flake.nix

{
  description = "NixOS module for Kupo";
  nixConfig = {
    extra-experimental-features = [ "nix-command" "flakes"];
    allow-import-from-derivation = "true";
    cores = "1";
    max-jobs = "auto";
    auto-optimise-store = "true";
  };
  inputs = {
    haskell-nix.url = github:input-output-hk/haskell.nix/974a61451bb1d41b32090eb51efd7ada026d16d9;
    iohk-nix.url = github:input-output-hk/iohk-nix/edb2d2df2ebe42bbdf03a0711115cf6213c9d366;
    nixpkgs.follows = "haskell-nix/nixpkgs";
    iohk-nix.inputs.nixpkgs.follows ="haskell-nix/nixpkgs";
    kupo = {
      url = github:CardanoSolutions/kupo;
      flake = false;
    };
    flake-utils.url = github:numtide/flake-utils;
  };
  outputs = inputs@{self, nixpkgs, flake-utils, ...}:
    let
      pins = (__fromJSON (__readFile ./flake.lock)).nodes;
      haskellNixPin = pins.haskell-nix.locked;
      iohkNixPin = pins.iohk-nix.locked;
      haskellNixSrc = builtins.fetchTarball {
        url = "https://github.com/input-output-hk/haskell.nix/archive/${haskellNixPin.rev}.tar.gz";
        sha256 = haskellNixPin.narHash;
      };
      iohkNixSrc = builtins.fetchTarball {
        url = "https://github.com/input-output-hk/iohk-nix/archive/${iohkNixPin.rev}.tar.gz";
        sha256 = iohkNixPin.narHash;
      };

      mkFlake = system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
        in
          ((import inputs.kupo)
            {
              inherit system;
              # we need pkgs here because of the way haskell.nix loads them
              haskellNix = import haskellNixSrc { inherit pkgs; };
              iohkNix = import iohkNixSrc { inherit system; };
              nixpkgsArgs = { inherit system; };
            })
            .flake {};

    in flake-utils.lib.eachDefaultSystem (system:
    # This one I use locally to run `nix flake show`
    # in flake-utils.lib.eachSystem ["x86_64-linux"] (system:
      rec {
        packages.kupo = (mkFlake system).packages."kupo:exe:kupo";
        defaultPackage = packages.kupo;
      }
    ) // {
      nixosModules.kupo = { pkgs, lib, ... }: {
        imports = [ ./kupo-nixos-module.nix ];
        services.kupo.package = lib.mkDefault self.packages.${pkgs.system}.kupo;
      };
    };
}