{ self, nixpkgs, ... }@inputs: let
  mapDir = dir: builtins.attrNames (nixpkgs.lib.filterAttrs (name: type: type == "directory") (
    builtins.readDir ../../${dir}));

  filterDir = filterBy: dir: builtins.filter (name: name != filterBy) (mapDir dir);

  filterSuffix = suffix: attr: nixpkgs.lib.filterAttrs (name: v: !(nixpkgs.lib.hasSuffix suffix name)) attr;

  genColmenaCfg = name: host: {
    deployment = {
      allowLocalDeployment = builtins.any (hostName: hostName == name) [ "ryuuko" ];
      buildOnTarget = true;
      targetHost = nixpkgs.lib.findFirst (el: el != null) host.config.networking.fqdn [ host.config.kyouma.deployment.targetHost ];
      targetPort = 22;
      # change back to null after switching ryuuko to nixos
      targetUser = "emily";
      tags = host.config.kyouma.deployment.tags;
    };
    imports = host._module.args.modules;
    nixpkgs.system = host.config.nixpkgs.system;
  };

  genNixosCfg = {
    hostname,
    system ? "x86_64-linux"
  }: 
  nixpkgs.lib.nixosSystem {
    system = system;
    specialArgs = { inherit inputs; };
    modules = [
      ../../config/hosts/${hostname}/configuration.nix
      inputs.sops-nix.nixosModules.sops
      ({ ... }: {
        nixpkgs.overlays = [ self.overlays.kyouma self.overlays.otherPkgs ];
        nixpkgs.hostPlatform.system = system;
        kyouma.deployment.auto-upgrade.hostName = hostname;
      })
    ];
  };
in {
  mapHosts = hostCfg: nixpkgs.lib.recursiveUpdate (
    nixpkgs.lib.genAttrs (filterDir "_minimal" "config/hosts") (host: { hostname = host; })) hostCfg;

  mapColmenaCfg = extraColmenaCfg: nixpkgs.lib.recursiveUpdate (builtins.mapAttrs (genColmenaCfg) (
      filterSuffix "-minimal" self.nixosConfigurations)) extraColmenaCfg;

  mapNixosCfg = extraNixosCfg: nixpkgs.lib.recursiveUpdate (builtins.mapAttrs (name: value:
      genNixosCfg value) self.hosts) extraNixosCfg;

  mapPackages = overlayPkgs: otherPackages: nixpkgs.lib.recursiveUpdate (
    nixpkgs.lib.genAttrs (mapDir "pkgs") (name: overlayPkgs.${name})) otherPackages;

  mapHydraHosts = hosts: builtins.mapAttrs (name: host: host.config.system.build.toplevel) hosts;
}