nix-community/nixvim";
    nixos-hardware.url = "github:NixOS/nixos-hardware";
    nix-index-database = {
      url = "github:nix-community/nix-index-database";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    mobile-nixos = {
      url = "github:chayleaf/mobile-nixos/sdm845";
      flake = false;
    };
    osu-wine = {
      url = "github:chayleaf/osu-wine.nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    impermanence.url = "github:nix-community/impermanence";
    nur.url = "github:nix-community/NUR";
    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    coop-fd = {
      url = "github:chayleaf/coop-fd";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    home-manager = {
      url = "github:chayleaf/home-manager/ci";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nix-gaming = {
      url = "github:fufexan/nix-gaming";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    notlua = {
      url = "github:chayleaf/notlua";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    notnft = {
      url = "github:chayleaf/notnft";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nixos-router = {
      url = "github:chayleaf/nixos-router";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nixos-mailserver = {
      url = "gitlab:simple-nixos-mailserver/nixos-mailserver";
      inputs.nixpkgs.follows = "nixpkgs";
      inputs.nixpkgs-24_05.follows = "nixpkgs";
    };
    unbound-rust-mod = {
      url = "github:chayleaf/unbound-rust-mod";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    flake-compat = {
      url = "github:edolstra/flake-compat";
      flake = false;
    };
  };

  outputs = base-inputs@{ self, nixpkgs, ... }:
  let
    # --impure required for developing
    # it takes the paths for modules from filesystem as opposed to flake inputs
    dev = {
      # coop-fd = true;
      # home-manager = true;
      # mobile-nixos = true;
      # nixos-router = true;
      # notnft = true;
      # nixpkgs = true;
      # unbound-rust-mod = true;
    };
    # IRL-related stuff I'd rather not put into git
    priv =
      if builtins.pathExists ./private.nix then import ./private.nix { }
      else if builtins.pathExists ./private/default.nix then import ./private { }
      # workaround for git flakes not having access to non-checked out files
      else if builtins?extraBuiltins.secrets then builtins.extraBuiltins.secrets
      # yes, this is impure, this is a last ditch effort at getting access to secrets
      else import /secrets/nixos { };
    devPath = priv.devPath or ../.;
    inputs = builtins.mapAttrs
      (name: input:
        if dev.${name} or false then
          (if input._type or null == "flake"
          then let inputs = input.inputs // { self = (import /${devPath}/${name}/flake.nix).outputs inputs; };
          in { __toString = _: "/${toString devPath}/${name}"; } // inputs.self
          else /${devPath}/${name})
          else input)
      base-inputs;
    # if x has key s, get it. Otherwise return def
    # All private config for hostname
    getPriv = hostname: priv.${hostname} or { };
    # Private NixOS config for hostname
    getPrivSys = hostname: (getPriv hostname).system or { };
    # Private home-manager config for hostname and username
    getPrivUser = hostname: user: (getPriv hostname).${user} or { };
    # extended lib
    lib = inputs.nixpkgs.lib // import ./lib.nix { inherit (nixpkgs) lib; };
    # can't use callPackage ./pkgs here, idk why; use import instead
    overlay' = args: self: super: import (if args.pluginsOverlay or false then ./pkgs/nix-plugins-overlay.nix else ./pkgs) ({
      pkgs = super;
      pkgs' = self;
      lib = super.lib;
      inherit inputs;
    } // args);
    overlay = overlay' { };
    nix-plugins-overlay = overlay' { pluginsOverlay = true; };
    all-overlays = [ nix-plugins-overlay overlay ];
    # I override some settings down the line, but overlays always stay the same
    mkPkgs = config: import (config.flake or nixpkgs) (builtins.removeAttrs config ["flake"] // {
      overlays = config.overlays or ([ ] ++ all-overlays);
    });
    # this is actual config, it gets processed below
    config = let
      mkBpiR3 = args: config: config // {
        system = "aarch64-linux";
        modules = config.modules or [ ] ++ [
          (import ./system/devices/bpi-r3-router.nix args)
        ];
      };
      routerConfig = rec {
        system = "aarch64-linux";
        modules = [
          { _module.args.server-config = self.nixosConfigurations.server.config;
            _module.args.notnft = inputs.notnft.lib.${system}; }
          inputs.nixos-router.nixosModules.default
        ];
      };
    in {
      router-emmc = mkBpiR3 "emmc" routerConfig;
      router-sd = mkBpiR3 "sd" routerConfig;
      ereader = {
        # TODO uncom
        flake = inputs.nixpkgs-kernel;
        system = "aarch64-linux";
        modules = [
          ./system/devices/kobo-clara-hd-ereader.nix
          {
            nixpkgs.crossSystem.system = "armv7l-linux";
            # nixpkgs.localSystem.system = "aarch64-linux";
          }
        ];
        home.user = [ ./home/hosts/ereader.nix ];
        home.common.enableNixosModule = true;
      };
      server = {
        system = "aarch64-linux";
        modules = [
          { _module.args.router-config = self.nixosConfigurations.router-emmc.config; }
          ./system/devices/radxa-rock5a-server.nix
        ];
      };
      nixmsi = rec {
        system = "x86_64-linux";
        modules = [ ./system/devices/msi-delta-15-workstation.nix ];
        home.common.modules = [ inputs.nixvim.homeManagerModules.default ];
        home.common.extraSpecialArgs = {
          notlua = inputs.notlua.lib.${system};
        };
        home.user = [ ./home/hosts/nixmsi.nix ];
      };
      phone = rec {
        system = "aarch64-linux";
        modules = [ ./system/devices/oneplus-6-phone.nix ];
        home.common.modules = [ inputs.nixvim.homeManagerModules.default ];
        home.common.extraSpecialArgs = {
          notlua = inputs.notlua.lib.${system};
        };
        home.user = [ ./home/hosts/phone.nix ];
      };
    };

