{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";

    libgourou-utils.url = "github:BentonEdmondson/libgourou-utils";
    libgourou-utils.inputs.nixpkgs.follows = "nixpkgs";

    inept-epub.url = "github:BentonEdmondson/inept-epub";
    inept-epub.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = { self, ... }@flakes: let
    nixpkgs = flakes.nixpkgs.legacyPackages.x86_64-linux;
    libgourou-utils = flakes.libgourou-utils.defaultPackage.x86_64-linux;
    inept-epub = flakes.inept-epub.defaultPackage.x86_64-linux;
  in {
    defaultPackage.x86_64-linux = nixpkgs.stdenv.mkDerivation {
      pname = "knock";
      version = "1.0.0-alpha";
      src = self;

      nativeBuildInputs = [ nixpkgs.makeWrapper ];

      buildInputs = [
        (nixpkgs.python3.withPackages
          (python3Packages: [
            python3Packages.python_magic
            python3Packages.xdg
          ])
        )
        libgourou-utils inept-epub
      ];

      installPhase = ''
        mkdir -p $out/bin
        chmod +x knock
        cp knock $out/bin
        wrapProgram $out/bin/knock --prefix PATH : ${nixpkgs.lib.makeBinPath [libgourou-utils inept-epub]}
      '';

      meta = {
        description = "A CLI tool to convert ACSM files to DRM-free EPUB files";
        homepage = "https://github.com/BentonEdmondson/knock";
        license = [ nixpkgs.lib.licenses.gpl3Only ];
        maintainers = [{
          name = "Benton Edmondson";
          email = "bentonedmondson@gmail.com";
        }];
        # potentially others, but I'm only listed those tested
        platforms = [ "x86_64-linux" ];
      };
    };
  };
}