{
  description = "Templates Helm deployments using Nix";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs";
    flake-utils.url = "github:numtide/flake-utils";
    haumea = {
      url = "github:nix-community/haumea/v0.2.2";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nixhelm = {
      url = "github:farcaller/nixhelm";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nix-kube-generators.url = "github:farcaller/nix-kube-generators";
  };

  outputs = inputs @ {
    self,
    flake-utils,
    haumea,
    nix-kube-generators,
    nixhelm,
    nixpkgs,
  }:
    flake-utils.lib.eachDefaultSystem (system: let
      pkgs = import nixpkgs {inherit system;};
      kubelib = nix-kube-generators.lib {inherit pkgs;};
      lib = import ./lib {inherit kubelib pkgs;};
      nixhelmCharts = nixhelm.chartsDerivations.${system};

      mkCharts = src:
        haumea.lib.load {
          inherit src;
          loader = {...}: p: lib.fetchers.helmChart (import p);
          transformer = haumea.lib.transformers.liftDefault;
          # TODO: split charts to own `.nix` files
          # and remove this transformer
        };
    in {
      lib = {
        mkDerivation = {
          charts ? nixhelmCharts,
          user ? {},
        }:
          (import self {
            inherit charts haumea lib pkgs user;
          }).mkDerivation;

        app-template = import src/app-template.nix {
          charts = nixhelmCharts;
          inherit lib pkgs;
        };

        inherit mkCharts;
        mkChartsWithNixhelm = src:
          pkgs.lib.attrsets.recursiveUpdate
          nixhelmCharts
          (mkCharts src);
      };
      # TODO: make a template
      formatter = pkgs.alejandra;
    });
}