  in {
    overlays = {
      default = overlay;
      nix-plugins = nix-plugins-overlay;
    };
    packages = lib.genAttrs [
      "x86_64-linux"
      "aarch64-linux"
      "armv7l-linux"
    ] (system: let self = overlay' { isOverlay = false; } (mkPkgs { inherit system; } // self) (import nixpkgs { inherit system; }); in self);
    nixosImages.router = let pkgs = mkPkgs { inherit (config.router-emmc) system; }; in {
      emmcImage = pkgs.callPackage ./system/hardware/bpi-r3/image.nix {
        inherit (self.nixosConfigurations.router-emmc) config;
        rootfsImage = self.nixosConfigurations.router-emmc.config.system.build.rootfsImage;
        bpiR3Stuff = pkgs.bpiR3StuffEmmc;
      };
      sdImage = pkgs.callPackage ./system/hardware/bpi-r3/image.nix {
        inherit (self.nixosConfigurations.router-sd) config;
        rootfsImage = self.nixosConfigurations.router-sd.config.system.build.rootfsImage;
        bpiR3Stuff = pkgs.bpiR3StuffSd;
      };
    };

    hydraJobs = {
      server.${config.server.system} = self.nixosConfigurations.server.config.system.build.toplevel;
      router.${config.router-emmc.system} = self.nixosConfigurations.router-emmc.config.system.build.toplevel;
      phone.${config.phone.system} = self.nixosConfigurations.phone.config.system.build.toplevel;
      phone-home.${config.phone.system} = self.homeConfigurations."user@phone".activation-script;
      workstation.${config.nixmsi.system} = self.nixosConfigurations.nixmsi.config.system.build.toplevel;
      workstation-home.${config.nixmsi.system} = self.homeConfigurations."user@nixmsi".activation-script;
    };

