dream2nix/flake.nix

{
  description = "dream2nix: A generic framework for 2nix tools";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-unstable";
    node2nix = { url = "github:svanderburg/node2nix"; flake = false; };
    npmlock2nix = { url = "github:nix-community/npmlock2nix"; flake = false; };
  };

  outputs = { self, nixpkgs, node2nix, npmlock2nix }:
    let

      lib = nixpkgs.lib;

      supportedSystems = [ "x86_64-linux" ];

      forAllSystems = f: lib.genAttrs supportedSystems (system:
        f system (import nixpkgs { inherit system; overlays = [ self.overlay ]; })
      );

      externalSourcesFor = forAllSystems (system: pkgs: pkgs.runCommand "dream2nix-vendored" {} ''
        mkdir -p $out/{npmlock2nix,node2nix}
        cp ${npmlock2nix}/{internal.nix,LICENSE} $out/npmlock2nix/
        cp ${node2nix}/{nix/node-env.nix,LICENSE} $out/node2nix/
      '');

      dream2nixFor = forAllSystems (system: pkgs: import ./src rec {
        externalSources = externalSourcesFor."${system}";
        inherit lib;
      });

    in
      {
        overlay = new: old: {
          nix = old.writeScriptBin "nix" ''
            ${new.nixUnstable}/bin/nix --option experimental-features "nix-command flakes" "$@"
          '';
        };

        lib.dream2nix = dream2nixFor;

        defaultApp = forAllSystems (system: pkgs: self.apps."${system}".cli);

        apps = forAllSystems (system: pkgs:
          lib.mapAttrs (appName: app:
            {
              type = "app";
              program = builtins.toString app;
            }
          ) dream2nixFor."${system}".apps
        );

        devShell = forAllSystems (system: pkgs: pkgs.mkShell {
          buildInputs = with pkgs; [
            cntr
            nixUnstable
          ];
          shellHook = ''
            export NIX_PATH=nixpkgs=${nixpkgs}
            export d2nExternalSources=${externalSourcesFor."${system}"}
          '';
        });
      };
}