    # this is the system config processing part
    nixosConfigurations = lib.flip builtins.mapAttrs config (hostname: args @ { modules, nixpkgs ? {}, home ? {}, ... }:
      (args.flake or base-inputs.nixpkgs).lib.nixosSystem {
        inherit (args) system;
        # allow modules to access nixpkgs directly, use customized lib,
        # and pass nixos-harware to let hardware modules import parts of nixos-hardware
        specialArgs = {
          inherit lib;
          hardware = inputs.nixos-hardware.nixosModules;
          inputs = inputs // lib.optionalAttrs (args?flake) {
            nixpkgs = args.flake;
          };
        } // args.specialArgs or { };
        modules = [
          ({ config, ... }: {
            _module.args = {
              pkgs-kernel = import inputs.nixpkgs-kernel { inherit (args) system; overlays = all-overlays ++ config.nixpkgs.overlays; };
            };
          })
          (getPrivSys hostname)
          { networking.hostName = lib.mkDefault hostname;
            nixpkgs.overlays = all-overlays; }
          inputs.impermanence.nixosModule 
        ]
        ++ args.modules or [ ]
        ++ map (x: ./system/modules/${x}) (builtins.attrNames (builtins.readDir ./system/modules))
        # the following is NixOS home-manager module configuration. Currently unused, but I might start using it for some hosts later.
        ++ lib.optionals (home != { } && home.common.enableNixosModule or false) [
          inputs.home-manager.nixosModules.home-manager
          { home-manager = builtins.removeAttrs (home.common or { }) [ "nixpkgs" "nix" "enableNixosModule" ]; }
          {
            home-manager.extraSpecialArgs = {
              inputs = inputs // lib.optionalAttrs (args?flake) {
                nixpkgs = args.flake;
              };
            };
            home-manager.useGlobalPkgs = true;
            home-manager.useUserPackages = true;
            home-manager.users = builtins.mapAttrs (username: modules: {
              imports = modules ++ [
                # { nixpkgs = home.common.nixpkgs or { };
                #   nix = home.common.nix or { }; }
                # ({ config, pkgs, lib, ...}: {
                #   nixpkgs.overlays = all-overlays;
                #   nix.package = lib.mkDefault pkgs.nixForNixPlugins; })
                (getPrivUser hostname username)
              ];
            }) (builtins.removeAttrs home [ "common" ]); }
        ];
      });

    # for each hostname, for each user, generate an attribute "${user}@${hostname}"
    homeConfigurations =
      {
        "chayleaf@hysteria" = inputs.home-manager.lib.homeManagerConfiguration {
          pkgs = mkPkgs {
            system = "x86_64-linux";
            overlays = [ overlay ];
          };
          extraSpecialArgs = { inherit inputs; };
          modules = [
            ./home/hosts/remote.nix 
            ({ pkgs, ... }: {
              home.file.hysteria.source = pkgs.hysteria;
              home.file.shadowsocks-libev.source = pkgs.shadowsocks-libev;
              home.file.shadowsocks-rust.source = pkgs.shadowsocks-rust;
            })
          ];
        };
      }
      // builtins.listToAttrs (builtins.concatLists
        (lib.flip lib.mapAttrsToList config
          (hostname: { system, home ? {}, ... }:
          let
            common' = builtins.removeAttrs (home.common or { }) [ "nix" "nixpkgs" "enableNixosModule" ];
            pkgs = mkPkgs ({ inherit system; } // home.common.nixpkgs or { });
            common = common' // { inherit pkgs; };
          in 
            lib.flip lib.mapAttrsToList (builtins.removeAttrs home [ "common" ])
              # this is where actual config takes place
              (user: homeConfig: lib.nameValuePair "${user}@${hostname}" 
              (inputs.home-manager.lib.homeManagerConfiguration (common // {
                extraSpecialArgs = (common.extraSpecialArgs or { }) // { inherit inputs; };
                modules =
                  homeConfig
                  ++ common.modules or [ ]
                  ++ [
                    (getPrivUser hostname user)
                    ({ pkgs, lib, ... }: {
                      nix.package = lib.mkDefault pkgs.nixForNixPlugins;
                    })
                  ];
              }))))));
  };
}